| Rhodamine B,one of the most typical xanthene dyes,has been extensively used in many industrial processes and biotechnology applications.As a derivative of triphenylmethane,Rhodamine B has bright color,high fixation rate,good color fastness,it’s structurally stable and hard to degrade at the same time.Solar energy,which has a wide range of applications in daily life,reserves largely and does not produce secondary pollution.Currently,solar photovoltaic technology and solar thermal conversion technology have been widely studied,however,there are rare studies on solar energy-energetic molecular conversion.Solar thermal electrochemical process（STEP）links solar energy utilization to electrochemical processing techniques,it uses the synergistic effect of optical,electrical and thermal effects of solar energy,which takes high temperature electrolysis as the core to transform the stable molecules into energetic molecules,which has high reaction energy,to achieve efficient oxidation of organic wastewater.This topic breaks the traditional method of wastewater treatment,which has low removal rate of COD and incomplete decomposition of the pollutants.In the decontamination ofthe wastewater containing Rhodamine B,we propose a new theory that introduce the application of solar energy STEP process to degrade the target product,separating the experiment into two parts as indoor and outdoor at the same time.In the indoor section,we compare the degradation rate and COD removal rate of Rhodamine B solution with graphite electrode,Ti/（RuO2&SnO2）electrode,Ti/（SnO2&Sb2O3）electrode,Ti/（IrO2&Ta2O5）electrode and Ti/（IrO2&RuO2&SnO2）electrode.As a result,we choose Ti/（IrO2&RuO2&SnO2）electrode as the best anode material.Then we investigate the degradation effect of Rhodamine B solution with Ti/（IrO2&RuO2&SnO2）electrode at different temperatures,initial concentrations of Rhodamine B,pH values,electrolyte densities,current densities,etc.Finally,we determine the optimum reaction condition that this treatment process should be conducted at T=200°C,c（Rhodamine B）=200 mg/L,pH=5,J=20mA/cm2,applied voltage=2V.In the outdoor experiment,in order to investigate the actual effect of the Rhodamine B wastewater treatment in the solar STEP process,we build a solar concentrating system,and degrade 200 mg/L rhodamine B solution at the optimalreaction conditions under the coupling effect of each unit.The experimental results correspond to the conclusions from indoor experiments.At last,we use UV spectroscopy,gas chromatography and cyclic voltammetry to speculate the degradation process of Rhodamine B in the solar STEP process. |
