Preparation Of Polycarboxylate Modified Cotton Fabric With Different Structures And Its Catalysis For Oxidative Degradation Of Azo Dyes

In this paper,the cotton fabric surface was modified with tartaric acid,citric acid and 1,2,3,4-butanetetracarboxylic acid to introduce carboxylic groups.Then,the complex was reacted with Fe3+ ion to obtain the polycarboxyl ic acid modified cotton fabric iron complex.The effects of polycarboxylic acid structure,modification reaction conditions and coordination reaction on carboxyl content and iron content of the fiber surface were investigated.The surface morphology,chemical structure and thermal properties of the iron complex were characterized by scanning electron microscopy(SEM),Fourier transform infrared spectrometer(FTIR),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS)and thermogravimetric analysis(TG-DSC).Then,three kinds of polycarboxylic acid modified cotton fabric Fe complexes were used as heterogeneous light Fenton reaction catalysts for the oxidative degradation reaction of azo dye reactive red 195.The effects of Fe3+ ion content,H2O2 concentration,pH value and radiation intensity on the catalytic activity of the complexes were investigated.The mechanical properties of cotton fabrics modified with polycarboxylic acids and their iron complexes were tested.The effects of polycarboxylic acid concentration and the amount of Fe3+ ion on the mechanical properties were investigated.The results show that the carboxyl content of the modified cotton fabric increased with the increase of polycarboxylic acid concentration and the drying temperature and the proper concentration of sodium dihydrogen phosphate.Three kinds of polycarboxylic acid modified cotton fabrics can react with Fe3+ ion to form polycarboxylic acid modified cotton fabric iron complex.Moreover,the increase of Fe3+ ion concentration or the increase of the reaction temperature are beneficial to the improvement of the coordination amount of Fe3+ ion.Under the same reaction conditions,tartaric acid modified cotton fabric is easier to coordinate with Fe3+ ion.The polycarboxylic acid modified cotton fabric Fe complex can be used as heterogeneous Fenton reaction catalyst to catalyze the oxidation degradation of azo dyes.With the increase of the coordination amount of Fe3+ and the introduction of visible light,the activity of the complexes can be significantly promoted.Under the same reaction conditions,tartaric acid modified cotton fabric Fe complexes showed better catalytic degradation performance.Under the same reaction conditions,tartaric acid modified cotton fabric Fe complexes showed better catalytic degradation performance.With the increase of polycarboxylic acid concentration,the mechanical properties of cotton fabric modified by polycarboxylic acid gradually decreased.After the coordination reaction with Fe3+ ion,the mechanical strength decreased firstly,and then increased with the increase of Fe3+ ion coordination amount.Under the same conditions,the mechanical strength of the cotton fabric modified by tartaric acid and its iron complex decreased most obviously.