Chemomechanical polishing of gallium arsenide and cadmium telluride to subnanometre surface finish. Evaluation of the action and effectiveness of hydrogen peroxide, sodium hypochlorite and dibromine as reagents

1994 ◽  
Vol 4 (1) ◽  
pp. 29 ◽  
Author(s):  
Laurence McGhee ◽  
Scott G. McMeekin ◽  
Irene Nicol ◽  
Max I. Robertson ◽  
John M. Winfield
Keyword(s):  
Hydrogen Peroxide ◽  
Gallium Arsenide ◽  
Cadmium Telluride ◽  
Sodium Hypochlorite ◽  
Surface Finish

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>

scholarly journals A Fuzzy MADM Approach for Selecting the Best Cyanide Removal Method from a Gold Mine Wastewater

2021 ◽  
Author(s):  
Mohammad Hayati ◽  
Seyed Mohammad Seyed Alizadeh Ganji ◽  
Seyed Hadi Shahcheraghi
Keyword(s):  
Hydrogen Peroxide ◽  
Decision Making ◽  
Sodium Hypochlorite ◽  
Fuzzy Topsis ◽  
Gold Mine ◽  
Calcium Hypochlorite ◽  
Gold Mines ◽  
Removal Method ◽  
Fuzzy Delphi ◽  
Cyanide Removal

Abstract The cyanidation process is the most common method applied for the extraction of gold and silver in the hydrometallurgy industry, in which, sodium cyanide is used as a leaching agent. Therefore, the wastewater of gold mines contains a wide variety of cyanide ions needing to be removed before these wastewaters can be discharged to the receiving environments. In this study, a fuzzy multi-attribute decision-making approach (Fuzzy Delphi AHP and Fuzzy TOPSIS) was used for selecting the best cyanide removal method from the wastewater of Muteh gold mine. According to the experts' opinion, three methods including calcium hypochlorite, hydrogen peroxide and sodium hypochlorite were selected as alternatives. Then, by introducing the criteria influencing decision making, including cyanide removal ability, cost of process, amount of material consumed, time, pH, ease of performance and safety, and performing separated experiments, the criteria for each of three methods were determined. Finally, sodium hypochlorite was proposed as the best method for eliminating cyanide from wastewater. It was found that the rank of methods was as sodium hypochlorite (0.517) > calcium hypochlorite (0.474) > hydrogen peroxide (0.463).

scholarly journals Bleaching of Microcrystalline Cellulose Produced by Gas-Phase Hydrolysis

2021 ◽  
pp. 173-183
Author(s):  
Alexander I. Sizov ◽  
◽  
Sergey D. Pimenov ◽  
Anastasia D. Stroiteleva ◽  
Katherine D. Stroiteleva ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Pharmaceutical Industry ◽  
Gas Phase ◽  
Sodium Hypochlorite ◽  
Microcrystalline Cellulose ◽  
High Rate ◽  
Subsequent Formation ◽  
Hydrolysis Of Cellulose ◽  
Yellow Tint ◽  
Hydrolysis Of

One of the main consumers of microcrystalline cellulose (MCC) is the pharmaceutical industry, where MCC is used as a binder and filler in direct compression of tablets. MCC is produced by acidic hydrolysis of cellulose, which usually results in a decrease in whiteness. This is due to the destruction of sugars formed during hydrolysis and the subsequent formation of colored products. The composition and properties of these products depend on the method of hydrolysis, acid concentration, temperature, and process duration. One of the most promising methods for producing MCC is gas-phase hydrolysis of cellulose with hydrogen chloride gas-air mixtures. The method has a high rate of hydrolysis, low reagent and energy consumption. The requirements of the pharmaceutical industry determine the need to produce MCC with high whiteness. The research purpose is to select bleaching modes for MCC using sodium hypochlorite and hydrogen peroxide as bleaching agents. MCC produced by gas-phase hydrolysis of bleached wood pulp was used during the study. The whiteness and intensity of the yellow tint of MCC in the bleaching process were determined by digital colorimetry on a flatbed scanner. The paper shows that sodium hypochlorite and hydrogen peroxide allow achieving the whiteness not less than 90 % and the intensity of the yellow tint not more than 3 standard units. High-quality bleaching can be carried out even for MCC samples with an initial whiteness of about 40 %. The most effective bleaching agent is sodium hypochlorite when the pH of the bleaching solution is 2–3. Hydrogen peroxide also provides high whiteness of MCC at pH of 10–11. However, the consumption of active oxygen (AO) for bleaching is more than three times higher in comparison with the consumption of active chlorine (ACh). It was found that the dyes of MCC produced by gas-phase hydrolysis consist of two chromophore groups that decolorize at different rates. The easily oxidized group of components makes up about 90 % of the total amount of dyes, and the resistant to oxidation components make up about 10 % and determine the intensity of the yellow tint of MCC. The modes of bleaching MCC with sodium hypochlorite and hydrogen peroxide to product samples with whiteness comparable to that of imported samples were determined. For citation: Sizov A.I., Pimenov S.D., Stroiteleva A.D., Stroiteleva K.D. Bleaching of Microcrystalline Cellulose Produced by Gas-Phase Hydrolysis. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 173–183. DOI: 10.37482/0536-1036-2021-6-173-183

Evaluation of a Sporicidal Peracetic Acid/Hydrogen Peroxide–Based Daily Disinfectant Cleaner

2014 ◽  
Vol 35 (11) ◽  
pp. 1414-1416 ◽  
Author(s):  
Abhishek Deshpande ◽  
Thriveen S. C. Mana ◽  
Jennifer L. Cadnum ◽  
Annette C. Jencson ◽  
Brett Sitzlar ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Staphylococcus Aureus ◽  
Clostridium Difficile ◽  
Sodium Hypochlorite ◽  
Peracetic Acid ◽  
Infect Control Hosp ◽  
Organic Load ◽  
Methicillin Resistant

OxyCide Daily Disinfectant Cleaner, a novel peracetic acid/hydrogen peroxide–based sporicidal disinfectant, was as effective as sodium hypochlorite for in vitro killing of Clostridium difficile spores, methicillin-resistant Staphylococcus aureus, and vancomcyin-resistant enterococci. OxyCide was minimally affected by organic load and was effective in reducing pathogen contamination in isolation roomsInfect Control Hosp Epidemiol 2014;35(11):1414–1416

scholarly journals Chemical Cleaning of Ultrafiltration Membrane Fouled by Humic Substances: Comparison between Hydrogen Peroxide and Sodium Hypochlorite

2019 ◽  
Vol 16 (14) ◽  
pp. 2568 ◽  
Author(s):  
Kai Li ◽  
Shu Li ◽  
Tinglin Huang ◽  
Chongzhe Dong ◽  
Jiawei Li ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Humic Substances ◽  
Sodium Hypochlorite ◽  
Alkaline Condition ◽  
Chemical Cleaning ◽  
H2o2 Treatment ◽  
Cleaning Agent ◽  
Cleaning Agents ◽  
Cleaning Efficacy ◽  
By Products

Chemical cleaning is indispensable for the sustainable operation of ultrafiltration (UF) system in water and wastewater treatment. Sodium hypochlorite (NaClO) is an established cleaning agent for membranes subject to organic and microbial fouling, but concerns have been raised about the generation of toxic halogenated by-products during NaClO cleaning. Hydrogen peroxide (H2O2) is a potential “green” cleaning agent that can avoid the formation of halogenated by-products. In this work, cleaning efficacy of H2O2 and NaClO for UF membrane fouled by humic substances (HS) was evaluated under a wide pH range, and change of HS’s properties due to reaction with cleaning agents was examined. The cleaning efficacy of H2O2 was lower than that of NaClO at pH 3–9, but it increased to a level (91.4%) comparable with that of NaClO at pH 11. The extents of changes in properties and fouling potential of HS due to reacting with cleaning agents were consistent with their cleaning efficacy. H2O2 treatment at pH 11 significantly increased negative charge of HS molecules, decomposed high-MW molecules, and reduced its fouling potential. Therefore, considering treatment/disposal of cleaning waste and cleaning efficacy, H2O2 cleaning under strong alkaline condition can be a good choice for HS-fouled membrane.

scholarly journals Pilot Study Evaluating the Efficacy of Four Cleaning Solutions and Two Types of Mops in Delimited Areas of a Floor Contaminated with Cyclophosphamide

2017 ◽  
Vol 2 (3) ◽  
Author(s):  
Christel Roland ◽  
Apolline Adé ◽  
Johann-François Ouellette-Frève ◽  
Sébastien Gagné ◽  
Nicolas Caron ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Pilot Study ◽  
Sodium Hypochlorite ◽  
Quaternary Ammonium ◽  
Optimal Strategy ◽  
Environmental Surveillance ◽  
Cleaning Agents ◽  
Cleaning Products ◽  
Hazardous Drugs

AbstractBackgroundHazardous drugs (HD) traces are measured in most hospitals that perform environmental surveillance. Uncertainties exist regarding the cleaning agents and procedures needed to completely remove HD contamination The objective was to evaluate the efficacy of four cleaning solutions and two types of mops in reducing contamination on a floor contaminated with a predetermined amount of cyclophosphamide (CP).MethodsThis pilot study was divided into three steps: 1) the voluntary contamination of a pre-delimited area on the floor (3600cmResultsThe average decontamination efficacy of the four cleaning products used was: 99.53%±0.41 % for the detergent, 99.74%±0.15 % for quaternary ammonium, 99.86%±0.11 % for sodium hypochlorite, 99.75%±0.15 %, for hydrogen peroxide. The average decontamination efficacy for disposable mops was 99.58%±0.28 % and 99.86%±0.09 % for non-disposable mops.ConclusionSodium hypochlorite, hydrogen peroxide, quaternary ammonium and a detergent applied with a disposable or a non-disposable mop were efficient to reduce the CP concentration on the floor contaminated with a predetermined quantity of CP. However, no cleaning scenarios was able to remove 100 % of CP after one cleaning session. Further studies are required to identify an optimal strategy.

scholarly journals Resistance of Pseudomonas aeruginosa to Liquid Disinfectants on Contaminated Surfaces before Formation of Biofilms

2000 ◽  
Vol 83 (6) ◽  
pp. 1415-1422 ◽  
Author(s):  
Jose-Luis Sagripanti ◽  
Aylin Bonifacino
Keyword(s):  
Hydrogen Peroxide ◽  
Pseudomonas Aeruginosa ◽  
Sodium Hypochlorite ◽  
Peracetic Acid ◽  
Biofilm Formation ◽  
Step Method ◽  
Quantitative Test ◽  
Viable Bacteria ◽  
One Step ◽  
Respective Product

Abstract A comparison was made of the effectiveness of popular disinfectants (Cavicide, Cidexplus, Clorox, Exspor, Lysol, Renalin, and Wavicide) under conditions prescribed for disinfection in the respective product labels on Pseudomonas aeruginosa either in suspension or deposited onto surfaces of metallic or polymeric plastic devices. The testing also included 7 nonformulated germicidal agents (glutaraldehyde, formaldehyde, peracetic acid, hydrogen peroxide, sodium hypochlorite, phenol, and cupric ascorbate) commonly used in disinfection and decontamination. Results showed that P. aeruginosa is on average 300-fold more resistant when present on contaminated surfaces than in suspension. This increase in resistance agrees with results reported in studies of biofilms, but unexpectedly, it precedes biofilm formation. The surface to which bacteria are attached can influence the effectiveness of disinfectants. Viable bacteria attached to devices may require dislodging through more than a one-step method for detection. The data, obtained with a sensitive and quantitative test, suggest that disinfectants are less effective on contaminated surfaces than generally acknowledged.

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