Adsorption of selected micropollutants on powdered activated carbon and biochar in the presence of kaolinite

AbstractCommercially available powdered activated carbon (PAC) and activated biochar (produced in the laboratory), combined with kaolinite, were used to determine the adsorption of a beta-blocker (atenolol, ATN) and sunscreen compounds (benzophenone, BZP; and benzotriazole, BZT); a hypothesis was made that the presence of kaolinite would increase the adsorption of those target compounds. Various synthetic solutions were prepared by altering the pH, background ions, ionic strength, and glucose/humic acid content to mimic various natural water conditions. The removal efficiency of biochar–kaolinite was higher than that of PAC–kaolinite, presumably because the relatively high surface area and pore volume of biochar resulted in a higher adsorption capacity for the target compounds. Removal of the compounds in the absence of kaolinite followed the order BZP > ATN > BZT (a (mg/g); Langmuir maximum adsorption capacities were as follows: 85.0, 20.6, and 15.6 for PAC, and 125, 37.5, and 25.9 for biochar, respectiv...