Study On Adsorption And Fixation Behavior Of Organic Arsenic In Paddy Soil And Adsorption Of Organic Arsenic By Hematite

With the development of economy and society and people’s constant pursuit of living standards,livestock and poultry farming gradually transformed from decentralized type,in order to solve the growing public demand for meat products.Organic arsenic feed additives are widely used in livestock and poultry breeding to resist germsthey,inhibit the growth of intestinal bacteria and parasites breeding,improve the pigmentation of livestock and poultry products.Only a small portion of organic arsenic will be taken by livestock and poultry,and the majority of organic arsenic is excreted into the environment in the form of prototypes by excrement and urine,which has not been absorbed by livestock and poultry.Organic arsenic will be transformed into the more migratory and more toxic compounds by biological interactions and environmental substances when they enter into the environment,finally causing environmental pollution problems.Therefore,it is necessary to study the chemical behavior and biological response of organic arsenic in soil and find out how to adsorb or remove organic arsenic efficiently and avoid its further conversion.Firstly,we systematically studied the adsorption and fixation behavior of organic arsenic in paddy soils.Soil is a complex natural body with a mixture of many different components.Therefore,the adsorption performance exhibited by the soil is constrained by various components.While studying soil adsorption properties,we also evaluated the effects of various soil components on soil adsorption performance by a variety of methods.The results showed that the adsorption of organic arsenic in soil was mainly caused by the soil organic matter and irons combined with organic matter.This not only deepened our theoretical understanding of the the factors that affect the sorption of roxarsone on soil,but also provided a theoretical reference for adjusting the soil composition to improve the soil adsorption capacity of organic arsenic,in order to achieve a greener and more efficient immobilization effect of organic arsenic.Secondly,the interaction of hematite facets and organic arsenic(phenylarsonic acid)was systematically investigated with attenuated total reflectance Fourier transform infrared(ATR-FTIR)spectroscopy,macroscopic adsorption,kinetics model,density-functional theory(DFT)calculation and surface complexation models.The results illustrated that different organic arsenic complexes were formed on the hematite facets with different exposed facets.And different coordination modes will directly affect the sorption performance of organic arsenic on hematite on.By exposing some special iron oxide surface can improve the performance of iron oxide adsorption of organic arsenic to achieve a better fixed effect of organic arsenicThis paper deepened our understanding of the factors affecting the migration of organic arsenic in soil,while also provided the strong evidence for our elucidation of the roles of hematite in the bioavailability and mobility of organic arsenic in the environment.