Application and mechanism of sludge-based activated carbon for phenol and cyanide removal from bio-treated effluent of coking wastewater

Abstract

The toxic pollutants phenol and cyanide in the bio-treated effluent of coking wastewater still need advanced treatment to meet environmental requirements. In this study, activated carbon prepared from municipal sludge and bamboo waste (SBAC) was used for simultaneous adsorption of phenol and cyanide from bio-treated effluent of coking wastewater. The results showed that the optimum removal efficiencies of volatile phenol (69.7%) and total cyanide (80.1%) were observed at a SBAC dosage of 8 g/L, a pH value of 8.0, and a contact time of 80 min. The physical and chemical properties of SBAC were analyzed using Brunauer-Emmett-Teller (BET) surface area (SBET), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. SBAC had high SBET (289.58 m2/g) and rich mesoporous structure (average pore diameter of 3.688 nm), and carboxylic groups on SBAC surfaces were enhanced due to the addition of bamboo waste. In addition, a kinetic model of pseudo-first-order fitted well with the experimental data of volatile phenol, while the adsorption of total cyanide onto the SBAC was better described by a pseudosecond- order kinetic model.