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.

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 Determination of an effective method of Citrus aurantifolia lime and Citrus lemon varieties plant explants sterilization for in vitro introduction into the culture

2020 ◽  
pp. 185-191
Author(s):  
S. Shokh ◽  
Z. Sych ◽  
L. Karpuk
Keyword(s):  
Hydrogen Peroxide ◽  
Sodium Hypochlorite ◽  
Ethanol Solution ◽  
In Vitro Cultivation ◽  
Citrus Aurantifolia ◽  
Planting Material ◽  
Mother Plants ◽  
Cultivation Techniques

Potted citrus plants are in constant demand, but the propagation of such plants requires the use of a winter greenhouse and several well-developed mother plants to obtain planting material. The use of microclonal propagation can accelerate the production of seed material though it requires detailed development of in vitro cultivation techniques. The aim of the research was to study the effectiveness of sterilizing substances and methods of sterilization on the yield of viable micro shoots of lime plants (Citrus aurantifolia) as well as Meyer and Jubilee lemon varieties and their growth in vitro. The research was conducted in the interdepartmental "Biotechnological Laboratory" of the Agrobiotechnological Faculty of Bila Tserkva NAU. The source material was microshoots from lime plants (Citrus aurantifolia), and lemon varieties (Citrus lemon) Meyer and Jubilee. The objects of the study were selected according to the diversity of genotypes, development type and varietal characteristics. The possibility of using different parts of plants for reproduction is a feature of in vitro culture. We used microshoots with a bud in our research. To neutralize the exogenous bacterial and fungal microflora, we used 70 % ethanol solution C2 H5 OH, sodium hypochlorite 5 %, 15 % solution of hydrogen peroxide H2 O2 , sulema (0.1) and washed the material in sterile water (for 5–10 min) under several schemes. The study revealed the influence of different sterilization regimes for obtaining sterile explants and the introduction into plant culture of explants of the species of lime Citrus aurantifolia as well as Meyer and Jubilee lemon varieties. It was found that the use of step sterilization using 2.5 % solutions of sodium hypochlorite gives a high percentage of sterile viable material – 27.7 %, which is significantly higher than in other variants of the experiment. Key words: microshoots, lime, sterile material, micropropagation, sterilization, hydrogen peroxide, viability of explants.

Direct Determination of Calcium in Icteric Serum

1963 ◽  
Vol 9 (3) ◽  
pp. 360-364 ◽  
Author(s):  
B Fingerhut ◽  
H Miller
Keyword(s):  
Hydrogen Peroxide ◽  
Rapid Method ◽  
Sodium Hypochlorite ◽  
Direct Determination ◽  
Potassium Ferricyanide ◽  
Tetraacetic Acid ◽  
Ethylenediamine Tetraacetic Acid ◽  
Calcium Indicator ◽  
Titrimetric Determination

Abstract A rapid method suitable for the direct titrimetric determination of calcium in icteric sera is presented. The major portion of serum chromogens are oxidized to colorless products by either a mixture of hydrogen peroxide and potassium ferricyanide or by sodium hypochlorite. Ethylenediamine tetraacetic acid (EDTA) is the titrant used and either calcein or Cal-Red is suitable as the specific calcium indicator. Results compare favorably with those obtained by the method of Clark and Collip.

Use of hydrogen peroxide in scrubbing towers for odor removal in wastewater treatment plants

2004 ◽  
Vol 50 (4) ◽  
pp. 267-274 ◽  
Author(s):  
I. Charron ◽  
C. Féliers ◽  
A. Couvert ◽  
A. Laplanche ◽  
L. Patria ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Wastewater Treatment ◽  
Hydrogen Sulfide ◽  
Sodium Hypochlorite ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Operating Conditions ◽  
Odor Removal ◽  
Economical Process

The aim of this work was to replace sodium hypochlorite (NaClO) with hydrogen peroxide (H2O2) in chemical scrubbing towers, in order to avoid the formation of chlorinated species, harmful for human health. Some previous studies have already shown the ability of H2O2 to treat the hydrogen sulfide (H2S) pollution. However, an important decomposition of the oxidant was observed in the scrubbing solution (carbonates, transition metal and high pH are responsible for this decomposition) leading to high reactant consumption. Consequently, this study first focused on research into a compound able to reduce the hydrogen peroxide degradation. Experiments were conducted on a pilot unit (3,000 m3 h-1) in a wastewater treatment plant. The sodium silicate (Na2SiO3) proved to be a good scrubbing solution stabilizer. A very good removal of hydrogen sulfide (up to 98%) was also obtained. Finally, the study resulted in the determination of the best operating conditions to achieve both an efficient and economical process.

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%.

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