Abstract
This study proposes electrolysis of alkaline water that has dissolved lignin (LG) that is often termed black liquor. It was demonstrated that, H_2 was formed as the ratio of 1:2 to electrons at the cathode, but O_2 wasn't evolved in a continuously electrolysis. It means that lignin oxidation had occurred at the anode instead of O_2 generation in the electrolysis, in other words, electrochemical gasification. Linear-sweep voltammetry of LG showed that the oxidation occurred at voltage of -0.1-0 V, which was lower than the theoretical voltage in the absence of the lignin, i.e., 0.4 V. The oxidation of LG was further enhanced by its hydrothermal treatment (HT) prior to the electrolysis. HT caused depolymerization producing reactive monomers such as guaiacol and syringol. It was thus concluded that use of LG potentially but significantly raised the efficiency of the electrolysis and further, the reactivity is enhanced through depolymerization of lignin by HT.
