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201. Apparatus for providing disinfection and deodorization gases to
desired indoor spaces.
Aoyagi, Kohei; Fujita, Sanai; Akatsuka, Shigetaka (Sun Seal K. K.;
Fujita, Sanai, Japan). Jpn. Kokai Tokkyo Koho JP 10024095 A2 27
Jan 1998 Heisei, 5 pp. (Japanese). (Japan). CODEN: JKXXAF.
CLASS: ICM: A61L009-015. APPLICATION: JP 96-200965 12 Jul
1996. DOCUMENT TYPE: Patent CA Section: 59 (Air Pollution and
Industrial Hygiene)
The app. includes a means for generating a compressed clean dry air,
a means for branching the generated air into two loops, a means for
mixing disinfection and deodorization substances (e.g., chlorine
dioxide, sodium hypochlorite) into the air in one loop, a means for
mixing activation substances (e.g., ceramics) into the air in another
loop, and a means for combining the resp. mixed air to be injected into
desired spaces (e.g., air craft, ambulance, hospital).
202. Environmentally acceptable nuclear fuel cycle - development of a new
reprocessing system.
Tomiyasu, H.; Asano, Y. (Research Laboratory for Nuclear Reactors,
Tokyo Institute of Technology, Tokyo 152, Japan). Prog. Nucl. Energy,
Volume Date 1998, 32(3/4), 421-427 (English) 1997 Elsevier Science
Ltd. CODEN: PNENDE. ISSN: 0149-1970. DOCUMENT TYPE:
Journal CA Section: 71 (Nuclear Technology)
The aim of the present study is to establish a new reprocessing system
for spent nuclear fuel, which would overcome the environmental
problems in the nuclear fuel cycle. In order to achieve this, the following
subjects have to be conquered: recoveries of high ratios of uranium
and transuranium elements from spent nuclear fuel, sepns. of strong
radioactive elements, such as Sr and Cs, and assurance of the
extreme safety during operation. The last subjects might be of
particular importance in order to avoid any potential danger. Therefore,
in the present system all processes were performed under mild aq.
conditions. Expts. were carried out for a simulated spent fuel soln.,
which was calcd. from the ORIGEN CODE contg. uranium and 17
major elements. The system consists of the following processes: 1.
dissoln. of spent UO2 fuel involving off-gas treatment of I and Ru; 2.
neutralization of the dissolved fuel soln. with NaHCO3-Na2CO3 mixed
soln. to be slightly basic at pH about 9 followed by the sepn. of pptd.
fission products by centrifugation; 3. sepn. of Cs by a pptn. method
using tetraphenylborate ion; 4. recovery of U, Np and Pu as ppts. of
hydrolyzed compds. from alk. soln.; and 5. sepn. of Am and Cm from
lanthanide elements. The concn. of residual uranium in the final soln.
was measured to be ppm order, indicating that the decontamination
factor of U was as large as 104. Other hexavalent actinide ions, NpO22+
and PuO22+, also have extremely large stability consts. for the complex
formation with carbonate ion, and are expected to behave similarly with
UO22+. In conclusion, the present reprocessing system enables one to
recover U, Pu and Np from spent nuclear fuel by means of a simple
pptn. method in much higher ratios compared with other reprocessing
methods, to sep. hazardous Cs and Sr from high-level waste, and to
exclude any potential danger owing to chem. processes under mild aq.
conditions.
203. Removal of residual chlorine dioxide from drinking water or swimming
pool water after disinfection treatment.
Ogawa, Katsutoshi; Oyama, Masako (Chisso Corp., Japan). Jpn.
Kokai Tokkyo Koho JP 10028979 A2 3 Feb 1998 Heisei, 4 pp.
(Japanese). (Japan). CODEN: JKXXAF. CLASS: ICM: C02F001-70.
ICS: B01D035-02; C02F001-58. APPLICATION: JP 96-207915 17
Jul 1996. DOCUMENT TYPE: Patent CA Section: 61 (Water)
After disinfection or deodorization, the treated drinking water or
swimming pool water is filtered through an adsorbent column packed
with water-insol. Fe sulfide and/or natural magnesium hydroxide fibers
for redn. and removal of oxidizing substances such as residual ClO2
and ClO- ions. The Fe sulfide may be ferrimagnetic greigite (Fe3S4),
pyrrhotite (Fe1-xS), and/or marcasite.
204. Process for producing stable chlorine dioxide.
Wang, Yatie; Sun, Jichang (Rongxin New and High Technology Co.,
Jiangxi, Peop. Rep. China). Faming Zhuanli Shenqing Gongkai
Shuomingshu CN 1143604 A 26 Feb 1997, 4 pp. (Chinese). (People's
Republic of China). CODEN: CNXXEV. CLASS: ICM: C01B011-02.
APPLICATION: CN 96-107956 29 May 1996. DOCUMENT TYPE:
Patent CA Section: 49 (Industrial Inorganic Chemicals)
The process comprises continuously dripping chlorate oxidant and aq.
methanol reductant into an acidic medium and reacting at *50* and at
medium acidity 20-25%, purifying the chlorine dioxide gas using phys.
adsorption with a filler and chem. purifn. using part of raw liq. mixt., and
then stabilizing the gas product with flaky alkali, boric acid, and
hydrogen peroxide. The process is carried out at normal pressure and
the completeness of the utilization of raw materials is high.
205. Reactor vessel and process for preparing a controlled-dosage chlorine
dioxide solution.
Pastore, Mauro (Pastore, Mauro, Italy). Eur. Pat. Appl. EP 822162 A2
4 Feb 1998, 12 pp. DESIGNATED STATES: R: AT, BE, CH, DE, DK,
ES, FR, GB, GR, IT, LI, LU, NL, SE, MC, PT, IE, SI, LT, LV, FI, RO.
(English). (European Patent Organization). CODEN: EPXXDW.
CLASS: ICM: C01B011-02. APPLICATION: EP 97-113121 30 Jul
1997. PRIORITY: IT 96-MI1702 2 Aug 1996; IT 96-MI806 6 Dec 1996.
DOCUMENT TYPE: Patent CA Section: 47 (Apparatus and Plant
Equipment) Section cross-reference(s): 60, 61
A reactor vessel and an assocd. process for prepg. a
controlled-dosage chlorine dioxide soln is described. The vessel
comprises a hollow body inside which there are provided two
chambers which have different vols.; each chamber has, in an upper
region, an opening which is closed by a removable closure and the
chambers are mutually connected by a substantially horizontal duct with
openings arranged in a region which is spaced upward with respect to
the bottom of the two chambers. The vessel is particularly suitable for
prepg. a disinfectant and highly pure chlorine dioxide soln., minimizing
the risk of developing noxious gases.
206. Bleaching of oak kraft pulp by O, Eo and C/D stage.
Kim, Dong-Ho; Paik, Ki-Hyon (Dept. of Forest Resources Graduate
School, Korea University, Seoul 136-701, S. Korea). Palpu, Chongi
Gisul, 29(3), 43-50 (Korean) 1997 Korea Technical Association of the
Pulp and Paper Industry. CODEN: PCGIDY. ISSN: 0253-3200.
DOCUMENT TYPE: Journal CA Section: 43 (Cellulose, Lignin, Paper,
and Other Wood Products)
The purpose of this study was to decrease pollutants of effluents from
KP bleaching. Multistage bleaching that combined with O, Eo
(O-alkali-extn.), and C/D stage was conducted, after optimum
bleaching conditions of O, Eo, and C/D stage were detd. Moreover,
the properties for bleached pulps and pollution level of bleaching
effluent were measured by each std. method. Due to increase on the
brightness and delignification of pulps by O, EO, and C/D stage
bleaching. It was possible that bleaching sequences were reduced
from five stage to four stage. In addn. to, OC/DEoD and OC/DEopD
bleaching sequences had higher brightness than CEDED bleaching
sequence. The pulps bleached by O and Eo stage had higher in tensile
index than conventional bleaching sequences with the similar results in
burst and tear index. While each bleaching sequences had little
differences, bleaching sequences with Eo stage had higher in phys.
properties than with EOP stage. The pollution level measured by
COD(COD). BOD(BOD) and Color of bleaching effluents were much
lower in combined bleaching sequences of O, EO and C/D stage than
that of CEDED sequence. Particularly, a pollution index of bleaching
effluents generated by C/DEoDED and OC/DEopDED bleaching
sequences were lower than that from the other bleaching sequences.
207. Soil amendments by using chlorine dioxide.
Osamu, Takaaki (Matsumoto Biseibutsu Kenkyusho K. K., Japan).
Jpn. Kokai Tokkyo Koho JP 10030091 A2 3 Feb 1998 Heisei, 4 pp.
(Japanese). (Japan). CODEN: JKXXAF. CLASS: ICM: C09K017-42.
ICS: A01N059-08; A01N063-00; C09K017-48; C09K101-00.
APPLICATION: JP 96-204336 15 Jul 1996. DOCUMENT TYPE:
Patent CA Section: 19 (Fertilizers, Soils, and Plant Nutrition)
Soil is impregnated with dild. solns. of ClO2 and then mixed with
microorganisms.
208. Density functional study of chlorine-oxygen compounds related to the
ClO self-reaction.
Fangstrom, Torbjorn; Edvardsson, David; Ericsson, Marie; Lunell, Sten;
Enkvist, Christer (Department of Quantum Chemistry, Uppsala
University, Uppsala S-751 20, Swed.). Int. J. Quantum Chem., 66(3),
203-217 (English) 1998 John Wiley & Sons, Inc. CODEN: IJQCB2.
ISSN: 0020-7608. DOCUMENT TYPE: Journal CA Section: 65
(General Physical Chemistry) Section cross-reference(s): 59, 67, 73,
74, 76
Geometrical parameters, vibrational frequencies, relative stabilities,
and dissocn. energies of the three stable Cl2O2 isomers and the OClO
and ClOO radicals were investigated by d.-functional theory (DFT). The
present anal. shows that DFT using hybrid functionals is capable of
describing these systems to at least the same degree of accuracy as
ab initio methods. The av. abs. bond-length deviation of ClClO2,
ClOOCl, and ClO2 from exptl. results is 0.024/0.027 *, with a max.
deviation for the dichlorine peroxide O-O bond equal to 0.072/0.063 *,
for the B3PW91 and B3LYP functionals, resp. The av. abs. bond-angle
deviation for the hybrid functionals is 0.8*. Harmonic vibrational
frequencies calcd. with DFT give for all Cl-O compds. good agreement
with expts. The dissocn. energies of ClOOCl, OClO, and ClOO were
found to be in good agreement with expts., the av. error being less than
1.2 kcal/mol. The two isomers chloryl chloride (ClClO2) and dichlorine
peroxide (ClOOCl) were found to be approx. 9 kcal/mol more stable
than the chlorine chlorite (ClOClO) isomer. The ClOO isomer is
predicted to be 3.0 kcal/mol more stable than OClO, in accordance
with the exptl. value of 4 kcal/mol.
209. Environmental aspects of the use of chlorine and chlorine dioxide in the
treatment of drinking water and wastewater.
Korzhenyak, I. G.; Romashin, O. P.; Kharitonov, V. N.; Mirkis, V. I. (NII
"Sintez", Russia). Khim. Prom-st. (Moscow), (9), 623-627 (Russian)
1997 Izdatel'stvo Teza. CODEN: KPRMAW. ISSN: 0023-110X.
DOCUMENT TYPE: Journal; General Review CA Section: 61 (Water)
Section cross-reference(s): 60
A review, with 23 refs., covers the advantages of using ClO2 as an
alternative to Cl in water and wastewater treatment.
210. Fine-structure analysis of ClO fragments in the mode-specific
predissociation of chlorine dioxide.
Delmdahl, R. F.; Welcker, S.; Gericke, K. H. (Institut Physikalische
Theoretische Chemie, Technische Universitaet Braunschweig,
Braunschweig D-38106, Germany). Ber. Bunsen-Ges., 102(2),
244-248 (English) 1998 Wiley-VCH Verlag GmbH. CODEN:
BBPCAX. ISSN: 0940-483X. DOCUMENT TYPE: Journal CA
Section: 74 (Radiation Chemistry, Photochemistry, and Photographic
and Other Reprographic Processes) Section cross-reference(s): 73
The photodissocn. of OClO (2A2) * ClO (X2PW,v,J,L) + O(3P) in the
424-450 nm region and in the 356-371 nm region was investigated by
monitoring the ClO (X2PW,v = 0,J,L) fragments using 2-photon
laser-induced fluorescence. In the long-wavelength regime the product
vibrational excitation is clearly a function of the particular initial type of
motion of OClO (2A2n1,n2,n3). This behavior is significantly reduced at
shorter photolysis wavelengths. The population of the fragments
rotational levels is obsd. to resemble Boltzmann distributions of around
1000 K. A population ratio of P(2P3/2):P(2P1/2) u 3.5 is obtained for the
2 spin-orbit states of ClO. The L-doublet states (A') and (A'') of the ClO
fragments are equally preferred in the dissocn. process.
211. Method using an oxidizing agent for disinfecting red blood cells.
Rubinstein, Alan I. (USA ). U.S. US 5709992 A 20 Jan 1998,8 pp.
Cont.-in-part of U.S. Ser. No. 291,442, abandoned. (English). (United
States of America). CODEN: USXXAM. CLASS: ICM: A01N001-02.
NCL: 435002000. APPLICATION: US 95-506589 25 Jul 1995.
PRIORITY: US 94-291442 17 Aug 1994. DOCUMENT TYPE: Patent
CA Section: 63 (Pharmaceuticals)
A process is disclosed for disinfecting units of red blood cells by
adding an oxidizing agent, e.g. an ozone-generating compd., in soln. to
a unit of RBC's, or compds. generating ClO2. The RBC reducing
enzymes, e.g. cytochrome b5 reductase, will prevent or reverse
oxidative changes. However, viruses or other microorganisms do not
have such enzymes. By adding RBC reducing enzymes to the RBC's
before sterilization, the RBC's are further protected from the oxidizing
sterilizing soln. The RBC's can be put in storage medium contg. a
reducing agent. The oxidizing agent may be generated from activated
ceramic particles which will generate O3 (ozone) in soln. This is a
convenient and economic method of RBC sterilization. The activated
ceramic particles generating O3 in soln. may also be added to units of
whole blood.
212. Chlorine dioxide tooth whitening compositions.
Montgomery, Robert Eric (Montgomery, Robert Eric, USA). PCT Int.
Appl. WO 9804235 A1 5 Feb 1998, 20 pp. DESIGNATED STATES:
W: AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ,
DE, DK, EE, ES, FI, GB, GE, GH, HU, IL, IS, JP, KE, KG, KP, KR, KZ,
LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL,
PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, UZ, VN,
YU, ZW, AM, AZ, BY, KG, KZ, MD, RU, TJ, TM; RW: AT, BE, BF, BJ,
CF, CG, CH, CI, CM, DE, DK, ES, FI, FR, GA, GB, GR, IE, IT, LU, MC,
ML, MR, NE, NL, PT, SE, SN, TD, TG. (English). (World Intellectual
Property Organization). CODEN: PIXXD2. CLASS: ICM:
A61K007-20. ICS: A61K007-16. APPLICATION: WO 97-US13467
28 Jul 1997. PRIORITY: US 96-22384 29 Jul 1996. DOCUMENT
TYPE: Patent CA Section: 62 (Essential Oils and Cosmetics)
A compn. having an effective dosage of chlorine dioxide for causing a
visible change in the whiteness of a tooth surface is disclosed. The
compn. includes a first formulation having a chlorine dioxide precursor
and a second formulation having an acidulant capable of generating
chlorine dioxide upon contact with the precursor. Upon admixt. of the
first and second formulations to produce chlorine dioxide, the compn.
has a pH in the range of from about 3.0 to about 4.5. To whiten teeth,
the first and second formulations may be mixed with one another prior
to application of the resulting mixt. to the teeth. Alternatively, one of the
first and second formulations may initially be applied to the teeth prior
to the application of the remaining formulation. The inventive compn. is
formulated to cause a visible change in the whiteness of a tooth surface
in a relatively short period of time. A chlorine dioxide precursor compn.
contained water 983.3, and sodium chlorite 16.7g. An acidulant
compn. contained water 913.1, glycerin 50.0, methylparaben 1.5,
Carbopol 974P 50.0, anhyd. citric acid 3.0, and sodium hydroxide
2.4g. The mixt. of above compns. was effective in removing tooth
stains in an in vitro stained bovine enamel model.
213. Stable water treatment compositions for release of chlorine dioxide.
Zahradnik, Rudolf; Barber, Bruce (USA ). U.S. US 5719100 A 17 Feb
1998,13 pp. (English). (United States of America). CODEN:
USXXAM. CLASS: ICM: B01J020-20. NCL: 502417000.
APPLICATION: US 92-854903 20 Mar 1992. DOCUMENT TYPE:
Patent CA Section: 61 (Water) Section cross-reference(s): 60
Stable compns. in the form of tablets, capsules or powders are
presented which can be used to treat water through the release of
chlorine dioxide. The compns. comprise sodium chlorite and an acid
activator, esp. anhyd. citric acid. A protective coating on the sodium
chlorite prevents reaction with the citric acid before water treatment.
The compn. may also include activated carbon, which may be
ion-impregnated, esp. Fe-impregnated, for removal of org. compds.
such as humic acids. Water treatment kits are described utilizing the
compns. In an example, water treatment tablets contained a first
premix contg. NaClO2 (20%) 115, MgCO3 50, polyvinylpyrrolidone 10
and stearyl alc. 10 mg and a second premix contg. NaHCO3 100,
anhyd. citric acid 450, glycine 4 and monobasic calcium phosphate 3
mg. The premix compns. were tableted together in a low humidity area.
214. Successful operation of a large film-fill electric utility cooling tower
system using treated secondary municipal waste water as makeup
source.
Freedman, Arthur J.; Hays, George F.; Kujawski, Paul (Arthur
Freedman Associates, Inc., East Stroudsburg, PA, USA). Off. Proc. -
Int. Water Conf., 57th, 269-288 (English) 1996 Engineers' Society of
Western Pennsylvania. CODEN: OIWCEQ. ISSN: 0739-4977.
DOCUMENT TYPE: Journal CA Section: 61 (Water)
Start-up and first year operation of a film fill elec. utility cooling water
system using treated secondary municipal wastewater as make-up is
described. Chem. treatment includes ClO2 for biofouling control, a
calcium phosphate-dispersing polymer, and pH control, with automated
control of all cooling water parameters.
215. Ozone, chlorine dioxide combination gains appeal in bleaching
sequences.
Finchem, Kirk J. (USA). Pulp Pap., 72(2), 53-54, 57 (English) 1998
Miller Freeman Inc. CODEN: PUPAA8. ISSN: 0033-4081.
DOCUMENT TYPE: Journal CA Section: 43 (Cellulose, Lignin, Paper,
and Other Wood Products)
Having learned to control the tendency of O3 to degrade pulp,
researchers, pulp producers, and O3 suppliers continue to fine-tune its
delignification and bleaching performance, as well as decrease its
effective operating costs. No longer viewed as an unpredictable
bleaching agent, O3 is becoming a more common element in bleach
plants worldwide. With the final promulgation of the Cluster Rule, mills
that are developing strategies to convert to full-time elemental Cl-free
(ECF) operations -- without expanding their ClO2 generating capacity --
are taking a 2nd look at O3. For many, the least expensive option for
adding O3 to their bleaching sequence will be to add it to the 1st ClO2
bleaching stage, creating either a DZ or ZD stage, depending on which
chem. is added 1st. For mills with sufficient ClO2 generator capacity --
or effluent discharge flexibility -- there is little need for DZ or ZD
bleaching, but if a mill does not have an O delignification stage and(or)
sufficient ClO2 generator capacity, a combined bleaching stage offers
a low capital cost option. Also, a combined DZ or ZD bleaching stage
can be less expensive to operate than a D100 stage.
216. Growth promotion and pest control of lawn with chlorine dioxide.
Ito, Kunio (Saver Oxidation technology K. K., Japan). Jpn. Kokai
Tokkyo Koho JP 10036209 A2 10 Feb 1998 Heisei, 3 pp.
(Japanese). (Japan). CODEN: JKXXAF. CLASS: ICM: A01N059-00.
ICS: A01G001-00; A01N059-08. APPLICATION: JP 96-206395 18
Jul 1996. DOCUMENT TYPE: Patent CA Section: 5 (Agrochemical
Bioregulators)
Aq. solns. contg. 1-20 wt.% stabilized ClO2 are applied to lawn at
0.2-3.0 kg/10 are to control pest and to promote growth. Golf green
Zoysia matrella infected with rust was sprayed with 280 ppm aq. ClO2
and sprayed with H2O after 1 min to show complete control of the fungi
and growth promotion.
217. Composition for disinfecting and for inhibiting scale.
Fredericks, Stuart Markham (Water Technology Ltd, UK). Brit. UK Pat.
Appl. GB 2313369 A1 26 Nov 1997, 13 pp. (English). (United
Kingdom). CODEN: BAXXDU. CLASS: ICM: C02F005-08. ICS:
A01N025-02; C02F001-76. APPLICATION: GB 96-10468 18 May
1996. DOCUMENT TYPE: Patent CA Section: 61 (Water)
A pH of >9 compn. consists of a stabilized chlorine dioxide precursor,
an alkali metal polyphosphate and an alkali metal hydroxide. The
stabilized chlorine dioxide precursor is a soln. comprising sodium
chlorite/chlorate stabilized with sodium carbonate. The polyphosphate
contains a mixt. of dimer and other polyphosphates having an av.
polymer length equiv. to a tetramer. The alkali metal hydroxide includes
KOH, NaOH and NH4OH. The method for forming the soln. includes
adding the alkali metal hydroxide to a soln. of the polyphosphate in
order to raise the pH, adding the chlorine dioxide precursor and adding
addnl. alkali metal hydroxide to raise the pH to >9. In use, an acid such
as HCl, H3PO4 or citric acid is added to the soln. to lower the pH to <7
and the soln. is then injected into the water to be treated. The compn.
acts as a disinfectant, threshold scale inhibitor and corrosion inhibitor.
218. Identification of cooling water biofilms using a novel ATP monitoring
technique and their control with the use of biodispersants.
Chault, Josee; D'Arsie, L.; Bodkin, P. M. (BetzDearborn, Inc.,
Mississauga, ON, Can.). Off. Proc. - Int. Water Conf., 57th, 98-106
(English) 1996 Engineers' Society of Western Pennsylvania. CODEN:
OIWCEQ. ISSN: 0739-4977. DOCUMENT TYPE: Journal CA
Section: 61 (Water) Section cross-reference(s): 9, 10, 11, 80
Current trends in industrial water systems are to minimize water
consumption and discharge by recycling/re-using as much water as
possible. Use of such waters results in increased dissolved and
suspended substance concns., which promote growth of waterborne
microorganisms. This will increase the potential for biofouling, which
then may create corrosion problems in industrial water systems.
Biofilm control is most effective when the formation mechanism is
understood. It may be possible to reduce biomass by adding an
appropriate biodispersant to the system; however, biodispersant
activity in water systems is poorly understood, partly because of a lack
of screening methods to rapidly evaluate these chems. The key to
measuring the effectiveness of any biodispersant is the ability to quickly
and accurately measure its efficacy to remove biofilms from all
surfaces. Use of traditional microbiol. analyses, such as plate counts
and dip-slides provide insufficient information about viable cell content
and their role in deposit formation. The ATP assay, a newer technol., is
more useful in correlating results to biofilm removal.
219. Sodium chlorate-based generation of chlorine dioxide yields improved
corrosion rate results and fewer equipment failures compared to
chlorine treatment in a cooling system.
Marckini, Scott A. (Drew Industrial Division, Ashland Chemical
Company, Boonton, NJ, USA). Off. Proc. - Int. Water Conf., 57th,
107-121 (English) 1996 Engineers' Society of Western Pennsylvania.
CODEN: OIWCEQ. ISSN: 0739-4977. DOCUMENT TYPE: Journal
CA Section: 61 (Water)
Detailed corrosion coupon data was collected at a Southeastern
United States chem. manufg. plant from Jan. 1986 through Mar. 1996.
During this period the plant progressed from gaseous chlorine addn.
for the control of microorganisms to sodium hypochlorite and finally
chlorine dioxide. Thirty day, corrosion coupon studies were conducted
throughout this transition period. Initial results indicate that since the
introduction of chlorine dioxide and despite numerous incidents of
process contamination, mild steel corrosion rate avs. have declined
dramatically and single incident corrosion rates have been significantly
reduced.
220. Correlation analysis of environmental reactivity of organic substances.
Tratnyek, Paul G. (Department of Environmental Science and
Engineering, Oregon Graduate Institute of Science and Technology,
Portland, OR 97291-1000, USA). Perspect. Environ. Chem., 167-194.
Edited by: Macalady, Donald L. Oxford University Press: New York, N.
Y. (English) 1998. CODEN: 65QWAJ. DOCUMENT TYPE:
Conference CA Section: 61 (Water)
Quant. structure-activity relationships (QSARs) are ubiquitous in
environmental chem. because they provide a powerful tool for
assimilating properties of the many environmentally important org.
substances. The abundance of QSARs also reflects the ease with
which statistically significant correlations can be obtained. This is
evidenced by the correlation matrix of substituted phenol properties,
which shows that many variable combinations exhibit patterns that
suggest significant relationships. However, rather few of these
apparent relationships yield useful QSARs. QSARs are most valuable
when they are based on appropriate predictor variables, an explicit
mechanistic model, and appropriate statistics. These criteria are met
to varying degrees by the many published QSARs that describe the
rates of oxidn. of substituted phenols. A problematic application in
which QSARs are often employed is predicting the reactivity of
compds. outside the scope of their resp. training sets. The abundance
of data on correlation anal. of phenol oxidn. makes it possible to
explore the limits and possibilities of this activity.
221. Reduction of the formation of AOX during chlorine dioxide bleaching.
Lachenal, D.; Joncourt, M. J.; Froment, P.; Chirat, C. (Ecole Francaise
de Papeterie, Ind. Graphiques de Grenoble, Saint Martin d'Heres
38402, Fr.). J. Pulp Pap. Sci., 24(1), 14-17 (English) 1998 Canadian
Pulp and Paper Association, Technical Section. CODEN: JPUSDN.
ISSN: 0826-6220. DOCUMENT TYPE: Journal CA Section: 43
(Cellulose, Lignin, Paper, and Other Wood Products)
The formation of chloro org. compds. (AOX) during ClO2 pulp bleaching
can be decreased by additives, e.g. DMSO is particularly efficient. It
reacts with HOCl, generated in situ, to give di-Me sulfone.
Unfortunately, the capture of HOCl results in poorer delignification.
Therefore, the use of DMSO must be limited to relatively low AOX
abatement. The addn. of FeSO4, which should regenerate ClO2 from
the HClO2 bleaching, has no pos. effect on AOX. However, Fe2+
causes some viscosity loss, probably because it induces the formation
of Cl* radicals. ClO2 splitting, coupled with an addn. of alkali to raise
the pH to neutrality at the start of each ClO2 phase, leads to AOX
decrease without any neg. effect on delignification.
222. Applications of ozone in elemental chlorine-free (ECF) bleaching of
kraft pulp.
Rodrigues da Silva, Marcelo; Campos H. de Brito, Ana; Colodette,
Jorge Luiz (Universidade Federal de Vicosa, Brazil). Papel, 59(1),
55-62 (Portuguese) 1998 Associacao Brasileira Tecnica de Celulose
e Papel. CODEN: PAPLA3. ISSN: 0031-1057. DOCUMENT TYPE:
Journal CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood
Products)
The use of ozone in ECF bleaching of kraft pulp was evaluated in
various bleaching sequences combining chelation, chlorine dioxide
bleaching, and alk. extn. The results were evaluated in terms of ozone
consumption to reach 90 * 0.5% ISO brightness, bleaching costs
(chem. and steam), chlorine dioxide savings, and selectivity and
efficiency of ozone stages. The ozone treatment was most effective
when applied in the last stage of the chlorine dioxide sequences. The
efficiency of delignification with ozone was higher for lower ozone
dosages.
223. Bleaching softwood kraft pulp: the role of chlorine dioxide dosage and
final pH in the D stages.
Dahl, Olli; Niinimaki, Jouko; Tirri, Tapio; Kuopanportti, Hannu
(Department of Process Engineering, University of Oulu, Oulu 90570,
Finland). Pap. Puu, 79(8), 560-564 (English) 1997 Suomen Paperi- ja
Puutavaralehti Oy. CODEN: PAPUAU. ISSN: 0031-1243.
DOCUMENT TYPE: Journal CA Section: 43 (Cellulose, Lignin, Paper,
and Other Wood Products)
The effects of ClO2 dosage and final pH in the D stages of the pulp
bleaching process were investigated in lab. expts. using batch-cooked
and oxygen-pre-delignified softwood kraft pulp. The results clearly
indicated that the optimum final pH was different in each stage, i.e., Do,
D1, and D2, and depended on the ClO2 doses. The more ClO2 used,
the lower the optimum final pH after each stage. The lowest kappa no.,
measured after the first alkali stage, in the Do state was achieved at
final pH values of 2.0-3.5 at all of the ClO2 doses tested. When the final
pH was controlled with alkali in the D1 stage, the optimum pH range of
3.0-4.0 was attained, with an av. increase in brightness of 1.5-2.0%
ISO at all ClO2 doses. Correspondingly, the optimum pH range in the
D2 stage was 4.0-5.0 and the av. improvement in brightness ~1%. The
use of alkali lowered the viscosity by an av. of 50 dm3/kg per addnl. kg
of NaOH at all ClO2 doses in the D2 stage. Final pH control had no
direct effect on ClO2 consumption in the D stages.
224. Analysis of the ECETOC aquatic toxicity (EAT) database. III -
Comparative toxicity of chemical substances to different life stages of
aquatic organisms.
Hutchinson, Thomas H.; Solbe, John; Kloepper-Sams, Pamela J.
(Brixham Environmental Laboratory, ZENECA Ltd., Brixham, UK).
Chemosphere, Volume Date 1998, 36(1), 129-142 (English) 1997
Elsevier Science Ltd. CODEN: CMSHAF. ISSN: 0045-6535.
DOCUMENT TYPE: Journal CA Section: 4 (Toxicology)
In the context of current risk assessment procedures, the ECETOC
Aquatic Toxicity (EAT) database has been used to assess the
comparative sensitivity of different life stages of aquatic organisms to a
range of chem. substances. Both EC50 and NOEC data were
analyzed using Hazen percentiles in order to compare key life stages of
both fish and aquatic invertebrates (no data available on aquatic algae
or plants). Based on fish NOEC data, larvae were more sensitive (ratio
> 2.0) than embryos for 68% of substances, while fish larvae were of
greater than or equal sensitivity to juvenile fish for 83% of substances.
Based on fish EC50 data (NOECs unavailable), juveniles were more
sensitive than adults for 92% of substances. For a limited no. of
available substances, fish embryo-larval tests (as NOECs) were of
greater than or equal sensitivity to lifecycle tests for 42% of substances.
Based on EC50 data (NOECs unavailable), aquatic invertebrate
larvae were of greater than or equal sensitivity to juvenile invertebrates
for 66% of substances, while the juveniles were of greater than or equal
sensitivity to adults for 54% of substances. Full details are presented
for the calcd. sensitivity ratios for individual org. and inorg. substances.
The results are discussed with respect to current ecotoxicol. test
procedures and recommendations made for future work in this
important area of environmental risk assessment.
225. Comparison of chlorine dioxide photochemistry in acetonitrile and
water using subpicosecond pump-probe spectroscopy.
Philpott, Matthew J.; Charalambous, Sophia; Reid, Philip J. (Box,
Department of Chemistry, University of Washington, Seattle, WA
98195 351700, USA). Chem. Phys. Lett., 281(1,2,3), 1-9 (English)
1997 Elsevier Science B.V. CODEN: CHPLBC. ISSN: 0009-2614.
DOCUMENT TYPE: Journal CA Section: 74 (Radiation Chemistry,
Photochemistry, and Photographic and Other Reprographic
Processes)
The photochem. reaction dynamics of chlorine dioxide (OClO)
dissolved in water and acetonitrile are investigated using
subpicosecond pump-probe spectroscopy. The spectral dynamics
obsd. at 267 and 400 nm demonstrate that the quantum yield for
geminate recombination of ClO and O to form OClO is reduced in
acetonitrile relative to water. However, the dynamics at 800 nm are
similar for both solvents consistent with ClOO rather than OClO being
responsible for the evolution at this wavelength. The kinetics for
ground-state ClOO prodn. and decompn. are significantly slower in
acetonitrile relative to water suggesting that solvent-solute hydrogen
bonding is important in defining the ground state reactivity of this
photoproduct.
226. Photodissociation dynamics of OClO: O(3PJ) state and energy
distributions.
Roth, Melanie; Maul, Christof; Gericke, Karl-Heinz (Institut fur
Physikalische und Theoretische Chemie, Technische Universitat
Braunschweig, Hans-Sommer-Strasse 10, Braunschweig 38106,
Germany). J. Chem. Phys., 107(24), 10582-10591 (English) 1997
American Institute of Physics. CODEN: JCPSA6. ISSN: 0021-9606.
DOCUMENT TYPE: Journal CA Section: 74 (Radiation Chemistry,
Photochemistry, and Photographic and Other Reprographic
Processes)
The photodissocn. dynamics of OClO in the near-UV was investigated
in a state specific and energy selective manner. At a dissocn.
wavelength of 308 nm, OClO(X2B1) was excited to the
OClO(*2A2(18,0,0)) state, from which it decays into ClO(X2P3/2,1/2) and
O(3P2,1,0). The nascent oxygen fragments were detected spin
selectively by resonant enhanced multiphoton ionization and time of
flight measurements (REMPI-TOF). Based on the measurements and
the conservation of energy and linear momentum, the internal energy of
the ClO partner fragment was obtained. On av., more than 60% of the
available energy is transferred into internal excitation of the ClO radical.
Nearly the whole internal energy is vibrational energy with vibrational
levels populated up to the energetic limit. Besides, the internal energy
depends on the oxygen spin-orbit state because the fraction of highly
excited ClO fragments increases with increasing total angular
momentum J. The bimodal behavior of the fragment energy distribution
indicates two different dissocn. pathways, in which one leads to ClO
radicals excited up to n = 10 and the other one up to n = 15.
Furthermore, the decay is anisotropic, which was proved by
polarization expts. This is a hint for a short decay time estd. to be in the
order of a few hundred femtoseconds.
227. Method for disinfection of water in swimming pools.
Brown, Geoffrey A.; Starkey, Ron (Bio-Lab, Inc., USA). PCT Int. Appl.
WO 9800368 A1 8 Jan 1998, 24 pp. DESIGNATED STATES: W: AU,
CA; RW: AT, BE, CH, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL,
PT, SE. (English). (World Intellectual Property Organization). CODEN:
PIXXD2. CLASS: ICM: C02F001-50. APPLICATION: WO
97-US11076 25 Jun 1997. PRIORITY: US 96-675042 3 Jul 1996.
DOCUMENT TYPE: Patent CA Section: 61 (Water)
A method for treating swimming pool water with peroxyacids and/or
chlorine dioxide to supplement polyhexamethylene biguanide and/or
H2O2 and/or polyquaternary ammonium compds. and/or boron-contg.
compds. is described.
228. Generation and storage of chlorine dioxide in a non-aqueous medium.
Pitochelli, Anthony R. (Rio Linda Chemical Co., Inc., USA). U.S. US
5707546 A 13 Jan 1998, 14 pp. Cont.-in-part of U.S. 5,409,549.
(English). (United States of America). CODEN: USXXAM. CLASS:
ICM: C01B011-02. NCL: 252187210. APPLICATION: US 95-416153
4 Apr 1995. PRIORITY: US 91-716638 17 Jun 1991; US 93-64756 19
May 1993. DOCUMENT TYPE: Patent CA Section: 49 (Industrial
Inorganic Chemicals)
A method of prepg. and storing a stable soln. of chlorine dioxide in a
non-aq., water-immiscible liq. comprises mixing vigorously an aq. soln.
of chlorine dioxide with a non-aq. water immiscible hydrocarbon liq.
and, in a single extn., extg. the chlorine dioxide into the non-aq. liq. to
form a concn. of chlorine dioxide ranging from 1822-17200 mg/L in the
liq. The aq. and non-aq. phases are sepd. and the chlorine
dioxide-contg. non-aq. liq. is stored in a closed light-free environment.
In an alternate embodiment, gaseous chlorine dioxide is introduced into
the non-aq., water-immiscible liq. A high-purity aq. soln. of chlorine
dioxide is prepd. by mixing the non-aq. soln. of chlorine dioxide with
water and extg. chlorine dioxide into the water.
229. Method for production of pulps.
Krzywanski, Romuald S.; Chow, Suezone (Canadian Forest Products
Ltd., Can.). Ger. Offen. DE 19729155 A1 15 Jan 1998, 10 pp.
(German). (Germany). CODEN: GWXXBX. CLASS: ICM:
D21C009-16. ICS: D21C009-14. APPLICATION: DE 97-19729155 8
Jul 1997. PRIORITY: US 96-676704 8 Jul 1996. DOCUMENT TYPE:
Patent CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood
Products)
Pulps are first bleached with ClO2 and then at alk. pH with H2O2 in the
presence of chelating agents. The resulting product has little org.
halogen content, improved whiteness, and good strength properties.
Suitable chelating agents are DTPA or its Na salt,
diethylenetriaminepentakis(methylenephosphonic acid) or its Na salt,
and HEDP.
230. Preliminary treatment of sulfite pulp.
Milovidova, L. A.; Komarova, G. V. (Arkhangel'sk. Gos. Tekh. Univ.,
Arkhangelsk, Russia). Tsellyul., Bum., Karton, (11-12), 14-15 (Russian)
1997 Tsellyuloza, Bumaga, Karton. CODEN: TBKAEY. ISSN:
0869-4923. DOCUMENT TYPE: Journal CA Section: 43 (Cellulose,
Lignin, Paper, and Other Wood Products)
Good ash content reducing activity at simultaneous delignification
action was attained in oxygen-peroxide bleaching of sulfite pulp by
introducing a stage consisting of a short-term (~5 min) treatment of pulp
with ClO2 at concn. ~5 kg/ton, i.e., a concn. at which no significant amt.
fo toxic Cl compds. is formed. Such action of ClO2 is superior to that or
water, H2SO4, or Trilon B, which lead only to ash content redn. Various
technol. aspects of the ClO2-stage contg. oxygen-hydrogen peroxide
bleaching are evaluated.
231. Apparatus for regeneration of wastewater from water purification
device and utilization of regenerated water.
Yasui, Aya; Kasai, Tsunezou (Daisen Membrane Systems K. K.,
Japan). Jpn. Kokai Tokkyo Koho JP 09313895 A2 9 Dec 1997
Heisei, 3 pp. (Japanese). (Japan). CODEN: JKXXAF. CLASS: ICM:
B01D061-18. ICS: B01D063-02; B01D071-16; C02F001-50;
C02F001-76. APPLICATION: JP 96-136889 30 May 1996.
DOCUMENT TYPE: Patent CA Section: 61 (Water) Section
cross-reference(s): 47, 60, 63
In purifn. of water for artificial dialysis by reverse-osmosis membranes,
the membrane-concd. wastewater is purified by filtration membrane
modules having an automatic cleaning system, and a chlorine
agent-injection device is arranged at the upstream- or downstream
side of the filtration membrane modules. The chlorine agent can be
chlorine, NaClO, Ca(ClO)2, ClO2, etc. The filtration membrane modules
are * 1 kinds of modules selected from microfilters, ultrafilters and
nanofilters. The filtration membrane modules are cellulose
acetate-based hollow-fiber membrane ultrafilters. The regenerated
water is utilized as tap water.
232. Cleaning of immersion-type ceramic membrane separator with
chemicals.
Narukami, Yoshihisa; Ishihara, Katsuo; Yoshisaki, Takeshi; Osaki,
Shunya (Kubota, Ltd., Japan). Jpn. Kokai Tokkyo Koho JP 09313902
A2 9 Dec 1997 Heisei, 5 pp. (Japanese). (Japan). CODEN: JKXXAF.
CLASS: ICM: B01D065-06. ICS: B01D071-02; B08B003-10;
B08B009-06. APPLICATION: JP 96-132475 28 May 1996.
DOCUMENT TYPE: Patent CA Section: 47 (Apparatus and Plant
Equipment) Section cross-reference(s): 57, 60, 61
In cleaning an immersion-type ceramic membrane separator by
pressure pumping liq. chems. to the flow path of the water-permeated
side of the ceramic membrane separator in the reverse water-flow
direction of the filtration process, the liq. chem. cleaning process is
operated at time intervals of once per wk to once per 6 mo. The liq.
chems. are retained in the flow path of the water-permeated side of the
ceramic membrane separator for 30 min to 24 h. The liq. chem.
cleaning is a multistage process using * 2 kinds of the following
chems.: oxidizing agent solns., acid or basic solns., and reducing agent
solns. The chems. are: (1) oxidizing agent solns., e.g., NaClO aq.
solns., chlorine water, or chlorine dioxide solns., (2) acid or base solns.,
e.g., HCl, H2SO4, HNO3, oxalic acid, citric acid, or NaOH aq. solns., or
(3) reducing agent solns., e.g., Na2SO3, NaHSO3, or Na2S2O3 aq.
solns., etc. The app. is suitable for treatment of water, sewage, urine
and feces and industrial waste water, and desalination of seawater,
etc.
233. Pressurized chlorine dioxide bleaching of paper pulp with recovery of
chlorine dioxide.
Boman, Rolf; Bokstrom, Monica; Germgard, Ulf; Mellander, Pia;
Norden, Solveig; Sundin, Matts (Sunds Defibrator Industries AB;
Boman, Rolf; Bokstrom, Monica; Germgard, Ulf; Mellander, Pia;
Norden, Solveig; Sundin, Matts, Swed.). PCT Int. Appl. WO 9800602
A1 8 Jan 1998, 9 pp. DESIGNATED STATES: W: AU, BR, CA, CN,
JP, NO, NZ, US; RW: AT, BE, CH, DE, DK, ES, FI, FR, GB, GR, IE, IT,
LU, MC, NL, PT, SE. (English). (World Intellectual Property
Organization). CODEN: PIXXD2. CLASS: ICM: D21C009-14.
APPLICATION: WO 97-SE1060 16 Jun 1997. PRIORITY: SE 96-2602
28 Jun 1996. DOCUMENT TYPE: Patent CA Section: 43 (Cellulose,
Lignin, Paper, and Other Wood Products)
Paper pulp is bleached in a multistage process in which at least one of
the bleaching stages is carried out in a pressurized vessel with ClO2 at
90-110* and 0.1-10 bar overpressure for 1-90 min and pulp concn. of
8-40%. The pressure of the pulp is lowered in a downstream tower in a
manner that also lowers the temp. of the pulp and enables ClO2
residues to be extd. in a gas phase using cold water. The ClO2-contg.
water is recycled to the bleaching stage. The bleaching is effected
more quickly at the higher temp., reducing equipment and building
costs, while minimizing environmental problems.
234. Studies on pulp bleaching for decreasing AOX. I. The pulp bleaching
method using A and D(H/L) treatment.
Yoon, Byung-Ho; Kim, Kee-Seon; Lee, Seon-Ho (Dept. of Paper
Science and Engineerig, Kangwon Nat'l Univ. 200-701, S. Korea).
Palpu, Chongi Gisul, 29(1), 52-61 (English) 1997 Korea Technical
Association of the Pulp and Paper Industry. CODEN: PCGIDY. ISSN:
0253-3200. DOCUMENT TYPE: Journal CA Section: 43 (Cellulose,
Lignin, Paper, and Other Wood Products)
An attempt was made to decrease AOX by applying bleaching
methods of A(HNO3 + NaNO3) and D(H/L)(dual pH ClO2 bleaching) to
conventional OCEDED bleaching stages. The effects of NSA
treatment and the influence of prodn. rate of ion species in ClO2 and
pulp mixts., according to various pH-s as well as dual pH, on pulp
bleaching were investigated. Finally the effects of AOCDED(H/L)ED(H/L)
bleaching stage were investigated by measuring AOX, brightness,
kappa no., and viscosity of pulps. A stage was treated by using 4%
HNO3 and 0.05~2.0% NaNO2 on pulp and D(H/L) stage was like that
pulp mixed with ClO2 soln. was adjusted at pH 7.0 and reacted in pulp
consistency 3%, 5~20 min, 70*, and then successively for 160~175 min
at pH 4.0. Suitable NaNO2 addn. rate was at 0.6% where the
brightness of pulp was highest and pulp viscosity was not decreased
much. Chlorate (ClO3-) was decreased according to pH increase, but
chlorite(ClO2-) was highly decreased according to pH increase, and
chloride was slightly increased with pH increase. The application of A
and D(H/L) bleaching stages to some various multiple bleaching stages
(AOCED(H/L)EopD(H/L) etc.) had good results, in that brightness was
increased >2~3% ISO over the conventional method (OCEDEopD), but
viscosity was decreased by only 1~2 cps.
235. Reduced AOX and biological effects by modification of a mill chlorine
dioxide stage.
Ljunggren, Sten; Gidnert, Elisabeth Bergnor; De Sousa, Filipe (Wood
Chemistry, STFI, Swedish Pulp Paper Research Institute, Stockholm
S-114 86, Swed.). Tappi J., 81(1), 267-273 (English) 1998 TAPPI.
CODEN: TAJODT. ISSN: 0734-1415. DOCUMENT TYPE: Journal
CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood Products)
The 1st ClO2 stage in a modern OD(EPO)DD sequence for bleaching
softwood kraft pulp at a Swedish paperboard mill was modified by
decreasing the ClO2 charge, increasing the pH level, and introducing a
more effective reinforced EPO stage. However, the ClO2 charge in the
last D-stage was increased slightly to maintain the same high pulp
brightness of 90%. The mixed D and EPO effluents obtained before
and after this modification were compared. The chem. analyses
included AOX, EOX, COD, TOC, BOD7, CHCl3, and chlorinated
phenolics and extractives. The bioassays consisted of acute toxicity
(Microtox), growth inhibition [green algae (S. carpicornutum)], survival
and reprodn. (C. dubia), and embryo-larval toxicity with zebra-fish (B.
rerio) tests. Effluents were also tested in a mini-model ecosystem. The
chem. characterization study clearly showed that the process
modifications resulted in a decrease in the amt. of chlorinated matter in
the bleach plant effluent. An AOX decrease of 20% was obsd.,
whereas chlorinated acetic acids and chlorinated phenolic compds.
were decreased by 55% and 35%, resp. With some of the test
methods used in the bioassay study, an improvement in effluent quality
was obsd. By using this process modification, it is possible for a mill to
decrease chloro org. compds., e.g. AOX. From the results of the chem.
and biol. anal. of the bleaching effluent, no apparent significant
disturbance of an ecosystem will occur.
236. Oxidation of Formaldehyde by Chlorite in Basic and Slightly Acidic
Media.
Chinake, Cordelia R.; Olojo, Oluwarotimi; Simoyi, Reuben H.
(Department of Chemistry, University of Natal, Scottsville 3209, S. Afr.).
J. Phys. Chem. A, 102(3), 606-611 (English) 1998 American Chemical
Society. CODEN: JPCAFH. ISSN: 1089-5639. DOCUMENT TYPE:
Journal CA Section: 22 (Physical Organic Chemistry)
The reaction of chlorite and formaldehyde was studied in basic and
slightly acidic media. Though the expected product was CO2, the
oxidn. of HCHO, however, gave nearly quant. formation of ClO2, the
oxidn. product of ClO2-. In excess HCHO the stoichiometry of the
reaction was deduced as 3ClO2- + HCHO + 2H+ * HCOOH +
2ClO2(aq) + Cl- + 2H2O; but in high excess of ClO2- the stoichiometry
was 6ClO2- + HCHO + 4H+ * CO2(g) + 4ClO2(aq) + 3H2O + 2Cl-. The
reaction is autocatalytic in HOCl. The first step of the reaction
produces HOCl, which catalyzes the formation of ClO2 and further
oxidn. of HCOOH to CO2. ClO2 was found to be relatively unreactive
toward HCHO and HCOOH, and hence it accumulated rapidly.
238. Reduction Potential of the tert-Butylperoxyl Radical in Aqueous
Solutions.
Das, Tomi Nath; Dhanasekaran, T.; Alfassi, Z. B.; Neta, P. (Physical
and Chemical Properties Division, National Institute of Standards and
Technology, Gaithersburg, MD 20899, USA). J. Phys. Chem. A,
102(1), 280-284 (English) 1998 American Chemical Society. CODEN:
JPCAFH. ISSN: 1089-5639. DOCUMENT TYPE: Journal CA Section:
22 (Physical Organic Chemistry) Section cross-reference(s): 74
Rate consts. for oxidn. of tert-Bu hydroperoxide anion (t-BuO2-) by
several oxidants were detd. by pulse radiolysis. Rapid oxidn. was
found with N3* (4.4 * 108 L mol-1 s-1) and 稯- (2.6 * 108 L mol-1 s-1), but
others (Br2*-, I2*-, ClO2*, CO3*-, C6H5N(CH3)2*+) reacted much more
slowly. Since the redn. potentials of these oxidants are much higher
than that estd. for t-BuO2*, the obsd. rate consts. suggest that the
self-exchange rate for t-BuO2*/t-BuO2- is very slow and that it would be
difficult to establish rapid equil. by pulse radiolysis with a suitable redox
pair. Therefore, to det. the redn. potential for this peroxyl radical, the
forward and reverse rate consts. for reaction 6, t-BuO2* + Fe(CN)64- t
t-BuO2- + Fe(CN)63-, were measured independently. The forward rate
const. was measured by kinetic spectrophotometric pulse radiolysis in
N2O-satd. solns. contg. high concns. of N3- (1 mol L-1), t-BuO2- (0.4 mol
L-1), and varying concns. of Fe(CN)64- (0.012-0.036 mol L-1) at pH 13.7.
The rate const. k6 was found to be 2.5 * 102 L mol-1 s-1. Such a low
rate const. was possible to measure by pulse radiolysis only because
the self-decay of t-BuO2* is very slow compared to those of other
peroxyl radicals. The reverse reaction rate const. was measured by
mixing the reactants and following the disappearance of Fe(CN)63- in
the presence of spin traps to remove the peroxyl radicals from the equil.
A rate const. of k-6 = 1.4 * 10-2 L mol-1 s-1 was derived. By taking the
redn. potential of Fe(CN)63-/Fe(CN)64- as 0.459 V vs NHE for the
conditions used in these expts., we calc. E(t-BuO2*/t-BuO2-) = 0.71 V
and E(t-BuO2*/t-BuO2H) = 1.05 V at pH 7 and 1.47 V at pH 0. The rate
consts. for oxidn. of Fe(CN)64- and other compds. by various peroxyl
radicals were then utilized for the estn. of the redn. potentials of these
peroxyl radicals.
239. Evidence for the 2B1-2A1 electronic transition in chlorine dioxide from
resonance Raman depolarization ratios.
Reid, Philip J.; Esposito, Anthony P.; Foster, Catherine E.; Beckman,
Robert A. (Box 351700, Department of Chemistry, University of
Washington, Seattle, WA 98195, USA). J. Chem. Phys., 107(20),
8262-8274 (English) 1997 American Institute of Physics. CODEN:
JCPSA6. ISSN: 0021-9606. DOCUMENT TYPE: Journal CA Section:
73 (Optical, Electron, and Mass Spectroscopy and Other Related
Properties) Section cross-reference(s): 74
The resonance Raman depolarization ratios of Cl dioxide (OClO)
dissolved in cyclohexane are measured and analyzed to establish the
existence of a 2A1 excited state that is nearly degenerate with the
optically stronger, 2A2 excited state. The depolarization ratio of the
sym. stretch fundamental transition is measured at several excitation
wavelengths spanning the lowest-energy electronic transition centered
at ~360 nm. The depolarization ratio of this transition reaches a max.
value of 0.25 * 0.04 directly on resonance suggesting that scattered
intensity is not derived from a single excited state. The depolarization
ratios are modeled using the time-dependent formalism for Raman
scattering. This anal. demonstrates that the obsd. Raman
depolarization ratios are derived from contributions of 2 excited states
of 2A1 and 2A2 symmetry to the obsd. scattering. The results presented
here support the emerging picture of OClO excited-state reaction
dynamics in which photoexcitation to the 2A2 excited state is followed
by internal conversion from this state to the 2A1 surface. Both the role of
the 2A1 state in the photochem. of OClO and the importance of this
state in modeling resonance Raman intensities are discussed.
240. Study on a nuclear fuel reprocessing system based on the precipitation
method in mild aqueous solutions.
Asano, Yuichiro; Asanuma, Noriko; Ito, Toshihiko; Kataoka, Makoto;
Fujino, Shinya; Yamamura, Tomoo; Sugiyama, Wataru; Tomiyasu,
Hiroshi; Mizumachi, Kunihiko; Ikeda, Yasuhisa; Wada, Yukio; Asou,
Masami (REs. Lab. Nucl. Reactors, Tokyo Inst. Technol., Tokyo 152,
Japan). Nucl. Technol., 120(3), 198-210 (English) 1997 American
Nuclear Society. CODEN: NUTYBB. ISSN: 0029-5450. DOCUMENT
TYPE: Journal CA Section: 71 (Nuclear Technology)
A new reprocessing system for spent nuclear fuels based on a pptn.
method is proposed to recover uranium and transuranium elements
from spent nuclear fuels in high ratios and to achieve extreme safety
without any potential dangers. Expts. were carried out for a simulated
fuel soln. contg. uranium and 17 major fission product elements. The
main reprocessing processes are as follows: (a) dissoln. of UO2 fuel
under mild conditions; (b) neutralization of the dissolved fuel soln. with
Na2CO3-NaHCO3 mixed solns., followed by the sepn. of pptd. fission
products by centrifugation; (c) sepn. of cesium by a pptn. method using
a tetraphenylborate ion; and (d) recovery of uranium (U) as ppt. of the
hydrolyzed compd. from an alk. soln. As a result, 99.95% of the U was
recovered with the least in the recovered 1 g of U with the only
exceptions being zirconium and molybdenum.
241. Alternative disinfectants for drinking water.
Richardson, S. D.; Thruston, A. D., Jr.; Collette, T. W.; Caughran, T. V.;
Patterson, K. S.; Lykins, B. W., Jr. (U.S. Environmental Protection
Agency, Athens, GA 30605, USA). Chlorine Chlorine Compd. Pap.
Ind., [Int. Symp.], Meeting Date 1995, 183-192. Edited by: Turoski,
Victor. Ann Arbor Press: Chelsea, Mich. (English) 1998. CODEN:
65MVAU. DOCUMENT TYPE: Conference CA Section: 61 (Water)
Using a combination of spectral identification techniques (gas
chromatog. coupled with low- and high-resoln. electron-impact mass
spectrometry [GC/EI-MS], low- and high-resoln. chem. ionization mass
spectrometry [GC/CI-MS], and Fourier transform IR spectroscopy
[GC/FT-IR]), many drinking water disinfection byproducts (DBP) formed
using alternative disinfectants were identified. The alternative
disinfectants included O3, ClO2, chloramine, and TiO2 with UV irradn.
Many of these byproducts are not present in any spectral libraries and
are not on any regulatory list. Because some alternative disinfectants,
such as O3 and TiO2/UV, do not persist in water, full-scale drinking
water treatment plants typically need to use a secondary disinfectant,
such as Cl or chloramine (in addn. to the primary disinfectant) to
maintain a disinfectant residual throughout the distribution system.
Because of this, the effect of secondary Cl and chloramine treatment on
formation of DBP was studied. Secondary chlorination produced
numerous chlorinated DBP, including halomethanes. Chloramine also
produced chlorinated DBP, but they were fewer in no. and lower in
concn. than those produced with secondary chlorination.
242. The effect of chlorine and chlorine dioxide on microbial populations in
drinking water.
Rouf, M. A. (Department of Biology and Microbiology, University of
Wisconsin-Oshkosh, Oshkosh, WI 54901, USA). Chlorine Chlorine
Compd. Pap. Ind., [Int. Symp.], Meeting Date 1995, 303-317. Edited
by: Turoski, Victor. Ann Arbor Press: Chelsea, Mich. (English) 1998.
CODEN: 65MVAU. DOCUMENT TYPE: Conference; General Review
CA Section: 61 (Water) Section cross-reference(s): 4, 10
A review with 88 refs. concerning the effect of Cl and ClO2 on microbial
populations in drinking water is given. Topics discussed include:
nature of Cl and ClO2; mechanisms of biocidal activity; water treatment;
sensitivity and resistance of various microbes to free Cl (bacteria,
viruses, protozoa); and toxicity and health risk of disinfection with Cl
compds.
243. A comparison of chlorinated organic material produced by chlorine and
chlorine dioxide bleaching of kraft pulp.
Mckague, A. B.; Shen, X.; Reeve, D. W. (Department of Chemical
Engineering and Applied Chemistry, Pulp & Paper Centre, University of
Toronto, Toronto M5S 3E5, Can.). Chlorine Chlorine Compd. Pap.
Ind., [Int. Symp.], Meeting Date 1995, 247-252. Edited by: Turoski,
Victor. Ann Arbor Press: Chelsea, Mich. (English) 1998. CODEN:
65MVAU. DOCUMENT TYPE: Conference; General Review CA
Section: 43 (Cellulose, Lignin, Paper, and Other Wood Products)
A review with 18 refs. on the amt. and nature of the chlorinated org.
material produced by Cl and ClO2 bleaching of kraft pulp is presented,
showing that adsorbable org. halide (AOX) and solvent-extractable org.
halide (EOX) levels in effluent, the EOX level in pulp, and the no. of
chlorinated org. compds. produced decrease dramatically when ClO2
is substituted for Cl. Studies of the chlorinated org. material in pulp
bleached with 100% ClO2 showed that trace levels of chlorinated fatty
and resin acids and chlorinated stilbenes were present.
244. Measurement of chlorine dioxide of low concentration by reverse FIA
spectrophotometry.
Chen, Hui; Wang, Gaizhen; Yuan, Li (Dep. Chemistry, Northwest
Normal University, Lanzhou 730070, Peop. Rep. China). Xibei Shifan
Daxue Xuebao, Ziran Kexueban, 33(2), 41-44 (Chinese) 1997 Xibei
Shifan Daxue. CODEN: XDXKEH. ISSN: 1001-988X. DOCUMENT
TYPE: Journal CA Section: 79 (Inorganic Analytical Chemistry) Section
cross-reference(s): 61
A reverse FIA spectrophotometry method based on the decoloration
reaction of rhodamine B with chlorine dioxide was applied to the detn.
of ClO2 in the presence of other chlorine species. The linear range was
0-2.4 mg L-1. The detection limit was 0.02 mg L-1. The injection
frequency was 120/h. Free chlorine at concn. <70 mg L-1, chlorate,
chlorite, and hypochlorite showed no effect on the detn. of ClO2. The
method has the advantages of simple operation, high selectivity,
sensitivity, and reproducibility, and can be used to det. residual ClO2 in
drinking water.
245. Reactions of polynuclear aromatic hydrocarbons with chlorine and
chlorine dioxide in coal tar lined pipes.
Merkel, T.; Maier, M.; Sacher, F.; Maier, D. (Engler-Bunte-Institut,
University of Karlsruhe, Karlsruhe D-76128, Germany). Aqua (Oxford),
46(6), 289-303 (English) 1997 Blackwell Science Ltd. CODEN:
AQUAAA. ISSN: 0003-7214. DOCUMENT TYPE: Journal CA
Section: 61 (Water) Section cross-reference(s): 4, 10, 12, 51, 67
In the presence of disinfectants, polycyclic arom. hydrocarbons (PAH)
are re-mobilized from the coal tar lining of water distribution mains.
PAH reactions with Cl and ClO2 can lead to chlorinated PAH that may
exhibit higher mutagenic effects than parent PAH. Detection limits in
the lower ng/L concns. for PAH and chlorinated PAH detn. were
achieved using solid phase micro-extn. and a gas chromatog.-mass
spectrometry. Reactions of 4 PAH (anthracene, fluoranthene, fluorene,
phenanthrene) with Cl and ClO2 under common conditions and concns.
in drinking water distribution systems were studied. In batch expts. with
demineralized and drinking water at pH 7, fluoranthene, fluorene, and
phenanthrene concns. remained const., whereas anthracene reacted
quant. with both disinfectants. The anthracene reaction followed a
pseudo-first order kinetic. In these reactions, no chlorinated products
could be detected, only monohydroxyanthracene and anthraquinone
were identified. A reaction mechanism for both reaction products is
suggested. Addnl., the toxic effect of a set of chlorinated and oxidized
PAH was examd.: at 0.5 mg/L, only hydroxyphenanthrene and
phenanthrene quinone reduced the activity of luminescent bacteria,
whereas no compd. affected the micro-crustacean, Daphnia magna.
Fluorescence emission spectra of oxidized and chlorinated PAH
showed significant alterations when compared to the spectra of parent
compds.
246. Sequential disinfection of Cryptosporidium parvum by ozone and
chlorine dioxide.
Liyanage, Lalith R. J.; Finch, Gordon R.; Belosevic, Miodrag
(Department of Civil and Environmental Engineering, University of
Alberta, Edmonton, AB T6G 2G7, Can.). Ozone: Sci. Eng., 19(5),
409-423 (English) 1997 Lewis Publishers. CODEN: OZSEDS. ISSN:
0191-9512. DOCUMENT TYPE: Journal CA Section: 61 (Water)
A 2-step disinfection approach was evaluated for control of
Cryptosporidium parvum using bench-scale expts. in 0.05M phosphate
buffer at pH 8 and 22*. Sequential application of ozone and chlorine
dioxide was evaluated in which ozone was applied first, followed by
chlorine dioxide. Infectivity in neonatal CD-1 mice was used to assess
oocyst viability after disinfection. The sequential treatment of oocysts
by ozone followed by chlorine dioxide resulted in addnl. inactivation of
C. parvum due to the synergism of the two disinfectants. The
inactivation kinetics for chlorine dioxide were modeled following
preconditioning with ozone at a given level using the Integral-Hom
model which takes the disinfectant decay into account. These
preliminary findings indicate that sequential disinfection with ozone
followed by chlorine dioxide may have potential in controlling
waterborne parasites.
247. Study on the selectivity of ClO2/Cl2 for H2SO4-NaClO3-NaCl reaction
system.
Liu, Yuejin; Zhou, Dajun; Xiong, Shuangxi; Chen, Change; Chen,
Dayuan (Department of Chemical Engineering, Xiangtan University,
Xiangtan 411105, Peop. Rep. China). Huaxue Fanying Gongcheng Yu
Gongyi, 13(4), 442-445 (Chinese) 1997 Zhejiangsheng Chuban Duiwai
Maoyi Gongsi. CODEN: HFGGEU. ISSN: 1001-7631. DOCUMENT
TYPE: Journal CA Section: 49 (Industrial Inorganic Chemicals)
The selectivity of ClO2/Cl2 for H2SO4-NaClO3-NaCl reacting system in a
batch reactor was studied. The results showed that high concn. of
NaClO3, H2SO4, at high temp. and 1*1 mol-ratio of NaCl/NaClO3 should
be kept in reactor in order to get high selectivity of ClO2/Cl2.
248. EPA's TSCREEN model as a first step toward characterizing
accidental releases of chlorine and chlorine dioxide.
Gaines, Joseph L.; Wohrley, Frank (Joseph Gaines & Accociates,
Charlotte, NC 28207, USA). Environ. Conf. Exhib., Volume 2, 759-768.
TAPPI Press: Atlanta, Ga. (English) 1997. CODEN: 65KSAB.
DOCUMENT TYPE: Conference CA Section: 43 (Cellulose, Lignin,
Paper, and Other Wood Products) Section cross-reference(s): 59
At the Flint River market pulp mill, compressed liq. chlorine (for water
treatment) and aq. ClO2 soln. (for pulp bleaching) are stored on-site.
Time-dependent max. ambient concns. resulting from an accidental
release were characterized using EPA's TSCREEN model. A
technique was devised to characterize the continuously declining
release rate of chlorine dioxide from a hypothetical tank puncture.
Similarly, the time-dependent nature of the chlorine release from a
storage cylinder valve breakage incident was calcd. In such an event,
the release will occur in two stages, i.e., an initial short-term
pressurized release, followed by a longer heat transfer-limited release.
The TSCREEN model assumes a const. mass release rate until the
cylinder is empty; in so doing, the model substantially overestimates
time-dependent mass release rates, and underestimates the duration
of the release. The model selects worst-case meteorol. conditions for
each receptor, including the assumption that each receptor, including
the assumption that each receptor is downwind of the source. Calcd.
concns. are also highly sensitive to assumed duration of release; this
sensitivity makes the incremental (sequential fixed-rate release calcns.)
approach to developing time-dependent release ests. highly uncertain,
esp. during the rapidly-changing initial release period. Accurate
time-dependent release characterization will require a more
sophisticated model.
249. Comparison of several enzymes in the bleaching of radiata pine kraft
pulps.
Vicuna, Rafael; Oyarzun, Elisa; Yeber, M. Cristina; Osses, Miguel
(Departamento de Biologia Celular y Molecular, Facultad de Ciencias
Biologicas, P. Universidad Catolica de Chile, Santiago, Chile). Int.
Symp. Wood. Pulping Chem., 8th, Volume 2, 373-378. Gummerus
Kirjapaino Oy: Jyvaskyla, Finland. (English) 1995. CODEN: 65KDAY.
DOCUMENT TYPE: Conference CA Section: 43 (Cellulose, Lignin,
Paper, and Other Wood Products) Section cross-reference(s): 16
Kraft pulps from Pinus radiata were treated with xylanase prior to their
chem. bleaching with the sequences C70/D30EODED1 and D100EODED.
The effect of enzyme pretreatment was also tested with the sequence
QEOPWZP. Enzymes utilized included Cartazyme from Sandoz,
Ecopulp from Alko-ICI, Irgazyme 40 from CIBA-Genencor and
Pulpzyme HB from Novo Nordisk. Pretreatment with enzymes led to
redns. in the consumption of chlorine dioxide of about 3.5 kg/ADT and
3.8 kg/ADT in the sequences C70/D30EODED and D100EODED, resp.,
and to a slight increase in the beatability of pulps. In the TCF
sequence, enzyme treatment had no effect on the final brightness of the
pulps, which reached a value near 90% ISO. In all cases, the four
enzymes tested exhibited minor differences in their performance.
250. A novel technology for the operation and control of absorption towers in
treating chlorinated compounds in the pulp and paper bleaching
process.
Roberge, D. M.; Thibault, F. (ENVIRONAIR S.I.P.A. Inc., Quebec, PQ
G1N 4L2, Can.). Environ. Conf. Exhib., Volume 1, 55-63. TAPPI
Press: Atlanta, Ga. (English) 1997. CODEN: 65KSAB. DOCUMENT
TYPE: Conference CA Section: 43 (Cellulose, Lignin, Paper, and Other
Wood Products)
The process control of absorption towers applied to the control of
chlorinated compd., e.g. Cl and ClO2, emissions in pulp bleaching is
discussed. The scrubbing liq. is normally an aq. soln. contg. NaOH or
sulfide which reacts with the contaminants contained in the effluent gas.
For economic reasons, the use of chem. reagents should be
minimized. Because of fluctuation in the concn. of pollutants, it is
difficult to maintain high removal efficiency without an excess of
reagents. A dynamic process control approach is therefore a soln. to
optimize the use of chem. reagents while maintaining high removal
efficiency. The dynamic process control uses a dual loops control
which gives a fast response in time as compared to the simple loop
feedback control system.