Study On The Preparation And Adsorption Properties Of GO/TA-HD Composite Materials

Recently,the development of modern industry has resulted in the discharge of large amounts of waste water containing dyes and heavy metal ions into water bodies.As the pollutants are complex compounds which was difficult to be degraded,and also easy to gather in organisms through the food chain,which they have posed serious threats to the ecological environment and human health.How to better treat water pollution is a problem that needs to be solved urgently.Water pollution has become a severe problem that need to be solved urgently.Herein,a graphene oxide/schiff base polymer composite adsorbent with selective adsorption properties was synthesied to solve the water pollution.Graphene oxide(GO)has large specific surface area and abundant oxygen-containing groups,and thus can be used as a new type of nano-adsorbent in environment protection field.Unfortunately,the main shortcoming of GO is agglomeration during storage or application,which results in the decline of adsorption capacity,difficult to separate the GO from water and difficulty in practical applications.Therefore,the GO is usually functionalized or used to composite with other materials.According to the investigation,most of the previous methods required high temperature and/or long reaction times to form the covalent modification GO.And on account of the non-covalent functionalized GO adsorbent with an organic gelator for adsorption of dye,endocrine-disruptor,pharmaceutical and metal ion was reported by our research team.Therefore,the study about the schiff base polymer used in the non-convalent functionalization of GO has attracted our tremendous research interest.Therefore,in this paper,the schiff base polymer TA-HD was prepared by dehydration and condensation of hexamethylene diamine(HD)and terephthalaldehyde(TA)at room temperature,and then the GO/TA-HD composite was prepared by non-covalent interaction with GO.Characterizations of the composites were confirmed by FT-IR,SEM,XPS,and TG.The effects of different influence factors on the pollutants removal from water were studied by the static adsorption of adsorbents.On this basis,various isotherm models,kinetic models,and thermodynamic models were used to fit the adsorption equilibrium data to the adsorption.The process and adsorption rate limiting steps were discussed.In addition,the adsorption force was explored through spectrum analysis,and the selective adsorption property and recycling performance of the composites are investigated.The results showed that the adsorbent can adsorb a variety of dyes.The adsorption ability of the adsorbent towards dyes and heavy metals was enhanced when increasing pH values.The adsorbent exhibits a high adsorption speed and excellent adsorption performance,with the maximum adsorption capacity of malachite green and Cd2+up of 2926.65 mg/g,1004.49 mg/g,respectively,which exceeded the adsorption capacity of most graphene-based modified materials.The Freundlich adsorption isotherm was suitable to describe the adsorption process of MG,indicating a multi-layer adsorption process.However,the adsorption process of Cd2+ was more consistent with the Langmuir isothermal model.Meanwhile,the adsorption behaviors of the composites towards MG and Cd2+obey fit the pseudo-second-order kinetics model and the adsorption process is endothermic and spontaneous.IR spectroscopy showed that the composites adsorbed cationic dyes through hydrogen bonds,π-π stacking and electrostatic interactions.XPS spectroscopy indicated that there existed synergistical coordination interactions complexes and synergy between the cadmium ions and the surface of the composites.After 6 recycles,the composites still exhibits satisfactory adsorption capacity,with the removal rates for MG as high as 86.2%,respectively,and the removal rate for Cd2+remained at 87.8%,indicating outstanding recycling and reutilization performance of the composites.At the same time,the preparation process of adsorbent is simple and does not need high temperature and high pressure,and so it is low in cost and energy efficient.TA,HD and GO need to be mixed and stirred in the solvent and then cleaned and freeze-dried.