Turan A, Keyikoglu R, Kobya M, Khataee A. Degradation of thiocyanate by electrochemical oxidation process in coke oven wastewater: Role of operative parameters and mechanistic study.
CHEMOSPHERE 2020;
255:127014. [PMID:
32679632 DOI:
10.1016/j.chemosphere.2020.127014]
[Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 05/06/2020] [Accepted: 05/07/2020] [Indexed: 06/11/2023]
Abstract
This study presents the removal of thiocyanate (SCN-) from coke oven wastewater by the electrooxidation (EO) process. Initially, the performances boron-doped diamond (BDD) and different DSA (Dimensionally stable anode) electrodes including Ti/IrO2, Ti/IrO2-RuO2, and Ti/IrO2-RuO2-TiO2 in SCN- removal were compared. BDD anode outperformed the Ti-based mixed metal oxide (MMO) anodes achieving 96.51% SCN- removal efficiency. The most favorable conditions for the removal of SCN- using BDD anode were determined as follows: pH = 9, current density = 43.10 A m-2, and the electrolyte concentration (Na2SO4) = 2.5 g L-1. The strong role of ⦁OH in the removal of SCN- was confirmed by the addition of radical quenching agents. The evolution of the intermediates as a result of the EO of SCN- was determined. Under the determined conditions, the EO process could remove 84.13% of SCN- and 94.67% of phenol from a real coke oven wastewater, which was comparable to that of the simulated solution. The electrical energy consumption cost of the process to remove 1 kg of SCN- was calculated as 0.208 US $. Overall, the study showed the EO using BDD anode is a cost-effective method for the removal of SCN- from a coke oven wastewater.
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