Highly efficient oxidation of chromium (III) with hydrogen peroxide in alkaline medium

2019 ◽  
Vol 79 (2) ◽  
pp. 366-374 ◽  
Author(s):  
Hao Peng ◽  
Jing Guo ◽  
Gang Li ◽  
Qinzhe Cheng ◽  
Yuju Zhou ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction Time ◽  
Alkaline Medium ◽  
Reaction Temperature ◽  
Volume Ratio ◽  
High Energy ◽  
Utilization Efficiency ◽  
Water Leaching ◽  
Stirring Rate ◽  
Oxidation Efficiency

Abstract Many technologies have been proposed to oxidize chromium, such as roasting-water leaching technology and hydrometallurgical methods such as pressure oxidative leaching coupled with oxygen, ozone, permanganate and ferrate, but the problems associated with the high temperature, low overall resource utilization efficiency, high energy consumption, and the environmental pollution, still remain unsolved. This paper focuses on the oxidation process of chromium (III) with hydrogen peroxide (H2O2) in an alkaline medium. The effect of parameters including dosage of H2O2, dosage of NaOH, reaction time, reaction temperature and stirring rate on the oxidation efficiency of chromium were investigated. The oxidation efficiency was significantly affected by the dosage of H2O2 and NaOH, reaction time and reaction temperature took second place; last was the stirring rate. Oxidation efficiency was nearly 100% under the optimal conditions: volume ratio of H2O2 to mass of Cr2(SO4)3 of 2.4 mL/g, mass ratio of NaOH to Cr2(SO4)3 0.6 g/g, reaction time of 90 min, reaction temperature of 90 °C and stirring rate of 500 rpm.

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.

Experimental Researches on the Preparation of High-Efficient Active Floridin by Mixed Acids

2012 ◽  
Vol 510 ◽  
pp. 713-718
Author(s):  
Ming Yong Shu ◽  
Hai Ying Yin ◽  
Guang Hui Liu
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Volume Ratio ◽  
Raw Material ◽  
Activation Effect ◽  
Solid Ratio ◽  
High Efficient ◽  
Main Factors ◽  
Experimental Researches ◽  
Mixed Acids

Taking ca-bentonite as the raw material, the activation effect of active floridin prepared by mixed acids of H2SO4, HCl and C2H2O4 is studied. The research results indicate that the main factors influencing the activity and decolorization ratio of floridin include volume ratio of mixed acids, liquid-to-solid ratio, reaction temperature and reaction time. When the volume ratio of mixed acids H2SO4: HCl: C2H2O4=5:5:1, liquid-to-solid ratio =4:1, reaction temperature 80 and reaction time 4h, it is possible to prepare high-efficient active floridin.

Study on the Preparation of Chitosan-Based Resin

2010 ◽  
Vol 160-162 ◽  
pp. 1810-1815
Author(s):  
Jing Xian Li ◽  
Juan Qin Xue ◽  
Ming Wu ◽  
Yu Jie Wang ◽  
Wei Bo Mao
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Experimental Results ◽  
Raw Material ◽  
Cross Linking ◽  
Reactant Ratio ◽  
Experimental Conditions ◽  
Stirring Rate ◽  
Formaldehyde Crosslinking ◽  
New Type

With chitosan as the raw material, a new type of resin material is synthesized through formaldehyde crosslinking. The effects of the reactant ratio, the reaction temperature, the reaction time, the stirring rate and the system pH on the cross-linking rate are studied in detail. The resin material is then characterized by means of IR. The experimental results show that the reaction occurs mainly on the amino and the hydroxyl of chitosan. The chitosan-based resin material with good properties of sphericity and acidresistivity can be prepared under the optimal experimental conditions, which are found to be 1:5 for the ratio of chitosan and formaldehyde, 60°C for the temperature, 1 h for the reaction time, 440r/min for the stirring rate and 10 for the pH.

Removal of Manganese(II) Ions from Wastewater by H2O2 as Oxidant

2014 ◽  
Vol 884-885 ◽  
pp. 125-128
Author(s):  
Wen Qiang Yang ◽  
Juan An ◽  
Jian Guo Yin ◽  
Xiao Li Yuan ◽  
Wen Tang Xia
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction Time ◽  
Calcium Oxide ◽  
Reaction Temperature ◽  
Removal Rate ◽  
Treated Wastewater ◽  
Manganese Removal

Removal of manganese (II) ions from wastewater by H2O2as oxidant was studied. Effects of reaction temperature, hydrogen peroxide concentration, reaction time and calcium oxide concen-tration on the manganese removal were investigated. The results indicated that the removal rate of manganese exceeded 99.9% and the Mn (II) ions concentration of treated wastewater was lower than 0.1 mg·L-1under the conditions of reaction temperature 55 °C, concentration of H2O20.1 mL·L-1, reaction time 70 min, concentration of CaO 0.25 g·L-1.

Research on Synthesis Regularity of Epoxysuccinic Acid

2013 ◽  
Vol 316-317 ◽  
pp. 942-945
Author(s):  
Qing He Gao ◽  
Yi Can Wang ◽  
Zhi Feng Hou ◽  
Hui Juan Qian ◽  
Yuan Zhang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction Time ◽  
Maleic Anhydride ◽  
Reaction Temperature ◽  
Raw Material ◽  
Molar Ratio ◽  
Mass Ratio ◽  
Synthesis System ◽  
Reaction Conditions ◽  
Sodium Hydrate

The yield of epoxysuccinic acid was obtained by determining the content of unreacted maleic anhydride and tartaric acid as a by-product in synthesis system. This method could calculate the yield of epoxysuccinic acid precisely and overcome the disadvantage of obtaining inpure product by recrystallization method. Epoxysuccinic Acid was synthesized using maleic anhydride as raw material, hydrogen peroxide as oxidizer and tungstate as catalyst. The effects of reaction temperature, reaction time, ratio of materials, dosage of oxidizer and catalyst on epoxidation and hydrolysis reaction was investigated. The results showed that the yield of epoxysuccinic acid was 88% when the reaction conditions were as follows: reaction temperature 65°C, reaction time 1.5h, catalyst dosage 3%(based on mass of maleic anhydride), molar ratio of sodium hydrate to maleic anhydride 2:1, mass ratio of hydrogen peroxide to maleic anhydride 1:1.

Double Oxidants Combined Oxidation of Oleic Acid Preparation of Azelaic Acid

2013 ◽  
Vol 804 ◽  
pp. 94-97
Author(s):  
Chun Wei Shi ◽  
Xiao Yan Zhang ◽  
Shan Lin Zhao ◽  
Ping Chen ◽  
Yu Ting Bai
Keyword(s):  
Hydrogen Peroxide ◽  
Oleic Acid ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Azelaic Acid ◽  
Phosphotungstic Acid ◽  
Hydrogen Peroxide Solution ◽  
Acid Hydrate ◽  
Major Factors

Oleic acid was oxidized to azelaic acid by ozone and hydrogen peroxide as an oxidant jointly in this paper. The effect of major factors, such as the volume and concentration of hydrogen peroxide, the volume and concentration of ozone. The results show that the yield of azelaic acid was up to 71 %, when the oxidation was taken under the following condition: oleic acid 20g, phosphotungstic acid hydrate 0.6g , 30% hydrogen peroxide solution 60ml, reaction temperature 70°C, reaction time 8h.

Selectively Catalyzed Oxidation of Benzyl Alcohol by FeIII–TAML/Hydrogen Peroxide

2015 ◽  
Vol 723 ◽  
pp. 601-604 ◽  
Author(s):  
Ran Li ◽  
Ge Wang ◽  
Yan Chun Liu ◽  
Xiao Bin Chen ◽  
Zhi Min Sun ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction Time ◽  
Benzyl Alcohol ◽  
Reaction Temperature ◽  
Oxidation Reaction ◽  
Macrocyclic Ligands ◽  
Temperature Reaction ◽  
Oxidation Of Benzyl Alcohol ◽  
Catalyzed Oxidation

Benzyl alcohol was selectively oxidized to benzaldehyde with iron (III) complexed to tetra amido macrocyclic ligands (FeIII–TAML) as catalyst and 30% H2O2 as oxidant. The effect of reaction temperature, reaction time, solvent, amount of catalyst and oxidant on the reaction of catalyzed oxidation of benzyl alcohol were explored. The conversion and selectivity of this oxidation reaction were calculated from calibrated GC yields of benzyl alcohol and benzaldehyde. When oxidation reaction was conducted under the conditions: solvent NMMO: ethanol = 1: 1, n (H2O2): n (benzyl alcohol) = 2, n (catalyst): n (benzyl alcohol) = 1%, temperature 80 ̊C and reaction time 60 minutes, the conversion was 91.23% and the selectivity was 90.12%.

scholarly journals Synthesizing environmentally friendly non-silicone oxygen bleaching stabilizer for linen yarn using oligomeric acrylic acid

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jie Liu ◽  
Chun Lv
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction Time ◽  
Acrylic Acid ◽  
Reaction Temperature ◽  
Metal Ion ◽  
Monomer Concentration ◽  
Environmentally Friendly ◽  
Test Method ◽  
Magnesium Salt ◽  
Oxygen Bleaching

AbstractUsing potassium peroxodisulfate as an initiator and acrylic acid as a monomer, an acrylic acid oligomer was synthesized and then compounded with magnesium salt to form a non-silicone oxygen bleaching stabilizer. By investigating the effects of reaction temperature, reaction time, initiator concentration, monomer concentration, and magnesium salt dosage on product performance, the effect of stabilizers on linen yarn bleaching was analyzed. The synthetic conditions of oxygen bleaching stabilizer were determined by orthogonal test method, namely, acrylic acid monomer concentration 25%, initiator dosage 5%, oligomeric acrylic acid and magnesium salt compound ratio 5:1, reaction temperature 65 °C, reaction time 4 h. At this time, the chelated iron value of the product was as high as 239.314 mg/g, and the chelated calcium value also reached 145.000 mg/g. The dosage of the synthesized stabilizer were determined to be 4 g/L through indicators such as the decomposition rate of hydrogen peroxide and whiteness. The results showed that the environmentally friendly non-silicone oxygen bleaching stabilizer not only had a good ability to inhibit the decomposition of hydrogen peroxide, but also provided bleached linen yarn with a superior degree of whiteness and less metal ion residue, which can effectively solve the “silicon scale” problem and improve the quality of the pre-treatmented products.

Experimental Study on Catalytic Oxidation of Cyclohexane Catalyzed by Phosphomolybdic Acid

2012 ◽  
Vol 549 ◽  
pp. 411-414
Author(s):  
Jiao Jing Zhang ◽  
Hua Lin Song ◽  
Jian Wang ◽  
Hua Song
Keyword(s):  
Hydrogen Peroxide ◽  
Experimental Study ◽  
Reaction Time ◽  
Catalytic Oxidation ◽  
Reaction Temperature ◽  
Phosphomolybdic Acid ◽  
Catalyst Amount

The catalytic oxidation of cyclohexane to cyclohexanone and cyclohexanol using hydrogen peroxide over phosphomolybdic acid were studied. Factors such as the amount of catalyst, amount of the oxidant (H2O2), reaction temperature and reaction time were investigated. The conversion of cyclohexane was 35.35%, the total selectivity to cyclohexanone and cyclohexanol was 97.68% at a reaction temperature of 70 °C, reaction time of 8 h, 10 mL of acetone, 0.01 g of phosphomolybdic acid and 0.5 mL of hydrogen peroxide.

The Study of Solubility of Barium Nitrate Prepared from Barium Chromate and Nitric Acid

2013 ◽  
Vol 803 ◽  
pp. 173-176
Author(s):  
Jing Wang ◽  
Ming Yu Li ◽  
Qing Xuan Zeng ◽  
Wen Qing Wang
Keyword(s):  
Nitric Acid ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Barium Nitrate ◽  
Optimum Conditions ◽  
Stirring Rate ◽  
Barium Chromate ◽  
Initial Content

In this paper, the solubility of barium nitrate prepared from barium chromate and nitric acid was investigated. The effects of reaction time, reaction temperature, stirring rate, the concentration of nitric acid and the amount of the initial content of barium chromate have been studied. The results showed that the solubility of barium nitrate decreased with increasing reaction time, stirring rate and concentration of nitric acid, increased with reaction temperature but had nothing to do with the amount of the initial content of barium chromate. Finally, the reaction optimum conditions were determined that the reaction time was kept at 30 min, reaction temperature was 40-50 °C, stirring rate was 100-200 rpm, and the concentration of nitric acid was 15 mol/L.

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