Degradation of basic violet 16 dye by electro-activated persulfate process from aqueous solutions and toxicity assessment using microorganisms: determination of by-products, reaction kinetic and optimization using Box–Behnken design

Abstract

This study was performed to determine the efficiency of the electro/persulfate process to remove basic violet 16 (BV16) dye and COD from aqueous solutions. The present study was experimentally performed on a laboratory scale. The effect of pH on the process was investigated independently, and after performing the experiments, the effect of voltage (volts), the dose of persulfate (g/L), initial concentration of BV16 dye, and electrolysis time was investigated with the model presented by Box Behnken design, and optimal conditions for BV16 dye removal was obtained. Under optimal conditions, COD removal efficiency and toxicity changes during the process were calculated, and the effect of distance between electrodes and surface of electrodes on process efficiency was investigated. By-products of oxidative degradation were determined with LS-MS. The amount of electrical energy consumed by the process was investigated by voltage changes and then the kinetics of the process was investigated by a pseudo-first-order model. The results showed that the electro/persulfate process in optimal conditions including pH of 5, a voltage of 11.43 V, persulfate dose of 0.09 g/L, initial BV16 concentration of 45 mg/L, and electrolysis time of 48.5 min could provide BV16 dye removal efficiency of 95% and COD removal efficiency of 57.14%. Findings of electrical energy consumption showed that with increasing voltage, the efficiency of the process increased, but the amount of energy consumption also increased. Under optimal conditions, increasing distance between the electrodes was led to a decrease in removal efficiency, but the removal efficiency increased with the increasing surface of the electrodes. Based on the kinetic results, the electro/persulfate process followed pseudo-first-order kinetics with R 2 = 0.9956. The present study showed that the electro/persulfate process as a useful technique has high efficiency in removing BV16 dye and its toxicity from aqueous solutions and can be effective and useful in removing the COD of solution.

Optimization and Modeling of Cr (VI) Removal from Tannery Wastewater onto Activated Carbon Prepared from Coffee Husk and Sulfuric Acid (H2SO4) as Activating Agent by Using Central Composite Design (CCD)

“…Te opposite is true for pH, as the pH of the solution increased, the adsorption capacity of Cr (VI) decreased and vice versa. Increasing the pH causes a decrease in adsorption, increasing the dosage causes an increase in adsorption capacity, and increasing the contact duration causes an increase in adsorption capacity for Cr (VI) [61].…”

Development and Use of a Real‐time In‐situ Monitoring Tool for Electrochemical Advanced Oxidation Processes

“…[9] As a result, any delay between electrolysis and sample analysis could artificially inflate decolorization values due to the slow propagation of hydroxyl radicals over time and the oxidizing power of persulfate. Since centrifugation [10,11] or queuing on an HPLC [12,13] autosampler are common practices, the possibility of downtime decolorization is important. However, it is generally ignored in literature reports.…”

Analysis of the Capacity of the Fenton Process for the Treatment of Polluted Wastewater from the Leather Dyeing Industry

“…The optimal operating conditions for Fenton oxidation can be determined through experimental design and the response surface methodology (RSM). RSM involves a group of mathematical and statistical techniques based on the adjustment of empirical models to the experimental data obtained according to the selected matrix [ 24 , 37 ]. Linear or square polynomial functions are used to describe the performance of the studied system and to examine the experimental conditions until their optimization [ 38 ].…”