氨基化氧化石墨烯(AGO)的制备及其对六价铬的吸附机制

以乙二胺盐酸盐(EDH)为改性剂改性氧化石墨烯(GO),水热法制备氨基化氧化石墨烯(Amino-functionalized;graphene;oxide,AGO).SEM、XRD、FTIR和Zeta电位表征分析发现,AGO表面含有羟基、羧基及氨基基团,Zeta电位为pH=10.14.以水中低浓度六价铬Cr(Ⅵ)为污染物,探讨了乙二胺盐酸盐(EDH)用量、pH、AGO用量、Cr(Ⅵ)初始浓度以及常见干扰离子对AGO吸附Cr(Ⅵ)影响.结果表明,在pH=6.0、7-AGO用量为0.8;mg·L^-1和Cr(Ⅵ)初始浓度为2.0;mg·L^-1,7-AGO对Cr(Ⅵ)去除率可达95.1%;SO₄^2-会明显抑制AGO对Cr(Ⅵ)的吸附.AGO对Cr(Ⅵ)的吸附过程符合二级动力学模型,吸附机制主要为静电作用.

Synthesis of amino-functionalized graphene oxide and adsorption performance to remove Cr(Ⅵ)in water

Amino-functionalized graphene oxide(AGO)was prepared by hydrothermal treatment of graphene oxide(GO)modified with ethylenediamine hydrochloride(EDH).AGO was characterized by SEM,XRD,FTIR and Zeta titration potentials.The results indicated that the hydroxyl group,carboxyl group and amino group were formed on the surface of AGO,while the zero potential appeared when pH was 10.14.The effects of EDH dosage,pH,AGO,initial concentration of Cr(Ⅵ)and the interfering ion in aqueous solution on Cr(Ⅵ)removal by AGO adsorption were investigated.The optimal adsorption removal efficiency for Cr(Ⅵ)by 7-AGO achieved to 95.1%based on the optimal condition of pH=6.0,AGO dosage 0.8 mg·L^-1,initial concentration of Cr(Ⅵ)2.0 mg·L^-1.Meanwhile,the SO₄^2-was capable to inhibit the adsorption of AGO for Cr(Ⅵ)removal significantly.Additionally,the kinetic experimental data was fitting to the pseudo-second-order kinetic model and the adsorption of Cr(Ⅵ)species could be facilitated through electrostatic attraction.