固定化酵母菌、纳米TiO_2复合吸附剂对Ni^(2+),Cr^(3+),Pb^(2+)吸附性能研究

STUDY ON THE ADORBABILITY OF Ni^(2+),Cr^(3+) AND Pb^(2+) BY IMMOBILIZED YEAST AND NANO TiO_2 AS COMPOSITE ADSORBENT

采用溶胶凝胶法制备纳米TiO2,通过XRD、TEM和红外光谱对样品的粒径、晶型及功能团进行测定表征分析,与酵母菌制成复合吸附剂,用于Ni2+、Cr3+、Pb2+的吸附研究。结果表明,酵母菌体由于吸附了纳米TiO2导致形态结构发生较大变化,且以1%海藻酸钠、1%明胶和2%的聚乙烯醇作为包埋剂进行固定化可以对Pb2+、Ni2+、Cr3+的吸附产生协同作用,最佳吸附率分别达90.25%、80.73%和79.33%;对Pb2+、Ni2+、Cr3+的最佳吸附条件:pH分别为5.0、6.0、5.0,吸附温度分别为35、35、30℃,反应时间分别为60、50、40 min。酸性解吸剂的洗脱效果较好,1 mol.L-1盐酸最佳解吸率可达92.1%。

Nano TiO2 catalysts were prepared by means of sol-gel method whose size,crystal form and functional groups were characterized by XRD,TEM and infrared spectra.The composite adsorbent composed of yeast and nano TiO2 was used to study its adsorption on Ni2＋,Cr3＋ and Pb2＋.The result showed that the morphological structure of yeast cell in composite adsorbent changed greatly owing to the absorption of nano TiO2.Further,immobilized by a certain proportion of 1% alginate sodium,1% gelatin and 2% polyvinyl alcohol as embedding agent,the composite adsorbent worked cooperatively to have synergistic effect on absorption of Pb2＋,Ni2＋ and Cr3＋ with the maximum adsorbance reaching 90.25%,80.73% and 79.33%.Meanwhile,the optimal reaction conditions were shown respectively as following： pH=5.0,6.0 and 5.0,reaction temperature 35 ℃,35 ℃ and 30 ℃,and reaction time 60 min,50 min and 40 min.The acid desorption reagent had comparatively better efficiency,especially the desorption rate of 1 mol·L-1 hydrochloric acid reached 92.1%.