嗜麦芽窄食单胞菌对铜镉的吸附特性与离子交换

Characteristic and Ion Exchanges During Cu^(2+) and Cd^(2+) Biosorption by Stenotrophomonas maltophilia

研究了投菌量、金属浓度和戊二醛浓度对嗜麦芽窄食单胞菌吸附水体中Cu2+和Cd2+特性的影响,分析了重金属生物吸附、NO3-去除与菌体离子释放的关联,从离子吸附、交换、转化与释放的角度探讨了重金属生物吸附机制.结果表明嗜麦芽窄食单胞菌对Cu2+和Cd2+吸附性能良好,0.2 g·L-1干重菌体处理浓度为0.05 mmol·L-1的Cu(NO3)2和Cd(NO3)2溶液120 min后,Cu2+和Cd2+的吸附率分别达96.3%和83.9%.菌体对Cu(NO3)2和Cd(NO3)2溶液的吸附过程存在Cu2+和Cd2+的表面吸附与胞内运输、NO3-胞内积累、NO3-还原为NO2-等行为,而且Cu2+和Cd2+的胞内运输、NO3-积累和还原需要消耗能量,并会促进Cl-、PO43-、SO42-、Na+、NH4+、K+和Ca2+等离子的释放.红外光谱分析表明菌体酰胺基、羟基与羧基均参与了Cu2+和Cd2+的吸附.X-光电子能谱分析显示吸附后Cu2+和Cd2+的价态不发生变化.

The characteristics of Cu2＋and Cd2＋ biosorption by Stenotrophomonas maltophilia（S.maltophilia） under different biomass,metal concentration and glutaraldehyde content were studied and the correlations among metal biosorption,NO-3 removal and ion release were analyzed.The mechanism was explored through ion biosorption,exchange,conversion and release.The experimental results demonstrated that S.maltophilia was an efficient strain to remove Cu2＋ and Cd2＋.The biosorption efficiencies of Cu2＋ and Cd2＋ achieved 96.3% and 83.9%,respectively after dealing with 0.05 mmol·L-1 aqueous solutions for 120 min with dry biosorbent dosage of 0.2 g·L-1.Cu2＋ and Cd2＋ biosorption by S.maltophilia included surface adsorption,transmembrane active transportation,bioaccumulation of NO3- and reduction of NO3- to NO2-.The intracellular transfer and reduction of NO3- to NO2- during biosorption by S.maltophilia were energy-consuming biological processes.It could also promote the release of Cl-,PO43-,SO42-,Na＋,NH＋4,K＋ and Ca2＋.From FTIR investigation,involvement of various functional groups like acetylamino,hydroxyl and carboxyl in the binding of Cu2＋ and Cd2＋was evident.Moreover,XPS results proved that the valence state of Cu2＋ and Cd2＋ did not changed by biosorption.