Fabrication Of The Tea Saponin Functionalized Reduced Graphene Oxide For Fast Adsorptive Removal Of Cd(?) From Water

With the rapid development of industrialization and urbanization,the problem of heavy metal wastewater pollution is becoming more and more serious.Industrial processing,electroplating industry,chemical industry,mining,smelting and other industries will discharge a lot of heavy metal waste water.However,when the low levels of heavy metals enter the water,they still have a toxic effect on the creatures in the water and pose a great threat to the environment.Cadmium is a kind of common heavy metal,and cadmium pollution accidents is also increasing in recent years,people's fears of cadmium pollution is also growing,so need to explore a nd try some effective methods of wastewater containing cadmium.As a traditional processing method,adsorption has the advantages of simple operation,obvious effect,low cost and easy to obtain of adsorption materials.Graphene is a new type of two-dimensional carbon material,which is favored by researchers because of its excellent structure and performance.A novel graphene-based material of tea saponin functionalized reduced graphene oxide?TS-RGO?was synthesized via a facil thermal method in this study,and it was characterized as the absorbent for Cd???removal from aqueous solutions.The factors on adsorption process including solution pH,contact time,initial concentration of Cd???and background electrolyte cations were studied to optimize the conditions for maximum adsorption at room temperature.The results indicated that Cd???adsorption was strongly dependent on pH and could be strongly affected by background electrolytes and ionic strength.The optimal pH and required equilibrium time was 6.0 and 10 min,respectively.The Cd???removal was decreased with the presence of background electrolyte cations(Na⁺<Ca²⁺<Al³⁺).The adsorption kinetics of Cd???followed well with the pseudo-second-order model.The adsorption isotherm fitted well to the Langmuir model,indicating that the adsorption was a monolayer adsorption process occurred on the homogeneous surfaces of TS-RGO.The maximum monolayer adsorption capacity was 127 mg/g at 313 K and pH 6.0.Therefore,the TS-RGO was considered to be a cost-effective and promising materials for the removal of Cd???from wastewater.