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Application of alternating current in electrocoagulation and activation of persulfate (AEC-PS) for the effective removal of humic acid (HA) from aqueous solution was evaluated. In order to optimize the removal efficiency HA by the AEC-PS process, several influencing parameters such as pH, reaction time, PS dose, current density (CD), concentration of NaCl, initial concentration of HA, and coexisting cations and anions influence were investigated. From the batch experiments, the highest HA removal efficiency obtained was 99.4 ± 0.5% at pH of 5, reaction time of 25 min, CD of 4.5 mA/cm 2 , PS dose of 200 mg/L, and NaCl concentration of 0.75 g/L for an initial HA concentration of 30 mg/L. When CD increased from 1.25 to 4.5 mA/cm 2 , the HA removal efficiency was improved from 88.8 ± 4.4% to 96.1 ± 1.5%. In addition, the type of coexisting cations and anions exerted a significant role, leading to a reduction in the removal efficiency of HA. To investigate the dominant free activated radical, radical scavengers such as tert-butyl alcohol and ethanol were employed. It was observed that both OH and SO 4 - radicals substantially contributed to the removal of HA, and the contribution of SO 4 - radical was higher than that of OH radical, suggesting that AEC-PS process could serve as a novel and effective treatment technique for the removal of organic matters from aqueous sources., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Separation under the influence of magnetic field has been widely explored to tackle environmental issues related to centrifuging and filtration. In this work, activated carbon produced from pomegranate husk (PHAC) using dual stage chemical activation was magnetized with iron salts and used for adsorption of 4-chlorophenol (4CP) from the synthetic wastewater. Adsorption experiments were conducted in batch mode to determine the removal efficiency of magnetized activated carbon pomegranate husk (MPHAC) as a function of initial 4CP concentration, solution pH, MPHAC dose, contact time, ionic strength, and temperature. The rough surface of MPHAC containing pores on the surface had a total pore volume of 0.623 cm 3 /g with a surface area of 1168 m 2 /g. The 4CP adsorption was highly dependent on ionic strength, solution pH, and temperature; the equilibrium was reached in 60 min of contact time. Kinetic models and equilibrium isotherms were employed to assess the fitness of adsorption data; results were fitted best with the Liu model giving maximum adsorption capacities of 446.89 ± 20.75 and 183.64 ± 17.85 mg/g for 1 and 2 g/L of MPHAC, respectively. For the investigation of the adsorption kinetics, Avrami fractionary-order model showed the best fit of the experimental data compared to other kinetic models., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)