Efficient phenol removal from petrochemical wastewater using biochar-La/ultrasonic/persulphate system: characteristics, reusability, and kinetic study

This research has analysed the physiochemical properties of a catalyst that has been developed – biochar-La, including BJH, BET, EDX, SEM, FTIR, pHpzc, and iodine number. The catalyst consisted of effective functional groups, including C=S, C–O, C=C, –COOH and O–H, with a specific surface area of 31.2 m2/g. The catalyst was used in the biochar-La/ultrasonic/persulphate system to remove phenol from wastewater. The kinetics, mechanism, and reusability of the catalyst for the phenol removal from synthetic wastewater were determined. The results suggested that phenol removal kinetics follows pseudo-first-order model (k = 0.0386 1/min), and the catalyst can be reused three times. The potential of operation of the biochar-La/ultrasonic/persulphate system – with the effective removal of phenol and other organic compounds from real petrochemical wastewater – was tested. The results indicated that the removal of phenol from the petrochemical wastewater with a relatively high total dissolved solid is >99%. The gas chromatography–mass spectrometry (GC-mass) test revealed that the complete decomposition of some contaminants in the petrochemical wastewater had occurred, as H2O and CO2 were detected. The contribution of a heterogeneous mechanism for phenol oxidation by biochar-La/ultrasonic/persulphate was calculated to be 60%. Overall, the results showed that the biochar-La/ultrasonic/persulphate system is very effective and promising for the removal of phenol from the petrochemical wastewater