Dimensionally stable anode (Ti/RuO2) mediated electro-oxidation and multi-response optimization study for remediation of coke-oven wastewater

Abstract

Electrochemical oxidation by means of dimensionally stable anodes (Ti/RuO2) was executed for the simultaneous elimination of various pollutants (such as COD, phenol, cyanide, and ammonia, etc.) from simulated and real coking-wastewater. A multiparameter variation study was also performed to investigate the operating range of certain operational parameters (such as pH, electrolyte, current density (CD), and H2O2 as a catalyst) and their effects on removal efficiencies of COD and rest of the pollutants of wastewater. To investigate the visual, morphological & elemental features of electrodes FE-SEM and EDX studies were performed before and after the treatment of wastewater. The electrochemical behavior was explored through cyclic voltammetry analysis. Moreover, the degradation and mineralization performance of organic material in wastewater was also investigated through LC-MS and total organic carbon (TOC) studies, respectively. A mathematical equation (model) was also developed to represent the multi-parameter optimization study using central composite design (CCD) through response surface methodology software (RSM tool). At the end of the process, the COD (90.13%), phenol (99.34%), cyanide (96.23%), and ammonia (94.43%) were eliminated within 180 min of reaction at optimum initial pH, NaCl (electrolyte), current density (CD), and H2O2 concentration of 8.0, 1.6 g/L, 24 mA/cm2 and 0.030 M, respectively.