scholarly journals Removal of sulphate from mine waters by electrocoagulation/rice straw activated carbon adsorption coupling in a batch system: optimization of process via response surface methodology

2018 ◽  
Vol 9 (2) ◽  
pp. 163-172
Author(s):  
Mijia Zhu ◽  
Xianqing Yin ◽  
Wu Chen ◽  
Zhengji Yi ◽  
Heyong Tian
Keyword(s):  
Response Surface Methodology ◽  
Activated Carbon ◽  
Reaction Time ◽  
Response Surface ◽  
Removal Efficiency ◽  
Current Density ◽  
Small Deviation ◽  
Mathematic Model ◽  
System Optimization ◽  
Sulphate Removal

Abstract The removal of sulphate ions constitutes one of the main challenges in mining, metallurgical and other industries. This work evaluated sulphate removal from aqueous solutions by an electrocoagulation (EC)/raw straw activated carbon (RSAC) adsorption coupled process. The process parameters affecting sulphate removal efficiency were investigated: current density (0–100 mA/cm2), RSAC dosage (0–0.8 g/L), initial pH (4–9) and reaction time (0–40 min). A central composite design coupled with response surface methodology (RSM) was used to construct a mathematic model of EC/RSAC process that considers three key variables, namely current density, RSAC dosage and reaction time. Under optimum conditions (current density of 75 mA/cm2, dosage of 0.46 g/L and reaction time of 19.2 min), the removal efficiency of sulphate reached 95.2%. The RSM predictive value was 94.08% with a small deviation (1.12%). Thus, the fundamental data and results can provide some useful information for further studies and applications of the EC/RSAC coupled system in sulphate-containing wastewater treatment.

Parametric and energy consumption optimization of Basic Red 2 removal by electrocoagulation/egg shell adsorption coupling using response surface methodology in a batch system

2015 ◽  
Vol 73 (11) ◽  
pp. 2572-2582 ◽  
Author(s):  
Helder Pereira de Carvalho ◽  
Jiguo Huang ◽  
Meixia Zhao ◽  
Gang Liu ◽  
Xinyu Yang ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Energy Consumption ◽  
Reaction Time ◽  
Response Surface ◽  
Removal Efficiency ◽  
Current Density ◽  
Batch System ◽  
Energy Consumption Optimization ◽  
Initial Ph ◽  
Rsm Model

In this study, response surface methodology (RSM) model was applied for optimization of Basic Red 2 (BR2) removal using electrocoagulation/eggshell (ES) coupling process in a batch system. Central composite design was used to evaluate the effects and interactions of process parameters including current density, reaction time, initial pH and ES dosage on the BR2 removal efficiency and energy consumption. The analysis of variance revealed high R2 values (≥85%) indicating that the predictions of RSM models are adequately applicable for both responses. The optimum conditions when the dye removal efficiency of 93.18% and energy consumption of 0.840 kWh/kg were observed were 11.40 mA/cm2 current density, 5 min and 3 s reaction time, 6.5 initial pH and 10.91 g/L ES dosage.

scholarly journals Application of electrochemical peroxidation (ECP) process for waste-activated sludge stabilization and system optimization using response surface methodology (RSM)

2018 ◽  
Vol 77 (6) ◽  
pp. 1765-1776 ◽  
Author(s):  
Gagik Badalians Gholikandi ◽  
Khashayar Kazemirad
Keyword(s):  
Response Surface Methodology ◽  
Activated Sludge ◽  
Response Surface ◽  
Removal Efficiency ◽  
Ph Value ◽  
System Optimization ◽  
Waste Activated Sludge ◽  
Operational Conditions ◽  
Sludge Stabilization ◽  
Rsm Optimization

Abstract In this study, the performance of the electrochemical peroxidation (ECP) process for removing the volatile suspended solids (VSS) content of waste-activated sludge was evaluated. The Fe2+ ions required by the process were obtained directly from iron electrodes in the system. The performance of the ECP process was investigated in various operational conditions employing a laboratory-scale pilot setup and optimized by response surface methodology (RSM). According to the results, the ECP process showed its best performance when the pH value, current density, H2O2 concentration and the retention time were 3, 3.2 mA/cm2, 1,535 mg/L and 240 min, respectively. In these conditions, the introduced Fe2+ concentration was approximately 500 (mg/L) and the VSS removal efficiency about 74%. Moreover, the results of the microbial characteristics of the raw and the stabilized sludge demonstrated that the ECP process is able to remove close to 99.9% of the coliforms in the raw sludge during the stabilization process. The energy consumption evaluation showed that the required energy of the ECP reactor (about 1.8–2.5 kWh (kg VSS removed)−1) is considerably lower than for aerobic digestion, the conventional waste-activated sludge stabilization method (about 2–3 kWh (kg VSS removed)−1). The RSM optimization process showed that the best operational conditions of the ECP process comply with the experimental results, and the actual and the predicted results are in good conformity with each other. This feature makes it possible to predict the introduced Fe2+ concentrations into the system and the VSS removal efficiency of the process precisely.

scholarly journals Optimization of electrocoagulation of instant coffee production wastewater using the response surface methodology

2017 ◽  
Vol 19 (2) ◽  
pp. 67-71 ◽  
Author(s):  
Ha Manh Bui
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Removal Efficiency ◽  
Current Density ◽  
Cod Removal ◽  
Coefficient Of Determination ◽  
Electrolysis Time ◽  
Instant Coffee ◽  
Operating Variables ◽  
Initial Ph

Abstract The COD removal efficiency from an instant coffee processing wastewater using electrocoagulation was investigated. For this purpose, the response surface methodology was employed, using central composing design to optimize three of the most important operating variables, i.e., electrolysis time, current density and initial pH. The results based upon statistical analysis showed that the quadratic models for COD removal were significant at very low probability value (<0.0001) and high coefficient of determination (R2 = 0.9621) value. The statistical results also indicated that all the three variables and the interaction between initial pH and electrolysis time were significant on COD abatement. The maximum predicted COD removal using the response function reached 93.3% with electrolysis time of 10 min, current density of 108.3 A/m2 and initial pH of 7.0, respectively. The removal efficiency value was agreed well with the experimental value of COD removal (90.4%) under the optimum conditions.

scholarly journals Treatment of Zn2+ in wastewater by sinusoidal alternating current coagulation: response surface methodology and removal mechanism

2020 ◽  
Vol 82 (9) ◽  
pp. 1950-1960
Author(s):  
Yihui Zhou ◽  
Tao Xu ◽  
Jinhua Ou ◽  
Gege Zou ◽  
Xiping Lei ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Energy Consumption ◽  
Response Surface ◽  
Removal Efficiency ◽  
Current Density ◽  
Alternating Current ◽  
Initial Ph ◽  
Freundlich Adsorption Isotherm ◽  
Pseudo Second Order ◽  
Main Component

Abstract A novel sinusoidal alternating current coagulation (SACC) technique was used to remove the Zn2+ from wastewater in the present study. The response surface methodology was used to analyze the effect of current density, time, initial pH and initial Zn2+ concentration in order to obtain the optimum removal efficiency and to lower energy consumption. The results show that SACC with a current density of 0.31 A·m−2 applied to treat wastewater containing 120 mg·dm−3 Zn2+ at pH = 9 for 21.3 min can achieve a removal efficiency of Zn2+ of 98.80%, and the energy consumption is 1.147 kWh·m−3. The main component of flocs produced in SACC process is Fe5O7OH·4H2O (HFO). Large specific surface area and good adsorption performance of HFO are demonstrated. There is strong interaction between Zn2+ and HFO. Zn2+ is adsorbed and trapped by HFO and then co-precipitated. Freundlich adsorption isotherm model and pseudo-second order kinetics model explained the Zn2+ adsorption behavior well. The Zn2+ adsorption on HFO is an endothermic and spontaneous process.

scholarly journals Removal of atrazine from aqueous solutions onto a magnetite/chitosan/activated carbon composite in a fixed-bed column system: optimization using response surface methodology

RSC Advances ◽  
2020 ◽  
Vol 10 (68) ◽  
pp. 41588-41599
Author(s):  
Ignace Agani ◽  
Jacques K. Fatombi ◽  
Sèmiyou A. Osseni ◽  
Esta A. Idohou ◽  
David Neumeyer ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Activated Carbon ◽  
Aqueous Solutions ◽  
Response Surface ◽  
Fixed Bed ◽  
System Optimization ◽  
Carbon Composite ◽  
Fixed Bed Column ◽  
Column System ◽  
Efficient Adsorbent

In this study, a magnetite/chitosan/activated carbon (MCHAC) composite is proposed as an efficient adsorbent for the removal of atrazine from aqueous solutions.

scholarly journals Investigating the Result of Current Density, Temperature, and Electrolyte Concentration on COD: Subtraction of Petroleum Refinery Wastewater Using Response Surface Methodology

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 835
Author(s):  
Sharon Chakawa ◽  
Mujahid Aziz
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Removal Efficiency ◽  
Current Density ◽  
Petroleum Refinery ◽  
Cod Removal ◽  
Refinery Wastewater ◽  
Cod Removal Efficiency ◽  
Petroleum Refinery Wastewater ◽  
Nacl Concentration

Electrochemical oxidation (EO) investigated chemical oxygen demand (COD) subtraction from petroleum refinery wastewater (PRW) as a capable remediation process. Titanium substrates coated with iridium–tantalum oxide mixtures (Ti/IrO2–Ta2O5) were used as the dimensional stable anode (DSA). The Box-Behnken Design (BBD), a statistical experimental design and response surface methodology (RSM), was used to matrix the current density, temperature, and electrolyte (NaCl) concentration variables, with COD removal efficiency as the response factor. A second-order verifiable relationship between the response and independent variables was derived where the analysis of variance displayed a high coefficient of determination value (R2 = 0.9799). The predicted values calculated with the model equations were very close to the experimental values where the model was highly significant. Based on the BBD for current density, the optimum process conditions, temperature and electrolyte (NaCl) concentration were 7.5 mA/cm2, 42 °C and 4.5 g/L, respectively. They were resulting in a COD removal efficiency of 99.83% after a 12-hour EO period.

scholarly journals Optimization of Electrocoagulation Conditions for the Purification of Table Olive Debittering Wastewater Using Response Surface Methodology

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1687
Author(s):  
Razieh Niazmand ◽  
Moslem Jahani ◽  
Farzaneh Sabbagh ◽  
Shahabaldin Rezania
Keyword(s):  
Response Surface Methodology ◽  
Energy Consumption ◽  
Central Composite Design ◽  
Response Surface ◽  
Removal Efficiency ◽  
Current Density ◽  
Quadratic Polynomial ◽  
Total Phenolic ◽  
Square Root ◽  
Central Composite

In the present study, the optimization of electrocoagulation (EC) conditions for the purification of olive debittering wastewater (ODW) was investigated by response surface methodology (RSM). For this purpose, a central composite design (CCD) was employed to optimize the process variables including current density (3.0–30.0 mA/cm2) and EC time (10.0–60.0 min). The results showed a significant effect of current density and EC time on the removal efficiency of total phenolic compounds (TPC) and chemical oxygen demand (COD). The best models obtained using the central composite design were quadratic polynomial for TPC (R2 = 0.993), COD (R2 = 0.982), and the inverse square root of turbidity (R2 = 0.926). Additionally, the square root of electrode consumption and energy consumption were appropriately fitted to the two-factor interaction (2FI) model (R2 = 0.977) and quadratic polynomial (R2 = 0.966) model, respectively. The predicted optimum conditions based on the highest removal efficiency for TPC were a current density of 21.1 mA cm−2 and an EC time of 58.9 min, in which the obtained model predicted 82.6% removal for TPC. This prediction was in agreement with the laboratory result (83.5%). The amount of energy consumption and the operating cost in these conditions was estimated to be 14.92 kWh and USD 6.49 m−3 per ODW, respectively.

scholarly journals Response Surface Methodology: Photocatalytic Degradation Kinetics of Basic Blue 41 Dye Using Activated Carbon with TiO2

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1068
Author(s):  
Emmanuel Kweinor Tetteh ◽  
Elorm Obotey Ezugbe ◽  
Dennis Asante-Sackey ◽  
Edward Kwaku Armah ◽  
Sudesh Rathilal
Keyword(s):  
Response Surface Methodology ◽  
Activated Carbon ◽  
Reaction Time ◽  
Photocatalytic Degradation ◽  
Response Surface ◽  
Quadratic Model ◽  
Phase Identification ◽  
Optimization Approach ◽  
Turbidity Removal ◽  
Catalyst Load

Water decontamination still remains a major challenge to some developing countries not having centralized wastewater systems. Therefore, this study presents the optimization of photocatalytic degradation of Basic Blue 41 dye in an aqueous medium by an activated carbon (AC)-TiO2 photocatalyst under UV irradiation. The mesoporous AC-TiO2 synthesized by a sonication method was characterized by X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy for crystal phase identification and molecular bond structures, respectively. The efficiency of the AC-TiO2 was evaluated as a function of three input variables viz. catalyst load (2–4 g), reaction time (15–45 min) and pH (6–9) by using Box-Behnken design (BBD) adapted from response surface methodology. Using color and turbidity removal as responses, a 17 run experiment matrix was generated by the BBD to investigate the interaction effects of the three aforementioned input factors. From the results, a reduced quadratic model was generated, which showed good predictability of results agreeable to the experimental data. The analysis of variance (ANOVA), signposted the selected models for color and turbidity, was highly significant (p < 0.05) with coefficients of determination (R2) values of 0.972 and 0.988, respectively. The catalyst load was found as the most significant factor with a high antagonistic impact on the process, whereas the interactive effect of reaction time and pH affected the process positively. At optimal conditions of catalyst load (2.6 g), reaction time (45 min), and pH (6); the desirability of 96% was obtained by a numerical optimization approach representing turbidity removal of 93% and color of 96%.

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