Effects Of Copper-lead Contaminated Sediment Remediation And Microbial Community By Biochar And Activated Carbon

The contaminant is deposited in the sediment after physical and chemical effects such as precipitation and adsorption through the river.When the sediment environment is changed,the sediment easily become pollution sources of river and the contaminant would be released into the river.The heavy metals contaminant presenting in the sediment have received widespread attention due to its non-degradability and bioaccumulation,which cause serious harm to the ecological environment and organisms.The Xiangjiang River is the largest river in Hunan Province.The heavy metal pollution is very serious in the Xiangjiang River due to the rapid industrial development and the discharge of waste water.The concentration of heavy metals such as cadmium(Cd),chromium(Cr),copper(Cu)and lead(Pb)is very high in the sediment of the Xiangjiang River.In this study,the Xiangjiang River sediment was collected as the research samples,and the biochar(RHB)and activated carbon(AC)purchased on the market were used as the remediation materials of the sediment.The effect of copper-lead contaminated sediment remediation and microbial community by biochar and activated carbon have been researched.The RHB and AC purchased on the market were characterized by elemental analysis,SEM,BET,FITR,XPS,XRD and so on.The main difference between the two materials is that specific surface area and micropore distribution of activated carbon are much higher than biochar.During the process of sediment remediation,AC had a better effect on sediment remediation,and the immobilization effect was better with the addition increasing.When the AC addition amount is 10%,the acid-soluble Cu and Pb were reduced by 93% and 60%,respectively.When the amount of RHB is 10%,the acid-soluble Cu and Pb were reduced by 23% and 31%,respectively.At the same time,the Cu and Pb content in the overlying water and the interstitial water were decreased.Among them,the remediation effect of the activated carbon treatment group is superior to biochar.RHB and AC could reduce the active components of Cu and Pb in the sediment,thereby inhibiting the release of heavy metals Cu and Pb from sediment into the water.The specific surface area and microporous structure according to the characterization analysis play a major role.The sediment is a complex ecological environment.While carbonaceous materials are added to the sediment to remediate contaminated sediment,we need to pay attention to the ecological balance.The abundance of the microbial community in the sediment are studied after RHB and AC addition.The results showed that AC has a negative impact on the microbial community in the sediment.When the amount of AC addition was large(5%,10%),the abundance of microbial community in the sediment was significantly reduced;however,the RHB not only did not inhibit the survival of the microbial community,but also increased the abundance of the microbial community,making the microbial community more diverse.Therefore,the AC treatment reduced the abundance of microbial community in the sediment,which was not conducive to the survival of microorganisms.To sum up,when we remediate environmental pollution,we need to consider the impact on the ecosystem and choose green technologies and materials to deal with pollution on the basis of ensuring effective pollution removal.