比较了10种菌株对纯溶液中铂(IV)的吸附效果,优选出大肠杆菌作为吸附剂,并对其吸附行为进行了表征和研究.吸附动力学及颗粒内扩散模型表明,大肠杆菌对铂(IV)的吸附过程经历了快速的表面吸附和缓慢吸收2个阶段,并可在60min内达到吸附平衡;吸附后的SEM、TEM形貌表征显示,大肠杆菌菌体细胞发生形变,皱缩并团聚;XPS结果显示,部分铂(IV)转化为铂(II),表明吸附过程中发生了还原.在25℃、pH=7.0、6h的条件下,大肠杆菌对初始浓度为100mg/L的Pt(IV)溶液的吸附率为96.66%.
Ten known strains were screened for the adsorption performance towards Pt(IV) in pure aqueous solutions, and E. coli was selected as the adsorbent. The adsorption behavior of E. coli was characterized and studied. Kinetic studies and intraparticle diffusion models showed Pt(IV) biosorption proceeded rapidly in the first 10 min, with an almost complete equilibrium being achieved within 60 min. Moreover, scanning electron microscopic (SEM) analysis revealed the changes in the surface morphology of E. coli cells after adsorption, which was further confirmed by transmission electron microscope (TEM) analyses. X-ray photo electron spectroscopy (XPS) results showed that the platinum existed in two valency states: tetravalent platinum Pt(IV) and divalent platinum Pt(II), indicating the occurrence of reduction reaction. The adsorption rate of E. coli on Pt(IV) solution at initial concentration of 100 mg/L was 96.66% at 25℃ and pH 7.0 within 6 h.