scholarly journals Degradation of phenol in wastewater using anolyte produced from electrochemical generation of brine solution

2013 ◽  
Vol 4 (2) ◽  
pp. 139-144
Keyword(s):  
Free Radicals ◽  
Reaction Time ◽  
Oxalic Acid ◽  
Fumaric Acid ◽  
Electrochemical Activation ◽  
Activation Process ◽  
Optimal Dosage ◽  
Optimum Conditions ◽  
Electrochemical Generation ◽  
Brine Solution

This paper presents the degradation of phenol in wastewater using anolyte, which is generated from electrochemical activation process. Anolyte consists of reactive ions and free radicals, which contribute to its oxidizing behavior. The optimum conditions, which facilitate a complete degradation of phenol, were found using variation of dosage of anolyte and reaction time. It was found that about 20% of anolyte was the optimal dosage which corresponded to 98% degradation of phenol after a reaction time of 60 minutes. The main products during degradation of phenol by anolyte were found to be benzoquinone, hydroquinone, catechol, maleic acid, fumaric acid and oxalic acid.

scholarly journals The rapid electrochemical activation of MoTe2 for the hydrogen evolution reaction

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Jessica C. McGlynn ◽  
Torben Dankwort ◽  
Lorenz Kienle ◽  
Nuno A. G. Bandeira ◽  
James P. Fraser ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Transition Metal ◽  
Catalytic Performance ◽  
Electrochemical Activation ◽  
Activation Process ◽  
Metal Chalcogenides ◽  
Enabling Technology ◽  
Electrochemical Generation ◽  
Transition Metal Chalcogenides ◽  
A Current

Abstract The electrochemical generation of hydrogen is a key enabling technology for the production of sustainable fuels. Transition metal chalcogenides show considerable promise as catalysts for this reaction, but to date there are very few reports of tellurides in this context, and none of these transition metal telluride catalysts are especially active. Here, we show that the catalytic performance of metallic 1T′-MoTe2 is improved dramatically when the electrode is held at cathodic bias. As a result, the overpotential required to maintain a current density of 10 mA cm−2 decreases from 320 mV to just 178 mV. We show that this rapid and reversible activation process has its origins in adsorption of H onto Te sites on the surface of 1T′-MoTe2. This activation process highlights the importance of subtle changes in the electronic structure of an electrode material and how these can influence the subsequent electrocatalytic activity that is displayed.

scholarly journals UV/Vis-Based Persulphate Activation for p-Nitrophenol Degradation

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 480
Author(s):  
Valentin Dubois ◽  
Carmen S. D. Rodrigues ◽  
Ana S. P. Alves ◽  
Luis M. Madeira
Keyword(s):  
Reaction Time ◽  
Oxidation Process ◽  
Activation Process ◽  
Direct Photolysis ◽  
Simulated Solar Light ◽  
Uv Visible ◽  
Oxidation Efficiency ◽  
Nitrophenol Degradation ◽  
Persulphate Oxidation ◽  
Radiation Type

In the present work, the degradation of p-nitrophenol (PNP) and its mineralization by a UV/Vis-based persulphate activation process was investigated. Firstly, a screening of processes as direct photolysis, persulphate alone and persulphate activated by radiation was performed. The incidence of radiation demonstrated to have an important role in the oxidant activation, allowing to achieve the highest PNP and total organic carbon (TOC) removals. The maximum PNP oxidation (100%) and mineralization (61.6%)—both after 2 h of reaction time—were reached when using T = 70 °C, (S2O82−) = 6.4 g/L and I = 500 W/m2. The influence of radiation type (ultraviolet/visible, visible or simulated solar light) was also evaluated, being found that the source with the highest emission of ultraviolet radiation (UV/visible) allowed to achieve the best oxidation efficiency; however, solar radiation also reached very-good performance. According to quenching experiments, the sulphate radical is key in the activated persulphate oxidation process, but the hydroxyl radical also plays an important role.

scholarly journals Chemical Removal of Cu and Zn from Swine Feces before Soil Application

Agriculture ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 377
Author(s):  
Moo-Joon Shim ◽  
Seung-Mok Lee
Keyword(s):  
Reaction Time ◽  
H2so4 Solution ◽  
Optimum Conditions ◽  
Liquid Ratio ◽  
Optimal Method ◽  
Zn Concentration ◽  
Swine Feces ◽  
Removal Efficiencies ◽  
Cu And Zn ◽  
Oxalic Acids

Cu and Zn are known to be abundant in swine feces; hence, concentrations of these metals need to be lowered before swine feces are applied to land in order to prevent potential environmental problems. The main objective of this study was to develop an appropriate chemical process to remove Cu and Zn from swine feces using acid extractions. The removal efficiencies of Cu and Zn decreased in the order of H2SO4 > HNO3 > organic acids (citric and oxalic acids). Owing to the highest removal efficiencies of Cu and Zn by using H2SO4, it was selected for further elimination of Cu and Zn from swine feces. By using H2SO4, the optimal concentration, solid-to-liquid ratio, and reaction time were 2%, 1:50, and 8 h, respectively. At the optimum conditions, Cu concentration was decreased from 198 mg/kg to 40.1 mg/kg and Zn concentration from 474 mg/kg to 80.0 mg/kg, with removal rates of 79.7% and 83.1%, respectively. The low Cu removal efficiency, resulting from the strong complexation between Cu and organic matter of swine feces, was improved by the increase in the reaction time and H2SO4 solution concentrations. However, about half of the total nitrogen (TN) was also removed by using H2SO4, indicating that the swine feces treated with H2SO4 may have poor value as fertilizer. Additional studies are required to find an optimal method to maintain TN concentrations while simultaneously removing Cu and Zn.

Degradation of chlorpyriphos in water by advanced oxidation processes

2010 ◽  
Vol 10 (1) ◽  
pp. 1-6 ◽  
Author(s):  
R. Murillo ◽  
J. Sarasa ◽  
M. Lanao ◽  
J. L. Ovelleiro
Keyword(s):  
Reaction Time ◽  
Light Source ◽  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
The Other ◽  
Molar Ratio ◽  
Optimum Conditions ◽  
Oxidation Processes ◽  
Other Hand ◽  
Initial Ph

The degradation of chlorpyriphos by different advanced oxidation processes such as photo-Fenton, TiO2, TiO2/H2O2, O3 and O3/H2O2 was investigated. The photo-Fenton and TiO2 processes were optimized using a solar chamber as light source. The optimum dosages of the photo-Fenton treatment were: [H2O2]=0.01 M; [Fe3 + ]=10 mg l−1; initial pH = 3.5. With these optimum conditions total degradation was observed after 15 minutes of reaction time. The application of sunlight was also efficient as total degradation was achieved after 60 minutes. The optimum dosage using only TiO2 as catalyst was 1,000 mg l−1, obtaining the maximum degradation at 20 minutes of reaction time. On the other hand, the addition of 0.02 M of H2O2 to a lower dosage of TiO2 (10 mg l−1) provides the same degradation. The ozonation treatment achieved complete degradation at 30 minutes of reaction time. On the other hand, it was observed that the degradation was faster by adding H2O2 (H2O2/O3 molar ratio = 0.5). In this case, total degradation was observed after 20 minutes.

scholarly journals Process optimization for biodiesel production from neutralized waste cooking oil and the effect of this biodiesel on engine performance

2018 ◽  
Vol 8 (1) ◽  
pp. 121-127 ◽  
Author(s):  
Tanzer Eryilmaz
Keyword(s):  
Reaction Time ◽  
Methyl Ester ◽  
Reaction Temperature ◽  
Direct Injection ◽  
Engine Performance ◽  
Waste Cooking Oil ◽  
Biodiesel Production ◽  
Phase Reaction ◽  
Optimum Conditions ◽  
Cooking Oils

In this study, the methyl ester production process from neutralized waste cooking oils is optimized by using alkali-catalyzed (KOH) single-phase reaction. The optimization process is performed depending on the parameters, such as catalyst concentration, methanol/oil ratio, reaction temperature and reaction time. The optimum methyl ester conversion efficiency was 90.1% at the optimum conditions of 0.7 wt% of potassium hydroxide, 25 wt% methanol/oil ratio, 90 min reaction time and 60°C reaction temperature. After the fuel characteristics of the methyl ester obtained under optimum conditions were determined, the effect on engine performance, CO and NOx emissions of methyl ester was investigated in a diesel engine with a single cylinder and direct injection. When compared to diesel fuel, engine power and torque decreased when using methyl ester, and specific fuel consumption increased. NOx emission increases at a rate of 18.4% on average through use of methyl ester.

scholarly journals Treatment of oilfield wastewater by combined process of micro-electrolysis, Fenton oxidation and coagulation

2017 ◽  
Vol 76 (12) ◽  
pp. 3278-3288 ◽  
Author(s):  
Zhenchao Zhang
Keyword(s):  
Reaction Time ◽  
Removal Efficiency ◽  
Treatment Process ◽  
Cod Removal ◽  
Fenton Oxidation ◽  
Oily Wastewater ◽  
Optimum Conditions ◽  
Combined Process ◽  
Cod Removal Efficiency ◽  
Optimized Conditions

Abstract In this study, a combined process was developed that included micro-electrolysis, Fenton oxidation and coagulation to treat oilfield fracturing wastewater. Micro-electrolysis and Fenton oxidation were applied to reduce chemical oxygen demand (COD) organic load and to enhance organic components gradability, respectively. Orthogonal experiment were employed to investigate the influence factors of micro-electrolysis and Fenton oxidation on COD removal efficiency. For micro-electrolysis, the optimum conditions were: pH, 3; iron-carbon dosage, 50 mg/L; mass ratio of iron-carbon, 2:3; reaction time, 60 min. For Fenton oxidation, a total reaction time of 90 min, a H2O2 dosage of 12 mg/L, with a H2O2/Fe2+ mole ratio of 30, pH of 3 were selected to achieve optimum oxidation. The optimum conditions in coagulation process: pH, cationic polyacrylamide dosage, mixing speed and time is 4.3, 2 mg/L, 150 rpm and 30 s, respectively. In the continuous treatment process under optimized conditions, the COD of oily wastewater fell 56.95%, 46.23%, 30.67%, respectively, from last stage and the total COD removal efficiency reached 83.94% (from 4,314 to 693 mg/L). In the overall treatment process under optimized conditions, the COD of oily wastewater was reduced from 4,314 to 637 mg/L, and the COD removal efficiency reached 85.23%. The contribution of each stage is 68.45% (micro-electrolysis), 24.07% (Fenton oxidation), 7.48% (coagulation), respectively. Micro-electrolysis is the uppermost influencing process on COD removal. Compared with the COD removal efficiency of three processes on raw wastewater under optimized conditions: the COD removal efficiency of single micro-electrolysis, single Fenton oxidation, single coagulation is 58.34%, 44.88% and 39.72%, respectively. Experiments proved the effect of combined process is marvelous and the overall water quality of the final effluent could meet the class III national wastewater discharge standard of petrochemical industry of China (GB8978-1996).

Synthesis of light-colored rosin glycerol ester

Holzforschung ◽  
2007 ◽  
Vol 61 (5) ◽  
pp. 499-503 ◽  
Author(s):  
Shifa Wang
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Softening Point ◽  
Acid Number ◽  
Total Weight ◽  
Molar Ratio ◽  
Optimal Dosage ◽  
Weight Percentage ◽  
Glycerol Ester ◽  
Ring Method

Abstract A light-colored rosin glycerol ester was synthesized from gum rosin and glycerol in the presence of a highly effective decolorizing agent. The effects of the type and dosage of the decolorizing agent and the reaction temperature and time on the yield, softening point, color, and acid number of the rosin glycerol ester were investigated. Experimental results showed that 4,4′-thio-bis(6-tert-butyl-3-methyl phenol) was the best decolorizing agent. It promoted esterification at an optimal dosage of 0.5% (based on the weight percentage of starting material rosin). Suitable conditions for esterification of rosin and glycerol were: reaction temperature, 260–270°C; reaction time, 6–8 h; and rosin/glycerol molar ratio, 2.5:1 (mol mol-1). The characteristics of the rosin glycerol ester obtained under these conditions were as follows: softening point, 90–94°C (ball and ring method); color, 1–2 (Gardner value); acid number, 7–8; and yield, >88% (based on the total weight of rosin and glycerol). The selected additive has a multifunctional effect involving bleaching, disproportionation, and catalysis.

scholarly journals Sulfamethoxazole and Trimethoprim Degradation by Fenton and Fenton-Like Processes

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1655 ◽  
Author(s):  
Antover Panazzolo Sarmento ◽  
Alisson Carraro Borges ◽  
Antonio Teixeira de Matos ◽  
Lincoln Lucílio Romualdo
Keyword(s):  
Reaction Time ◽  
Fenton Reaction ◽  
Desirability Function ◽  
Relative Concentration ◽  
Optimum Conditions ◽  
Degradation Model ◽  
Pareto Chart ◽  
Linear Effect ◽  
Ph Values ◽  
Antibiotic Degradation

In this work, the degradation of sulfamethoxazole (SMX) and trimethoprim (TMP) via Fenton and Fenton-like processes was evaluated using Mn2+ as supporting catalyst in the Fenton reaction. The optimum conditions of degradation were also evaluated. Besides that, the effect of independent factors pH, [H2O2], [Fe2+], [Mn2+] and reaction time (t) on the efficiency of the SMX and TMP degradation were assessed. Box–Behnken was the experimental design adopted, delineating the relative concentration (C/Co) of antibiotics after treatments as response variable. The inferences were conducted using variance analysis, Pareto chart, response surface methodology, and desirability function. Due to the lack of adjustment of the SMX degradation model, there are no more inferences about it. The significant variables (p ≤ 0.05) on TMP degradation were: reaction time quadratic and linear effect, [Fe2+] linear effect, [Mn2+] linear effect, interaction pH vs. [Mn2+]. The Mn2+ addition aided TMP degradation in environments with lower pH values. However, the addition may harm the efficiency of the antibiotic degradation at higher pH. The optimum condition for TMP degradation in the conventional process (without the addition of Mn2+) is: pH 5, [H2O2] equal to 4.41 mmol L−1, [Fe2+] equal to 0.81 mmol L−1 and 90 min reaction time.

Electrochemical generation of free radicals in an EPR loop-gap resonator

1988 ◽  
Vol 76 (1) ◽  
pp. 100-105 ◽  
Author(s):  
R.D Allendoerfer ◽  
W Froncisz ◽  
C.C Felix ◽  
James S Hyde
Keyword(s):  
Free Radicals ◽  
Electrochemical Generation

The Use of Super Base CaO from Eggshells as a Catalyst in the Process of Biodiesel Production

2019 ◽  
Vol 967 ◽  
pp. 150-154 ◽  
Author(s):  
Yoel Pasae ◽  
Lyse Bulo ◽  
Karel Tikupadang ◽  
Titus Tandi Seno
Keyword(s):  
Reaction Time ◽  
Heterogeneous Catalysts ◽  
Ammonium Carbonate ◽  
Raw Materials ◽  
Agricultural Waste ◽  
Acid Number ◽  
Biodiesel Production ◽  
National Standard ◽  
Activation Process ◽  
Biodiesel Quality

The use of heterogeneous catalysts in the biodiesel production process provides advantages because it is easier in the catalyst separation process. One type of heterogeneous catalyst that can be used is CaO. The raw materials for CaO are abundant in nature and can be obtained from various sources including agricultural waste such as eggshells. The alkalinity level of CaO can be increased to super baser CaO through the activation process of CaO by using an ammonium carbonate solution. Super base CaO which is used as a catalyst for transesterification reaction in the production of biodiesel made from palm oil. This research was carried out by varying the reaction time starting from 1, 2 and 3 hours. The highest yield was obtained at 3 hours reaction time of 93.92%. The results of the analysis of the physical properties of biodiesel obtained density in the range 853-854 kg/m3, kinematic viscosity 3.24-3.26 mm2/s (cSt), saponification number 193-201 mg-KOH/g biodiesel and acid number 0.3-0.7 mg-KOH/g. These characteristics meet the biodiesel quality standards based on Indonesian National Standard (SNI) 04-7182-2015. Thus the use of super base CaO from eggshells can be used as a catalyst in the process of biodiesel production.

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