Paper Title
Degradation of Methylene Blue using Mediated Electrochemical Oxidation: Effects of Supporting Electrolyte and Potential Oxidation

Abstract
Mediated Electrochemical Oxidation (MEO) is one of electrochemical method are widelyused to degrade organic pollutans from waters. Dyes represent one of problematic group. We have studied the degradation of methylene blue (MB) using MEO methode with batch system with Ce (IV) as mediator and Ag (I) as catalyst. Ce (IV) as mediator was made electrochemically from the oxidation of Ce (III). Ce (IV) candegrade textile dye waste by oxidizing them into simpler products so that the danger level is reduced. Voltammetric studies have been performed by the cyclic voltammetric technique using carbon paste electrodes as working electrodes, Ag/AgCl as comparative electrodes and platinum wires as auxiliary electrodes. The results show the potential of oxidation of Ce (III)/Ce(IV) and methylene blue at 1.25 volts and 0.27 volts. The study of methylene blue degradation was performed by electrolysis using platinum wire as anode and cathode. The total degradation percentage of 89.04% was obtained in the degradation of 250 mgL-1 methylene blue in 0.3 M H2SO4 as a supporting electrolyte, with the addition of 0.02 M Ce (III) for 30 min at the use of 7.5-volt potential difference. The effect of catalyst addition showed that in addition of Ag (I) 2 mM increased percent degradation to 100%. From the analysis results using HPLC and UV-Vis a decrease in peak MB after degradation, it shows that MB has been degraded into another compounds. The MB degradation process in H2SO4 0.3 M with the addition of Ce (III) 0.02 M and Ag (I) 2 M has resulted in simpler products such as CO2. The percentage of CO2 levels produced during the conventional degradation process using acid-base titration method was 52.88%. Keywords - Mediated Electrochemical Oxidation, Methylene Blue, Mediator Ce (IV), Catalyst Ag(II)