The Research Of The Electro-Fenton Depolymerization Of Cellulose By Modified Carbon Electrode

This paper presents an investigation on the degradation of cellulose via electro-Fenton method. The electrodes chosen for electro-Fenton method were graphite/PTFE electrodes modified by 2-ethylanthraquinone. The presence of 2-ethylanthraquinone greatly improved hydrogen peroxide formation rate on air-fed graphite/PTFE electrodes. Hydrogen peroxide can react with Fe²⁺ to form hydroxyl radical in an acidic medium. Hydroxyl radical can accelerate degradation of the cellulose by cleaving the glycosidic bond between glucose units. In this action we researched the cathode materials, electrolytic potential, reaction time, FeCl 2 and other electric-Fenton factors. The crystalline allomorphs of cellulose were determined by the resolution of wide-angle X-ray diffraction measurement. The average degree of polymerization of cellulose was determined via copper ethylenediamine solution method.Two different electrodes with 0% and 5% EAQ were contrastively used for the synthesis of hydrogen peroxide under the same experimental conditions mentioned above. The largest amount of H2O2 production was 23mg/L when using 5% MGDE with the potential being -1.2V vs. SEC, although the produced hydrogen peroxide concentrations with the two electrodes gave similar rising profiles from 0.4V to -1.2V vs. SEC.It was shown that 10 g cellulose and 0.4 g FeCl2 in 1 mol/L hydrochloric acid was electrolysed at -1.2 V (vs.SEC) for 4 h, the percentage of crystallinity for cellulose obviously decreased, the depolymerization rate of cellulose could reach to 85.8%. The degradation products of the cellulose contained soluble sugar and 5-hydroxymethylfurfural. The content of soluble sugar was determined by the phenol-sulfuric acid method, and the molar yield soluble sugar was 10.2%. 5-hydroxymethylfurfural was fully characterized by 1H NMR and 13C NMR, the largest molar yield of which in electro-Fenton methods was 5.6%.