Preparation Of Graphene/Natural Polymer Composite Adsorbent And Its Application In Printing And Dyeing

If the water contains excessive copper ions,it not only seriously affects the balance of the ecosystem,but also causes the humans to ingest excessive copper elements through the food chain to cause heavy metal poisoning.Methyl orange?MO?and methylene blue?MB?not only have toxic effects on human body,but also seriously affect the quality of water bodies and the health of aquatic organisms.Chitosan?CS?and sodium alginate?SA?are abundant in nature,non-toxic and harmless.It is biocompatible and biodegradable as well.The molecule contains a large amount of amino and carboxyl groups,which can effectively remove dyes and heavy metal ions,and is widely used as an adsorbent and flocculant material in water treatment.Graphene oxide?GO?can greatly improve the specific surface area and mechanical properties of the material,and the rich oxygen-containing functional groups are easy to conform to other materials,and its excellent properties have made it widely used in water treatment fields in recent years.In this study,a novel adsorbent has been successfully prepared by modifying graphene oxide/chitosan composite with glutamine.The morphology of the material was investigated by scanning electron microscopy?SEM?.And the adsorption properties of methyl orange dye and Cu²⁺were studied;The preparation and application of EDTA-2Na modified graphene oxide/sodium alginate composite microspheres?GSE?were studied.The morphology of the materials was characterized by scanning electron microscopy?SEM?.The adsorption properties of methylene blue and Cu²⁺were also studied.Batch adsorption experiments were carried out to evaluate the effects of contact time,pH and dosage on the adsorption of Cu²⁺?MO and MB by GCG and GSE.At the same time,the adsorption kinetics and adsorption isotherms were analyzed.In addition,the repeated regeneration performance of GCG and GSE were also studied.The results show that the modified GCG and GSE have greatly improved the adsorption performance compared with the GC and GS before the modification.Among them,the maximum adsorption amount of GCG to methyl orange reached 261.78 mg/g at pH=3 and 25°C,and the whole adsorption process reached adsorption equilibrium in about 120 min,which is a spontaneous endothermic process.The adsorption of Cu²⁺by GCG reached equilibrium in about 90 minutes,and it was an endothermic reaction.The maximum adsorption capacity at pH=6 and 25°C was 74.79 mg/g.The adsorption of methylene blue by GSE is an exothermic process,which is favorable for adsorption at lower temperature.The adsorption of methylene blue by GSE reached adsorption equilibrium in about 120 minutes;according to the Langmuir isotherm,the maximum adsorption capacity at 25°C reached 281.69 mg/g.The adsorption process of Cu²⁺by GSE is endothermic,and the adsorption equilibrium is reached in about 90min;the maximum adsorption at pH=6 and 25°C is 134.77 mg/g.At the same time,the above adsorption processes are consistent with pseudo second-order kinetics and Langmuir adsorption isotherm model.In the adsorbent regenerative experiment,after the adsorption-desorption was repeated 6 times,the adsorption amount remained above 85%of the first adsorption amount.