嗜麦芽窄食单胞菌对镉的吸附

摘要

利用从重金属镉污染地分离并纯化得到的1株嗜麦芽窄食单胞菌(Stenotrophomonas maltophilia)作为吸附剂,考察了镉初始浓度、菌浓度、吸附时间、温度及pH对镉吸附效果的影响.结果表明,在镉初始质量浓度为1.0 mg/L、30℃、pH为6～7条件下,菌质量浓度为2.0 g/L时,吸附120 min对镉吸附率达到81.15%;嗜麦芽窄食单胞菌对镉的吸附是一个先快后慢的过程,达到平衡需60 min;温度对镉吸附率的影响不显著,25℃时达到最高吸附率;pH为5时镉吸附效果最好;嗜麦芽窄食单胞菌对镉的吸附较好地符合Langmuir吸附等温方程.利用傅里叶变换红外光谱探讨了嗜麦芽窄食单胞菌吸附镉前后细胞壁表面官能团的变化情况,发现C-H、N-H、O-H作为主要官能团参与吸附过程.%A bacterial strain (Stenotrophononas maltophilia) was separated and purified from cadmium-contaminated areas,and it was applied as biosorbent for removal of Cd from aqueous solutions. The effect of initial Cd concentration,biosorbent dosage,adsorption time, temperature and pH on Cd adsorption efficiency was investigated. The experimental results showed that the highest adsorption efficiency was achieved when bacteria concentration was 2.0 g/L,initial Cd was 1.0 mg/L pH was 5 and temperature was 30 ℃. The adsorption was accomplished by a fast startup,followed by a slow process which took about 60 min to reach equilibrium. The biosorption equilibrium conformed to the Langmuir equations, the theory saturated adsorptive capacity was calculated as 5.51 mg/g and the actual equilibrium adsorbance was 6.86 mg/g,the absorption behavior was monolayer absorption. The functional groups on the cell wall of Stenotrophomonas maltophilia before and after adsorption process were observed by infrared spectroscopy,the results indicated that the main functional groups participated in Cd adsorption were C-H, N-H,O-H.