Hu Hong-Bo, Liu Yue-Ying, Fu Jin-Kun, Xue Ru, Gu Ping-Ying
School of Life Sciences, Xiamen University, Xiamen 361005, China.
Sheng Wu Gong Cheng Xue Bao. 2003 Jul;19(4):456-61.
The objective of this work was to develop a valuable adsorbent for recovery of platinum by studying the properties of Pt4+ -adsorption with immobilized Citrobacter freudii XP05 biomass. Five methods for immobilization of Citrobacter freudii XP05 biomass were compared. The method with gelatin-alginate sodium as entrapment matrix was considered to be the optimal. Spherical and uniform beads were produced and the SEM micrograph indicated that the cell of strain XP08 were uniformly dispersed within the matrix. The adsorption of Pt4+ by immobilized XP05 biomass was affected with adsorptive time, pH value of the solution, immobilized biomass concentration, Pt4+ initial concentration The adsorption was a rapid process. The optimal pH value for Pt4+ adsorption was 1.5, and its adsorptive capacity increased linearly with increasing Pt4+ initial concentrations in the range of 50 - 250 mg/L. The experimental data could be fitted to Langmuir and Freundlich models of adsorption isotherm. The adsorptive capacity reached 35.2 mg/g under the conditions of 250 Pt4+ mg/L, 2.0 g/L immobilized biomass, pH 1.5 and 30 degrees C for 60 min. 98.7% of Pt4+ adsorbed on immobilized biomass could be desorbed with 0.5 mol HC1/L. The characteristics of dynamic adsorption and desorption of immobilized XP05 biomass in packed-bed reactor were investigated. The saturation uptake was 24.66 mg Pt4+ /g under the conditions of flow rate 1.2 mL/min, pH 1.5, 50 mg Pt4+/L and 1.85 g biomass(dry weight) . Adsorptive efficiency of Pt4 + by the immobilized XP05 biomass was above 78% for 4 cycles of adsorption and desorption. The recovery of platinum from waste platinum catalyst was studied. The adsorptive capacity was 20.94 mg Pt4+/g immobilized biomass under the conditions of 4.0 g/L immobilized XP05 biomass, 117.76 mg Pt4+/L and pH 1.5 for 60 min. The immobilized XP05 biomass is potentially applicable to the recovery of platinum from waste and wastewater containing platinum.
本研究旨在通过研究固定化弗氏柠檬酸杆菌XP05生物质对Pt4+的吸附特性，开发一种用于回收铂的有价值吸附剂。比较了五种固定化弗氏柠檬酸杆菌XP05生物质的方法。以明胶-海藻酸钠为包埋基质的方法被认为是最佳方法。制备出了球形且均匀的珠子，扫描电子显微镜照片表明XP08菌株的细胞均匀分散在基质中。固定化XP05生物质对Pt4+的吸附受吸附时间、溶液pH值、固定化生物质浓度、Pt4+初始浓度的影响。吸附过程迅速。Pt4+吸附的最佳pH值为1.5，在50 - 250 mg/L范围内，其吸附容量随Pt4+初始浓度的增加呈线性增加。实验数据可拟合到Langmuir和Freundlich吸附等温线模型。在250 mg/L Pt4+、2.0 g/L固定化生物质、pH 1.5和30℃条件下吸附60 min时，吸附容量达到35.2 mg/g。用0.5 mol/L HCl可解吸固定化生物质上吸附的98.�%的Pt4+。研究了固定化XP05生物质在填充床反应器中的动态吸附和解吸特性。在流速1.2 mL/min、pH 1.5、50 mg Pt4+/L和1.85 g生物质（干重）条件下，饱和吸附量为24.66 mg Pt4+ /g。固定化XP05生物质对Pt4+的吸附效率在4次吸附-解吸循环中均高于78%。研究了从废铂催化剂中回收铂的情况。在4.0 g/L固定化XP05生物质、117.76 mg Pt4+/L和pH 1.5条件下吸附60 min时，吸附容量为20.94 mg Pt4+/g固定化生物质。固定化XP05生物质具有从含铂废物和废水中回收铂的潜在应用价值。
