Preparation And Application Of Multifunctional Double-modified Cotton Fiber Iron Complexes

In this paper,tartaric acid(TA),citric acid(CA)or butane tetracarboxylic acid(BTCA)were used to modify cotton fiber with Na₂EDTA to introduce carboxyl groups,and then which were coordinated with Fe³⁺ions to prepare polycarboxylic acid(PCA)and EDTA modified cotton fiber Fe complex(Fe-PCA/EDTA-cotton).The effect of molar ratio of polycarboxylic acid and EDTA,modification and coordination conditions on carboxyl group content on the surface of cotton fiber was investigated.The surface morphology,element composition,surface structure and light absorption property of Fe-CA/EDTA-cotton were characterized by using SEM,EDX,FTIR,XPS and DRS.Finally,three Fe-PCA/EDTA-cotton samples were used as photocatalysts in the oxidative degradation of reactive red 195 and the reduction of Cr(?).The effect of Fe-CA/EDTA-cotton,solution p H value and light irradiation on the decolorization percentage,Cr(?)reduction rate and Cr(?)removal capacity were also examined.In addition,Fe-CA/EDTA-cotton was used in the simultaneous removal of reactive red 195 and Cr(?)by catalytic oxidation and reduction processes.The interaction between the oxidative degradation of reactive red 195 and the reduction of Cr(?)in water was studied.The results indicated that Fe-PCA/EDTA-cotton could be prepared through the modification of cotton fabric with three PCAs and EDTA and showed the photocatalytic activity and adsorption property.Fe-TA/EDTA-cotton and Fe-CA/EDTA-cotton have excellent photocatalytic effect on the oxidative degradation of Reactive Red 195 and the reduction of Cr(?).Fe-CA/EDTA-cotton showed stronger adsorption removal capacity of Cr(?)than other complexes.Increasing Fe content of Fe-CA/EDTA-Cotton and elevation of irradiation enhanced its photocatalytic activity.However,higher Fe content lead to a lower removal performance of Cr(?)from water.Fe-CA/EDTA-Cotton exhibited better photocatalytic activity in acidic and neutral media.The removal performance of Cr(?)by Fe-CA/EDTA-Cotton was limited in stronger acidic range.More importantly,Fe-CA/EDTA-Cotton could effectively be used to simultaneously remove Reactive Red 195 and Cr(?)from water,which may provide a new way to purify the wastewater containing organic pigments and Cr(?)species in the future.