Abstract：In order to improve adsorbing performance and stability of chitosan in acid simultaneously, cross-linking was employed after the protection of amino groups for improving its stability, then the protection of amino groups was removed and protonated to obtain high adsorption performance. With formaldehyde as amino-group protective agent and glutaraldehyde as cross-linking reagent, cross-linked chitosan(CCTS) was prepared by reversed phase suspension method in this paper, then it was protonated to make protonation modified chitosan adsorbent(P-CCTS). The adsorption performance of sulfate ion onto P-CCTS was firstly studied and investigated by static adsorption test. Elemental analysis by energy dispersive spectrometer of X-rays (EDS) and identifying of functional groups by Fourier transform infrared spectroscopy (FTIR) were used to analyze the preparation and adsorption of the adsorbent, and the reaction mechanism of cross-linking and adsorption was investigated. The results show that the adsorption performance of P-CCTS towards sulfate ion is 10 times higher than that of unmodified chitosan, and formaldehyde and glutaraldehyde mainly react with amino (—NH2) and part of hydroxy (C6—OH) of chitosn. A salt of chitosan protonated amino chlorine was formed through the process of the protonation of amino, the adsorption of sulfate ion mainly occurs on the protonated amino on which ion exchange happened between chlorine ion and sulfate ion.
[1] Wan Ngah W S, Teong L C, Hanafiah M A K M. Carbohydrate Polymers, 2011, 83(4): 1446. [2] Miretzky P, Cirelli A F. Journal of Fluorine Chemistry, 2011, 132(4): 231. [3] LI Yong-fu, MENG Fan-ping, DU Xiu-ping, et al(李永福, 孟范平, 杜秀萍，等). Periodical of Ocean University of China(中国海洋大学学报), 2012, 42(6): 35. [4] Xie Yanhua, Li Shiyu, Wang Fei, et al. Chemical Engineering Journal, 2010, 156(1): 56. [5] Viswanathan Natrayasamy, Sundaram C Sairam, Meenakshi S. Journal of Hazardous Materials, 2009, 161(1-3): 423. [6] Guo Yingjuan, Xue Juanqin, Bi Qiang, et al. Advanced Materials Research, 2010, 160-162: 1797. [7] Wade L G Jr. Organic Chemistry(有机化学). Translated by WAN You-zhi, et al(万有志，等译). Beijing：Chemical Industry Press(北京：化学工业出版社), 2006. 776. [8] MENG Fan-ping, YI Huai-chang(孟范平, 易怀昌). Chemical Industry and Engineering Progress(化工进展), 2009, 28(10): 1861. [9] LI Yan-mei, ZHAO Sheng-yin, WANG Lan-ying(李艳梅, 赵圣印, 王兰英). Organic Chemistry(有机化学). Beijing: Science Press(北京: 科学出版社), 2011. 165. [10] Anitha A, Deepagan V G, Divya Rani V V, et al. Carbohydrate Polymers, 2011, 84(3): 1158.
