甲壳糖对Au^(3+)氧化还原吸附性能研究

Study on Redox Adsorptions of Au 3+ by Chitosan

研究了不同脱乙酰度甲壳糖对Ａｕ３＋的吸附性能．广角Ｘ－射线衍射实验证明甲壳糖能把Ａｕ３＋还原成Ａｕ０．静态吸附实验结果表明，甲壳糖对Ａｕ３＋的吸附量随脱乙酰度的增大而升高；脱乙酰时间为４ｈ的甲壳糖对Ａｕ３＋的吸附量随溶液ｐＨ值的升高而增加；在ｐＨ值等于５．０时吸附量达１１７３ｍｇ／ｇ；另外，随溶液离子强度升高甲壳糖对Ａｕ３＋的吸附量减少．吸附动力学实验结果表明，甲壳糖对Ａｕ３＋的吸附量在１２０ｍｉｎ达到饱和吸附量的一半．在扫描电子显微镜下观察到吸附在甲壳糖上的单质金或Ａｕ３＋聚集成粒状或网状．

Adsorptions of Au 3+ by chitosan deacetylated to different extents were studied.The result of WAXD experiment proved that chitosan reduced Au 3+ to Au 0.Data of static adsorption experiments showed that the amount of Au 3+ adsorbed by chitosans increased with the time of its deacetylation of the latter.When the time of deacetylation was 4h,this reached 1 173 mg/g at pH5.0,but decreased with the rise of ionic strength of the solution.Kinetic adsorption demonstrated that it took 120min for chitosan (deacetylation time being 4h)to adsorb half of its saturated amount.It was discovered that some nets or grains of gold were aggregated on the surfaces of the adsorbents under scanning electron microscope.