Engineering Development of Corn Cob Derived Biochar for Fluoroquinolones Removal in Least Developed Countries
Biochar-inspired (BC) tertiary removal system is beneficial in preventing antibiotic residue discharged from hospital wastewater treatment. Taking advantage of a simple kiln controlled at around 600°C, we succeeded in carbonizing corncobs to biochar with a surface area of 306 m2/g. The iodine adsorption fits Langmuir model with the maximum adsorption of 2.42 mg/g and 2.04 mg/g for MB. The kinetic parameter of MB and Iodine was 0.59 hr-1 and 0.13 hr-1 respectively. Using ciprofloxacin (CIP), ofloxacin (OFL), and delafloxacin (DEL), we demonstrated the performance of the corn cob biochar for the sorption removal. The pseudo-second-order rate of DEL was lower than CIP and OFL. The maximum sorption capacity (Qmax) of 93.9 µg/g for DEL, 399.6 µg/g for CIP and 306.0 µg/g for OFL were estimated using the Langmuir model. The parameter KL relating to binding strength for DEL is 8 times larger than CIP and OFL. The Qmax could be mainly determined by the pore size distribution of the biochar and the dimensions of fluoroquinolones (FQs) considering hydration. Furthermore, we discussed that these results might relate to the number of halogen atoms and functional groups in the fluoroquinolones. By use of the simple kiln, we succeeded to obtain corncob BC with large surface area. The results show that BC can bring an economic benefit to rural areas of developing countries for access to clean and safe water supply.
Keywords - Biochar, Delafloxacin, Fluoroquinolones, Sorption, Isotherm, Kinetics.