The Preparation Of Sludge-based Biomass Charcoal And The Adsorption Performance Of Organic Arsenic In Aqueous Solution By The Modified Material

Based on the sewage treatment plant sludge as raw material,sludge base biochar?SBC?was prepared with its adsorption capacity for Cu²⁺as evaluation index to optimize the different concentration of activator,impregnation ratio,dipping time,carbonization temperature,carbonization time.The results showed the optimization of the concentration was 15%KOH,impregnation ratio was 1:1,the dipping time was 4h,carbonization temperature was 750?and carbonization time was 40 min.Sludge based biochar?NZVI-SBC?modified with nanometer zero-valent iron significantly improved the removal effect of arsenic.Among them,nanometer zero-valent iron modified sludge-based biochar?NZVI-350SBC?was prepared by calcining biochar?350SBC?at 350?after modification,which increased the adsorption and removal rate of As?III?by 9.86 times.In this study,the specific surface area and pore size distribution analyzer?BET?,scanning electron microscope?SEM?,Fourier infrared spectrometer?FT-IR?were used to characterize the material before and after modification.The BET results showed that the specific surface area and pore volume of the material increased significantly after modification.SEM results showed that NZVI particles were evenly dispersed on the surface of biomass carbon.FTIR analysis showed that the surface oxygen-containing functional groups increased significantly after SBC load NZVI,which further enhanced the adsorption effect of NZVI-SBC on arsenic.This study also explored the removal capacity of arsenic in water by NZVI-SBC through a series of static experiments.The experimental results showed that the adsorption experiment basically reached equilibrium after 180min.The adsorption effect was the best when the material dosage was 0.2g·L^-1.The removal rate of NZVI-SBC decreased with the increase of pollutant concentration.The removal rate of NZVI-SBC was the highest when pH was 4.8.The adsorption of arsenic by NZVI-SBC conformed to the quasi-second-order kinetic model in the experiment,and the adsorption of arsenic by NZVI-SBC conformed to the Freundlich isothermal model,indicating that multi-layer adsorption occurred.Thermodynamic parameters also indicated that the adsorption reaction was beneficial to adsorption when the system temperature rises.In conclusion,the sludge-based biochar modified by nano zero-valent iron is a rare and excellent material in the treatment of heavy metal pollution in water due to its cheap and easy raw materials,significant adsorption of arsenic and stable physical and chemical properties.