生物吸附剂ZL5-2对六价铬离子吸附作用的红外光谱分析

研究了Agrobacterium.sp产生的具有吸附作用的蛋白聚糖类物质ZL5-2对Cr(Ⅵ)的吸附作用，并对吸附Cr(Ⅵ)前后及解吸附后的ZL5-2进行了红外光谱分析。结果表明，ZL5-2对Cr(Ⅵ)吸附的最佳pH为0．5～1．5，随着pH增大，吸附作用减弱。60min时吸附达到平衡，80min后所有的Cr(Ⅵ)都被吸附。被吸附的Cr(Ⅵ)可以被解吸附，解吸率为13．6％～67．9％。通过红外光谱分析，发现吸附后ZL5-2在3400cm^-1附近OH，NH伸缩振动峰强度减弱，并发生了约8cm^-1的位移，2900cm^-1附近C-H伸缩振动减弱，1600cm^-1处的酰胺Ⅰ带伸缩振动的相对强度减弱，并发生约13cm^-1的位移。解吸附后，OH，C-H伸缩振动又恢复到原来水平，而NH、酰胺Ⅰ带的伸缩振动未恢复到原来水平，推测该吸附过程存在可逆吸附和不可逆吸附，以可逆吸附为主。

Infrared Spectra Analysis of Chromium Cation Biosorbed by Biosorbent ZL5-2

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.