Removal of heavy metals lead and ciprofloxacin from farm wastewater using peanut shell biochar

Abstract

In this paper, peanut shells were used as the raw material for preparing biochar (PBC), and artificial simulated aging was used to age the PBC. To investigate the effectiveness of biochar before and after aging for the removal of Pb and ciprofloxacin (CIP) alone and the feasibility of simultaneous removal of Pb and CIP. The effects of different aging methods on the physicochemical properties of biochar were investigated by measuring the specific surface area (BET), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared absorption spectrometry (FTIR) of biochar. The results showed that the C content of biochar decreased after aging, while the O/C, H/C, (N+O)/C, and O contents increased. Kinetic adsorption, adsorption isothermal and competitive adsorption experiments were performed to study the adsorption properties of CIP and Pb2+ by aging biochar under single and combined pollution systems. Aging inhibited the adsorption of ciprofloxacin on biochar, and the inhibition size was ranked as high-temperature aging > freeze-thaw cycles aging > natural aging. However, the effect of aging on the adsorption of Pb2+ by biochar was insignificant. Pb2+ in the complex contamination system would compete with CIP for oxygen-containing functional groups and adsorption sites on biochar, indicating that the pollutant adsorption mechanism by biochar is complex and influenced by various factors such as aging methods and pollutant species. This study shows that regional climatic factors and target pollutant species must be considered when applying biochar for pollutant removal, which may affect the long-term effects of pollution remediation.