Abstract：Biosorption of Cr(Ⅵ) by the novel biosorbent ZL5-2 produced by Agrobacterium.sp was studied, and infrared spectra of native, absorbing and desorbing ZL5-2 were compared. The initial pH was important for biosorption. The optimum effect on Cr(Ⅵ) biosorption was acquired within initial pH 0.5-1.5, then with the pH increasing, the effect on Cr6＋ biosorption was reduced. The biosorption for Cr(Ⅵ) was a quick process, only within 10 min 65.4% Cr(Ⅵ) was biosorbed, and the biosorption was in equilibrium after 60 min, then all the Cr(Ⅵ) was biosorbed after 80 min. The absorbed Cr(Ⅵ) could be recovered by desorption, and the desorption rate reached 13.6%-67.9%. The absorbance peak around 3 400 cm-1, which reflected OH stretching vibration, moved about 8 cm-1, and its absorbance decreased; the absorbance peak around 2 900 cm-1 decreased, which reflected C—H stretching vibration; and the absorbance peak around 1 600 cm-1, which reflected amide Ⅰ group stretching vibration, moved about 13 cm-1, and its absorbance decreased. After desorption, the absorbance peaks which reflected OH and C—H were increased to the initial degree, and the absorbance peak which reflected NH and amide Ⅰ group did not increase. Therefore, authors presumed that the process of biosorption was reversible adsorption and irreversible adsorption simultaneously, however the reversible adsorption was more important in the biosorption.
[1] WU Juan, LI Qing-biao, DENG Xu, LU Ying-hua(吴 涓，李清彪，邓 旭，卢英华). Ion Exchange and Adsorption(离子交换与吸附), 1998, 14(2): 180. [2] HAN Rui-ping, YANG Guan-yu, WANG Miao-li, ZHAO Zhen-jiang(韩瑞平，杨贯羽，王妙丽，赵振江). Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2000, 20(5): 739. [3] Dilek F B, Erbay A, Yetis U. Process Biochemistry, 2002, 37: 723. [4] Goyal N, Jain S C, Banerjee U C. Advances in Envionmental Research, 2003，7: 311. [5] Dvis T A, Volesky B, Mucci A. Water Research, 2003(37): 4311. [6] HAN Rui-ping, LI Jian-jun, YANG Guan-yu, BAO Gai-ling(韩瑞平，李建军，杨贯羽，鲍改玲). Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2000, 20(4): 489. [7] Chinese Environmental Protection Bureau(国家环保局). Analytical Method for Monitoring Water and Water(水和废水监测分析方法). Beijing: China Environmental Science Press(北京：中国环境科学出版社)，1989. [8] ZHANG Shu-liang, YI Da-nian, WU Tian-ming(张叔良，易大年，吴天明). Infrared Spectroscopic Analysis and Technique(红外光谱分析与新技术). Beijing: Chinese Medicine Scientific and Technological Press(北京：中国医药科技出版社)，1993.
