Preparation And Adsorption Properties Of Functionalized Graphene Oxide Composites

According to incomplete statistics,the dye wastewater discharged into the environment by the textile industry accounts for about 50%of the total dye wastewater discharge,and the wastewater generated in the papermaking,pulping and printing and dyeing processes accounts for about 30%of the wastewater generated by the process.As a result,a large amount of wastewater is continuously discharged without prior treatment,causing serious negative impacts on the environment and human health.Dyes contaminate the habitat of aquatic organisms,and the toxicity of dyes is likely to accumulate in aquatic organisms and eventually enter humans through the ecological food chain,causing various diseases.Therefore,the treatment of dye wastewater in water is receiving increasing attention.To solve this problem,long-term,efficient and sustainable dye wastewater treatment methods must be found.After decades of development,researchers have developed different kinds of dye wastewater treatment technologies,of which adsorption treatment technology is one of the most effective.Regarding adsorption technology,although many schemes for synthesizing adsorption materials have been reported before,the development of adsorbents with higher adsorption capacity and better cycling performance is still the focus of researchers.Because graphite oxide(GO)is a special derivative chemically stripped out of graphene,it is a two-dimensional,monolayer carbon nanomaterial.Moreover,because pure GO is easy to aggregate between layers,the adsorption site of GO is reduced,resulting in a decrease in the adsorption capacity of GO to organic dyes.However,GO contains more oxygen-containing functional groups,such as carboxyls,hydroxyl groups,and epoxy groups.,and different kinds of physical and chemical modifications to its surface can be made through ionic,covalent bonding,and hydrogen bond interactions to improve the adsorption capacity of the dye.Therefore,oxalic acid is used to functionalize graphene oxide,so that graphene oxide can obtain more carboxyl oxygen-containing functional groups,thereby improving its adsorption capacity of the cationic dye methylene blue.On this basis,the influencing factors of different doses of zeolite after compounding with the above materials on the adsorption performance of methyl orange dye and the separation performance of the complex in aqueous solution were discussed.The research is as follows:(1)The GO used was prepared using the Hummers method provided in the literature.And the prepared graphene oxide was treated with a certain amount of HBr,which has been used to obtain the desired functional groups.(2)A new adsorbent was prepared by esterification of oxalic acid and graphene oxide.A new adsorbent was prepared by esterification reaction to successfully graft oxalic acid to graphene oxide.This adsorbent,called oxalic acid functionalized graphene oxide composite(GOO-COOH)adsorbent,uses this material to explore its influencing factors in a self-made simulated wastewater MB dye.The preparation scheme of GOO-COOH is to first weigh the oxygraphene on the electronic balance and prepare it into a well-dispersed liquid to make the solution uniform.Second,take an appropriate amount of hydrobromic acid to treat the mixed solution for 4 hours,and stir continuously at room temperature.Third,a certain quality of anhydrous oxalic acid is added to the mixed solution,the temperature is increased to 900C,and it is treated in this environment,stirred for 12 hours,and then washed and dried.The prepared GOOCOOH was characterized by different means,and various influencing factors were explored.And under the optimal conditions,the adsorption capacity of MB is as high as 1555.17 mg/g.(3)On the basis of the prepared oxalic acid functionalized graphene,a new adsorbent GOO-COOH-4A was prepared by hydrothermal method by combining zeolite with the material prepared in(2).The effect of GOO-COO-4 A on the adsorption performance of methyl orange dye under different experimental conditions was investigated.And the prepared materials are characterized by various characterization methods.Through the analysis of experimental data,GOO-COOH-4A-3 has the best adsorption performance,and the adsorption capacity of MO reaches 830.766mg/g under the best conditions in the experiment.The reason why the adsorption capacity can reach such a high is that MO is an acidic dye,and under very low pH experimental conditions,the functional groups contained in the prepared adsorbent under acidic conditions are combined with hydrated hydrogen ions,and chemical adsorption plays a major role.