Use of response surface methodology for optimization of fluoride removal efficiency by adsorption on black mustard husk ash

Wastewater produced from polymer flooding in oil production features high viscosity and chemical oxygen demand because of the residue of high-concentration polymer hydrolysed polyacrylamide (HPAM). In this study, steel slag, a waste from steel manufacturing, was studied as a low-cost adsorbent for HPAM in wastewater. Optimisation of HPAM adsorption by steel slag was performed with a central composite design under response surface methodology (RSM). Results showed that the maximum removal efficiency of 89.31% was obtained at an adsorbent dosage of 105.2 g/L, contact time of 95.4 min and pH of 5.6. These data were strongly correlated with the experimental values of the RSM model. Single and interactive effect analysis showed that HPAM removal efficiency increased with increasing adsorbent dosage and contact time. Efficiency increased when pH was increased from 2.6 to 5.6 and subsequently decreased from 5.6 to 9.3. It was observed that removal efficiency significantly increased (from 0% to 86.1%) at the initial stage (from 0 min to 60 min) and increased gradually after 60 min with an adsorbent dosage of 105.2 g/L, pH of 5.6. The adsorption kinetics was well correlated with the pseudo-second-order equation. Removal of HPAM from the studied water samples indicated that steel slag can be utilised for the pre-treatment of polymer-flooding wastewater.

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Electrocoagulation and nanofiltration integrated process application in purification of bilge water using response surface methodology

Water Science & Technology ◽

10.2166/wst.2016.168 ◽

2016 ◽

Vol 74 (3) ◽

pp. 564-579 ◽

Cited By ~ 11

Author(s):

Ceyhun Akarsu ◽

Yasin Ozay ◽

Nadir Dizge ◽

H. Elif Gulsen ◽

Hasan Ates ◽

...

Keyword(s):

Response Surface Methodology ◽

Response Surface ◽

Removal Efficiency ◽

Cod Removal ◽

Positive Sign ◽

Aluminum Electrode ◽

Integrated Process ◽

Bilge Water ◽

Cod Removal Efficiency ◽

Initial Ph

Marine pollution has been considered an increasing problem because of the increase in sea transportation day by day. Therefore, a large volume of bilge water which contains petroleum, oil and hydrocarbons in high concentrations is generated from all types of ships. In this study, treatment of bilge water by electrocoagulation/electroflotation and nanofiltration integrated process is investigated as a function of voltage, time, and initial pH with aluminum electrode as both anode and cathode. Moreover, a commercial NF270 flat-sheet membrane was also used for further purification. Box–Behnken design combined with response surface methodology was used to study the response pattern and determine the optimum conditions for maximum chemical oxygen demand (COD) removal and minimum metal ion contents of bilge water. Three independent variables, namely voltage (5–15 V), initial pH (4.5–8.0) and time (30–90 min) were transformed to coded values. The COD removal percent, UV absorbance at 254 nm, pH value (after treatment), and concentration of metal ions (Ti, As, Cu, Cr, Zn, Sr, Mo) were obtained as responses. Analysis of variance results showed that all the models were significant except for Zn (P > 0.05), because the calculated F values for these models were less than the critical F value for the considered probability (P = 0.05). The obtained R2 and Radj2 values signified the correlation between the experimental data and predicted responses: except for the model of Zn concentration after treatment, the high R2 values showed the goodness of fit of the model. While the increase in the applied voltage showed negative effects, the increases in time and pH showed a positive effect on COD removal efficiency; also the most effective linear term was found as time. A positive sign of the interactive coefficients of the voltage–time and pH–time systems indicated synergistic effect on COD removal efficiency, whereas interaction between voltage and pH showed an antagonistic effect.

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Study on the mutual interactions between the parameters of a CANON system and its coping strategy when operating at room temperature (15 to 25 °C) using response surface methodology

Water Science & Technology ◽

10.2166/wst.2014.062 ◽

2014 ◽

Vol 69 (9) ◽

pp. 1805-1812 ◽

Cited By ~ 1

Author(s):

Jian Zhou ◽

Guangxu Qin ◽

Jianbing Zhang ◽

Yancheng Li ◽

Qiang He ◽

...

Keyword(s):

Response Surface Methodology ◽

Response Surface ◽

Removal Efficiency ◽

Coping Strategy ◽

Room Temperature ◽

Loading Rate ◽

Nitrogen Loading ◽

Independent Variables ◽

Do Concentration ◽

N Loading

The coping strategy of a CANON (completely autotrophic nitrogen removal over nitrite) reactor working at room temperature was investigated using response surface methodology. The total nitrogen (TN) removal efficiency was taken as a dependent variable. The temperature (X), dissolved oxygen (DO) concentration (Y), and influent nitrogen loading rate (Z) were taken as independent variables. Results showed that the relation of these three independent variables can be described by the TN removal efficiency expressed as −5.03 + 1.51X + 45.16Y + 30.13Z + 0.26XY + 1.84XZ − 0.04X2 − 9.06Y2 − 99.00Z2. The analysis of variance proved that the equation is applicable. The response surface demonstrated that the temperature significantly interacts with the DO concentration and influent N loading rate. A coping strategy for the CANON reactor working at room temperature is thus proposed: altering the DO concentration and the N loading rate to counterbalance the impact of low temperature. The verification test proved the strategy is viable. The TN removal efficiency was 91.3% when the reactor was operated under a temperature of 35.0 °C, a DO of 3.0 mg/L, and a N loading rate of 0.70 kgN/(m³ d). When the temperature dropped from 35.0 to 19.2 °C, the TN removal efficiency was kept at 88.7% by regulating the influent N loading rate from 0.7 kgN/(m³ d) to 0.35 kgN/(m³ d) and the DO concentration from 3.0 to 2.6 mg/L.

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Optimization and Modeling of Microcystin-LR Degradation by TiO2 Photocatalyst Using Response Surface Methodology

Journal of Environmental Health and Sustainable Development ◽

10.18502/jehsd.v5i3.4278 ◽

2020 ◽

Author(s):

Negar Jafari ◽

Afshin Ebrahimi ◽

Karim Ebrahimpour ◽

Ali Abdolahnejad

Keyword(s):

Response Surface Methodology ◽

Response Surface ◽

Removal Efficiency ◽

Contact Time ◽

High Performance ◽

Operating Variables ◽

Effective Removal ◽

Positive Effect ◽

Harmful Effects ◽

Maximum Removal

Introduction: Microcystin-leucine arginine (MC-LR) is a toxin with harmful effects on the liver, kidney, heart, and gastrointestinal tract. So, effective removal of MC-LR from water resources is of great importance. The aim of this study was to remove microcystin-LR (MC-LR) from aqueous solution by Titanium Dioxide (TiO2). Materials and Methods: In the present study, TiO2, as a semiconductor, was used for photodegradation of MC-LR under ultraviolet light (UV). The Response Surface Methodology was applied to investigate the effects of operating variables such as pH (A), contact time (B), and catalyst dose (B) on the removal of MC-LR. The MC-LR concentration was measured by high-performance liquid chromatography (HPLC). Results: The results showed that single variables such as A, B, and C had significant effects on MC-LR removal (pvalue < 0.05). In other words, increase of the contact time and catalyst dose had a positive effect on enhancing the removal efficiency of MC-LR, but the effect of pH was negative. The analysis of variance showed that BC, A2, and C2 variables had a significant effect on the MC-LR removal (pvalue < 0.05). Finally, the maximum removal efficiency of MC-LR was 95.1%, which occurred at pH = 5, contact time = 30 minutes, and catalyst dose = 1 g/l. Conclusion: According to the findings, TiO2, as a photocatalyst, had an appropriate effect on degradation of the MC-LR.

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Optimization of Coagulation-Flocculation Process of Landfill Leachate by Tin (IV) Chloride Using Response Surface Methodology

Avicenna Journal of Environmental Health Engineering ◽

10.34172/ajehe.2019.06 ◽

2019 ◽

Vol 6 (1) ◽

pp. 41-48 ◽

Cited By ~ 1

Author(s):

Abdul Aziz Hamidi ◽

Syed Zainal Sharifah Farah Fariza ◽

Alazaiza Motasem Y.D

Keyword(s):

Response Surface Methodology ◽

Response Surface ◽

Removal Efficiency ◽

Landfill Leachate ◽

Chemical Properties ◽

Oxygen Demand ◽

Statistical Design ◽

Water Infiltration ◽

Flocculation Process ◽

Maximum Removal

Landfill leachate is highly polluted and generated as a result of water infiltration through solid waste produced domestically and industrially. This study investigated the applicability of the response surface methodology (RSM) to optimize the removal performances of chemical oxygen demand (COD), color, and suspended solids (SS) from landfill leachate by coagulation process using Tin tetrachloride pentahydrate. The leachate samples were collected from Alor Pongsu Landfill (APLS) in Perak, Malaysia. Before starting the experiments, general characterization was carried out for raw leachate samples to investigate their physical and chemical properties. The effects of the dosage and pH of SnCl4 on the removal performances were evaluated as well. An ideal experimental design was performed based on the central composite design (CCD) by RSM. In addition, this RSM was used to evaluate the effects of process variables and their interaction toward the attainment of their optimum conditions. The statistical design of the experiments and data analysis was resolved using the Design-Expert software. Further, the range of coagulant dosage and pH was selected based on a batch study which was conducted at 13000 mg/L to 17000 mg/L of SnCl4 and pH ranged from 6 to 10. The results showed that the optimum pH and dosage of SnCl4 were 7.17 and 15 g/L, respectively, where the maximum removal efficiency was 67.7% for COD and 100% for color and SS. The results were in agreement with the experimental data with a maximum removal efficiency of 67.84 %, 98.6 %, and 99.3%, for COD, color, and SS, respectively. Overall, this study verified that the RSM method was viable for optimizing the operational condition of the coagulation-flocculation process.

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

Water Science & Technology ◽

10.2166/wst.2018.066 ◽

2018 ◽

Vol 77 (6) ◽

pp. 1765-1776 ◽

Cited By ~ 1

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.

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A rapid and efficient removal approach for degradation of metformin in pharmaceutical wastewater using electro-Fenton process; optimization by response surface methodology

Water Science & Technology ◽

10.2166/wst.2019.312 ◽

2019 ◽

Vol 80 (4) ◽

pp. 685-694 ◽

Cited By ~ 8

Author(s):

Maryam Dolatabadi ◽

Saeid Ahmadzadeh

Keyword(s):

Response Surface Methodology ◽

Response Surface ◽

Removal Efficiency ◽

Degradation Mechanism ◽

Pharmaceutical Products ◽

Oh Radicals ◽

Order Kinetic ◽

Pharmaceutical Wastewater ◽

Efficient Removal ◽

Solution Ph

Abstract Presence of emerging contaminants such as pharmaceutical products in aquatic environments has received high concern due to their undesirable effect on wildlife and human health. Current work deals with developing a treatment model based on the electro- Fenton (EF) process for efficient removal of metformin (MET) from an aqueous medium. The obtained experimental results revealed that over the reaction time of 10 min and solution pH of 3, the maximum removal efficiency of 98.57% is achieved where the value of MET initial concentration, current density, and H2O2 dosage is set at 10 mg.L−1, 6 mA.cm−2, and 250 μL.L−1, respectively, which is in satisfactory agreement with the predicted removal efficiency of 98.6% with the desirability of 0.99. The presence of radical scavengers throughout the mineralization of MET under the EF process revealed that the generation of •OH radicals, as the main oxidative species, controlled the degradation mechanism. The obtained kinetics data best fitted to the first order kinetic model with the rate constant of 0.4224 min−1 (R2 = 0.9940). The developed treatment process under response surface methodology (RSM) was employed for modeling the obtained experimental data and successfully applied for efficient removal of the MET contaminant from pharmaceutical wastewater as an adequate and cost-effective approach.

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Application of response surface methodology for optimization of zinc elimination from a polluted soil using tartaric acid

Adsorption Science & Technology ◽

10.1177/0263617420916592 ◽

2020 ◽

Vol 38 (3-4) ◽

pp. 79-93

Author(s):

Zahra Sheikhi Alman-Abad ◽

Hossein Pirkharrati ◽

Farrokh Asadzadeh ◽

Mahdi Maleki-Kakelar

Keyword(s):

Heavy Metal ◽

Response Surface Methodology ◽

Response Surface ◽

Tartaric Acid ◽

Removal Efficiency ◽

Acid Concentration ◽

Health Hazard ◽

Polluted Soil ◽

Zinc Removal ◽

Washing Process

Heavy metal wastes generated from mining activities are a major concern in developing countries such as Iran. Increasing concentrations of these metals in the soil make up a severe health hazard due to their non-degradability and toxicity. In this study, batch washing experiments were conducted in order to investigate the removal efficiency of zinc by biodegradable chelates, tartaric acid. For this purpose, soil samples were collected from the zinc contaminated soil in the region of the Angouran, Zanjan, Iran. Hence, optimization of batch washing conditions followed using a three-level central composite design approach based on the response surface methodology. The results demonstrated that the effects of pH, tartaric acid concentration, and interaction between selective factors on the zinc removal efficiency were all positive and significant (P < 0.05). An optimum zinc removal efficiency of 89.35 ±2.12% was achieved at tartaric acid concentration of 200 mM l−1, pH of 4.46, and incubation time of 120 min as the optimal conditions. Accordingly, response surface methodology is appropriately capable to determine and optimize chemical soil washing process to remediate heavy metal polluted soil.

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