摘要
通过静态吸附试验,研究了苏云金芽胞杆菌原粉对水溶液中铬离子(Cr6+)的吸附热力学特性。铬离子初浓度依次为50、100、150、200、250、300、400、500mg·L^(-1),菌体浓度固定为1g·L^(-1),pH值为2,分别在5℃、20℃、35℃、50℃条件下进行等温吸附,采用Freundlich方程和Langmuir方程进行拟合。结果显示,苏云金芽胞杆菌原粉对铬离子的吸附符合Langmuir(r>0.979)方程和Freundlich(r>0.977)方程。吸附焓△H为1.39 ̄2.33kJ·mol^(-1),吸附自由能ΔG为-3.75 ̄-2.84kJ·mol-1,吸附熵ΔS为15.2 ̄18.8J·mol^(-1)。苏云金芽胞杆菌原粉对铬离子的吸附是吸热过程,吸附能够自发进行。
The adsorption thermodynamics of chromium (VI) ions on Bacillus thuringiensis powder under static conditions was studied. The initial concentration of Cr^6+ was 50, 100, 150, 200, 250, 300, 400 and 500 mg· L^1, respectively, the concentration of B. thuringiensis powder was 1 g·L^-1,pH was adjusted to 2. The adsorption of Cr^6+ on B. thuringiensis powder was carried out at 5℃, 20℃, 35 ℃ and 50 ℃, respectively. The adsorption data were simulated with Langmuir equation and Freundlich equation, and the results showed that the adsorption isotherms followed Langmuir equation (0.979) and Freundlich equation (0.977). The adsorption enthalpy AH ranged from 1.39 to 2.33 kJ· mol^-1 the adsorption free energy AG ranged from -3.75 kJ·mol^-1to -2.84 kJ·mol^1- and the adsorption entropy AS ranged from 15.2 to 18.8 J ·mol^1, suggesting that the adsorption of Cr^6+on B. thuringiensis was an endothermic process and belonged to spontaneous process.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2007年第4期1292-1295,共4页
Journal of Agro-Environment Science
基金
湖北省教育厅科研计划青年基金项目(Q200611007)
武汉科技大学重点资助项目(2006XZ4)
关键词
苏云金芽胞杆菌
吸附
铬离子
热力学
Bacillus thuringensis
adsorption
chromium (VI) ions
thermodynamics