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51. Three-stage process for bleaching cellulose pulp with chlorine dioxide.
Germgaard, Ulf; Forslund, Kjell; Sundin, Matts; Soedersten, Per-Aake
(Sunds Defibrator Industries AB, Swed.). Swed. SE 507164 C2 20
Apr 1998, 6 pp. (Swedish). (Sweden). CODEN: SSXXAY. CLASS:
ICM: D21C009-14. APPLICATION: SE 97-884 12 Mar 1997.
DOCUMENT TYPE: Patent CA Section: 43 (Cellulose, Lignin, Paper,
and Other Wood Products)
The process comprise (1) bleaching the pulp with ClO2(g) at acidic pH
and pulp concn. 25-45%, (2) dilg. the pulp to a concn. of 8-16% and
adjusting the pH to the alk. range of *6, and (3) acidifying the pulp, and
bleaching the pulp at a concn. of 8-16% with ClO2 soln. This method is
more effective than bleaching at medium or high concn. only, and is
esp. suitable for bleaching O-delignified pulp.
52. Kinetics of chlorine dioxide delignification.
Chandranupap, Panitnad; Nguyen, Kien Loi (Department of Chemical
Engineering, Australian Pulp and Paper Institute, Monash University,
Clayton VIC 3168, Australia). Appita J., 51(3), 205-208 (English) 1998
Appita. CODEN: APJOES. ISSN: 1038-6807. DOCUMENT TYPE:
Journal CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood
Products)
The transformation function, developed for oxygen delignification of
kraft pulps, can be also used to characterize chlorine dioxide
delignification. The transformation function can be applied to different
types of kraft pulp treated under well-mixed conditions at different pulp
stock consistencies. Simulations of the obtained transformation
functions show clearly the effect of stock consistency on the
delignification rate. At low temp. there are marked differences in
delignification rate between high and low consistencies. However
these differences diminish when the temp. is increased to about
100癈.
53. Absorption and fluorescence of OClO A 2A2-X 2B1 in solid Ne, Ar, and
Kr. I. Vibrationally unrelaxed A X emission.
Liu, Chin-Ping; Lai, Lih-Huey; Lee, Ying-Yu; Hung, Shao-Ching; Lee,
Yuan-Pern (Sec. 2, 101, Department of Chemistry, National Tsing Hua
University, Kuang Fu Road, Hsinchu 30043, Taiwan). J. Chem. Phys.,
109(3), 978-987 (English) 1998 American Institute of Physics.
CODEN: JCPSA6. ISSN: 0021-9606. DOCUMENT TYPE: Journal
CA Section: 73 (Optical, Electron, and Mass Spectroscopy and Other
Related Properties)
Dispersed laser-induced fluorescence of the A 2A2 X 2B1 transition of
OClO in solid Ne in the spectral range 500-770 nm was recorded when
the origin at 20,991 cm-1 was excited. Progressions with spacings
near 939 and 446 cm-1 are assocd. with vibrational modes n1 and n2 of
the X state. A simultaneous fit of both modes yields w1''=957.1 * 1.4,
w2''=452.6 * 0.4, x11''=4.47 * 0.04, x22''=0.54 * 0.05, and x12''=4.00 *
0.05 cm-1. When the 101 line of the A-X system at 21,699 cm-1 was
excited, vibrationally unrelaxed emission was obsd. in the spectral
region 480-600 nm. Excitation of the 201 line at 21,284 cm-1 generated
weak vibrationally unrelaxed progressions. The visible absorption
spectrum of OClO in solid Ne in the region 415-488 nm was recorded
with a Fourier-transform spectrometer, yielding n00=20,991.3,
n1'=707.9, n2'=292.5, and 2n3'=887.6 cm-1 for the A state. Simultaneous
fits considering either only n1 and n2 modes or all 3 modes yield
corresponding spectral parameters. Similar expts. were performed
with OClO in solid Ar and Kr. Pronounced increases in n1' (716.0 cm-1
in Ar and 712.5 cm-1 in Kr) and n2' (302.3 cm-1 in Ar and 303.0 cm-1 in
Kr) and a decrease in n00 (188 cm-1 and 331 cm-1 red shifted, resp.)
from that in the gas phase indicate substantial perturbation of the A
state in solid Ar and Kr. An absorption continuum underlying the A-X
system is attributed to absorption to the 1 2A1 state above the
predissocn. barrier. The phonon interaction increases and the
threshold of the continuum decreases as the matrix host is altered from
Ne to Ar to Kr.
54. Kinetics and Mechanism of the Reaction between Thiosulfate and
Chlorine Dioxide.
Horvath, Attila K.; Nagypal, Istvan (Institute of Physical Chemistry,
Jozsef Attila University, Szeged H-6701, Hung.). J. Phys. Chem. A,
102(37), 7267-7272 (English) 1998 American Chemical Society.
CODEN: JPCAFH. ISSN: 1089-5639. DOCUMENT TYPE: Journal
CA Section: 67 (Catalysis, Reaction Kinetics, and Inorganic Reaction
Mechanisms)
The reaction between thiosulfate and chlorine dioxide in slightly alk.
medium has been studied by stopped-flow techniques. The reaction
cannot be studied under pseudo-first-order condition, thus a new
approach based on the improved calibration and use of stopped-flow
spectrophotometers was applied. The reaction starts with irreversible
formation of 稴2O3ClO22- radical. The main path of the reaction
produces tetrathionate and chlorite through the formation of light
absorbing tetrathionate radical (稴4O63-). Any of the reactant present in
excess slightly modifies the 1:1 stoichiometry, and sulfate as well as
chloride ions are also formed. A detailed mechanism based on a
rigorous simultaneous fitting of the exptl. data is proposed.
55. Groundbased DOAS UV/visible measurements at Kiruna (Sweden)
during the SESAME winters 1993/94 and 1994/95.
Otten, C.; Ferlemann, F.; Platt, U.; Wagner, T.; Pfeilsticker, K. (Institut
fur Umweltphysik, Heidelberg D-69126, Germany). J. Atmos. Chem.,
30(1), 141-162 (English) 1998 Kluwer Academic Publishers. CODEN:
JATCE2. ISSN: 0167-7764. DOCUMENT TYPE: Journal CA Section:
59 (Air Pollution and Industrial Hygiene) Section cross-reference(s): 53
Zenith sky observations of O3, NO2, OClO and BrO are reported, which
were performed at Kiruna (67.9'N, 21.2癊) within the SESAME winters
1993/1994 and 1994/95. For both winters large total amts. of OClO
were obsd. inside the polar vortex at twilight, indicating the degree and
the temporal variation of the halogen activation of the polar
stratosphere. Occasionally, OClO could also be obsd. outside the
polar vortex, most likely due to export of halogen activated vortex air
masses into the ambient stratosphere. BrO could also be detected in
winter 1994/95, with the largest slant column amts. (5.1014/cm2)
occurring in the polar vortex in mid-winter. Similar abundances of
stratospheric BrO were obsd. at dusk and dawn, for both, air masses
inside and outside the vortex. This observation is in reasonable
agreement with previous studies on stratospheric BrO (observations
and models) of Wahner et al. (1992), Arpag et al. (1994), Krug et al.
(1996), and Lary et al. (1996a,b), but partly in disagreement with those
of Solomon et al. (1989), Fish et al. (1995), and Sessler et al. (1996).
56. Bleaching process for kraft pulp employing high consistency
chlorinated pulp treated with gaseous chlorine and ozone.
Tsai, Ted Yuan (International Paper Co., USA). U.S. US 5792316 A 11
Aug 1998, 5 pp. Cont. of U. S. Ser. No. 843,832, abandoned.
(English). (United States of America). CODEN: USXXAM. CLASS:
ICM: D21C009-14. ICS: D21C009-153; D21C009-16. NCL:
162065000. APPLICATION: US 93-132686 6 Oct 1993. PRIORITY:
US 92-843832 28 Feb 1992. DOCUMENT TYPE: Patent CA Section:
43 (Cellulose, Lignin, Paper, and Other Wood Products)
In the bleaching of kraft cellulosic pulp employing a stage in which the
pulp is contacted simultaneously with gaseous chlorine and ozone, the
improvement in which the pulp at a low to high consistency is initially
chlorinated with hypochlorous acid and thereafter is contacted
substantially simultaneously with gaseous chlorine and ozone. The pulp
so processed exhibits enhanced brightness and good viscosity, and
the process produces low quantities of environmentally undesirable
chlorinated orgs. The bleaching sequence is disclosed.
57. Method and apparatus for mixing liquid with medium-consistency paper
pulp stock.
Gallagher, Brian J.; Lariviere, Christopher J.; Bedard, Maurice P.
(Beloit Technologies, Inc., USA). PCT Int. Appl. WO 9833584 A1 6
Aug 1998, 28 pp. DESIGNATED STATES: W: BR, CA, CN, JP; 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: B01F005-06. ICS: D21B001-34. APPLICATION: WO
98-US100 6 Jan 1998. PRIORITY: US 97-792548 31 Jan 1997.
DOCUMENT TYPE: Patent CA Section: 43 (Cellulose, Lignin, Paper,
and Other Wood Products)
A rotor shaft mounted for rotation at 1 end extends axially through an
interior cylinder defined by a housing. A flow of medium-consistency
stock is introduced axially to the cylinder, while a chem. inlet supplies
bleaching chems. axially to a rotor mounted on the shaft. The head of
the rotor has turbine passages, which accelerate the impinging
bleaching chems. along radial lines to be distributed across the whole
aperture of the cylinder. Tapered vanes extend from the rotor adjacent
to the rotor head and create circulating vortexes which mix the bleach
chems. with the pulp. As the tapered vanes extend radially towards the
cylindrical walls of the cylindrical housing, the vortexes extend to the
housing walls. The finely mixed bleaching chems. and pulp are then
forced through a foraminous cylinder, which separates the interior of the
cylindrical housing from an outlet volute by vanes, which extend to near
engagement with the foraminous cylinder. The foraminous cylinder has
a porosity of ~10%, the holes (10) formed in the foraminous being on
the order of 1 in. in diam. The shear produced between by the radial
vanes fluidizes the pulp and completely mixes the bleach chems. and
the pulp.
58. Formation of radical species during ClO2 delignification.
Joncourt, M. J.; Froment, P.; Lachenal, D. (Lab. Chim. Procedes, Ec.
Francaise Papeterie, Saint Martin d'Heres 38402, Fr.). J. Wood
Chem. Technol., 18(2), 159-170 (English) 1998 Marcel Dekker, Inc.
CODEN: JWCTDJ. ISSN: 0277-3813. DOCUMENT TYPE: Journal
CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood Products)
Spin-trapping ESR spectroscopy was used to demonstrate that Cl
radicals (Cl*) were formed in conditions simulating ClO2 bleaching, in
presence of Fe cations. Cl* radicals most probably originate from
reaction of Fe2+/Fe3+ with HClO2 and with Cl2OH, equally produced
when ClO2 reacts with a phenolic unit. Adding Fe2+/Fe3+ in a D
bleaching stage of a softwood kraft pulp had a detrimental effect on
both pulp viscosity and delignification. At the same time AOX and
chlorate formation were increased. These effects were in accordance
with the proposed mechanism for the formation of Cl* and showed that
Fe might be potentially harmful, if in a sufficient quantity in pulp or
process water.
59. Drinking water disinfection with chlorine and chlorine dioxide.
Roeske, Wolfgang (USF Wallace & Tiernan, Guenzburg, Germany).
WLB, Wasser, Luft Boden, 42(7/8), 21-22,24-25 (German) 1998
Vereinigte Fachverlage. CODEN: WWBOE7. ISSN: 0938-8303.
DOCUMENT TYPE: Journal; General Review CA Section: 61 (Water)
A review with no refs. on the title subject. The topics include (i) Cl2
dosage and control units; (ii) NaClO and Ca(ClO)2 prodn. and dosage
units; (iii) description of ClO2, chlorite/Cl2/ClO2, and chlorite/HCl/ClO2
plants; and (iv) dosage and control units for ClO2 solns.
60. Process and apparatus for generation of chlorine dioxide gas.
Ogawa, Katsutoshi; Oyama, Masako (Chisso Corp., Japan). Jpn.
Kokai Tokkyo Koho JP 10182106 A2 7 Jul 1998 Heisei, 7 pp.
(Japanese). (Japan). CODEN: JKXXAF. CLASS: ICM: C01B011-02.
ICS: B01J007-02. APPLICATION: JP 97-122896 28 Apr 1997.
PRIORITY: JP 96-312952 8 Nov 1996. DOCUMENT TYPE: Patent CA
Section: 49 (Industrial Inorganic Chemicals) Section
cross-reference(s): 61
ClO2 gas is manufd. from a mixed soln. contg. nonvolatile org. acid
soln., chlorite soln., and chlorides which are used for enhancing the
formation of ClO2 product. The org. acid is selected from citric acid,
tartaric acid, lactic acid, malic acid, and maleic acid, and chlorite is
selected from sodium chlorite, potassium chlorite, and calcium chlorite.
The app. comprises a reaction container, an air pump, a connection
tube for connecting the air pump and a chamber full of air-stones, a
closable opening on the top of the reaction container, and a bubbling
device.
61. Production of chlorine dioxide.
Dufour, Pascal (Elf Atochem S. A., Fr.). Fr. Demande FR 2757500 A1
26 Jun 1998, 35 pp. (French). (France). CODEN: FRXXBL. CLASS:
ICM: C01B011-02. ICS: B01J023-44; B01J023-34; B01J031-12.
APPLICATION: FR 96-15872 23 Dec 1996. DOCUMENT TYPE:
Patent CA Section: 49 (Industrial Inorganic Chemicals) Section
cross-reference(s): 40, 43, 59, 60, 61
ClO2 is produced by redn. of a chlorate with a chloride in a strong acid
in an evapn.-crystn. reactor at 25-90* and 20-400 torr. PdCl2, MnCl2, or
their organometallic complexes are used as catalysts. A gaseous flow
contg. ClO2 and a byproduct of a crystd. salt of the strong acid are
formed. The crystd. salt is charged downwards into a washing column
and contacted countercurrently with an ascending satd. salt soln. (e.g.,
brine) which is fed into the reactor. Washing is done at -5 to 90*
(preferably at 15-70*). Optionally, the reaction is performed in the
presence of H2O2 to reduce the Cl2 byproduct to HCl. ClO2 is suitable
for bleaching of paper, textile fibers, wastewater treatment, water
purifn., denitrification of waste gases, and decoloration of greases.
62. A control scheme for rapid pulp delignification and bleaching.
Pangalos, George; Falcone, Ronald A., Jr.; Mayo, William L.; Bosch,
Gregory J. (Union Camp Patent Holding, Inc., USA). PCT Int. Appl. WO
9832914 A1 30 Jul 1998, 58 pp. DESIGNATED STATES: W: BR,
CA, FI, JP, SE. (English). (World Intellectual Property Organization).
CODEN: PIXXD2. CLASS: ICM: D21C009-153. ICS: D21C011-06;
D21C007-12. APPLICATION: WO 97-US1512 5 Feb 1997.
PRIORITY: US 97-789493 27 Jan 1997. DOCUMENT TYPE: Patent
CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood Products)
Section cross-reference(s): 48
A process control method for adjusting chem. application in response
to the pulp brightness and/or lignin content is realized by utilizing a
coupled control feedforward, feedback or combination
feedforward/feedback control system, wherein brightness
measurements are made between successive lignin content
measurements and adjustments made to the chem. application in
response to a comparison value.
63. Evaporation of acidic effluents from ECF bleaching: effect of feed pH
on the quality and re-usability of the condensate.
Dahl, O.; Tirri, T.; Kuopanportti, H.; Niinimaki, J.; Kiiskila, E. (University
of Oulu, Oulu 90570, Finland). Pulping Conf., Volume 2, 1121-1129.
TAPPI Press: Atlanta, Ga. (English) 1997. CODEN: 66GYAG.
DOCUMENT TYPE: Conference CA Section: 43 (Cellulose, Lignin,
Paper, and Other Wood Products)
The effect of feed pH on the condensate and conc. quality upon evapn.
of acidic effluents from elemental Cl-free (ECF) bleaching, was
investigated, in view of the re-usability of the condensates in the final
ClO2 stage of the bleaching process. The expts. were carried out
under lab. conditions. The results indicated that it is advantageous to
neutralize the feed pH of the Do and Q effluents before evapn.
Neutralization of the feed essentially prevents the transfer of inorg. and
org. compds. into the condensate during evapn. Further addn. of alkali
had no clear pos. addnl. effect on condensate's quality. Neg. impacts
can also be partly avoided by evapg. acidic effluents only up to a 30%
level of total solids of the conc. In the conc., the main ppt. compd. in the
very acidic condition was CaSO4. When the pH of the concs. was
increased, the predominant compds. were Ca oxalate hydrates,
whereas at higher total solids, the Na compds. Na2SO4 and NaCl were
dominant. The quality of the condensates was good enough for re-use
in the final ClO2 stage of the ECF bleaching process. No appreciable
effects on pulp quality or chem. consumption in the final D stage were
obsd.
64. Effluent quality characteristics at North American kraft mills employing
complete substitution bleaching.
Wiegand, Paul S.; Miner, Reid A.; Eppstein, Laurel K. (NCASI West
Coast Regional Center, Corvallis, OR 97339, USA). Pulping Conf.,
Volume 2, 1035-1040. TAPPI Press: Atlanta, Ga. (English) 1997.
CODEN: 66GYAG. DOCUMENT TYPE: Conference CA Section: 43
(Cellulose, Lignin, Paper, and Other Wood Products)
U.S. EPA's 1993 proposal to revise effluent limitations guidelines for
the pulp and paper industry sparked a significant industry-sponsored
effort to increase the amt. of data describing the characteristics of
effluents discharged by kraft mills using complete ClO2 substitution
bleaching, and a summary of these data are presented. Data
comparable to the proposed effluent guidelines limitations show that
complete substitution bleaching effluents do not normally contain
measurable levels of 2,3,7,8-TCDD and rarely contain measurable
levels of 2,3,7,8-TCDF or highly substituted chlorinated phenolic
compds. CHCl3 levels measured in bleaching effluents range from
0.16 to 4.8 g/ton and represent only a fraction of the total CHCl3
generated during bleaching. Available data describing the levels of
AOX and COD in biol. treated effluents suggest that the use of
extended and(or) O delignification can decrease effluent loads for
these parameters.
65. Chlorine dioxide bleaching of single species samples of three
hardwood kraft pulps; oak, maple and gum.
Reeve, Douglas W.; Weishar, Kathleen M. (Department of Chemical
Engineering and Applied Chemistry, University of Toronto, Toronto, ON
M5S 3E5, Can.). Pulping Conf., Volume 1, 121-126. TAPPI Press:
Atlanta, Ga. (English) 1997. CODEN: 66GYAG. DOCUMENT TYPE:
Conference CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood
Products)
Pure species samples of three hardwood kraft pulps, Acer saccharum
(maple), Quercus falcata (oak) and Liquidambar styraciflua (gum) were
bleached to a final brightness of 86 ISO with chlorine dioxide bleaching
sequences D(EO)D and D(EO)(D/N)D, with and without prior oxygen
delignification. Oak was more difficult to bleach than maple or gum.
As a predictor of chem. required to reach final brightness, post-(EO)
brightness was better than post-(EO) kappa no. Final brightening with
(D/N)D compared to D saved 2 to 5 kg chlorine dioxide per tonne of
pulp.
66. Laser photolysis of OClO in solid Ne, Ar, and Kr. II. Site selectivity,
mode specificity, and effects of matrix hosts.
Lai, Lih-Huey; Liu, Chin-Ping; Lee, Yuan-Pern (Sec. 2, 101,
Department of Chemistry, National Tsing Hua University, Kuang Fu
Road, Hsinchu 30043, Taiwan). J. Chem. Phys., 109(3), 988-996
(English) 1998 American Institute of Physics. CODEN: JCPSA6.
ISSN: 0021-9606. DOCUMENT TYPE: Journal CA Section: 74
(Radiation Chemistry, Photochemistry, and Photographic and Other
Reprographic Processes)
Irradn. of low-lying vibronic levels of A2A2 of OClO isolated in solid Ne,
Ar, or Kr produces ClOO. Destruction of OClO and prodn. of ClOO in
various matrix sites were monitored with IR absorption lines near 1100
and 1440 cm-1, resp. For OClO in solid Ar at 5 K, site selectivity is
obsd. after irradn. at the vibronic line assocd. with a specific site;
decreased intensity of the IR line assocd. with a specific site of OClO
correlates well with increased intensity of the corresponding line of
ClOO. Similar behavior is obsd. for OClO in solid Kr except that
formation of ClOO in one site (1412.1 cm-1) is invariably dominant. The
nature of the carriers of two major sites of ClOO (corresponding to
1416.7 and 1442.5 cm-1 in solid Ar, 1412.1 and 1440.7 cm-1 in solid
Kr) is discussed. Temporal profiles of absorbance AOClO and AClOO
were probed after various periods of irradn. until approx. 20%-60% of
OClO was destroyed. Excitation of the n3 vibrational mode of OClO
A2A2 enhances photodissocn. of OClO appreciably. Rates of
destruction of OClO in solid Ar or Kr are much smaller than that in solid
Ne. The apparent conversion factor, DAClOO/(-DAOClO) is greater for
OClO in solid Ne than that in solid Ar or Kr. Effects of matrix host on
photolysis are discussed.
67. Single and double electron-impact ionization of chlorine dioxide.
O'Connor, Caroline S. S.; Tafadar, Nurun; Price, Stephen D.
(Chemistry Department, Christopher Ingold Laboratories, University
College London, London WC1H 0AJ, UK). J. Chem. Soc., Faraday
Trans., 94(13), 1797-1803 (English) 1998 Royal Society of Chemistry.
CODEN: JCFTEV. ISSN: 0956-5000. DOCUMENT TYPE: Journal
CA Section: 73 (Optical, Electron, and Mass Spectroscopy and Other
Related Properties) Section cross-reference(s): 76
Electron-impact single and double ionization of Cl dioxide, OClO, were
studied using time-of-flight mass spectrometry and ion-ion coincidence
techniques. Relative partial single ionization cross sections of OClO
were detd. for incident electron energies from 30 to 450 eV using
time-of-flight mass spectrometry. The expts. detect stable parent ions,
OClO+, the fragmentation products O+, O2+, Cl+ and ClO+. The
formation and fragmentation of the OClO dication was studied using
ion-ion coincidence techniques coupled with time-of-flight mass
spectrometry. The coincidence spectra show that OClO2+ dissocs. to
form the following pairs of ions: O++ClO+ and O++Cl+. Interpretation of
the coincidence spectra suggests that there is a multiple kinetic energy
release upon dicationic dissocn. to form the O++Cl+ ion pair, and also
yields a detn. of the excitation energy required to form the lowest
energy dication electronic states which dissoc. to form O++ClO+ and
O++Cl+. The similarity of these excitation energies indicate that these
dissocn. reactions might occur from the same electronic state of
OClO2+. Comparison of these excitation energies with estd. values of
the double ionization energy of OClO indicate that this state is probably
the ground electronic state of OClO2+ and, hence, these studies provide
a 1st est. for the double ionization energy of OClO.
68. Biotechnology in the paper industry. Color removal from waste paper.
Colom, J. F.; Vidal, T.; Torres, A. L. (Especialidad Papelera y Grafica,
E.T.S.I.I. (UPC), Tarrrasa, Barcelona, Spain). Invest. Tec. Pap.,
35(136), 210-224 (Spanish) 1998 Asociacion de Investigacion Tecnica
de la Industria Papelera Espanola. CODEN: IVTPA3. ISSN:
0368-0789. DOCUMENT TYPE: Journal CA Section: 43 (Cellulose,
Lignin, Paper, and Other Wood Products)
Enzymic treatments were carried out for stripping off coloring materials
from waste paper to obtain white paper with adequate optical
characteristics. Various bleaching reagents were used in conjunction
with enzymic treatments using xylanase, cellulase with a small quantity
of xylanase, and a new cellulase. Enzymic pretreatments improved
bleaching and produced papers with 4% improved whiteness.
69. Control of bio-film in alkaline white water systems with chlorine dioxide.
Wadsworth, James W.; Simpson, Greg D. (Vulcan Chem. Tech., Inc.,
Charlotte, NC 28226, USA). Eng. Papermakers: Form. Bonds Better
Papermaking, Volume 3, 1095-1105. TAPPI Press: Atlanta, Ga.
(English) 1997. CODEN: 66GXAD. DOCUMENT TYPE: Conference
CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood Products)
The use of ClO2 in bio-film control in alk. white water systems in a
paper mill is described. A brief overview of the problems assocd. with
bacterial growth in alk. whitewater, the properties of bio-film and
bacteriol. of alk. white water, the chem. of and equipment for ClO2
generation, and feed and control strategies are given. In addn., the
economic evaluation of use of ClO2 vs. non-oxidizing biocides for 1 mill
is discussed.
70. Structural changes in lignin during kraft pulping and chlorine dioxide
bleaching.
Froass, Peter Matthew (Institute of Paper Science and Technology,
Atlanta, GA, USA). 633 pp. Avail. UMI, Order No. DA0598871 From:
Diss. Abstr. Int., B 1998, 59(2), 633 (English) 1996. DOCUMENT
TYPE: Dissertation CA Section: 43 (Cellulose, Lignin, Paper, and
Other Wood Products)
Abstract Unavailable
71. Characterization of extractable organic material in hardwood pulps
bleached with chlorine dioxide.
Irving, Jason; Mckague, A. Bruce; Reeve, Douglas W. (Department of
Chemical Engineering and Applied Chemistry, University of Toronto,
Toronto, ON M5S 3E5, Can.). Pulping Conf., Volume 2, 609-614.
TAPPI Press: Atlanta, Ga. (English) 1997. CODEN: 66GYAG.
DOCUMENT TYPE: Conference CA Section: 43 (Cellulose, Lignin,
Paper, and Other Wood Products)
The extractable org. material in hardwood pulps bleached with ClO2
was characterized with respect to quantity, Cl content, lipophilicity, and
compn. Acetone-extractable content ranged from 450-3400 mg/kg o.d.
pulp, which was 25-30% lower than for the unbleached pulp. Approx.
65% of the acetone-extractable material was sol. in heptane, similar to
that of the ext. from unbleached pulp. Total Cl content of the bleached
pulp ranged from 243-425 mg/kg, an av. of 70% of which was
non-extractable. Characterization of the heptane-sol. material showed
it contained 1.2-3.8% Cl, and had an av. mol. wt. in the range 370-660
Daltons. Seventy-three to 90% of the heptane-sol. material and
50-76% of the Cl in the heptane-sol. material was highly lipophilic,
having a log Kow > 4.8. A range of long chain fatty acids were
identified in the heptane-sol. material from the bleached eucalyptus
pulp. A similar series of fatty acids and b-sitosterol were present in the
unbleached pulp and 1 sample of totally Cl-free bleached eucalyptus
pulp included for comparison. Comparable results were obtained for
aspen and eucalyptus pulp bleached in the lab. and at the mill.
72. VUV photodissociation dynamics of OClO: binary and triple
dissociation.
Hwang, Dennis W.; Lin, Jim J.; Lee, Yuan T.; Yang, Xueming
(Department of Chemistry, National Taiwan University, Taipei, Taiwan).
Proc. SPIE-Int. Soc. Opt. Eng., 3271(Laser Techniques for
State-Selected and State-to-State Chemistry IV), 15-25 (English) 1998
SPIE-The International Society for Optical Engineering. CODEN:
PSISDG. ISSN: 0277-786X. DOCUMENT TYPE: Journal CA Section:
74 (Radiation Chemistry, Photochemistry, and Photographic and Other
Reprographic Processes)
Photodissocn. of OClO at 157.6 nm excitation has been investigated
using the photofragment translational spectroscopic technique. Two
distinctive chem. dissocn. channels have been obsd.: one is the binary
dissocn. process, OClO + hn * ClO + O; the other one is the triple
dissocn. process, OClO + hn * Cl + O + O. The branching ratio of the
binary dissocn. channel to the triple dissocn. channel is detd. to be
0.59: 0.41. Bimodal vibrational distribution of the ClO product has
been obsd. for the OClO * ClO (X 2p) + O(3P, 1D) channel, implying
that two distinctive dissocn. routes possibly exist in the binary dissocn.
process. The bimodal distribution is likely caused by the two dissocn.
pathways from two excited electronic states: the D(2A1)and E(2B1)
states of OClO. These arguments are further supported by the results
of the anisotropy parameter measurements for the binary dissocn.
channels. Exptl. results also show that the OClO + hn * ClO(X 2p) +
O(1S) and OClO + hn * ClO(A 2p) + O(3P) channels might also exist in
addn. to the ClO(X2p) + O(3P, 1D) channel. In the triple dissocn.
process, exptl. results show that the main product channel is the OClO
+ hn * Cl(2P) + O(1D) + O(3P) channel, while the OClO + hn * Cl(2P) +
O(3P) + O(3P) channel is the minor one. The branching ratio of these
two channels is detd. to be 0.89: 0.11. From the modeling of the time
of flight spectra of the O atom product, it is believed that the triple
dissocn. process of OClO is a simultaneous process within the time
scale of one rotation period.
73. Use of fluoride in biofilm treatment.
Rose, Richard Keith (Medical Research Council; Rose, Richard Keith,
UK). PCT Int. Appl. WO 9830250 A1 16 Jul 1998, 46 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, GM, GW,
HU, ID, 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, US, 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: A61L002-16. ICS: A61L002-18;
A61K007-18. APPLICATION: WO 98-GB118 14 Jan 1998.
PRIORITY: GB 97-667 14 Jan 1997. DOCUMENT TYPE: Patent CA
Section: 63 (Pharmaceuticals) Section cross-reference(s): 48, 62
The invention relates to the use of fluoride to treat biofilms in both
industrial, domestic and medical environments including the dental
environment. Fluoride weakens the assocns. between neighboring
cells in a biofilm and has the effect of opening up the film rendering it
more permeable. Thus the invention provides inter alia the use of
fluoride to prep. a fluoride-contg. agent for contacting with a biofilm to
increase the permeability of a biofilm.
74. Effects of ethanol media on chlorine dioxide and extraction stages for
kraft pulp bleaching.
Brogdon, Brian Noah (Institute of Paper Science and Technology,
Atlanta, GA, USA). 751 pp. Avail. UMI, Order No. DA0598867 From:
Diss. Abstr. Int., B 1998, 59(2), 751 (English) 1997. DOCUMENT
TYPE: Dissertation CA Section: 48 (Unit Operations and Processes)
Section cross-reference(s): 43
Abstract Unavailable
75. Treatment of bleach plant filtrates with oxygen.
Bokstrom, Monica; Hardmeier, Peter; Jansson, Bjorn; Petersson,
Martin; Tigerstrom, Anna (Aga Aktiebolag (Publ), Swed.). PCT Int.
Appl. WO 9829598 A1 9 Jul 1998, 21 pp. DESIGNATED STATES: W:
AL, AM, AT, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ,
CZ, DE, DE, DK, DK, EE, EE, ES, FI, FI, GB, GE, GH, HU, ID, 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, SK, SL,
TJ, TM, TR, TT, UA, UG, US, 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: D21C009-10. ICS: D21C011-00.
APPLICATION: WO 97-SE2214 23 Dec 1997. PRIORITY: SE
96-4802 27 Dec 1996. DOCUMENT TYPE: Patent CA Section: 43
(Cellulose, Lignin, Paper, and Other Wood Products)
A pulp is prepd., and subjected to *1 bleaching step by the addn. of an
oxidizing bleaching agent. After the bleaching, liq. is removed from the
pulp while obtaining a residue liq. and at least a part flow of the residue
liq. obtained is conveyed back to the pulp stream via a transport
conduit by means of a pump device. The part flow of the residue liq. is
treated by oxygen by the supply of oxygen to the part flow downstream
of the pump device. This method provides a less environmentally
harmful residue liq. which is more appropriate for being utilized during
the treatment of cellulose fibers.
76. Use of chlorine dioxide for the bleaching of pulp: a re-evaluation of
ecological risks based on scientific progress since 1993.
Bright, D. A.; Mckague, B.; Hodson, P. V.; Rodgers, J.; Lehtinen, K. -J.;
Solomon, K. (Royal Roads University, Victoria, BC V9B 5Y2, Can.). Int.
Environ. Conf. Exhib., Volume Bk. 3, 1051-1054. TAPPI Press:
Atlanta, Ga. (English) 1998. CODEN: 66BYAP. DOCUMENT TYPE:
Conference; General Review CA Section: 4 (Toxicology)
A review and discussion with 11 refs. A science advisory panel
reviewed studies published since 1993 to assess the ecol. risks
assocd. with final effluents from pulp mills using 100% ClO2 in
bleaching processes (often referred to as elemental chlorine free, or
ECF mills). The panel addressed two major questions: (i) What are the
risks to aquatic organisms and ecosystems due to the release of final
effluent from ECF pulp mills, including all contributing factors in the
process stream and (ii) What are the specific risks, if any, contributed
by the use of ClO2 as opposed to other mill processes. All available
data indicate that chlorinated compds. in effluents from ECF bleaching
have a much lower degree of chlorine substitution than those produced
during bleaching with Cl2, and are therefore generally less persistent
and bioaccumulative. A screening level, or - where merited -
probabilistic risk assessment of chlorinated compds. in ECF mill final
indicated a negligible risk to aquatic organisms. With regard to the
broader, first question, it is becoming increasingly clear that there are
non-chlorinated substances, which are unmodified or slightly modified
wood extractives released primarily during pulping, that appear to
induce biochem. responses and changes in reproductive parameters in
some fish species in the receiving environments for some pulp mills.
These substances are produced by a variety of pulp extn. and
bleaching technologies, and also occur naturally; e.g., retene and other
resin acids, b-sitosterol and other plant steroid, and/or various polar,
lignin-derived substances. A quant. risk assessment of these compds.
is not yet possible, owing to the current lack of knowledge-of concns. in
final effluent and the receiving environment, toxicol. dose-response
relationships, and ecol. relevance of the biochem. and physiol. changes
that have been measured. In general, significant environmental gains
have come from 100% ClO2 substitution and the widespread adoption
of efficient secondary treatment.
77. Method of environmental disinfection with chlorine dioxide gas.
Ogawa, Katsutoshi; Kikuchi, Koji (Chisso Corp.; National Federation
of Agricultural Co-Operative Assoc., Japan). Jpn. Kokai Tokkyo Koho
JP 10192377 A2 28 Jul 1998 Heisei, 8 pp. (Japanese). (Japan).
CODEN: JKXXAF. CLASS: ICM: A61L002-20. ICS: A61L002-20.
APPLICATION: JP 97-17590 14 Jan 1997. DOCUMENT TYPE:
Patent CA Section: 63 (Pharmaceuticals) Section cross-reference(s):
17
A method for disinfection of pharmaceutical manufg. factories,
hospitals and others with chlorine dioxide gas produced by a generator
and that for removal of used chlorine dioxide gas with a remover are
claimed.
78. The comparative toxicities of filtrates from conventional and alternative
bleaching agents.
Ard, Teri Ann (Institute of Paper Science and Technology, Atlanta, GA,
USA). 585 pp. Avail. UMI, Order No. DA0598864 From: Diss. Abstr.
Int., B 1998, 59(2), 585 (English) 1997. DOCUMENT TYPE:
Dissertation CA Section: 60 (Waste Treatment and Disposal) Section
cross-reference(s): 4, 9, 43
Abstract Unavailable
79. Preparation of slow-releasing R-type ClO2 as an air refreshing agent.
Wang, Suwen; Li, Zhongfang; Liu, Shengwen; Liu, Yu (Department of
Chemical Technology, Shandong College of Engineering, Zibo
255022, Peop. Rep. China). Huaxue Shijie, 38(11), 583-585
(Chinese) 1997 Shanghaishi Huaxue Huagong Xuehui. CODEN:
HUAKAB. ISSN: 0367-6358. DOCUMENT TYPE: Journal CA
Section: 59 (Air Pollution and Industrial Hygiene) Section
cross-reference(s): 10
The development of ClO2 as an air refreshing agent was introduced, a
method for prepg. slow-releasing R-ClO2 from solid KClO3, Na2SO4
and dild. H2SO4 was proposed. The effects of the concn. of H2SO4 and
types of supports on the performance of the product were studied.
90. Oxalic acid formation during ECF and TCF bleaching of kraft pulp.
Elsander, Anna; Ek, Monica; Gellerstedt, Goran (Stora Corporate
Research AB, Saffle S-661 29, Swed.). Minimum Effluent Mills Symp.,
63-66. TAPPI Press: Atlanta, Ga. (English) 1997. CODEN: 66FSAR.
DOCUMENT TYPE: Conference CA Section: 43 (Cellulose, Lignin,
Paper, and Other Wood Products)
The formation of oxalic acid (I) during bleaching of softwood kraft pulp
was studied. Bleaching agents used were O, H2O2, ClO2, peracetic
acid (II), and O3. The formation of I acid increased linearly with the
decrease in kappa no. II bleaching gave less I than the other bleaching
agents. In O3 bleaching ~1/3 of the formed I was adsorbed on the pulp
and not released until a later stage.
91. Radiation effect of oxychloride in aqueous solution - radiation effect of
ClO2 ion in aqueous solution.
Dohi, K.; Katsumura, Y.; Hiroishi, D.; Ishigure, K. (Dep. Quantum Eng.
System Sci., Fac. Eng., Univ. Tokyo, Japan). Tokyo Daigaku
Genshiryoku Kenkyu Sogo Senta Shinpojumu, 5th, 104-108
(Japanese) 1996 Tokyo Daigaku Genshiryoku Kenkyu Sogo Senta.
CODEN: TDGSFF. DOCUMENT TYPE: Journal CA Section: 71
(Nuclear Technology) Section cross-reference(s): 60, 61
As a part of study on the effect of very high level radioactive wastes on
the ground water, radiation effects on ClO2 in water was investigated
using g-ray irradn. and electron beam pulse radiolysis. The rate consts.
for the ClO2 + e-aq and ClO2 + OH reactions were 2.1 x 1010 M-1s-1 and
6.7 x 109 M-1s-1, resp. from the pulse radiolysis results in agreement
with the simulation calcn. The pH changes and the yields of various
chem. species produced in the g-ray irradn. of the aq. soln. also agreed
with the simulation calcns.
92. Method for water purification with oxides of chlorine.
Rafter, John D.; Grenier, Joseph W.; Denkewicz, Raymond P., Jr.
(Fountainhead Technologies, Inc., USA). PCT Int. Appl. WO 9830502
A1 16 Jul 1998, 17 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. ICS: C02F001-76; C02F001-72.
APPLICATION: WO 97-US22717 10 Dec 1997. PRIORITY: US
97-783558 14 Jan 1997. DOCUMENT TYPE: Patent CA Section: 61
(Water)
A method for purifying water includes contacting water contg. an oxide
of chlorine, such as chlorine dioxide, chlorite, or chlorate, with a water
purifn. compn. that includes a Group 11 or Group 12 metal such as
silver, copper, or zinc.
93. Effects of chlorine dioxide on removal of phenolic compounds from
water.
Huang, Junli; Li, Chunlan; Wang, Xuefeng; Li, Wenge; Lu, Yufen (Harbin
Univ. Architecture & Eng., Harbin 150008, Peop. Rep. China).
Huanjing Huaxue, 17(2), 174-179 (Chinese) 1998 Kexue Chubanshe.
CODEN: HUHUDB. ISSN: 0254-6108. DOCUMENT TYPE: Journal
CA Section: 61 (Water) Section cross-reference(s): 60
Effects of doses and dosing point of chlorine dioxide on removal of
phenolic compds. in water was studied by using simulation treatment
process of coagulation sedimentation-filtration in waterworks as
compared with liq. chlorine. The result showed the effects of ClO2 on
the removal of phenolic compds. are better than that of liq. chlorine.
94. Pretreatment options for water with high disinfection byproducts
formation potential.
Armenter, J. Ll.; Cristia, J.; Matia, Ll. (Societat General d'Aigues de
Barcelona, Barcelona 08009, Spain). Water Supply, 16(1/2, 21st
International Water Services Congress and Exhibition, 1997), 543-550
(English) 1998 Blackwell Science Ltd. CODEN: WASUDN. ISSN:
0735-1917. DOCUMENT TYPE: Journal CA Section: 61 (Water)
In order to comply with new regulations regarding disinfection
byproducts, it is necessary to review the treatment stages for supplies
with high disinfection byproduct formation potential. This is the case
with the water the Llobregat River, which supplies Barcelona (Spain),
and which has a high potential for the formation of trihalomethane and
bromate. Using comparative parallel studies between the present
treatment process, with stages of prechlorination and intermediate
ozonization and others carried out in a pilot plant, it is intended to det.
which is the most suitable treatment to substitute the break-point
prechlorination at present responsible for the generation of high levels
of trihalomethanes (THM). All the processes tested, without
prechlorination, chlorination below the break point (4 mg/L), addn. of K
permanganate (1 mg/L) and the addn. of ClO2 (0.5 mg/L) are based on
the biol. elimination of ammonia from the raw water. Of all these
processes, pretreatment with ClO2 was the one which achieved the
best results with respect to the formation of trihalomethanes and
bromate, enabling the values set by the proposed new European Union
Directive to be met.
95. Chlorine-free chlorine dioxide gas for drinking water treatment at
Roanoke County, Virginia.
Benninger, Robert W.; Hoehn, Robert C.; Rosenblatt, Aaron A.
(Roanoke County (VA) Utility Dep., Salem, VA 24153, USA). Proc. -
Water Qual. Technol. Conf., Volume Date 1996 85/B-93/B (English)
1997 American Water Works Association. CODEN: PWQCD2. ISSN:
0164-0755. DOCUMENT TYPE: Journal CA Section: 61 (Water)
Chlorine dioxide is widely recognized for its advantages in the
oxidative treatment of drinking water with respect to pre-oxidn. of
trihalomethane (THM)-forming precursors and metals such as iron and
manganese; disinfection of common waterborne pathogens such as
Giardia and Cryptosporidium; and control of taste, odor, and color by
oxidn. of phenolic compds. Because chlorine dioxide does not form
chlorinated org. species as a disinfection byproduct, finished water
treated with chlorine dioxide generally exhibits substantially lower THM
levels than waters receiving treatment with chlorine solns. Treatment
with chlorine dioxide allows many utilities to consistently and effectively
meet the primary max. contaminant level (PMCL) of 0.10 mg/L for
THMs currently mandated by state and federal drinking water
regulations. Since the early 1940皊, chlorine dioxide for drinking water
treatment has been produced by conventional wet chem. methods, all
of which employ the reaction of aq. sodium chlorite (NaClO2) with
chlorine or acid to produce a chlorine dioxide-contg. soln. Newly
available technol. employs a controlled reaction of specially-processed
solid sodium chlorite with a dil. chlorine-gas blend, to produce
chlorine-free (1 percent free chlorine [Cl2]) chlorine dioxide gas. The
process effectively eliminates formation of ClO- and ClO3-, which are
often produced by traditional ClO2 generation systems or carried
through such systems as a result of poor generation efficiency. The 15
million gal/day Spring Hollow water treatment facility, owned and
operated by Roanoke County, Virginia, incorporates a "gas:solid" ClO2
generation system to produce chlorine dioxide for the pre-oxidn. and
pre-disinfection of raw water prior to prodn. of potable drinking water.
This is the first full-scale application of the gas:solid technol. for
generation of chlorine dioxide in the world. The technol. provides
flow-pacing control of the ClO2 feed rate without requiring storage of
either chlorine dioxide gas or soln. Infinite turndown capability of the
ClO2 generation system allows for dosage adjustments required to
meet changing demands or seasonal variations, as well as variable
process flow rates encountered during backwashing of filters.
96. Columns for removing acidic compounds and removal of chlorine
dioxide from gases.
Ogawa, Katsutoshi; Oyama, Masako (Chisso Corp., Japan). Jpn.
Kokai Tokkyo Koho JP 10156134 A2 16 Jun 1998 Heisei, 4 pp.
(Japanese). (Japan). CODEN: JKXXAF. CLASS: ICM: B01D053-40.
ICS: B01D053-34; B01D053-68. APPLICATION: JP 96-332770 28
Nov 1996. DOCUMENT TYPE: Patent CA Section: 59 (Air Pollution
and Industrial Hygiene)
The title columns are filled with activated C and sulfite-type hydrotalcite.
Alternatively, the columns are filled with sulfite-type hydrotalcite contg.
0.001-0.01% of diethyl-p-phenylenediamine. ClO2 is removed from
gases by using the columns.
97. Photodissociation dynamics of OClO at 157 nm.
Lin, Jim J.; Hwang, Dennis W.; Lee, Yuan T.; Yang, Xueming
(Department of Chemistry, National Taiwan University, Taipei, Taiwan).
J. Chem. Phys., 108(24), 10061-10069 (English) 1998 American
Institute of Physics. CODEN: JCPSA6. ISSN: 0021-9606.
DOCUMENT TYPE: Journal CA Section: 74 (Radiation Chemistry,
Photochemistry, and Photographic and Other Reprographic
Processes)
Photodissocn. of OClO at 157.6 nm excitation has been investigated
using the photofragment translational spectroscopic technique. Two
distinctive chem. dissocn. channels have been obsd.; one is the binary
dissocn. process, OClO + hn * ClO + O; the other one is the triple
dissocn. process, OClO + hn * Cl + O + O. The branching ratio of the
binary dissocn. channel to the triple dissocn. channel is detd. to be
0.59:0.41. Bimodal vibrational distribution of the ClO product has been
obsd. for the OClO * ClO(X 2P) + O(3P,1D) channel, implying that two
distinctive dissocn. routes possibly exist in the binary dissocn. process.
The bimodal distribution is likely caused by the two dissocn. pathways
from two excited electronic states: the D(2A1) and E(2B1) states of
OClO. These arguments are further supported by the results of the
anisotropy parameter measurements for the binary dissocn. channels.
Exptl. results also show that the OClO + hn * ClO(X 2P) + O(1S) and
OClO + hn * ClO(A 2P) + O(3P) channels might also exist in addn. to
the ClO(X 2P) + O(3P,1D) channel. In the triple dissocn. process, exptl.
results show that the main product channel is the OClO + hn * Cl(2P) +
O(1D) + O(3P) channel, while the OClO + hn * Cl(2P) + O(3P) + O(3P)
channel is the minor one. The branching ratio of these two channels is
detd. to be 0.89:0.11. From the modeling of the time of flight spectra of
the O atom product, it is believed that the triple dissocn. process of
OClO is a simultaneous process within the time scale of one rotation
period. Two-photon dissociative ionization process OClO + hn * Cl+ +
O2 + e- has also been obsd.
98. Compositions for reducing oral malodor comprising stabilized chlorine
dioxide.
Kross, Robert D. (USA ). U.S. US 5772986 A 30 Jun 1998,6 pp.
(English). (United States of America). CODEN: USXXAM. CLASS:
ICM: A61K007-20. NCL: 424053000. APPLICATION: US 96-629357
8 Apr 1996. DOCUMENT TYPE: Patent CA Section: 62 (Essential
Oils and Cosmetics)
The oral malodorant redn. activity of stabilized chlorine dioxide solns.
and chlorite solns. may be significantly enhanced through the use of
oral-cavity pre-conditioning solns. such as fruit juices, natural fruit-acid
solns. and a no. of com. soft drinks which have pH's below about 6.
The liqs. predispose the oral surfaces and tissues of the mouth and the
malodorant mols. assocd. with these surfaces to be more reactive to
and/or affected by the subsequent exposure to the stabilized chlorine
dioxide and chlorite oral rinse solns. A subject rinses his mouth for 30
s with 15 mL of fresh orange juice, and then swallows it. Immediately
thereafter he takes into his mouth 15 mL of a 0.1% stabilized chlorine
dioxide soln., and rinses the oral cavity for 30 s prior to spitting out the
soln. (no data).
99. Effect of chlorine dioxide preconditioning on inactivation of
Cryptosporidium by free chlorine and monochloramine. Process design
requirements.
Liyanage, Lalith R. J.; Gyurek, Lyndon L.; Belosevic, M.; Finch, Gordon
R. (Dep. Civil Environmental Eng., Univ. Alberta, Edmonton T6G 2G7,
Can.). Proc. - Water Qual. Technol. Conf., Volume Date 1996
75/B-85/B (English) 1997 American Water Works Association.
CODEN: PWQCD2. ISSN: 0164-0755. DOCUMENT TYPE: Journal
CA Section: 61 (Water)
Chlorine dioxide, free chlorine, and monochloramine were evaluated for
their effect on Cryptosporidium parvum oocysts. Animal infectivity
using neo-natal, CD-1 mice was used to det. viability after disinfection.
Sequential disinfection with chlorine dioxide followed by free chlorine or
monochloramine showed significantly more inactivation of oocysts due
to synergism between the oxidants. A process design approach is
presented that uses a 2-step disinfection concept: primary disinfection
using chlorine dioxide followed by secondary disinfection using free
chlorine or monochloramine. Kinetic models are developed that
adequately describe the C. parvum oocyst inactivation by sequential
application of chlorine dioxide followed by monochloramine, and
sequential application of chlorine dioxide followed by free chlorine.
Process design charts are calcd. at pH 8 and 22*. These design
charts will enable engineers and utilities to evaluate the feasibility of
using chlorine dioxide, free chlorine, and monochloramine for
controlling C. parvum in drinking water.
100. Chlorine dioxide for control of Cryptosporidium and disinfection
byproducts.
LeChevallier, Mark W.; Arora, Harish; Battigelli, David; Abbaszadegan,
Morteza (American Water Works Service Company, Inc., Voorhees, NJ
08043, USA). Proc. - Water Qual. Technol. Conf., Volume Date 1996
46/B-53/B (English) 1997 American Water Works Association.
CODEN: PWQCD2. ISSN: 0164-0755. DOCUMENT TYPE: Journal
CA Section: 61 (Water)
Studies are reported which aim at developing a cost-effective method
for inactivating Cryptosporidium while maintaining drinking water
chlorite levels below 0.1 mg/L. Work on developing a tissue culture
method for Cryptosporidium is also reported.