摘要
以热灭活的植物乳杆菌为生物吸附剂,探讨了吸附U(VI)的影响,并采用扫描电镜-能谱、红外光谱等手段研究了U(VI)的吸附机理。结果表明,植物乳杆菌对U(VI)具有良好的吸附效果。在pH为6.0,温度30℃,灭活乳杆菌投加量为120 mg/L,初始U(VI)的质量浓度为10 mg/L时,植物乳杆菌对U(VI)的去除率可达94.28%,吸附平衡时间为4 h。吸附过程较好符合准2级动力学吸附模型和Freundlich模型。经过灭活的植物乳杆菌的菌体比表面积增加,能更好的吸附U(VI),配位络合是菌体吸附U(VI)的主要机理,参与吸附的官能团有细胞表面多糖与蛋白质羟基、蛋白质酰胺基、羧基与磷酸酯基等。此外菌体表面的静电作用也是吸附的方式之一。
The heat-killed Lactobacillus plantarum was used as biosorbent to investigate the effects on U(VI) adsorption. The adsorption mechanism was investigated by SEM-EDS, FTIR and other methods. The results showed that Lactobacillus plantarum had a good adsorption effect on U(VI). When the pH was 6, the temperature was 30 ℃, the inactivated Lactobacillus dosage was 120 mg/L, and the initial mass concentration of U(VI) was 10 mg/L,the U(VI) adsorption efficiency of heat-killed Lactobacillus plantarum was up to 94.28% and balanced at 240 minutes. The adsorption process fit well with the pseudo-second-order kinetics adsorption model and the Freundlich model. The specific surface area of the inactivated Lactobacillus plantarum was increased and U(VI) could be adsorbed better. Coordination was the main mechanism of uranium adsorption by bacteria. The functional groups involved in adsorption include cell surface polysaccharides and protein hydroxyl groups, protein amide groups, carboxyl groups, and phosphate ester groups. In addition, the electrostatic effect on the surface of bacteria was one of the adsorption methods.
引文
[1]ZHAO C,LIU J,LI X,et al.Biosorption and bioaccumulation behavior of uranium on Bacillus,sp.dwc-2:Investigation by Box-Behenken design method[J].Journal of Molecular Liquids,2016,221:156-165.
[2]PANG C,LIU Y H,CAO X H,et al.Biosorption of uranium(VI)from aqueous solutionby dead fungal biomass of Penicillium citrinum[J].Chemical Engineering Journal,2011,170(1):1-6.
[3]王亮,谢水波,杨金辉,等.氧化石墨烯/二氧化硅复合材料对铀(VI)的吸附性能[J].中国有色金属学报,2016,26(6):1264-1271.
[4]WANG X,WANG T,ZHENG X,et al.Isotherms,thermodynamic and mechanism studies of removal of low concentration uranium(VI)by Aspergillus niger[J].Water Science&Technology A Journal of the International Association on Water Pollution Research,2017,75(12):2727.
[5]KESHTKAR A R,MOHAMMADI M,MOOSAVIAN M A.Equilibrium biosorption studies of wastewater U(VI),Cu(II)and Ni(II)by the brown alga cystoseira indica,in single,binary and ternary metal systems[J].Journal of Radioanalytical&Nuclear Chemistry,2015,303(1):363-376.
[6]BAROT N S,BAGLA H K.Biosorption of radiotoxic 90 Sr by green adsorbent:dry cow dung powder[J].Journal of Radioanalytical&Nuclear Chemistry,2012,294(1):81-86.
[7]WANG T,ZHENG X,WANG X,et al.Different biosorption mechanisms of Uranium(VI)by live and heat-killed Saccharomyces cerevisiae under environmentally relevant conditions[J].Journal of Environmental Radioactivity,2017,167:92-99.
[8]MONACHESE M,BURTON J P,REID G.Bioremediation and Tolerance of humans to heavy metals through microbial processes:a potential role for probiotics?[J].Applied&Environmental Microbiology,2012,78(18):6397-404.
[9]MOLIN G.Probiotics in foods not containing milk or milk constituents,with special reference to Lactobacillus plantarum 299v[J].American Journal of Clinical Nutrition,2001,73(2 Suppl):380S-385S.
[10]YOUNAN S,SAKITA G Z,ALBUQUERQUE T R,et al.Chromium(VI)bioremediation by probiotics[J].Journal of the Scienceof Food&Agriculture,2016,96(12):3977-3982.
[11]SEKI H,NOGUCHI A,SUZUKI A,et al.Biosorption of heavy metals onto gram positive bacteria,lactobacillus plantarum and micrococcus luteus[J].Kag-aku Kogaku Ronbunshu,2006,32(4):352-355.
[12]翟齐啸.乳酸菌减除镉危害的作用及机制研究[D].无锡:江南大学,2015.
[13]TSURUTA T.Removal and recovery of Uranium using microorganisms isolated from japanese uranium deposits[J].Journal of Nuclear Science&Technology,2006,43(8):896-902.
[14]YIN R,ZHAI Q,YU L,et al.The binding characters study of lead removal by Lactobacillus plantarum CCFM8661[J].European Food Research&Technology,2015,242(10):1621-1629.
[15]TIAN F W,CHEN W,ZHAI Q X,et al.Lactobacillus plantarum able to relieve lead toxicity and use thereof:EP2708599[P].2014-03-19.
[16]GB/T 6768-86水中微量铀分析方法[S].
[17]SOLGY M,TAGHIZADEH M,GHODDOCYNEJAD D.Adsorption of uranium(VI)from sulphate solutions using Amberlite IRA-402resin:Equilibrium,kinetics and thermodynamics study[J].Annals of Nuclear Energy,2015,75:132-138.
[18]陈华柏,谢水波,刘金香,等.厌氧颗粒污泥吸附铀(VI)的特性与机理[J].中国有色金属学报,2014(9):2418-2425.
[19]SAR P,KAZY S K,D'SOUZA S F.Radionuclide remediation using a bacterial biosorbent[J].International Biodeterioration&Biodegradation,2004,54(2/3):193-202.
[20]WANG J,ZHAO X,TIAN Z,et al.Characterization of an exopolysaccharide produced by Lactobacillus plantarum YW11 isolated from Tibet Kefir[J].Carbohydrate Polymers,2015,125:16-25.
[21]BRON P A,TOMITA S,VAN SWAM I I,et al.Lactobacillus plantarum possesses the capability for wall teichoic acid backbone alditol switching[J].Microbial Cell Factories,2012,11(1):1-15.
[22]ZAMUDIO M,GONZ魣LEZ A,MEDINA J A.Lactobacillus plantarum phytase activity is due to non-specific acid phosphatase[J].Letters in Applied Microbiology,2001,32(3):181-184.
[23]谢水波,马华龙,唐振平,等.微氧条件下硫酸盐还原菌颗粒污泥处理废水中铀(VI)的实验研究[J].原子能科学技术,2015,49(1):26-33.