Preparation Of Multifunctional Graphene Composites And Its Removal Of Pollutants In Wastewater

Rare Earth Elements as a national strategic resource are raw materials to produce many high-tech products.China is a major producer and supplier of rare earth resources,accounting for most of the global market share.However,a large amount of rare earth wastewater will be produced during the exploitation of rare earth resources,and it is an urgent problem to dispose the wastewater containing rare earth metal ions.Moreover,in the process of oil exploitation,transportation by sea accident leakage and oily wastewater emissions from industrial production etc.also cause serious ecological environment problems.Therefore,this article making use of rich pore structure of graphene oxide,large specific surface area,such as a variety of functional groups generated after introducing the function of a polymer as a component,both covalent bond or a covalent bond cross-linking and synergistic effects between oxidized graphene and polymers facilitate their composites assemble.It not only efficiently and quickly removes metal ions and organic pollutants in wastewater,but also is still robust after recycled many times.Firstly,the novel 3D reduced graphene oxide/poly(amino-phosphonic acid)(PAPA)aerogels(rGO/PAPAs)with different PAPA content were developed by solvothermal reduction of the graphene oxide.The materials were characterized by infrared spectroscopy(FT-IR),XRD,SEM,BET,TGA,contact Angle(CA),Zeta potential and XPS.Aerogels(rGO/PAPAs)synthesized by cross-linking rGO with different content of PAPA chains were used to treat simulate contaminants in wastewater,Benefiting from the synergistic effect of the reduced graphene oxide(rGO)sheet and PAPA component,as well as its unique 3D structure,the resultant aerogel(rGO/PAPA-2)gained amphiphilic,ultralight,and multifunctional properties.Thus,it showed a fast adsorption rate(within 15 min)and high adsorption capacity(up to 868.5 mg/g)forGd(?)ion at an optimal pH of 5.5.The uptake of Gd(?)by rGO/PAPA-2 was fitted well with the Langmuir isotherm and pseudo-second-order kinetic model.The results of adsorption experiments on organic pollutants showed that the rGO/PAPA-2 displayed an excellent adsorption performance for sulfonated kerosene and 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester(P507),which were the typical diluent and extractant employed in rare earth extraction system.Moreover,the rGO/PAPA-2 exhibited a good regeneration ability and satisfactory recovery for the tested adsorbates.Notably,PAPA chains can be easily prepared from acrylic fibers(a very cheap and widely available textile material).Therefore,this work provides a new design strategy to fabricate the rGO/PAPA-2 aerogel with showing a great prospect for sophisticated extraction wastewater cleanup.