Study On The Adsorption Behavior Of Heavy Metal Copper Ions On Graphene Oxide And Its Composites

Copper, as one of extensively used heavy metal materials is widely used inelectrical, light industry, machinery manufacturing, construction industry, defenseindustry and other fields, has posed a risk to both human beings and ecologicalenvironment. Therefore, how to remove copper ions from wastewater has become animportant subject today. Compared with other methods, adsorption is one of the mostpromising treatments for the removal of metal ions because it is simple andcost-effective.A series of heavy metal ions adsorbent materials were prepared based on grapheneoxide modified with physical and chemical methods. The adsorption performance ofgraphene oxide and its composite materials for copper ion in aqueous solution wereinvestigated. The three main results are listed as follows:（1） Graphene oxide （GO） prepared by modified hummers method was used asadsorbent for removal of heavy metal ions. The effects of the parameters of pH value,contact time, Cu（Ⅱ） concentration and adsorbent dosage on adsorption performancewere examined. The sorption process conformed to the Freundlich isotherm, and themaximum sorption capacity of117.5mg/g was observed at an initial pH value of5.3after agitating for150min. It was also found that Cu-pretreated GO could be desorbedby HCl and the reusability of GO could still maintain above90%of its initialcapability after10cycles. The results suggest that GO is an effective adsorbent forcopper ions removal in water treatment.（2） Cross-Linked chitosan（CS）, Cross-Linked chitosan/graphene(CS/RGO₁₀) andCross-Linked chitosan/graphene oxide(CS/GO₁₀) were prepared for the adsorption ofcopper ions in aqueous solution. The effects of the parameters of pH value, contacttime, adsorbent dosage and initial concentration of Cu（Ⅱ） on adsorbing ability of CS,CS/RGO₁₀, CS/GO₁₀ to Cu（Ⅱ） were examined. The results demonstrated that theadsorption capacities of Cu（Ⅱ） on CS/GO10₁₀, CS/RGO₁₀were greater than that of Cu（Ⅱ）on CS. The maximum adsorption capacity of CS, CS/RGO₁₀, CS/GO10₁₀were137.5,150,202.5mg/g respectively at pH5.0after agitating for120min. It can be concluded thatCS/GO10₁₀can be used as an effective Cu（Ⅱ） adsorbent. The Freundlich isotherm modelmatched the experimental data very well.（3） CS/GO-SH prepared by the functional graphene oxide modified with sulfydryl mixed with Cross-Linked chitosan was used as adsorbent for removal of heavy metalcopper ions. The FTIR characterization proved that the sulfhydryl groups have beensuccessfully grafted to the material. CS/GO-SH became an effective adsorbent forcopper ions because it contains a large number of hydroxyl, carboxyl group, epoxygroup, alkoxy and sulfhydryl groups. The static adsorption experiment results showedthe maximum sorption capacity of145mg/g was observed at an initial pH value of5.0after agitating for20min. In addition, the sorption process conformed to theFreundlich isotherm.