Remediation And Improvement Of Heavy Metal Contaminated Soil By Biomass Fuel Ash

In recent years,soil heavy metal pollution in China is becoming more and more serious,which seriously affects soil environmental quality and human food safety.Soil heavy metal pollution in China has gradually become the subject of in-depth research at home and abroad.The results show that biomass fuel ash has good heavy metal adsorption performance and is a good soil heavy metal passivator.The application of biomass fuel ash also helps to increase plant biomass.This paper takes biomass fuel ash as the research object,and through a series of research methods such as XRD,SEM,BET,XRF and FT-IR,conducts a comprehensive and systematic study on the basic characteristics of biomass fuel ash;using adsorption kinetics,Isothermal adsorption,and soil heavy metal passivation experiments have deeply studied the heavy metal adsorption stability of biomass fuel ash.The main research contents and conclusions are as follows:1.In this experiment,biomass fuel ash is rich in nutrient elements required by plants and rich in surface pores.The Langmuir,Freundlich,Koble-Corrigan and Redlich-Peterson adsorption models can better describe the isothermal adsorption process of biomass fuel ash for Pb2+,Cu2+,Co2+,Cr6+,Cd2+ and the adsorption of biomass fuel ash for Pb2+,Cu2+,Co2+,Cr6+,Cd2+in water follows the quasi second-order kinetic adsorption,the equilibrium adsorption amount obtained by the fitting is closer to the actual measured value,the adsorption basically reaches saturation within 10 minutes,and the process is biased towards chemical adsorption.The intra-particle diffusion curve shows that the adsorption process of biomass fuel ash to heavy metals in water is not controlled by a diffusion,but is divided into two stages.In the first stage,the adsorption is relatively fast,which is a rapid adsorption process.In the initial stage,the active sites of biomass fuel ash can quickly accumulate a large number of heavy metal ions,and the outer surface diffusion is strengthened;in the second stage,the linear slope decreases until it tends to balance,it is the adsorption process from internal diffusion to equilibrium.2.After ball milling,the particle size of biomass fuel ash is significantly reduced,the particle gradation of ash is improved,and the specific surface area is increased.On the 15th day of passivation,the passivation efficiency is higher than 50%except for effective Cd2+,among which QBFAM2 has the best passivation effect.Compared with YBFA,the passivation efficiency of effective Pb2+,Cu2+,Co2+,Cr6+,Cd2+is increased by about 9%,2%,12%,47%and 19%respectively.The speciation distribution of heavy metals in soil showed that the exchangeable form of the five heavy metals decreased after the addition of biomass fuel ash.Compared with YBFA and QBFA,the residual form of the five heavy metals after passivation and remediation of QBFAM1,QBFAM2 and QBFAM3 increased,indicating that magnesium oxide promoted the transformation of soil heavy metals to residual form,it has better long-term stability.The biomass fuel ash used in this research has a wide range of sources,low cost and easy mass production.Through comprehensive analysis and research on it,it provides a systematic research method for the specific application of biomass fuel ash,which has a good actual application value.Figure[33]Table[20]Reference[140]...