银离子在斛壳丹宁酸树脂表面的吸附和解吸(英文)

将斛壳丹宁酸与甲醛聚合来形成的凝胶作为吸附剂能有效地移去水溶液中的银离子。研究了不同银离子初始浓度、溶液温度、pH值条件下斛壳丹宁酸树脂的附和解吸行为。研究了有关经验动力学模型的适应性。伪二级动力学模型表明银离子的吸附是很快的。用FTIR和SEM对吸附和解吸银离子后的斛壳彤宁酸和斛壳丹宁酸树脂进行表征。银离子在斛壳宁酸树脂上的吸附随着银离子初始浓度的增加而增加,随着溶液温度的升高而减少。在低pH值的H2SO4、HNO3和HCl溶液中进行解吸实验。斛壳丹宁酸树脂在pH2.0~7.0溶液中对银离子表现出高的吸附容量,在银离子初始浓度100.0mg/L、温度296K和pH5.0的条件下达到最大的吸附量97.08mg/g。在1mol/LHCl+1%硫脲溶液中银离子的脱吸率达99.6%。

Adsorption and desorption behavior of silver ions onto valonia tannin resin

Valonia tannin （VT） was gelated through polymerization with formaldehyde to prepare an adsorbent, which was found effective to remove Ag＋ from aqueous solution. The adsorption-desorption behaviors of valonia tannin resin （VTR） were investigated under various initial Ag＋ concentrations, solution temperatures, pH values etc. The applicability of empirical kinetic models was also studied. The pseudo-second-order model studies revealed the Ag＋ sorption was very rapid. VT and VTR were characterized using FTIR and SEM before and after adsorption. The Ag＋ biosorption on VTR increased with a rise in initial concentration of Ag＋ and with a decrease in temperature. Desorption experiments were conducted at low pH values and the solutions of H2SO4, HNO3 and HCl were used for desorption. The VTR shows high adsorption capacity to Ag＋ in a wide pH range of 2.0-7.0, and a maximum adsorption capacity of 97.08 mg/g was obtained at pH 5.0 and 296 K when the initial concentration of Ag＋ was 100.0 mg/L. Ag＋ ion desorption could reach 99.6% using 1 mol/L HCl＋1% thiourea （NH2CSNH2） solution. By utilizing such characteristics of VTR, it is expected that it can be applied to recovering Ag＋ efficiently and simply with low cost.