scholarly journals Removal of Trace Thallium from Industrial Wastewater by Fe0-Electrocoagulation

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 163 ◽  
Author(s):  
Xianghui Fu ◽  
Li Li ◽  
Guochao Yang ◽  
Xiangyang Xu ◽  
Lihua He ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Current Density ◽  
Industrial Wastewater ◽  
Ph Value ◽  
Operation Time ◽  
Single Step ◽  
Toxic Heavy Metal ◽  
Effective Removal ◽  
Initial Ph ◽  
Effects Of Ph

As thallium (Tl) is a highly toxic heavy metal, there are compulsory environmental regulations in many countries on minimizing its release. This research investigated the treatment of real industrial wastewater with low Tl(I) concentration by Fe0-electrocoagulation (Fe0-EC) in a batch aeration-forced pump cycle reactor. The effects of pH (7–12), current density (8.3–33.3 mA/cm2), dissolved oxygen (DO) in wastewater, and initial Tl(I) concentration (66–165 µg/L) on Tl(I) removal efficiency were investigated. The removal efficiency of Tl(I) is pH-dependent, to be exact, it increases significantly with pH rising from 8 to 11. Initial pH of influent and DO concentration were the key operation parameters which strongly affect Tl(I) removal. After the water sample with initial Tl(I) concentration of 115 µg/L was treated for 12 min by a single-step process at pH of 11 and current density of 16.7 mA/cm2, the residual Tl(I) concentration was decreased to beneath the emission limit in China (2 µg/L) with a low energy consumption of 0.82 kWh/m3. By prolonging the operation time, the concentration was further reduced to 0.5 µg/L or even lower. The main composition of the flocculent sludges is iron oxyhydroxide, yet its crystal structure varies dependent on pH value which may result in different Tl(I) removal efficiency. Feroxyhyte nanosheets generate in situ by Fe0-EC, which contributes to the rapid and effective removal of Tl(I), while the speedy oxidation under DO-enriched conditions benefits the feroxyhyte formation. The mechanism of Tl(I) removal by Fe0-EC is attributed to the combination of electrostatic attraction and the formation of inner-sphere complexes. As shown in the technical and mechanical studies, Fe0-EC technology is an effective method for low Tl concentration removal from wastewater.

scholarly journals Electrochemical Degradation of Crystal Violet Using Ti/Pt/SnO2 Electrode

2021 ◽  
Vol 11 (18) ◽  
pp. 8401
Author(s):  
Rachid El Brychy ◽  
Mohamed Moutie Rguiti ◽  
Nadia Rhazzane ◽  
Moulay Driss Mellaoui ◽  
Khalid Abbiche ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Crystal Violet ◽  
Current Density ◽  
Ph Value ◽  
Supporting Electrolyte ◽  
Chloride Concentration ◽  
Oxygen Demand ◽  
Electrochemical Treatment ◽  
Electrochemical Process ◽  
Initial Ph

Today, organic wastes (paints, pigments, etc.) are considered to be a major concern for the pollution of aqueous environments. Therefore, it is essential to find new methods to solve this problem. This research was conducted to study the use of electrochemical processes to remove organic pollutants (e.g., crystal violet (CV)) from aqueous solutions. The galvanostatic electrolysis of CV by the use of Ti/Pt/SnO2 anode, were conducted in an electrochemical cell with 100 mL of solution using Na2SO4 and NaCl as supporting electrolyte, the effect of the important electrochemical parameters: current density (20–60 mA cm−2), CV concentration (10–50 mg L−1), sodium chloride concentration (0.01–0.1 g L−1) and initial pH (2 to 10) on the efficiency of the electrochemical process was evaluated and optimized. The electrochemical treatment process of CV was monitored by the UV-visible spectrometry and the chemical oxygen demand (COD). After only 120 min, in a 0.01mol L−1 NaCl solution with a current density of 50 mA cm−2 and a pH value of 7 containing 10 mg L−1 CV, the CV removal efficiency can reach 100%, the COD removal efficiency is up to 80%. The process can therefore be considered as a suitable process for removing CV from coloured wastewater in the textile industries.

Study on Advanced Pretreatment of Seawater by Electrolysis and Neutralization of Acidic Waste Water with By-Product Magnesium Hydroxide

2013 ◽  
Vol 821-822 ◽  
pp. 1071-1080
Author(s):  
Jing Nie ◽  
Shou Zhi Yi ◽  
Di Miao
Keyword(s):  
Removal Efficiency ◽  
Magnesium Hydroxide ◽  
Current Density ◽  
Industrial Wastewater ◽  
Removal Rate ◽  
Influence Factors ◽  
Operation Time ◽  
Wastewater Discharge ◽  
Electrode Distance

The advanced pretreatment by electrolysis of Bohai seawater in Tianjin used a diaphragm electrolyzer in the experiment. Removal efficiency and influence factors of the method were analyzed. Results show that turbidity, organic compounds, SDI and chroma of seawater were effectively decreased by electrolysis. Removal efficiency was significantly increased by current density, operation time and inter-electrode distance, and the optimum electrolytic conditions was determined as inter-electrode distance of 2 cm, current density of 15.87 mA·cm-2, operation time of 10 minutes. It was investigated that when the water quality after electrolysis was of pH 8.6, the chroma and turbidity decreasing trend slowed down, with chroma of 0.052 A, removal rate reached 88.4%; the residual turbidity reduced to 2.52 NTU, removal rate reached 90.71%. A PH of about 8.5, CODCr decreasing trend slowed down, and when CODCr < 750 mg/L, it conformed to the requirements of the reverse osmosis water. With the study on neutralization of steel pickling waste liquor by the by-product of magnesium hydroxide, it is found that the quality of treated water reached 3rd level national emissions standards (300-1000 mg/L). Magnesium hydroxide slurry of Cr (VI) removal rate reached 100%, conforming to the 1st level national industrial wastewater discharge standards (< 0.5 mg/L).

Experimental Study of Treating Petroleum Refinery Wastewater by Vacuum Distillation

2014 ◽  
Vol 955-959 ◽  
pp. 371-375
Author(s):  
Long Yan ◽  
Yu Fei Wang ◽  
Jian Li Li
Keyword(s):  
Removal Efficiency ◽  
Vacuum Distillation ◽  
Ph Value ◽  
Petroleum Refinery ◽  
Operation Time ◽  
Refinery Wastewater ◽  
Experimental Conditions ◽  
Vacuum Degree ◽  
Petroleum Refinery Wastewater ◽  
Initial Ph

Vacuum distillation (VD) by NaOH was used for treatment of petroleum refinery wastewater, and the optimal experimental conditions including operation vacuum degree, initial pH, feeding process were also investigated. Chemical oxygen demand (COD), conductivity and pH value were utilized to estimate the removal efficiency for treatment of refinery wastewater. Based on experimental results, it can be concluded that NaOH displays higher efficiency for the treatment of refinery wastewater, the pellucid effluents with satisfied COD removal efficiency (99%) and low salinity were obtained in fully batch process at operation vacuum degree of-0.085 MPa, operation time of 50 min, initial pH of 11, and the corresponding pH values of effluents varied from 7 to 9. Thus, in view of fine COD and mineralization removal efficiency, the VD technology is an effective approach to treat petroleum refinery wastewater.

Effects of pH Value in the Electrolyte on the Properties of Cu2ZnSnS4Thin Film Fabricated by Single Step Co-Electrodeposition

2016 ◽  
Vol 5 (9) ◽  
pp. P521-P525 ◽  
Author(s):  
Hong Zhang ◽  
Shuying Cheng ◽  
Jinling Yu ◽  
Yunfeng Lai ◽  
Haifang Zhou ◽  
...  
Keyword(s):  
Ph Value ◽  
Single Step ◽  
Effects Of Ph

Electrochemical Treatment of Simulated Dye Wastewater

2012 ◽  
Vol 441 ◽  
pp. 555-558
Author(s):  
Feng Tao Chen ◽  
San Chuan Yu ◽  
Xing Qiong Mu ◽  
Shi Shen Zhang
Keyword(s):  
Current Density ◽  
Oxygen Demand ◽  
Electrochemical Treatment ◽  
Dye Wastewater ◽  
Electrolysis Time ◽  
Electrochemical Degradation ◽  
Mild Conditions ◽  
Thermal Decomposition Method ◽  
Initial Ph ◽  
Effects Of Ph

The Ti/SnO2-Sb2O3/PbO2 electrodes were prepared by thermal decomposition method and its application in the electrochemical degradation of a heteropolyaromatic dye, Methylene blue (MB), contained in simulated dye wastewater were investigated under mild conditions. The effects of pH, current density and electrolysis time on de-colorization efficiency were also studied. Chemical oxygen demand (COD) was selected as another parameter to evaluate the efficiency of this degradation method on treatment of MB wastewater. The results revealed that when initial pH was 6.0, current density was 50 mA·cm2, electrolysis time was 60 min, Na2SO4 as electrolyte and its concentration was 3.0 g·dm3, the de-colorization and COD removal efficiency can reach 89.9% and 71.7%, respectively.

scholarly journals Electrochemical oxidation of sulfamethoxazole using Ti/SnO2-Sb/Co-PbO2 electrode through ANN-PSO

2019 ◽  
Vol 84 (7) ◽  
pp. 713-727 ◽  
Author(s):  
Jiteng Wan ◽  
Chunji Jin ◽  
Banghai Liu ◽  
Zonglian She ◽  
Mengchun Gao ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Electrochemical Oxidation ◽  
Removal Efficiency ◽  
Current Density ◽  
Ph Value ◽  
Ann Model ◽  
Solution Ph ◽  
Pbo2 Electrode ◽  
Artificial Neural Network Ann ◽  
Major Factors

Even in a trace amounts, the presence of antibiotics in aqueous solution is getting more and more attention. Accordingly, appropriate technologies are needed to efficiently remove these compounds from aqueous environments. In this study, we have examined the electrochemical oxidation (EO) of sulfamethoxazole (SMX) on a Co modified PbO2 electrode. The process of EO of SMX in aqueous solution followed the pseudo-first-order kinetics, and the removal efficiency of SMX reached the maximum value of 95.1 % within 60 min. The effects of major factors on SMX oxidation kinetics were studied in detail by single-factor experiments, namely current density (1?20 mA cm-2), solution pH value (2?10), initial concentration of SMX (10?500 mg L-1) and concentration of electrolytes (0.05?0.4 mol L-1). An artificial neural network (ANN) model was used to simulate this EO process. Based on the obtained model, particle swarm optimization (PSO) was used to optimize the operating parameters. The maximum removal efficiency of SMX was obtained at the optimized conditions (e.g., current density of 12.37 mA cm-2, initial pH value of 4.78, initial SMX concentration of 74.45 mg L-1, electrolyte concentration of 0.24 mol L-1 and electrolysis time of 51.49 min). The validation results indicated that this method can ideally be used to optimize the related parameters and predict the anticipated results with acceptable accuracy.

scholarly journals Comparison of sorption efficiency of natural and MnO2 coated zeolite for copper removal from model solutions

2021 ◽  
Vol 900 (1) ◽  
pp. 012003
Author(s):  
M Balintova ◽  
Z Kovacova ◽  
S Demcak ◽  
Y Chernysh ◽  
N Junakova
Keyword(s):  
Heavy Metals ◽  
Removal Efficiency ◽  
Ph Value ◽  
Batch Experiments ◽  
Modified Zeolite ◽  
Optimum Ph ◽  
Removal Of Heavy Metals ◽  
Initial Ph ◽  
Correlation Factors ◽  
Maximum Removal

Abstract Removal of heavy metals from the environment is important for living beings. The present work investigates the applicability of the natural and MnO2 - coated zeolite as sorbent for the removal of copper from synthetic solutions. Batch experiments were carried out to identify the influence of initial pH and concentration in the process of adsorption. A maximum removal efficiency of Cu(II) was observed in 10 mg/L for natural (95.6%) and modified (96.4%) zeolite, where the values was almost identical, but at concentration of 500 mg/L was the removal efficiency of modified zeolite three times higher. Based on the correlation factors R2, the Langmuir isotherms better describe the decontamination process than Freundlich. The optimum pH value was set at 5.0.

Electrochemical Disintegration of Activated Sludge Using Ti/RuO2 Anode

2014 ◽  
Vol 567 ◽  
pp. 44-49 ◽  
Author(s):  
Gan Chin Heng ◽  
Mohamed Hasnain Isa
Keyword(s):  
Current Density ◽  
Biological Treatment ◽  
Ph Value ◽  
Electrochemical Process ◽  
Operating Conditions ◽  
Electrolysis Time ◽  
Initial Ph ◽  
Electrode Surface Morphology ◽  
Alkaline Range ◽  
Sludge Concentration

Electrochemical process is one of the most effective methods to enhance sludge disintegration. In this study, Ti/RuO2 anodes were prepared by Pechini’s method and the electrode surface morphology was characterized by FESEM and EDAX. The effects of various operating conditions were investigated including initial pH value of sludge, sludge concentration, electrolysis time and current density. The study showed that the removal efficiencies of TS, VS, TSS and VSS increased with the increase of pH in the alkaline range, electrolysis time and current density but decreased with the increase of initial sludge concentration. The application of electrochemical process using Ti/RuO2 electrodes enhanced the sludge disintegration for possible subsequent biological treatment.

Effect of Environment Factors on Phosphorus Removal Efficiency of Phosphate Reduction System

2011 ◽  
Vol 255-260 ◽  
pp. 2797-2801
Author(s):  
Chen Yao ◽  
Chun Juan Gan ◽  
Jian Zhou
Keyword(s):  
Removal Efficiency ◽  
Phosphorus Removal ◽  
Ph Value ◽  
Removal Rate ◽  
Mass Rearing ◽  
Phosphate Removal ◽  
Environment Factors ◽  
Reduction System ◽  
Initial Ph ◽  
The Impact

Effect of environment factors such as initial pH value, dissolved oxygen (DO) and temperature on phosphorus removal efficiency of phosphate reduction system was discussed in treating pickled mustard tube wastewater. Results indicate that environment factors have significant influence on dephosphorization efficiency. And, the impact of DO on phosphate reduction is mainly by affecting the distribution of micro-environment inner biofilm, manifest as phosphate removal rate decreased with a fall in DO concentration, while overhigh DO can lead to detachment of biofilm, thus causing the increase of effluent COD concentration, and so DO need to be controlled in the range of 6 mg/L. Moreover, a higher temperature is more beneficial to phosphorus removal by PRB. Unfortunately, exorbitant temperature can result in mass rearing of Leuconostoc characterized with poor flocculability in reactor, and that cause turbidity in effluent appeared as a rise in COD of effluent. Hence, the optimal temperature is found to be about 30°C.

The Pulse Electrolysis Treatment of Waste Emulsion Orthogonal Experimental Study

2013 ◽  
Vol 303-306 ◽  
pp. 2616-2619
Author(s):  
Xiao Yan Sun ◽  
Pei Dao Pan ◽  
Jang Jie Wang
Keyword(s):  
Experimental Study ◽  
Removal Efficiency ◽  
Current Density ◽  
Pulse Width ◽  
Ph Value ◽  
Operating Conditions ◽  
Cod Removal ◽  
Pulse Electrolysis ◽  
Cod Removal Efficiency ◽  
Plate Distance

This mechanical processing waste emulsion for the study, handled by pulse electrolysis. Arrangements by orthogonal testing, experimental study on plate distance (d), current density (i), the pH value and the pulse width (tP) impact on COD removal efficiency, very poor analysis of test data to determine various factors affecting the COD removal efficiency of primary and secondary sort: pH value > current density > pulse width > plate distance, optimal operating conditions. Orthogonal experimental data derived from regression analysis, determination of cross of quadratic polynomial regression equations, mathematical model. Tests confirmed that pulse electrochemical method for treatment of waste emulsion with low energy consumption, short response time, and other advantages, strong applicability of wastewater, building mathematical models, providing theoretical basis for subsequent design.

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