Study On Synergistic Removal Of Adsorption And Catalytic Oxidation Of Tetracycline In Water By Modified Biochar

Water pollution by antibiotics has become a potential risk for humans,and it is an environmental problem that needs to be solved urgently.Advanced oxidation technology has high removal efficiency of organic pollutants,a wide range of degradable organic substances,and fast reaction.Many studies have shown that biochar（BC）has both adsorption and oxidation catalysis for organic pollutants,but its performance is limited.Thus this study used Ficus virens Ait.var.sublanceolata（Miq.）Corner as raw material to prepare biochar,and discussed the effect of ultraviolet irradiation and urea modification on the adsorption and catalytic oxidation degradation of tetracycline（TC）and its mechanism.The main findings are as follows:（1）In the biochar/H₂O₂ reaction system,adsorption and catalytic oxidation are responsible for the removal of tetracycline by Phellodendron amurense biochar,in which catalytic oxidation plays a major role.The removal rate of TC by BC700 biochar adsorption was only 14.66%,but the removal rate of tetracycline by BC700/H₂O₂catalysis system could reach 83.34%.The adsorption capacity and the catalytic oxidation of biochar increased with the increasing of the temperature for biochar preparation.（2）The ultraviolet irradiation modification resulted in limited improvement in adsorption of tetracycline onto biochar,but could obviously promote the catalytic performance of biochar.The catalytic performance of biochar prepared at all temperatures was improved under 4 hours of irradiation.The highest removal rate of tetracycline in the modified BC700/H₂O₂ system could reach 98%.The effect of ultraviolet modification on biochar catalytic performance improving is mainly attributed to the formation of basic functional groups on surface of biochar.（3）Urea-modified biochar had the enhanced performance of tetracycline adsorption as well as the ascending catalyzing of hydrogen peroxide for tetracycline degradation.BC700 modified by urea with a mass ratio of 1:1(M_biochar:M_urea)presented the highest tetracycline removal rate of 98.98%in all modified biochars.The increasing removal of tetracycline by modified biochar was attributed to the synergistic effect of adsorption and catalysis on the surface of biochar.