Application Of Modified Biofuel Ash To Stabilize Bioavailable Cadmium In Soil

The problem of Cd pollution in our country is very serious.In situ passivation technology is one of the most economical and effective technologies for remediation of Cd pollution in farmland.As a low cost heavy metal remediation agent,biofuel ash has preliminarily demonstrated its good passivation effect on Cd,but there are still some problems such as large dosage and low effect of Cd reduction in crops.The study on the in-depth analysis of biofuel ash on Cd passivation mechanism,by adding magnesium oxide and polyphenols reduction iron nanoparticles on modification,used to improve the adsorption properties of biofuel ash on Cd.The effects of the two materials on the modified ash were explored by a series of characterization methods such as SEM、XRF、XRD、FTIR、BET.The main conclusions obtained are as follows:1.Using the different mass ratio of magnesia and biofuel ash to modifiy.the biofuel ash.When the mass ratio of magnesia and ash was 0.1:1,the adsorption effect was the best,the maximum adsorption reached 38.55mg/g,which was a simple biofuel ash adsorption capacity of 4.6 times.Magnesium oxide to add the same time improving the biomass power plant ash acid buffering capacity,and with the increase of percentage of magnesium oxide in the composite,and with the increase of the proportion of MgO in the mixed material,the equilibrium concentration of Mg²⁺gradually increased,but the amount of Mg²⁺per unit mass of MgO released Reduce,but larger than the unit of pure magnesium oxide release.MgO-modified biofuel ash not only improves the ash adsorption capacity of biofuel ash,but also improves its acid-base buffer capacity.2.Polyphenol reduced nano-iron modified biofuel ash in the iron-ash ratio of 0.3:1,the modified biofuel ash adsorption capacity of Cd is maximum,the maximum adsorption capacity of 38.3904mg/g.The adsorption of Cd（Ⅱ）by polyphenol reduced nano-iron modified biofuel ash conformed to the Freundlich isotherm model（R2>0.93）,shows that modified biofuel ash adsorption of Cd（Ⅱ）for multilayer adsorption,the adsorption process there are a variety of mechanisms.Through the above research,it is expected to prepare two modified biofuel ash,both have good adsorption capacity of Cd,has good potential for promotion and application.