Dimensionally stable anode (Doped-MMO) mediated electro-oxidation and multi-response optimization study for remediation of urea wastewater.

In the present study, the potential application of novel doped-MMO (Ti/IrO2/Ta2O5/SnO2-Sb2O4) anodes as an alternative source to costly electrodes have been visualized for the EO treatment of urea. Parametric optimization for the treatment of urea through the EO process by doped-MMO has been done successfully. The high R2 values of both responses i.e. % Degradation and energy consumption for quadratic suggested by BBD under RSM advocates a good correlation between predicted and experimental data. The maximum % Degradation and energy consumption at optimized were found to be 91.2%, 51.53 kWh m-3 for urea respectively. Additionally, efforts were made to minimize treatment time further by implementing a dual effect, namely photo-electrocatalysis. The anode was found to be relatively stable even after 120 runs. The analysis of treated urea solution was verified in terms of total organic carbon (TOC) 90.0% reduction. The average operating cost of the electro-oxidation treatment process is determined to be 1.91 $ m-3. The results of this study demonstrate the potential of doped-MMO as a promising concept for the treatment of wastewater that can be successfully applied in real life.

Application of mixed metal oxide anode for the electro-oxidation/disinfection of synthetic urine: Potential of harnessing molecular hydrogen generation.

The efficacy of electro-oxidation has been checked for the deterioration of synthetic urine (SU) using mixed metal oxide anode along with the potential of harnessing the commercially useful byproduct i.e. molecular hydrogen gas. The results from batch have been used to execute the scale-up studies for the continuous electro-oxidation treatment of SU in a photovoltaic driven reactor. The effect of different operational variables like pH, time, current density and N/Cl ratio on process efficiency was evaluated in terms of %COD removal and specific energy consumption using response surface methodology. The results showed that 87.25% removal in COD and 85.88% in TOC were achieved in 8.8 h. The complete deactivation of E. coli spiked synthetic urine wastewater was achieved in 45 min only. The main strength lies in the demonstration of the significant reduction in treatment time to 6 h by incorporating dual effect i.e. Photo-electrocatalysis. The anode used was proven to be stable and effective even after 100 recycles (207.5 h). The intermediates formed during the treatment process were analyzed through LC-MS. The techno-economic analysis for the proposed technology under optimized conditions was calculated to be 0.85 $/kg of COD removed.