Effect Of Biochar Modification On Anion Adsorption And Microbial Chromium(VI)Reduction In Soil

Biochar has played an important role in mitigating global climate change,water environment protection,soil improvement and soil biochemistry.At present,the modification and application of biochar is still a hot point.Surface modification of biochar by organic or other modifiers can alter the surface characteristics of biochar,thereby enhancing the adsorption properties of biochar.Biological carbon surface negative charge dominates,the adsorption capacity of cation,at present there are many researches focused on the adsorption of biochar on adsorption of organic pollutants and heavy metal cations,few involved in the research on adsorption capacity of anion,however the sewage and soil environmental governance will involve the processing of corresponding toxic anion,so take measures on the biological carbon was modified so that it can enhance the adsorption capacity of anion,have important significance to the study of environmental protection,agriculture and other fields.This study by the iron oxide surface modification of biochar,to explore their different anions(ions)adsorption capacity;by comparing the effects of adding biomass carbon reduction in flooded soil iron and chromium,clear biological carbon in the treatment of Cr(VI)in the process of pollution effect;comparison of different dosage and different biomass carbon the size of biochar in waterlogged soil Cr(VI)impact reduction capacity;verification of adding biochar on Fe(III)-Cr(VI)control system of competition reduction;put forward biological carbon in Cr(VI)pollution system in repairing mechanism.The main conclusions of this study are as follows:(1)Biochar has certain adsorption to chromate and phosphate,but its adsorption capacity is limited.(2)Using ferric hydroxide modified biochar can increase the adsorption ability of chromate and phosphate,compared with,The modified biochar has more obvious adsorption effect on monovalent phosphates.(3)The adsorption ability of biochar to chromate and phosphate increased with the decrease of particle size of biochar.With the increase of biochar content,the removal rate of chromate increased gradually,but the adsorption capacity of unit quality biochar to chromate decreased.(4)Adding biochar and ferric oxide to two kinds of soil,iron oxide has obvious holding ability to chromate in soil slurry.(5)Cr(VI)and Fe(III)reduction process showed a competitive mechanism in flooded soils,biochar can promote Fe to the system(III)reduction process,the particle size of biochar and the large and small biological carbon dosage on Fe(III)reduction process effect is more obvious,but the biological carbon particle size and dosage of Cr(VI)difference did not significantly affect the reduction process.The reduction of chromate in the system can be accelerated by adding ferric oxide.The microbial fermentation process can reduce the pH value of the system.