氧化石墨烯/壳聚糖复合微球的制备及其对铌的吸附性能

Preparation of graphene oxide/chitosan composite beads and its adsorption performance for nibium

实验采用改进Hummers法合成了氧化石墨烯(GO),再用壳聚糖(CS)与GO制备了交联壳聚糖微球(GCCS)和GO质量分数分别为2%、5%、10%的氧化石墨烯/壳聚糖复合微球(GOCS),对其进行了表征,并研究了其对Nb的草酸配合物的吸附性能。结果表明,在1mmol/L的H_2C_2O_4溶液介质中,优化的吸附条件为GOCS中GO的质量分数为5%、pH=3。该吸附反应符合Langmuir等温吸附模型,为单层吸附,理论最大吸附量为38.46mg/g。动力学实验表明,该吸附反应符合准二级动力学模型。热力学实验表明,该吸附反应为自发反应、放热反应。采用5mL 1mol/L的HNO_3溶液进行洗脱实验,洗脱率为84.9%。3次吸附洗脱循环实验,吸附率和洗脱率并未出现明显下降,表明再生性能良好。

Graphene oxide （GO） was synthesized wi th improved Hummers method. Glutaraldehyde cross- linked chitosan （GCCS） and graphene oxide/chitosan composite beads （GOCS） with three different mass fraction of GO （2 %,5 % and 10 % ） were prepared by chitosan （CS） and GO, and characterized. The ad-sorption property of niobic oxalic acid complex onto GOCS was studied. The results showed that the adsorption of Nb onto GOCS was optimum at 5 % GO and pH 3 in 1 mmol/L H2C2O4 solution . The adsorption isotherm obeyed the Langmuir isotherm model, implying that the adsorption was monolayer adsorption, and the maximum adsorption capacity was estimated to be 38. 46 mg/g. The adsorption kinetics of Nb onto GOCS followed a pseudo-second-oder kinetic model. Thermodynamic experiments showed that the adsorption of Nb onto GOCS was spontaneous and exothermic. The desorption rate was 84. 9 % using 5 mL of 1mol/L HN03. The adsorption rate and desorption rate were not significantly decreased after three cycles of adsorption-desorption, implying that the reproductively was good.