Adsorption performance and mechanism of diuron from water by calcium-modified water hyacinth-based biochar
This study used water hyacinth as the raw material and CaCl2 as the modifier to prepare calcium-modified water hyacinth-based biochar(CWHBC)by one-step pyrolysis.Based on characterization techniques,the surface morphology,specific surface area,pore size distribution,and main functional group composition of CWHBC were analyzed,and its adsorption efficiency and mechanism for removing diuron from water were explored.The results showed that compared with unmodified biochar(WHBC),CWHBC had a larger specific surface area,a more abundant pore structure,more oxygen-containing functional groups,and stronger hydrophilicity.These changes in physicochemical properties enhanced the adsorption ability of biochar.The adsorption of diuron by CWHBC conformed to the pseudo-second-order adsorption kinetic model and the Langmuir adsorption isotherm model,indicating that the adsorption was mainly a monolayer chemical adsorption.The main adsorption mechanisms were hydrogen bonding,π-πinteractions,and surface complexation.The results of single-factor experiment showed that CWHBC had good adsorption performance under various conditions,and the adsorption capacity after five cycles of adsorption/desorption with 0.2mol/L HCl was still as high as 94.62%of the initial adsorption capacity.Therefore,the CWHBC prepared by one-step pyrolysis could effectively remove diuron from water and had good environmental adaptability and repeatability.This study provided a low-cost and efficient adsorbent that could effectively achieve the resource utilization of water hyacinth and had good engineering application prospects and potential.
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