Kinetics of catalytic treatment of coking wastewater (COD, phenol and cyanide) using wet air oxidation

Abstract

Abstract Coking wastewater (CWW) is known as a highly polluting effluent. This study deals with the degradation of pollutants in terms of COD, phenol and cyanide present in CWW using catalytic wet air oxidation (CWAO) process. CWAO was carried out in batch mode using various catalysts. The investigated operating parameters are initial pH (pH i ) 3–11, temperature (T) 100–160 °C, air partial pressure (p air) 2–6 MPa, catalyst mass loading (C w ) 2–5 g/L and treatment time (t R ) of 0–6 h. Among various catalysts, the copper chloride was proved to be best for degradation of pollutants. The optimum conditions were evaluated for the degradation of organic compounds as T 130 °C, p air 8.8 MPa, C w 3 g/L and t R  = 6 h. The maximum percentage reduction of COD, phenol, and cyanide was achieved through experiment at T 160 °C, p air 12.2 MPa, C w 5 g/L and t R 6 h as 97.32%, 97.94% and 99.87%, respectively. The kinetics studies were also performed to evaluate the rate constant (k), and reaction order with respect to COD, phenol, CN, CW and p air.