School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, China.
J Environ Sci (China). 2011;23(7):1104-12. doi: 10.1016/s1001-0742(10)60522-0.
The biosorption characteristics of Cs(I) ions from aqueous solution using exopolymers (PFC02) produced from Pseudomonas fluorescens C-2 were investigated as a function of pH, biosorbent dosage, contact time and initial concentration. pH played a major role in the adsorption process, and the optimum pH for the removal of Cs(I) was 8.0. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherm of the Cs(I) ions by PFC02. The Lagergren first-order, pseudo second-order kinetic and intraparticle diffusion models were used to test the kinetic data. Langmuir model and D-R model fitted the equilibrium data better than the Freundlich isotherm. The monolayer adsorption capacities of PFC02 as obtained from Langmuir isotherm at 25 degrees C was found to be 32.63 mg/g. From the D-R isotherm model, the mean free energy was calculated as 26.73 kJ/mol, indicating that the biosorption of cesium was chemisorption. The biosorption process was rapid, and the kinetic rates were best fitted to the pseudo second-order model, which indicated the biosorption process operated through chemisorption mechanism. FT-IR analysis of PFC02 showed the possible functional groups responsible for cesium adsorption were hydroxyl, carboxyl, carbonyl and sulphonate groups. SEM analysis showed the porous structure of the material while EDX analysis confirmed the adsorption of Cs(I) on PFC02. Cesium adsorbed onto the PFC02 could be desorbed efficiently using 1 mol/L HNO3, and the enrichment factor was 50.0. Furthermore, PFC02 could be reused five times with only about 8.25% regeneration loss. The developed method was successfully utilized for the removal of Cs(I) ions from aqueous solution.
采用荧光假单胞菌 C-2 产生的胞外聚合物（PFC02）研究了 Cs(I)离子从水溶液中的生物吸附特性，作为 pH、生物吸附剂用量、接触时间和初始浓度的函数。pH 在吸附过程中起主要作用，去除 Cs(I)的最佳 pH 值为 8.0。Langmuir、Freundlich 和 Dubinin-Radushkevich（D-R）模型被应用于描述 PFC02 对 Cs(I)离子的吸附等温线。Lagergren 一级、拟二级动力学和内扩散模型用于测试动力学数据。Langmuir 模型和 D-R 模型比 Freundlich 等温线更适合拟合平衡数据。在 25°C 下，从 Langmuir 等温线获得的 PFC02 的单层吸附容量为 32.63mg/g。从 D-R 等温线模型计算得到的平均自由能为 26.73kJ/mol，表明铯的吸附是化学吸附。吸附过程迅速，动力学速率最适合拟二级模型，表明吸附过程通过化学吸附机制进行。PFC02 的 FT-IR 分析表明，可能负责铯吸附的官能团为羟基、羧基、羰基和磺酸盐基团。SEM 分析显示了材料的多孔结构，而 EDX 分析证实了 Cs(I)在 PFC02 上的吸附。用 1mol/L HNO3 可以有效地将吸附在 PFC02 上的铯解吸，富集因子为 50.0。此外，PFC02 可以重复使用五次，再生损失仅约 8.25%。所开发的方法成功地用于从水溶液中去除 Cs(I)离子。
