【摘要】 为寻找Cd²⁺经济、高效、环保的微生物吸附剂,探讨微生物对重金属的吸附特性和机理,从采自韶关大宝山矿区的土壤样品中分离、筛选耐镉功能菌株,以BP-2菌株为研究对象,采用16S r DNA方法对菌株进行了分子鉴定;通过批式试验系统研究了不同环境变量对菌株吸附Cd²⁺的影响;利用等温吸附模型、动力学模型模拟了吸附过程;采用红外光谱（FTIR）、X射线衍射（XRD）和X射线光电子能谱（XPS）分析手段,探讨了菌株吸附镉的作用机理。结果表明,16S r DNA序列相似性表明该菌株隶属芽孢杆菌属,将其命名为Bacillus coagulans BP-2。当Cd²⁺初始质量浓度为100 mg·L^-1,吸附时间为80min,菌株生物量为2.5 g·L^-1时,菌株对Cd²⁺的吸附效果最好,吸附量可达73.26 mg·g^-1;菌株对Cd²⁺的吸附过程符合Langmuir等温模型（r²=0.991 1）,最大吸附量为86.19 mg·g^-1,二级动力学方程（r²=0.981 4）能够更准确地描绘菌株对Cd²⁺的吸附过程。XRD分析显示,吸附后在13.3°、39.1°处出现Cd²⁺的特征峰,说明Cd²⁺成功被吸附到菌株的表面。FTIR和XPS结果表明Bacillus coagulans BP-2细胞壁上的-OH、-NH和-C=O基团参与了Cd²⁺的吸附。利用Bacillus coagulans BP-2非活性菌株作为经济、高效、环境友好生物材料能够有效吸附溶液中Cd²⁺。该研究可为含镉重金属废水的去除提供理论基础和实践依据。更多还原

【Abstract】 The aim of this paper is to isolate and screen Cd²⁺-resistant functional strains,investigating the adsorption characteristics of Cd²⁺,adsorption kinetics and mechanism.So that it can provide theoretical foundation and practical platform for the bioremediation of other heavy metals.The functional strain BP-2 was studied as research object,molecular identification was carried out based on 16S r DNA.The influence of different environmental variables on the adsorption of Cd²⁺was studied by batch test system,and the adsorption process was analyzed by isothermal adsorption model and kinetic model.The mechanism for the adsorption of Cd²⁺was discussed by Infrared spectroscopy（FTIR）,X-ray diffraction（XRD）and X-ray photoelectron spectroscopy（XPS）analysis methods.The results indicated that the 16S r DNA sequence similarity of the strain belonged to be Bacillus,and named as Bacillus coagulans BP-2.The optimum adsorption capacity was achieved at initial Cd²⁺mass concentration of 100 mg·L^-1,biomass 2.5 g·L^-1 with the contact time of 80 min,and under this condition,the maximum adsorption capacity could reach 73.26mg·g^-1.The adsorption isotherm and kinetic models showed that the adsorption processes followed the pseudo-second-order kinetic model（r²=0.991 9）,and were well described by Langmuir isotherm（r²=0.981 4）.XRD characterization results exhibited that the area of 13.3°and 19.1°appeared a strong characteristic peak after adsorption,which implied the successfully adsorption of Cd²⁺to the surface of the inactive strain.The results of FTIR and XPS demonstrated that the functional groups such as-OH,-NH and-C=O on the surface of strain were the involvement of the adsorption for Cd²⁺.Thus,the inactive strain Bacillus coagulans BP-2 can be employed as a potential economic,efficient and environmental-friendly biological material for the effective removal of Cd²⁺from the aqueous solutions,and it is of great practical significance to the sustainable development of ecological environment.更多还原