三维氮掺杂石墨烯对水中铅和镉的吸附

Absorption of Pb^(2+) and Cd^(2+) in Water Using 3D Nitrogen-doped Graphene

采用多巴胺(DA)作为还原剂和功能化试剂,进行了氧化石墨烯的功能化,制备了三维结构的氮掺杂石墨烯材料(rGO-DA)。与还原性氧化石墨烯(rGO)对比,rGO-DA具有更大的吸附容量。rGO-DA对Pb^(2+)和Cd^(2+)的吸附容量分别为91.4,43.5 mg/g。考察了吸附时间、pH值、初始浓度对Pb^(2+)和Cd^(2+)吸附效果的影响。结果表明,rGO-DA对Pb^(2+)和Cd^(2+)吸附达到平衡的时间为120 min,最佳pH值为5.0。在Pb^(2+)和Cd^(2+)初始浓度小于30μg/m L时,二者的吸附去除率分别为100%和87.7%。在吸附Pb^(2+),Cd^(2+)后,rGO-DA可轻松从水体中移除。用HCl脱附,循环使用3次后,rGO-DA对Pb^(2+)和Cd^(2+)的吸附容量无明显变化,可再生并重复使用。

An approach was presented for the preparation of 3D nitrogen-doped graphene（ 3D r GO-DA） using dopamine（ DA） as both reductant and functionalizing agents. Compared with reduced graphene oxide（ r GO）,the 3D rGO-DA shows an excellent absorption ability toward Pb^（2＋）and Cd^（2＋）.The adsorption capacities of 3D rGO-DA toward Pb^（2＋）and Cd^（2＋）were found to be 91. 4 mg / g and43. 5 mg / g,respectively. The effect factors,including adsorption times,pH values and initial concentrations of Pb^（2＋）and Cd^（2＋）,were studied. Adsorption time of 120 min and pH 5. 0 was found to be the suitable condition for Pb^（2＋）and Cd^（2＋）adsorption. The removal efficiency of Pb^（2＋）and Cd^（2＋）reached maximum value of 100% and 87. 7% at the initial concentration lower than 30 μg / m L,respectively. After 3 cycle absorption / desorption,the 3D rGO-DA still remained an excellent absorptive capacity,and could be easily removed from water with HCl after adsorption process,indicating its applicability in the water purification.