Electrodegradation of Acid Mixture Dye through the Employment of Cu/Fe Macro-Corrosion Galvanic Cell in Na2SO4 Synthetic Wastewater

Traditional wastewater purification processes are based on a combination of physical, chemical, and biological methods; however, typical electrochemical techniques for removing pollutants require large amounts of electrical energy. In this study, we report on a process of wastewater purification, through continuous anodic dissolution of iron anode for aerated Cu/Fe galvanic cell in synthetic Na2SO4 wastewater solution. Electrochemical experiments were conducted by means of a laboratory size electrolyzer, where electrocoagulation along with electrooxidation phenomena were examined for wastewater containing Acid Mixture dye. The above was visualized through the employment of electrochemical (cyclic voltammetry and ac impedance spectroscopy techniques) along with instrumental spectroscopy analyses.

Speciation Change of Flocs During Electrocoagulation for Wet Flue Gas Desulfurization Wastewater

Wastewater produced from wet flue gas desulfurization (WFGD) process contains large amounts of suspended solids (SS), heavy metals and salinity. Compared to traditional chemical coagulation, electrocoagulation (EC) technology is a novel technology to remove these pollutants with lower O&M costs and simplified facilities. In order to achieve better EC effects, the speciation change of flocs generated from two kinds of sacrificed electrodes (e.g., Al and Fe) is investigated in various operation parameters. The results show that iron anode performed better compared to aluminium anode. At 20V of voltage and 6cm of electrode gap, the percentage of polymeric species of iron flocs can reach more than 50%. The significant domination of polymeric species under the optimal conditions during electrocoagution is responsible for the turbidity removal.

Degradation of Sulfamethoxazole by Electrochemically Activated Persulfate Using Iron Anode

In this study, sulfamethoxazole (SMX) was removed by electrochemically activated persulfate using iron anode. Different oxidation processes (persulfate alone, Fe2+/persulfate, electrolysis alone, electrochemically/Persulfate) were investigated, the results showed SMX could be more efficiently degraded under the electrochemically/Persulfate system. Central composite design (CCD) based Response surface methodology (RSM) was used to optimize and elucidate the individual and interactive effects of independent variables on the degradation kinetics of sulfamethoxazole. The maximum kinetics was predicted by CCD as pH 3.6, 18 mA applied current and 3.55 mM/L persulfate concentration. The results of free-radical scavenging experiments and electron paramagnetic resonance (EPR) indicated that both {\text{SO}}_4^{ \cdot - } and HO· were responsible for the degradation of SMX. The inhibition of methanol (MeOH) was lower than tertiary butanol (TBA), due to the generation of methanol radical (·CH2OH), which promoted the reduction of Fe3+to Fe2+. LC-ESI-TOF-MS analysis was done on SMX and its intermediates. The SMX degradation pathway during the electrochemical treatment was proposed. In addition, two typical inorganic anions ( {\text{C}}{{\text{l}}^ - },{\text{HCO}}_3^ -) were investigated and the inhibitory effect of {\text{HC}}O_3^ - was more obvious.