Study On Passivation And Repair Of Cadmium-arsenic Compound Contaminated Soil By Iron Modified Biomass Power Plant Ash

In China,due to the large-scale mining and smelting of non-ferrous metals,sewage irrigation,unscientific fertilization and other reasons,heavy metals(metals)such as cadmi um and arsenic accumulate in the soil,which makes the soil heavy metals exceed the st andard.Cadmium and arsenic are both highly toxic elements,which not only harm the e cological function of the soil itself,but also enter the plant and ultimately endanger hum an health through the food chain.The soil cadmium and arsenic complex pollution has b ecome an important type of soil pollution in China.Previous studies have shown that biomass power plant ash(BFA)is a good soil Cd passivator,which has the advantages of low cost and high efficiency.Based on the large amount of research on biomass power plant ash in the early stage of the mentor team,t he biomass power plant Ash as a carrier,ferrous sulfate as a modifier,simultaneous use of ultrasound and pH adjustment,so that iron-modified biomass power plant ash(FeBFA)has the ability to simultaneously passivate cadmium and arsenic in soil,and through iso thermal adsorption Experiments,soil passivation experiments,pot experiments,and a serie s of characterization methods such as X-ray diffraction(XRD),X-ray fluorescence analysi s(XRF),Fourier integral infrared spectroscopy(FTIR),and specific surface spectroscopy for iron-modified biomass power plant ash The nature and passivation effects have been studied in depth,and the main connotations are as follows:1.The isothermal adsorption of cadmium and arsenic by FeBFA accords with Freundl ich(R2=0.96)and Langmuir(R2=0.98)isotherm adsorption model,which belongs to sing le-layer surface adsorption.The maximum adsorption capacity for cadmium can reach 20.16mg/g,the maximum for arsenic.The adsorption amount can reach 5.14mg/g,and the p assivation effect is very significant;2.In the composite contaminated soil with cadmium concentration of 2mg/kg and ars enic concentration of 60mg/kg,FeBFA with soil mass ratio of 0%,0.5%,1% and 2% w as passivated,and the removal rates of available cadmium and arsenic were The amount of passivation agent increased and the maximum removal rate of effective cadmium was 20.47%,and the maximum removal rate of available arsenic was 64.80%.The passivatio n effect was obvious.The raw materials used in this research are low in cost,simple in method and easy to realize industrial production.It is a heavy metal passivating agent that can be applied to the repair of cadmium-arsenic complex contaminated soil,and has a good market appl ication prospect.