壳聚糖/膨胀石墨对刚果红的吸附性能

Adsorption Properties of Congo Red by Chitosan/Expanded Graphite

先以天然鳞片石墨为原料,硝酸与磷酸为插层剂,高锰酸钾为氧化剂制备膨胀石墨,再与壳聚糖按一定的配比制备壳聚糖/膨胀石墨复合吸附剂;利用Fourier变换红外光谱(FT-IR)、扫描电子显微镜(SEM)、X射线衍射(XRD)对壳聚糖/膨胀石墨进行表征;以壳聚糖/膨胀石墨为吸附剂,对刚果红废水进行吸附,考察壳聚糖/膨胀石墨的配比、吸附剂用量、刚果红质量浓度、吸附时间对吸附效果的影响.实验结果表明:壳聚糖已与膨胀石墨成功结合;当m(膨胀石墨)∶m(壳聚糖)=3∶1、吸附剂用量为1.75 g/L、刚果红质量浓度为250 mg/L、在室温下吸附40 min时,吸附效果最好;吸附过程更符合Lagergren准二级动力学方程;实验数据与Langmuir等温吸附模型拟合度更好,壳聚糖/膨胀石墨对刚果红的吸附过程为单分子层吸附.

Expanded graphite was prepared by natural flake graphite as raw material,phosphoric acid and nitric acid as intercalating agent,potassium permanganate as oxidant.The chitosan/expanded graphite composite adsorbent was prepared by expanded graphite and chitosan in a certain proportion.The chitosan/expanded graphite was characterized by Fourier transform infrared spectroscopy(FT-IR),sc anning electron microscopy(SEM),X-ray diffraction(XRD).The effects of adsorption conditions such as the mass ratio of chitosan and expanded graphite,the dosage of adsorbent,the mass concentration of Congo red,and the adsorption time on the adsorption performance of Congo red wastewater by chitosan/expanded graphite were investigated.The experimental results show that chitosan is successfully combined with expanded graphite,the adsorption performance is best when the mass ratio of chitosan and expanded graphite is 3∶1,the dosage of adsorbent is 1.75 g/L,the mass concentration of Congo red is 250 mg/L,and the adsorption time is 40 min at room temperature.The adsorption process is more in line with Lagergren pseudo-second-order kinetic equation.The experimental data fit well with the Langmuir isotherm adsorption model.The adsorption process of Congo red on chitosan/expanded graphite is monolayer adsorption.