Preparation Of Graphite Oxide Materials And Study On Adsorption Properties Of Copper Ions

Water resources are one of the important resources for all life on earth to survive.Copper accumulated in water can not be decomposed by microorganisms,and will enter the human body through the food chain,endangering human health.Therefore,the treatment of copper in wastewater is of great significance.Adsorption method has unique advantages in the field of heavy metal contaminated wastewater treatment.The performance of adsorbent restricts the adsorption effect.A large number of studies have introduced active groups into adsorbent.The amino group,carboxyl group,phenol group,amide group,epoxy group and hydroxyl group contained in the active group can combine with heavy metal ions in the form of ionic bond or covalent bond to play an adsorption role and achieve the purpose of removing heavy metals from wastewater.Graphene is a typical carbon-based adsorption material,which can effectively remove toxic pollutants such as heavy metals,dyes,drugs,antibiotics,phenols,and polycyclic aromatic hydrocarbons.Graphene oxide synthesized by chemical exfoliation of graphite has excellent physical and chemical properties and surface structure,and can be used as an adsorbent in the field of water treatment.Graphene oxide is a product obtained by oxidation and exfoliation of graphene.It continues the characteristics of graphite with a large specific surface area and can ensure a large enough contact area with the target pollutants.Oxidation introduces a large number of oxygen-containing functional groups into the surface of graphene,and these reactive groups provide a large number of adsorption binding sites.The degree of oxidation directly determines the degree of functional grouping on the surface of graphene oxide,which affects the number and position of functional groups that play a role in adsorption,thereby affecting the adsorption capacity and removal rate of copper ions.In this paper,graphene oxide was prepared by the Hummers oxidation method,and the effect of oxidation degree on the adsorption performance of copper ions was explored by controlling the proportion of oxidant.In order to solve the problem that graphene oxide is difficult to separate from the solvent,Fe₃O₄nanoparticles were supported on graphene oxide by co-precipitation method,so that the adsorbent has sufficient magnetic properties and was easy to separate.Considering the economical applicability,the cost of adsorbent material was reduced by introducing cellulosic material.Carboxymethyl cellulose is a carboxymethyl group substitute of cellulose,and there are a large number of active groups on the surface that can provide adsorption sites.After carboxymethylcellulose was compounded with graphene oxide,the adsorption material formed showed good adsorption performance.The synthetic materials were used to adsorb copper ions.The effects of p H,initial copper ion concentration,oxidation degree and reaction time on the adsorption capacity were studied,and the adsorption mechanism was analyzed.The results showed that the equilibrium adsorption capacity of copper ions increased with the increase of oxidation degree of graphene oxide,and the equilibrium adsorption capacity of GO-5（molar ratio of potassium permanganate to graphite is 5:1）was the highest,which was83.33 mg/g(p H=5,initial Cu²⁺concentration was 100 mg/L,adsorbent dosage was 1 g/L).GO-5 had the lowest carbon-oxygen ratio,the highest oxygen atom content and the most oxygen-containing functional groups introduced into its surface,which may be the reason for its highest adsorption capacity for copper ions.Magnetic graphene oxide was prepared by coprecipitation method,the Fe-O structure produced made graphene oxide successfully loaded with magnetism.The magnetic loading of graphene with different oxidation degrees was different,and the loading magnetism may lead to the decrease of the adsorption capacity per unit mass of composites.Under the same conditions,the equilibrium adsorption capacity of magnetic graphene oxide was 39.28 mg/g.Using magnetic graphene oxide as raw material,carboxymethylcellulose magnetic graphene oxide was synthesized,and the equilibrium adsorption capacity under the same conditions was 60.38 mg/g.The adsorption of Cu²⁺by graphene oxide and magnetic graphene oxide was monolayer adsorption,and the adsorption of Cu²⁺by carboxymethyl cellulose graphene oxide was monolayer adsorption and multi-layer co-adsorption.