【摘要】 从芦苇根部筛选出一株耐镉内生细菌,经鉴定为Chryseobacterium rhizosphaerae SH-1;Cd²⁺对该菌株最小抑菌浓度高达450 mg/L,显微观察发现其细胞表面吸附机制参与了Cd²⁺的去除过程;FTIR分析表明菌株表面的O-H、N-H、C-H、N≡C-、-NO₂、C=S、P=O、S-O等基团均参与了吸附作用。采用海藻酸钠凝胶包埋法对菌株SH-1进行固定化,考察了吸附时间、pH和Cd²⁺初始浓度对固定化微生物吸附Cd²⁺影响,并对其吸附特性进行了动力学研究。结果表明:固定化内生菌SH-1在Cd²⁺初始浓度为100 mg/L,吸附时间为480 min,溶液pH值为5条件下,对Cd²⁺的去除率高达93.24%;Langmuir等温吸附模型能描述其吸附Cd²⁺的等温吸附特征,最大理论吸附量为187.41 mg/g。另一方面,准二级动力学模型较好地拟合了固定化SH-1吸附Cd²⁺的动力学过程,理论平衡吸附量为51.02 mg/g。这些结果均证实固定化内生菌SH-1是一种很有潜力的生物吸附剂。更多还原

【Abstract】 A cadmium-resistant endophytic bacterium was isolated from reed rhizosphere and identified as Chryseobacterium rhizosphaerae SH-1. The minimum inhibitory concentration of Cd²⁺ was up to 450 mg/L, and microscopic observation showed that the cell surface adsorption mechanism was involved in the removal process of Cd²⁺. FTIR analysis showed that O-H, N-H, C-H, N≡C-,-NO₂, C=S, P=O and S-O were all involved in the adsorption. The strain was immobilized using sodium alginate. The effects of contact time, pH and Cd²⁺ initial concentrations on Cd²⁺ adsorption by immobilized beads were investigated and the adsorption properties were also explored through adsorption kinetics. The result showed that the removal efficiency was over 93.24% while the initial Cd²⁺ concentration of 100 mg/L, contact time of 480 min and pH of 5.0. The isothermal adsorption characteristics of Cd²⁺ could be described by Langmuir isothermic adsorption model with the maximum theoretical adsorption capacity of 187.41 mg/g. On the other hand, the pseudo-second-order model well fitted the kinetic process of Cd²⁺ adsorption by immobilized SH-1 and the theoretical equilibrium adsorption capacity was 51.02 mg/g. The results showed that the immobilized endophytic bacterium SH-1 could be a great potential biosorbent.更多还原