以粉煤灰和氧化石墨烯为原料,采用水泥固化法制备出粉煤灰/水泥/氧化石墨烯复合材料(FACGO),研究其对Cu2+的吸附特性,并采用动力学模型、吸附等温线模型和热力学模型探讨其吸附机理。结果表明:FACGO比表面积较大,表面粗糙不规则,对Cu2+的吸附速率较快,2h内吸附率达98%以上;与准一级动力学模型相比,FACGO的吸附行为更符合准二级动力学模型,表明其吸附行为主要以化学吸附为主;与Freundlich模型相比,Langmuir等温线模型更能很好地描述FACGO对Cu2+的吸附,其最大吸附量可达到28.490mg/g,说明FACGO对Cu2+的吸附属于单分子层吸附;FACGO对Cu2+的吸附属于自发的吸热反应,且其最佳pH为6左右;FACGO对Cu2+的吸附行为主要是物理吸附、化学吸附和絮凝作用等共同作用的结果,且以化学吸附为主。所以,FACGO是一种吸附性能稳定且高效的吸附剂。
Fly ash/cement/graphene oxide composite (FACGO) was prepared by cement curing method using fly ash and graphene oxide as raw materials.The adsorption characteristics of FACGO to copper were studied.The reaction mechanism was discussed by using kinetic model,adsorption isotherm model and thermodynamic model.The results showed that FACGO had a large specific surface and irregular surface roughness.The adsorption rate of fac go to copper was faster and reached over 98% within 2h.Compared with the quasi-first-order kinetic model,the adsorption of FACGO conformed to the quasi-second-order kinetic model,and its adsorption behavior was mainly chemical adsorption.Compared with the Freundlich isotherm models,Langmuir isotherm models can well described the adsorption of copper by FACGO,with the maximum adsorption reached 28.490mg/g.It showed that the adsorption of Cu2+ by FACGO belongs to monolayer adsorption;The adsorption of copper by FACGO was a spontaneous endothermic reaction,and its optimum pH was about 6.The adsorption behavior of FACGO to Cu2+ was mainly the result of physical adsorption,chemical adsorption and flocculation,and mainly based on chemical adsorption and ion exchange adsorption.Thus,FACGO was proved to be a stable and efficient adsorbent.
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