Study On The Remediation Of Petroleum Contaminated Soil By Modified Biochar Immobilized Microorganism

Oil destroys the soil structure,persecutes the microorganism and causes the soil fertility to decline,using the biochar to immobilize the microorganism to repair the petroleum pollution soil.Raw materials such as bamboo charcoal?B?,wheat straw?W?,peanut shell?P?were used to prepare biochar,using MgCl₂ to prepare magnesium modified biochar.Obtained six kinds of biochar:bamboo charcoal biochar?BB?,wheat straw biochar?WB?,peanut shell biochar?PB?,modified bamboo charcoal biochar?M-BB?,modified wheat straw biochar?M-WB?and modified peanut shell biochar?M-PB?,determination and characterization of biochar before and after modification of the basic physical and chemical properties variety.M-WB and M-PB were immobilized carrier,the orthogonal experiment was designed by SPSS software and immobilized microorganism was prepared by adsorption method.The effects of biochar types,adsorption time,the amount of biochar and the rotational speed on the amount of bacteria were studied,and determining the best conditions for the preparation of immobilized microorganism;the M-PB with the highest amount of immobilized microorganism was used to prepare the immobilized microorganism,which was used to simulate the remediation of petroleum-contaminated soil.Combined with the content changes of TPH,PAHs and the amount of microorganisms in the process of soil remediation,studing the remediation effect of immobilized microorganisms on petroleum-contaminated soil;M-PB were left in the soil soil,column leaching experiments were conducted to determine the effect of M-PB on leaching and retention of different nitrogen and phosphate fertilizers such as soil nitrate,ammonia,to study the maintenance effect of M-PB on soil fertility.Conclusion as below:?1?after biochar modification,the pH of M-WB and M-PB decreased slightly,the pH of M-BB increased slightly,the ash content increased,the specific surface area increased,the specific surface area and pore volume of M-WB were the largest,the pore diameter of M-PB was the largest,the content of basic functional groups increased,the content of acidic functional groups increased significantly,FTIR showed that the functional groups basically did not change,XRD showed that magnesium was loaded on the biochar.?2?the orthogonal results showed that the H2 bacteria optimum immobilization rate was 78.90%and the H4 bacteria optimum immobilization rate was 72.41%when the volume ratio of bacteria and biochar was 20:1,stereo adsorption for 2 hours.?3?The degradation rate of soil petroleum hydrocarbon was 59.10%and the degradation rate of PAHs was 46.64%for 58 days.In soil,the number of bacteria,fungi and actinomycetes tended to increase firstly and then gradually stabilized.Among all soil remediation experiments,M-PB immobilized microorganism had the highest microbial activity,and the quantity advantage was obvious.?4?Soil column leaching experiments showed that M-PB had stronger water-holding ability to soil,contrast with soil without biochar,M-PB had the most obvious effect on PO₄^3-,it reduced 46.4%of PO₄^3-leaching loss,the reduction of NO₃^-was 40.3%and the reduction of NH₄⁺was 39.3%.Therefore,M-PB immobilized microorganisms can effectively repair petroleum contaminated soil and the addition of M-PB had a strong role of water and fertilizer on the soil.