Effects of a novel Mg-C micro-electrolysis system for phenolic wastewater degradation: material characterization, influencing factors, and model optimization

This study investigated a novel magnesium carbon micro-electrolysis (Mg-C ME) system for strengthening the removal of phenolic compounds in wastewater. The effects of the Mg/C mass ratio, aeration intensity, initial pH and reaction time on the degradation of three phenolic compounds and the COD removal efficiency in the simulated wastewater were evaluated using one-factor-at-a-time (OFAT) method. The optimum values obtained for the Mg/C mass ratio, aeration intensity, initial pH and reaction time were 3:1, 4.0 L/(L·min), 5.0 and 2.5 h, respectively. The experimental removal rates of catechol, resorcinol, and phenol, under the mentioned conditions, were obtained to be 95.6%, 71.5%, and 48.8%, respectively. Meanwhile, the COD removal rates were 63.8%,44.7%,34.0%, respectively. Moreover, experiments were designed and analyzed based on the box-based designing response surface (BBD-RSM) method. According to the results, the Mg/C mass ratio was the most significant variable showing incremental effect on the removal efficiency of catechol in a way that maximum removal efficiency of catechol was achieved in Mg/C mass ratio of 3.23:1. The validation experiments showed that the maximum removal efficiency of catechol was 96.24% under optimization conditions. Resorcinol degradation characteristics analysis indicated that the Mg-C ME system performed a key function in phenolic compounds elimination. Results showed that the Mg-C ME has a considerable capability in removing the phenolic compounds and COD. Thus, it could be considered as an efficient pretreatment choice for treating phenolic wastewater in the future.