Study On The Characteristics Of Soil Pollution In Lead-zinc Mining Area And The Adsorption Of Pb²⁺ By Microbe-induced Calcium Carbonate

Southwest my country is wealthy in lead-zinc natural resources,however,the matter of serious metal pollution caused by kith and kin within the method of development and utilization of the natural resource is changing into additional and additionally serious.Therefore,it’s pressing to analyze associate degreed develop an economical and environmentally friendly new repair material to manage serious metal pollution from the supply.the method of biomineralization could be a universal development in nature,that deeply affects the discharge,migration,transformation and fixation of varied serious metal components within the natural surface surroundings,Therefore,it’s received intensive attention from consultants and students within the fields of biogeochemistry,environmental and biological sciences,and geomicrobiology.By exploring the removal of serious metals by microbial-induced mineralization of carbonate minerals,it’s vital to repair the soil that impures by serious metal in lead-zinc mining areas.This paper takes the tailings reservoir space and close farmland soils of Xiangrong Mining Co.,Ltd.in Puding County,Guizhou Province because the analysis object,studies the soil serious metal pollution characteristics during this space,and uses high-throughput sequencing to investigate the soil microorganism diversity,sieve strains with Pb²⁺,and use this strain to induce carbonate.Explore the best adsorption conditions and mechanism of microorganism carbonate precipitation on Pb²⁺.Below are key analysis findings:（1）The heavy metals of Pb,Zn,Cd and As within the soil of the lead-zinc mining space all have completely different degrees of excess.The pollution degree of every heavy metal is graded as Cd,Zn,Pb,As.the great pollution index of the soil within the mining space is between 1.00 and 20.77.Among them,the soil samples with moderate and severe pollution account for 33.3%and 61.9%of the whole range of samples,severally.Analyzing the correlation of soil heavy metals,it’s found that at the amount of P<0.01,the heavy metals Pb-Zn,Pb-Cd,and Zn-Cd square measure very considerably absolutely correlate,indicating that the soil Pb,Zn,and Cd heavy metals within the lead-zinc mining space could have similar earth The chemical nature and will return from an equivalent pollution supply or the pollution degree is similar.（2）The heavy metal pollution of the lead-zinc mining area has a significant impact on the diversity of soil microorganisms.A total of 19 bacterial phyla were detected in the tested soil.The tailings reservoir area was the most polluted,with the lowest diversity and fewer species.The bacterial group with the highest relative abundance was the Proteobacteria;on the contrary,the relatively light pollution.The diversity of sampling points is high,the number of species and the dominant bacteria phyla is relatively large,and the distribution of bacterial numbers is relatively balanced,and the bacterial community is more stable.（3）One strain of lead-tolerant bacterium GW-1 was screened from the tested soil.The study found that the bacterium has a strong tolerance to lead,with a maximum lead tolerance of 1000 mg·L^-1.The morphological and physiological and biochemical characteristics of the bacteria were studied Based on the sequencing results of its 16S r DNA sequence and BLAST comparative analysis,it is inferred to be Bacillus pumilus.（4）Bacillus pumilus was used to induce calcium carbonate,and the effect of different Ca²⁺concentrations on the precipitation of calcium carbonate induced by microorganisms was studied.The mineralization products were characterized by combining SEM-EDS and XRD.（5）The calcium carbonate induced by Bacillus pumilus is used to explore its adsorption effect on Pb²⁺,when the initial concentration of Pb²⁺is 10 mg·L^-1（p H₀=6）,the amount of adsorbent added is 1 g·L^-1,and the reaction has oscillated at 25℃ and 180r·min^-1for 36 hours,the adsorption effect is the best,and the removal rate of Pb²⁺can reach 98.8%.Studies on adsorption kinetics and isotherms show that the adsorption process conforms to the pseudo-second-order kinetic equation and Langmuir equation,with a maximum adsorption capacity of 68.4 mg·g^-1.Combined with SEM-EDS,XRD,FTIR and other characterization methods,the mechanism results show that the adsorption of Pb²⁺ by this adsorbent is mainly physical.