scholarly journals Enzyme immobilization on activated carbon: Alleviation of enzyme deactivation by hydrogen peroxide

1977 ◽  
Vol 19 (5) ◽  
pp. 769-775 ◽  
Author(s):  
Y. K. Cho ◽  
J. E. Bailey
Keyword(s):  
Hydrogen Peroxide ◽  
Activated Carbon ◽  
Enzyme Immobilization ◽  
Enzyme Deactivation

Effect of Modification with Nitric Acid and Hydrogen Peroxide on Chromium (VI) Adsorption by Activated Carbon Fiber

2012 ◽  
Vol 518-523 ◽  
pp. 2099-2103
Author(s):  
Guang Zhou Qu ◽  
Hai Bing Ji ◽  
Ran Xiao ◽  
Dong Li Liang
Keyword(s):  
Hydrogen Peroxide ◽  
Activated Carbon ◽  
Nitric Acid ◽  
Carbon Fiber ◽  
Adsorption Capacity ◽  
Adsorption Kinetics ◽  
Ph Value ◽  
Activated Carbon Fiber ◽  
Order Kinetic ◽  
Adsorption Amount

The activated carbon fiber (ACF) was treated by different concentration nitric acid (HNO3) and hydrogen peroxide (H2O2) oxidization to enhance its adsorption capacity to hexavalent chromium (Cr6+) ion. The adsorption amount and adsorption kinetics of Cr6+ion on ACFs, and the surface chemical groups were investigated. The results showed that the modified ACFs with 1% HNO3and 10% H2O2had a better adsorption capacity, respectively. The adsorption amount of ACFs was affected strongly solution pH value, and decreased significantly with increasing of the pH value. The adsorption kinetics indicated that the adsorption rates of Cr6+ ion on different modified ACFs were well fitted with the pseudo-second-order kinetic model. After 1% HNO3and 10% H2O2modification, respectively, the total acidic oxygen-containing groups on ACFs surface had an increase obviously, which might be enhance the adsorption amount of Cr6+ion on ACFs.

Removal of Tributyltin in Shipyard Waters: Characterization and Treatment to Meet Low Parts per Trillion Levels

2003 ◽  
Vol 19 (03) ◽  
pp. 179-186
Author(s):  
Gary C. Schafran ◽  
R. Prasad ◽  
F. H. Thorn ◽  
R. Michael Ewing ◽  
J. Soles
Keyword(s):  
Hydrogen Peroxide ◽  
Activated Carbon ◽  
Hydroxyl Radical ◽  
Ultraviolet Irradiation ◽  
Treatment Plant ◽  
Full Scale ◽  
Radical Formation ◽  
Estuarine Waters ◽  
Treatment Conditions ◽  
Made In

Removal of tributyltin (TBT) from shipyard waters has been conducted in Virginia shipyards for over 2.5 years and has resulted in a 99% reduction of TBT discharged to coastal-estuarine waters. This has been achieved by conventional coagulation clarification for particulate TBT removal and removal of dissolved TBT using activated carbon. Although advances have been made in the understanding of TBT removal under various treatment conditions, TBT removal with the existing full-scale treatment plant to levels that would comply with a 50 parts per trillion (pptr) discharge limit are not possible. Results from study efforts that are currently ongoing suggest that the 50 pptr limit might be reached using ultraviolet irradiation or ozonation and that both processes would be substantially improved with the addition of hydrogen peroxide to promote hydroxyl radical formation.

scholarly journals Catalytic Degradation of Chitosan by Supported Heteropoly Acids in Heterogeneous Systems

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1078
Author(s):  
Hang Zhang ◽  
Zhipeng Ma ◽  
Yunpeng Min ◽  
Huiru Wang ◽  
Ru Zhang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Catalytic Activity ◽  
Activated Carbon ◽  
Reaction Time ◽  
High Molecular Weight ◽  
Reaction Temperature ◽  
Water Soluble ◽  
High Catalytic Activity ◽  
High Molecular Weight Chitosan

Several kinds of composite materials with phosphotungstic acid (PTA) as the catalyst were prepared with activated carbon as support, and their structures were characterized. According to the Box–Behnken central combination principle, the mathematical model of the heterogeneous system is established. Based on the single-factor experiments, the reaction temperature, the reaction time, the amount of hydrogen peroxide and the loading capacity of PTA were selected as the influencing factors to study the catalyzed oxidation of hydrogen peroxide and degradation of high molecular weight chitosan. The results of IR showed that the catalyst had a Keggin structure. The results of the mercury intrusion test showed that the pore structure of the supported PTA catalyst did not change significantly, and with the increase of PTA loading, the porosity and pore volume decreased regularly, which indicated that PTA molecules had been absorbed and filled into the pore of activated carbon. The results of Response Surface Design (RSD) showed that the optimum reaction conditions of supported PTA catalysts for oxidative degradation of high molecular weight chitosan by hydrogen peroxide were as follows: reaction temperature was 70 ℃, reaction time was 3.0 h, the ratio of hydrogen peroxide to chitosan was 2.4 and the catalyst loading was 30%. Under these conditions, the yield and molecular weight of water-soluble chitosan were 62.8% and 1290 Da, respectively. The supported PTA catalyst maintained high catalytic activity after three reuses, which indicated that the supported PTA catalyst had excellent catalytic activity and stable performance compared with the PTA catalyst.

Combinative dyebath treatment with activated carbon and UV/H2O2: a case study on Everzol Black-GSP®

2002 ◽  
Vol 46 (4-5) ◽  
pp. 51-58 ◽  
Author(s):  
N.H. Ince ◽  
D.A. Hasan ◽  
B. Üstün ◽  
G. Tezcanli
Keyword(s):  
Hydrogen Peroxide ◽  
Activated Carbon ◽  
Carbon Mineralization ◽  
Oxidative Degradation ◽  
Advanced Oxidation ◽  
Color Removal ◽  
Operating Parameters ◽  
Cost Reductions ◽  
H2o2 System

Treatability of textile dyebath effluents by two simultaneously operated processes comprising adsorption and advanced oxidation was investigated using a reactive dyestuff, Everzol Black-GSP® (EBG). The method was comprised of contacting aqueous solutions of the dye with hydrogen peroxide and granules of activated carbon (GAC) during irradiation of the reactor with ultraviolet light (UV). Control experiments were run separately with each individual process (advanced oxidation with UV/H2O2 and adsorption on GAC) to select the operating parameters on the basis of maximum color removal. The effectiveness of the combined scheme was tested by monitoring the rate of decolorization and the degree of carbon mineralization in effluent samples. It was found that in a combined medium of advanced oxidation and adsorption, color was principally removed by oxidative degradation, while adsorption contributed to the longer process of dye mineralization. Economic evaluation of the system based on total color removal and 50% mineralization showed that in the case of Everzol Black-GSP®, which adsorbs relatively poorly on GAC, the proposed combination provides 25% and 35% reduction in hydrogen peroxide and energy consumption relative to the UV/H2O2 system. Higher cost reductions are expected in cases with well adsorbing dyes and/or with less costly adsorbents.

scholarly journals Evaluation of cyanide and heavy metals removal in liquid effluents from small mining’s gold benefit, by adsorption with activated carbon and hydrogen peroxide in Segovia, Antioquia

DYNA ◽  
2020 ◽  
Vol 87 (212) ◽  
pp. 9-17
Author(s):  
Claudia Catalina Estrada-Montoya ◽  
Gloria Maria Restrepo Franco ◽  
Narmer Fernando Galeano Vanegas
Keyword(s):  
Heavy Metals ◽  
Hydrogen Peroxide ◽  
Activated Carbon ◽  
Gold Mining ◽  
Environmental Problem ◽  
Flow Chart ◽  
Toxic Substances ◽  
Adsorption Efficiency ◽  
Metals Removal ◽  
Lead Zinc

The small gold mining generates toxic substances discharges, being an environmental problem. The objective was to evaluate the removal of cyanide and heavy metals, in liquid effluents from the gold benefit, by adsorption with activated carbon and hydrogen peroxide. The residues were first treated with carbon to determine the adsorption efficiency with 20, 40, 60 g of carbon / L of solution at times of 4, 8, 12 hours. Then hydrogen peroxide (1.0, 1.5, 2.0 liters of peroxide / Kg CN in solution, was added over 4 hours). The response variables were concentrations of cyanide, lead, zinc, iron. The best treatment with carbon was 60 g of carbon / L of solution and 12 hours of contact and for the process with hydrogen peroxide: 2 liters of H2O2 / Kg of CN in solution, during 4 hours. A flow chart and tables for the implementation of the process were designed.

Sequential anaerobic/aerobic biodegradation of chlorinated hydrocarbons in activated carbon barriers

2002 ◽  
Vol 2 (2) ◽  
pp. 51-58 ◽  
Author(s):  
A. Tiehm ◽  
M. Gozan ◽  
A. Müller ◽  
H. Schell ◽  
H. Lorbeer ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Biological Activity ◽  
Activated Carbon ◽  
Vinyl Chloride ◽  
Reductive Dechlorination ◽  
Chlorinated Hydrocarbons ◽  
Aerobic Biodegradation ◽  
Anaerobic Conditions ◽  
Biological Activated Carbon ◽  
Batch Tests

The aim of this study is to develop a long lasting, sequential anaerobic/aerobic biological activated carbon barrier. In the biobarrier, pollutant adsorption on granular activated carbon (GAC) and biodegradation occur simultaneously. Trichloroethene (TCE), chlorobenzene (CB), and benzene were used as model pollutants. In the first barrier, that was operated under anaerobic conditions with sucrose and ethanol as auxiliary substrates, TCE was completely converted to lower chlorinated metabolites, predominantly cis-dichloroethene (cis-DCE). The reductive dechlorination process was stable for about 300 d, although the concomitant sulphate-reducing and methanogenic processes varied considerably. In the second barrier, that was operated with addition of hydrogen peroxide and nitrate, dechlorination was limited by a lack of oxygen and restricted mainly to CB biodegradation. Additional aerobic batch tests revealed that the metabolites of anaerobic TCE dechlorination, i.e. cis-DCE and vinyl chloride, were oxidatively dechlorinated in the presence of suitable auxiliary substrates such as ethene, CB, benzene, or sucrose and ethanol. During periods of low biological activity, elimination of TCE and CB occurred by adsorption in the GAC barriers. The pre-sorbed pollutants were available for subsequent biodegradation resulting in a bioregeneration of the activated carbon barriers.

Oxidation of activated carbon by hydrogen peroxide. Study of surface functional groups by FT-i.r.

Fuel ◽  
1994 ◽  
Vol 73 (3) ◽  
pp. 387-395 ◽  
Author(s):  
V GOMEZSERRANO ◽  
M ACEDORAMOS ◽  
A LOPEZPEINADO ◽  
C VALENZUELACALAHORRO
Keyword(s):  
Hydrogen Peroxide ◽  
Activated Carbon ◽  
Functional Groups ◽  
Surface Functional Groups
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