Study On Strengthening Degradation And Effect Of Sulfamethoxazole By Shewanella Oneidensis MR-1

Sulfonamide antibiotics are often used as veterinary drugs,which are difficult to effectively absorb and pass into the environment by passive objects,and are difficult to degrade in the soil;microbial remediation has the advantages of low cost and low environmental impact,and can be used to degrade pollutants in the environment.In this paper,the microorganism Shewanella oneidensis MR-1 was selected as the exogenous microorganism and sulfamethoxazole?SMX?was used as the target pollutant to study the degradation characteristics and enhancement effects of SMX under different conditions.It has certain significance and reference value for remediation of soil environment polluted by SMX.?1?The experimental results of microbial degradation characteristics of SMX showed that:the microbial OD=1 had the best degradation effect on SMX,and the best degradation rate could reach62.6%,the raw liquid humic acid PPHA?Pahokee Peat Humic Acids?inhibited the degradation process,and the molecular weight was less than the degradation rate of 14,000 Da with the addition of small molecular humic acid?LMWF?reached 59.5%,the degradation rates of magnetite and hematite suspensions were 61.8%and 64.5%respectively,the promotion of PPHA-Fe₂O₃ system The effect is better than that of the small molecule humic acid-hematite system.The optimal degradation rate is 74.9%when the TOC concentration is 15 mg C/L.?2?In the simulated soil environment experiment,the larger the amount of microorganism inoculation,the better the degradation effect,the higher the concentration of SMX,the more the degradation process will be inhibited;the optimal reaction temperature of the experiment is 30?,3,5 mmol/L sodium lactate will promote degradation,low-concentration potassium nitrate promotes degradation,while high-concentration inhibits degradation,stock solution humic acid with a concentration of less than 15 mg C/L strengthens the degradation system,while larger concentrations inhibit it;small-molecule humic acids with molecular weights less than 7000 Da and14000 Da When the TOC concentration is less than 2 mg C/L,the degradation process is accelerated,and riboflavin of 2,5,10?mol/L will strengthen the degradation system,the effect of synergistic hematite is obvious.?3?In the dynamic degradation experiment of simulated soil column,SMX has vertical mobility and the deeper the soil layer,the greater the concentration of SMX,in the SMX leaching experiment,the degradation rate of SMX in the leachate is maintained between 65.8-76.6%,In the leaching experiment,the final SMX was maintained at about 90.4%.