Activity and stability of biochar in hydrogen peroxide based oxidation system for degradation of naphthenic acid

This study investigated the stability and catalytic activity of wheat straw biochar (WS), hardwood biochar (HW) and commercial activated carbon (AC) in hydrogen peroxide (H2O2) based oxidation system for degradation of model naphthenic acids compound, 1-methyl-1- cyclohexane carboxylic acid (MCCA). WS showed excellent catalytic activity for decomposition of H2O2 and MCCA degradation as demonstrated by high H2O2 decomposition rate (2.0*10-4 M-1s-1), amount of hydroxyl (OH) radicals generated (182 mg/L) and degradation efficiency of MCCA (100% at Co - 100 mg/L). 2-Methyl pentatonic acid was identified as reaction intermediate and 99% mineralization of MCCA was obtained within 4 h. The real wastewater conditions were simulated by addition of chloride (Cl-) and bicarbonate ions (HCO3-) and found that lower concentrations of Cl- and HCO3- have minimal influence on MCCA removal. Overall, biochar catalyzed H2O2 based oxidation process has great potential and can be applied for degradation of NAs in oil-sand processed water.