scholarly journals Properties of Oxidized Starch Prepared by Hydrogen Peroxide, Chlorine Dioxide and Sodium Hypochlorite

2016 ◽  
Author(s):  
Bing Han
Keyword(s):  
Hydrogen Peroxide ◽  
Sodium Hypochlorite ◽  
Chlorine Dioxide ◽  
Oxidized Starch

Removal of Organic Micropollutants from Contaminated Groundwater by Oxidation and Stripping

1987 ◽  
Vol 22 (1) ◽  
pp. 187-196 ◽  
Author(s):  
L. Simovic ◽  
J.P. Jones
Keyword(s):  
Hydrogen Peroxide ◽  
Sodium Hypochlorite ◽  
Chlorine Dioxide ◽  
Chemical Oxidation ◽  
Appropriate Technology ◽  
Contaminated Groundwater ◽  
Organic Micropollutants ◽  
Air Stripping ◽  
Groundwater Samples ◽  
Iron Sulphate

Abstract In 1984, Environment Canada carried out a bench scale study on the removal of organic micropollutants from contaminated groundwater. The groundwater samples were obtained from the Special Waste Compound at Gloucester Landfill Site, near Ottawa, Ontario. The objective of the study was to evaluate the effectiveness of chemical oxidation to destroy the organic micropollutants present in this groundwater. Comparison was made between the results of ozonation and the air stripping effects. The oxidants evaluated were ozone (O3), sodium hypochlorite (NaOCl), chlorine dioxide (ClO2) and hydrogen peroxide (H2O2) with hydrated iron sulphate FeSO4 7H2O (Fenton’s reagent). The organics present in the contaminated groundwater included the following, predominantly volatile, compounds: bromodichloro-methane, bromoform, 1,1,1-trichloroethane, chloroform, 1,1-dichloroethane, dichloromethane, 1,2-dichloroethane, 1,1-dichloroethylene, and trichloroethylene. The process variables investigated were pH and oxidant dosage. The significance of low and high values of these variables was examined by using a full 22 factorial design. From the results, it appeared that the best removal efficiency was achieved by using ozone as an oxidant. However, during the experiments, it was observed that the ozonation process was being confounded with the air stripping process. Chlorine dioxide and hydrogen peroxide, in that order, were determined to be less effective oxidants. Sodium hypochlorite was found to be the least effective oxidant in this study. The results of this study demonstrated that air stripping was the most appropriate technology for the removal of the organic compounds from this groundwater.

scholarly journals Exploring the potential synergistic effects of chemical disinfectants and UV on the inactivation of free-living bacteria and treatment of biofilms in a pilot-scale system

2011 ◽  
Vol 64 (6) ◽  
pp. 1247-1253 ◽  
Author(s):  
E. Vankerckhoven ◽  
B. Verbessem ◽  
S. Crauwels ◽  
P. Declerck ◽  
K. Muylaert ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Sodium Hypochlorite ◽  
Chlorine Dioxide ◽  
Peracetic Acid ◽  
Synergistic Effects ◽  
Pilot Scale ◽  
Bacterial Suspension ◽  
Additive Effects ◽  
Free Living ◽  
Living Bacteria

The main objective of this study is to explore possible synergistic or additive effects of combinations of chemical disinfectants (sodium hypochlorite, peracetic acid, hydrogen peroxide, chlorine dioxide) and UV in their efficacy in inactivating free-living bacteria and removing biofilms. In contrast to most studies, this study examines disinfection of municipal water in a pilot-scale system using a mixed bacterial suspension, which enables a better simulation of the conditions encountered in actual industrial environments. It was shown that the combination of either hypochlorite, hydrogen peroxide, peracetic acid, or chlorine dioxide with UV yielded additive effects on the inactivation of free-living bacteria. Actual synergy was observed for the combination of UV and 5 ppm hydrogen peroxide. Regarding biofilm treatment, additive effects were observed using the combination of hydrogen peroxide and UV. The promising results obtained in this study indicate that the combination of UV and chemical disinfectants can considerably reduce the amount of chemicals required for the effective disinfection and treatment of biofilms.

scholarly journals The influence of bleaching scheme technology on the content of total and bound chlorine in cellulose

2020 ◽  
Author(s):  
Е.Д. Софронова ◽  
В.А. Липин ◽  
А.В. Орлова ◽  
А.Ю. Добош
Keyword(s):  
Hydrogen Peroxide ◽  
Sodium Hypochlorite ◽  
Chlorine Dioxide ◽  
Lignin Content ◽  
Cellulose Fiber ◽  
Chlorine Content ◽  
Molecular Chlorine ◽  
Sanitary Products ◽  
Alkaline Delignification

Наблюдается ужесточение требований по содержанию хлора в целлюлозе для санитарно-гигиенических изделий и ряда других целей. Содержание хлора в целлюлозе зависит от применяемой схемы отбелки. В процессе отбелки с применением молекулярного хлора, диоксида хлора или гипохлорита натрия небольшая часть соединений хлора присутствует в целлюлозном волокне. На большинстве современных предприятий применяется технология ECF, где в качестве альтернативы молекулярному хлору на одной или нескольких ступенях используются диоксид хлора (ClO2) или гипохлорит натрия (NaClO). Также существует технология отбелки TCF, которая позволяет полностью отказаться от применения хлорсодержащих агентов путем использования только кислородсодержащих реагентов, таких как кислород, пероксид водорода, озон. Применение полностью бесхлорных технологий ограничено в виду высокой себестоимости продукции при сравнительных качественных характеристиках продукции. Проведен анализ образцов целлюлозы различных производителей. Определение содержания общего хлора и органически связанного хлора осуществлялось путем сжигания пробы целлюлозы при температуре от 950 до 1000 С. Анализ образцов целлюлозы российских заводов показал, что в целлюлозе, полученной с использованием схем отбелки КЩОД0ЩП1Д1ЩП2Д2К и Д0ЩОПД1ЩПД2К, содержание хлора в готовой продукции меньше всего. Это может объясняться тем, что кислородно-щелочная обработка позволяет эффективно снизить содержание лигнина. Низкое содержание последнего позволяет сократить количество используемого диоксида хлора на стадиях Д. По совокупности предъявляемых к целлюлозе свойств и экономических показателей наиболее приемлемыми являются схемы отбелки с оптимизированными расходами диоксида хлора и пероксида водорода, озона без использования молекулярного хлора (ECF-light). Они позволяют достичь низкого содержания соединений хлора в целлюлозе, близкого к технологии TCF. There is a tightening of requirements for the content of chlorine in cellulose for sanitary products and a number of other purposes. The chlorine content in cellulose depends on the bleaching scheme used. In the bleaching process using molecular chlorine, chlorine dioxide or sodium hypochlorite, a small part of the chlorine compounds is replaced on cellulose fiber. Most modern plants use ECF technology, where, as an alternative to molecular chlorine, chlorine dioxide (ClO2) or sodium hypochlorite (NaClO) is used at one or several stages. There is also TCF bleaching technology, which allows you to completely abandon the use of chlorine-containing agents by using only oxygen-containing reagents such as oxygen, hydrogen peroxide, ozone. The use of completely chlorine-free technologies is limited in view of the high cost of production with comparative qualitative characteristics of the products. Pulp samples from various manufacturers were analyzed. The determination of total chlorine and organically bound chlorine was carried out by burning a cellulose sample at a temperature of from 950 to 1000 C. Analysis of cellulose samples from Russian plants showed that in the pulp obtained using the bleaching scheme O1D0EP1D1EP2D2A and D0EOPD1EPD2A bleaching schemes, the chlorine content in the finished product is the least. This can be explained by the fact that oxygen-alkaline delignification can effectively reduce the lignin content. The low content of the latter makes it possible to reduce the amount of chlorine dioxide used in stages D. According to the combination of properties and economic indicators presented to cellulose, bleaching schemes with optimized consumption of chlorine dioxide and hydrogen peroxide, ozone without the use of molecular chlorine (ECF-light) are most acceptable. It allows to achieve a low content of chlorine compounds in cellulose, close to TCF technology.

Bleaching optimization at WestRock mill in Covington, Virginia

TAPPI Journal ◽  
2016 ◽  
Vol 15 (9) ◽  
pp. 581-586 ◽  
Author(s):  
RICARDO B. SANTOS ◽  
PETER W. HART ◽  
DOUGLAS C. PRYKE ◽  
JOHN VANDERHEIDE
Keyword(s):  
Hydrogen Peroxide ◽  
Sodium Hydroxide ◽  
Chlorine Dioxide ◽  
Capital Expenditures ◽  
Equipment Repair ◽  
Optimization Program ◽  
Hardwood Pulp ◽  
Improved Performance

The WestRock mill in Covington, VA, USA, initiated a long term diagnostic and optimization program for all three of its bleaching lines. Benchmarking studies were used to help identify optimization opportunities. Capital expenditures for mixing improvement, filtrate changes, equipment repair, other equipment changes, and species changes were outside the scope of this work. This focus of this paper is the B line, producing southern hardwood pulp in a D(EP)DD sequence at 88% GE brightness. The benchmarking study and optimization work identified the following opportunities for improved performance: nonoptimal addition of caustic and hydrogen peroxide to the (EP) stage, carryover of D0 filtrate to the (EP) stage, and carryover of (EP) filtrate to the D1 stage. As a result of actions the mill undertook to address these opportunities, D0 kappa factor decreased about 5%, sodium hydroxide consumption in the (EP) stage decreased about 35%, chlorine dioxide consumption in the D1 stage decreased about 25%, and overall bleaching cost decreased about 15%.

Comparative evaluation of disinfection mechanism of sodium hypochlorite, chlorine dioxide and electroactivated water on Enterococcus faecalis

LWT ◽  
2019 ◽  
Vol 102 ◽  
pp. 205-213 ◽  
Author(s):  
Zeynep Girgin Ersoy ◽  
Ozge Dinc ◽  
Buse Cinar ◽  
Sedef Tunca Gedik ◽  
Anatoli Dimoglo
Keyword(s):  
Enterococcus Faecalis ◽  
Sodium Hypochlorite ◽  
Chlorine Dioxide ◽  
Comparative Evaluation

scholarly journals Oxidation of Citalopram with Sodium Hypochlorite and Chlorine Dioxide: Influencing Factors and NDMA Formation Kinetics

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3065
Author(s):  
Juan Lv ◽  
Yan Wang ◽  
Na Li
Keyword(s):  
Sodium Hypochlorite ◽  
Chlorine Dioxide ◽  
Wastewater Treatment Plants ◽  
Ph Value ◽  
High Reactivity ◽  
Secondary Effluent ◽  
Water Matrix ◽  
Formation Kinetics ◽  
Operational Variables ◽  
Two Stages

The highly prescribed antidepressant, citalopram, as one of newly emerging pollutants, has been frequently detected in the aquatic environment. Citalopram oxidation was examined during sodium hypochlorite (NaOCl) and chlorine dioxide (ClO2) chlorination processes since conventional wastewater treatment plants cannot remove citalopram effectively. Citalopram has been demonstrated to form N-nitrosodimethylamine (NDMA) during chlorination in our previous study. Further investigation on NDMA formation kinetics was conducted in the present study. Influences of operational variables (disinfectant dose, pH value) and water matrix on citalopram degradation, as well as NDMA generation, were evaluated. The results indicated high reactivity of citalopram with NaOCl and ClO2. NDMA formation included two stages during CIT oxidation, which were linear related with reaction time. NaOCl was more beneficial to remove CIT, but it caused more NDMA formation. Increasing disinfectant dosage promoted citalopram removal and NDMA formation. However, no consistent correlation was found between citalopram removal and pH. Contrary to the situation of citalopram removal, NDMA generation was enhanced when citalopram was present in actual water matrices, especially in secondary effluent. DMA, as an intermediate of citalopram chlorination, contributed to NDMA formation, but not the only way.

scholarly journals Hydrogen peroxide and chlorine dioxide against parasite Ichthyophthirius multifiliis (Protozoa, Ciliophora) in jundiá fingerlings

2017 ◽  
Vol 47 (12) ◽  
Author(s):  
Natalia da Costa Marchiori ◽  
Fabiano Muller Silva ◽  
Maurício Laterça Martins ◽  
Hilton Amaral Junior ◽  
Bruno Corrêa da Silva
Keyword(s):  
Hydrogen Peroxide ◽  
Chlorine Dioxide ◽  
Fish Farming ◽  
Control Group ◽  
Chemical Agent ◽  
Ichthyophthirius Multifiliis ◽  
Larval Phase ◽  
Group Data ◽  
Active Chemical ◽  
Continuous Bath

ABSTRACT: Ichthyophthiriasis is a worldwide fish disease with great financial impact on freshwater fish farming due to its associated high mortality rates. Current study assesses the parasiticidal capacity of hydrogen peroxide (H2O2) and chlorine dioxide (ClO2) against the causative agent, Ichthyophthirius multifiliis, in jundiá. Median lethal concentration (LC50, 96h) of each chemical agent was established, as well as the minimum inhibitory concentration of hydrogen peroxide for the parasite´s infectious larval phase (theront). Products were tested asynchronously in parasitized fingerlings for short and long baths at the following concentrations and exposure times: 1. Hydrogen peroxide: (T1) continuous bath - 30ppm and (T2) 50ppm; (T3) short bath - 150ppm, during 1h and (T4) 250ppm during 1h; control group (without any chemical agent). 2. Chlorine dioxide: (T1) continuous bath - 4ppm and (T2) 20ppm; (T3) short bath - 200ppm, during 1min; (T4) short bath - 400ppm, during 1min and control group. Data analysis demonstrated a concentration of 82.54ppm of the commercial product (or 24.76ppm of the active chemical agent) as LC50, 96h of H2O2 and 38.4ppm product (or 2.68ppm of the active chemical agent) for ClO2. Hydrogen peroxide concentration causing 100% mortality rate of theronts in 1h was 25ppm (product, or 7.5ppm of the active chemical agent). At the end of the fourth day of curative experiment, 98% of the animals died by ichthyophthiriasis. No treatment was effective against the parasite.

scholarly journals Impact of two disinfectants on detachment of Enterococcus faecalis from polythene in aquatic microcosm

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
C. Lontsi Djimeli ◽  
A. Tamsa Arfao ◽  
V Rossi ◽  
N Nsulem ◽  
V Raspal ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Cell Adhesion ◽  
Enterococcus Faecalis ◽  
Sodium Hypochlorite ◽  
Growth Phases ◽  
Planktonic Cells ◽  
Stationary Growth ◽  
Experimental Conditions ◽  
The Impact ◽  
Aquatic Microcosm

<p><strong>After cell adhesion processes in microcosm, the impact of sodium hypochlorite (NaOCl) and hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) on the detachment of <em>Enterococcus faecalis </em>from polythene fragments immersed in water under stationary and dynamic conditions was assessed. The abundance of planktonic cells was also evaluated. The density of <em>E. faecalis</em> adhered in absence of disinfectant fluctuated between 2 and 4 units (Log CFU/cm<sup>2</sup>). </strong><strong>After living in disinfected water, </strong><strong>the density of <em>E. faecalis</em> remained adhered to polythene sometimes reached 2 units (Log CFU/Cm<sup>2</sup>)</strong><strong>. </strong><strong>This highest abundance of cells remained adhered was recorded with cells coming from the lag, exponential and stationary growth phases in water treated with 0.5‰ NaOCl. In H<sub>2</sub>O<sub>2</sub> disinfected water, the highest value was recorded at all cells growth phases with 5‰ H<sub>2</sub>O<sub>2 </sub>concentration. Adhered <em>E. faecalis</em> cells have been sometimes completely or partially decimated respectively by NaOCl and H<sub>2</sub>O<sub>2</sub> treated water. Considering separately each experimental condition, it was noted that increasing the concentration of disinfectant caused a significant decrease (P≤0.01) in abundance of cells stay adhered after living in water disinfected by the two disinfectants. Changes in disinfectant concentrations in different experimental conditions had an impact on the detachment of <em>E. faecalis</em> cells from the substrates. </strong></p>

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