| With the development of social economy,the pollution of dyes and heavy metals in the environment is becoming more and more serious,and the demand for the removal of pollutants in wastewater is increasing.In recent years,the application of graphene oxide（GO）has been developed.In this study,graphene oxide aerogel（rGO）and graphene oxide-montmorillonite composite aerogel（M-rGO）were prepared using GO as raw materials.And cadmium（Cd）single type and composite type sewage dynamic removal effect and adsorption mechanism,using SEM,FTIR and XPS to characterize aerogel.The aim is to prepare low-cost adsorption materials,and to provide a scientific basis for the application of aerogels in dye and heavy metal pollution remediation.The main conclusions of the study are as follows:（1）The prepared graphene oxide and graphene oxide-montmorillonite composite aerogels all contain C=C,C=O and other functional groups.SEM analysis shows that both gels have an ordered porous structure.Introduced into the graphene oxide framework.Aerogels can maintain good mechanical properties even after they adsorb MB and Cd and are washed with distilled water.FTIR spectrum analysis shows that the vibration peaks of some functional groups of rGO and M-rGO after Cd adsorption have shifted or changed in abundance.After MB adsorption,there are new C-H bond stretching vibration peaks and out-of-plane bending of polyaromatic heterocycles.The phenomenon of vibration peaks indicates that the functional groups interact with MB and Cd.XPS characterization found that the content ratio of C-O group and C=O group in rGO and M-rGO decreased after MB and Cd adsorption,which also indicated that these two oxygen-containing groups interacted with MB and Cd.（2）In the filtration and removal of MB by the gel-packed sand column,the removal of MB by the two aerogels,rGO and M-rGO,is affected by external conditions.The adsorption capacity of the two gels basically decreased with the increase of MB concentration,p H value and flow rate.With the increase of ionic strength,the ability of rGO to adsorb MB weakens,while M-rGO shows the opposite trend.M-rGO has a stronger adsorption capacity for MB.Montmorillonite as an additive material not only has low cost,but also improves the adsorption capacity of graphene oxide aerogel,which not only increases the utilization efficiency of aerogel,but increases graphite Possibility of ene composite materials used in environmental remediation.（3）When exploring the physical and chemical factors on the removal of Cd under the aerogel-packed column,it was found that the ionic strength has the least influence on the adsorption of rGO and M-rGO,and at the same time,low Cd concentration in a neutral or alkaline environment And the lower flow rate of the contaminated liquid is conducive to the progress of the adsorption reaction,which is obtained by increasing the contact time of Cd and aerogel,changing the position of the surface or interior of the adsorption material,and the anions and cations in the liquid phase.Compared with rGO,the mechanical properties and decontamination ability of M-rGO have been improved accordingly.The adsorption force of M-rGO is more affected by external factors.The affinity of the two gels for Cd is less than that for MB.（4）The isothermal adsorption results of rGO and M-rGO on MB-Cd composite pollution are most consistent with the Langmuir model,indicating that the adsorption of rGO and M-rGO on the two pollutants is mainly monolayer adsorption.The maximum adsorption capacity of rGO for simultaneous adsorption of MB and Cd was 188.6792 mg g-1 and 65.7894 mg g-1,respectively.The maximum adsorption capacity of M-rGO for simultaneous adsorption of MB and Cd are 454.5455 mg g-1 and 39.5256 mg g-1,respectively.The adsorption kinetics of the two aerogels on MB and Cd are the most consistent with the pseudo-second-order kinetic model.Compared with rGO,M-rGO takes longer to reach adsorption equilibrium.In the MB and Cd composite pollution system,the removal capacity of the two aerogels for MB is greater than the removal capacity for Cd,and theπ-πstacking effect between the aerogel and the benzene ring structure in the MB molecule is stronger than that of the complexing effect between Cd,so the existence of MB inhibits the aerogel’s adsorption of Cd. |
