Mechanism Research On Electrochemical Reduction Of Vat Dye

Vat dye dyeing dyeing process is complex, traditional dye in the reduction process need to add a lot of insurance powder, and it was produced by oxidation of sulfate and sulfite can bring certain impact on the environment. Therefore, the electrochemical reduction technology in recent years to replace traditional impregnation dyeing method, to reduce the use of insurance powder dosage or take the place of powder. This topic systematically on the electrochemical reduction mechanism of Vat brown BR and dyeing process were studied.Paper firstly separately for each component(ferric sulfate(Fe2(SO4)3), sodium hydroxide(Na OH), triethanolamine(TEA)) orthogonal experiments, according to get optimum conditions and process conditions(applied voltage(U), cathode area(S), VAT dyeing temperature(T), VAT dyeing time(t)) orthogonal experiments, get VAT brown BR electrochemical reduction dyeing optimized process conditions. According to the optimization of process conditions on the single factor analysis of factors influencing the dye Vat brown BR electrochemical reduction:Fe2(SO4)3 concentration, the quality of the quality of Na OH concentration and the concentration of the quality of the TEA, U, S, T and t, finally got the best process conditions. Finally under the condition of optimum process test cotton fabric after dyeing levelness and color fastness with the traditional dyeing dyeing effect is almost the same.Secondly, according to the experiment of the optimum process conditions, according to Fe2(SO4)3 concentration and the quality of the Na OH concentration and the quality of the TEA quality concentration ratio, respectively in the three electrode system by using cyclic voltammetry and square wave voltammetry of Fe3+/Fe2+-TEA complexes and dyeing system on the silver electrode electrochemical behavior was studied. Using cyclic voltammetry, respectively tested the blank base solution(Na OH) and TEA mixed solution,Fe3+/Fe2+-TEA complexes and dyeing system on the silver electrode of electrochemical behavior. Our research results show that the blank bottom liquid in the potential range is no obvious current response; Fe3+/Fe2+-TEA number of complexes in the process of electron transfer reaction of 2, reaction process is reversible system, its are controlled by adsorption, oxidation and reduction process simple and charge transfer reaction; Dyeing system in obvious redox peak appeared on the silver electrode, the system is reversiblesystem, the oxidation and reduction processes are controlled by adsorption; Based on the dyeing system analysis on the impact of the cyclic voltammograms curve and the number of scanning, it is concluded that the leuco dye body on the silver electrode electrode reaction. Using square wave voltammetry of Fe3+/Fe2+-TEA complexes and dyeing system on the silver electrode electrochemical behavior was studied. The results showed that Fe3+/Fe2+-TEA complexes in the process of electron transfer reaction number is 2, on the silver electrode of dye leuco electrode reaction, the experimental results are consistent with cyclic voltammetry.