고체 고분자 전해질(SPE)을 이용한 전기분해 공정에서 Rhodamine B 분해

Abstract

Objectives: Feasibility of electrochemical oxidation of the aqueous non-biodegradable wastewater such as cationic dye Rhodamine B (RhB) has been investigated in an electrochemical reactor with solid polymer electrolyte (SPE). Methods: Nafion 117 cationic exchange membrane as SPE has been used. Anode/Nafion/cathode sandwiches were constructed by sandwiching Nafion between two dimensionally stable anodes (JP202 electrode). Experiments were conducted to examine the effects of applied current (0.5~2.0 A), supporting electrolyte type (0.2 N NaCl, <TEX>$Na_2SO_4$</TEX>, and 1.0 g/L NaCl), initial RhB concentration (2.5~30.0 mg/L) on RhB and COD degradation and <TEX>$UV_{254}$</TEX> absorbance. Results: Experimental results showed that an increase of applied current in electrolysis reaction with solid polymer electrolyte has resulted in the increase of RhB and <TEX>$UV_{254}$</TEX> degradation. Performance for RhB degradation by electrolyte type was best with NaCl 0.2 N followed by SPE, and <TEX>$Na_2SO_4$</TEX>. However, the decrease of <TEX>$UV_{254}$</TEX> absorbance of RhB was different from RhB degradation: SPE > NaCl 0.2 N > <TEX>$Na_2SO_4$</TEX>. RhB and <TEX>$UV_{254}$</TEX> absorbance decreased linearly with time regardless of the initial concentration. The initial RhB and COD degradation in electrolysis reaction using SPE showed a pseudo-first order kinetics and rate constants were 0.0617 (<TEX>$R^2=0.9843$</TEX>) and 0.0216 (<TEX>$R^2=0.9776$</TEX>), respectively. Conclusions: Degradation of RhB in the electrochemical reactor with SPE can be achieved applying electrochemical oxidation. Supporting electrolyte has no positive effect on the final <TEX>$UV_{254}$</TEX> absorbance and COD degradation. Mineralization of COD may take a relatively longer time than that of the RhB degradation.