Preparation Of Graphite Oxide/Modified Magnetic Chitosan Composite And Its Adsorption Properties On Heavy Metal Ions

The main way of water pollution is the emission of heavy metal pollutants.The adsorption method has the advantages of high efficiency,low cost,easy operation and so on to treat heavy metal wastewater,so it has good application prospect.In many adsorbents,the molecular structure of chitosan and oxidized graphene contains a large number of active functional groups which can chelate heavy metal ions,which makes chitosan and graphite oxide as adsorbent in the field of heavy metal wastewater treatment has been widely concerned.In this paper,graphene oxide hydrosol was added dropwise to the surface of chitosan,and graphene oxide/chitosan composites(GC)were successfully obtained.The composite material was characterized by scanning electron microscope and X-ray diffraction.At the same time,it was applied to simulate the static adsorption of copper,lead and cadmium ions in simulated wastewater.The experimental results show that: in100 mL,50mg/L simulated wastewater,the pH is 6,the initial dosage is 70 mg,the adsorption time is 90 min,and the temperature is 20°C to obtain the graphene oxide/chitosan composite.The adsorption capacities of copper,lead,and cadmium were60.7 mg/g,48.7 mg/g,and 32.3 mg/g respectively.The adsorption and desorption cycle experiments showed that the adsorption capacity of the copper ion on the graphene oxide/chitosan composite could reach 86% of the initial adsorption capacity after 10 cycles.In addition,a kind of carboxymethyl-amine magnetic chitosan was prepared,which made the oxidized graphene/modified magnetic chitosan compound(MCGO)with oxidized graphene.The composite was characterized by scanning electronmicroscope,X-ray diffraction and FT-IR spectrum test methods.At the same time,it is applied to simulate the static adsorption of Cu,Pb and Cd ions in wastewater samples.The results show that: in 100 ml,50mg/l simulated wastewater sample,PH is 6,initial dosing is 70 mg,adsorption time is 90 min,temperature is 20?,the adsorption capacity of graphite oxide/modified magnetic chitosan to Cu,Pb and Cd is 70.3mg/g,56.4mg/g,36.7mg/g.The adsorption desorption cycle experiment showed that the adsorption capacity of graphite oxide/modified magnetic chitosan Composites was 95% of the initial adsorption capacity after 10 times of cyclic utilization.The adsorption isotherm of Langmuir and Freundlich adsorption isothermal model is fitted,the two kinds of composites prepared in this paper conform to the Freundlich adsorption isothermal model.The comparison between the two kinds of composite materials in the treatment of simulated wastewater samples was carried out.The static adsorption capacity of graphite oxide/modified magnetic chitosan is higher than that of oxidized graphene/chitosan composite in simulated waste water samples,and the recycled value of graphite oxide/modified magnetic chitosan composite is higher;on the other hand,graphene oxide/ The modified magnetic chitosan composite is more beneficial to recycle under the action of magnetic field,simplifies the process of reclaiming adsorbent,and can reduce the cost of production.