Preparation And Adsorption Properties Of Two Modified Graphene Sponge Material

Due to its special structure, with a large specific surface area, but also a large adsorption capacity,rapid adsorption characteristics, graphene can be used as a new adsorbent material. However, the conventional two‐dimensional graphene material can not be well collected and separated from water,and these problems bring some obstacles to their application. In this paper, two graphene spongy materials, ATMP‐GS and PA‐GS, were synthesized by the reaction of graphene oxide with amino trimethylene phosphonic acid(ATMP) and phytic acid(Phytic acid), respectively, then the two material were used in the uranium and methylene blue adsorption experiments, and the effects of various experimental conditions on adsorption were studied. In order to investigate the adsoption process,adsorption kinetics and adsorption thermodynamics of the two graphene sponge materials for uranium and methylene blue were studied. The results are shown here:1. The material ATMP‐GS has the best adsorption performance for uranium ions at pH=5.0,and the adsorption can be completed within 3 hours, the largest adsorption capacity for U was found to be96mg/g, temperature has little effect on the adsorption. The adsorption system belongs to the pseudo‐second‐order kinetic model and the adsorption isotherms can be described well by the Freundlich model as well as by the Langmuir model; at room temperature, the methylene blue adsorption process reached equilibrium in about 2.5 hours, when the concentration was 70mg/L, the maximum adsorption capacity is 112.46 mg/g, Langmuir isotherm model is more appropriate for the description of adsorption equilibrium process of methylene blue by ATMP‐GS, and further thermodynamics investigation of the adsorption of methylene blue with ATMP‐GS showed that the adsorption process is thermodynamically spontaneous.2. The material PA‐GS has the best adsorption performance for uranium ions at pH=5.5, the largest uranium adsorption capacity is 110.23 mg / g, the adsorption reached equilibrium in about 4 hours,temperature has little effect on the adsorption of uranium capacity,the adsorption process belongs to the pseudo‐second‐order kinetic model and the data fitted to Langmuir isotherm model; in the adsorption process of PA‐GS for methylene blue, it reached equilibrium in about 240 min, the maximumadsorption capacity is 92.7mg /g when the methylene blue concentration was 60mg/L, at room temperature, the adsorption process can be more appropriately described by pseudo‐second‐order kinetic model, the adsorption results fitted to the Langmuir isotherm model shows that the adsorption was a monolayer process. The thermodynamic results showed that the adsorption process is spontaneous, and at higher temperatures the adsorption of methylene blue could be more easily.3. The two materials were characterized by SEM and XRD,respectively, the results showed that the two materials have more pore structures, which will favor the adsorption of pollutants.