Pb-0.6%Sb/α-PbO2/β-PbO2-MnO2 Electrode Electrodeposited In Methanesulfonic Acid With Application To The Electrocatalytic Degradation of AYR Wastewater

In the present work, a novel Pb-0.6%Sb/α-PbO2/β-PbO2-MnO2 composite electrode with high electrocatalytic activity was obtained by electrodeposition in methanesulfonic acid and further investigated in the electrochemical degradation of alizarin yellow R(AYR) wastewater. The selection of temperature ranges was found to cause a quantitative difference in the formation of α/β-PbO2 phases. In this way, both phases were simultaneously electrodeposited in the same methanesulfonic acid, and electrodes with corresponding proportions of phases were fabricated. Furthermore, performance tests indicated that composite electrodes with the most appropriate corresponding proportions of phases co-deposited with proper amount of MnO2 could obviously improve the COD removal efficiency and degradation efficiency of AYR to 78.1% and 80.3%. They also showed commendable recyclability and fine economic applicability. Ultimately, the paper proposed a proper electrocatalytic degradation pathway of AYR based on the identification of the major intermediate products. The results proved that MnO2-co-doped composite electrodes had more promising application potential in the electrocatalytic degradation of AYR wastewater.

Polyaniline/attapulgite-supported nanoscale zero-valent iron for the rival removal of azo dyes in aqueous solution

In this paper, polyaniline/attapulgite (PANI/APT)-supported nanoscale zero-valent iron (nZVI) composites were synthesized by liquid-phase chemical reduction method and used for the removal of two kinds of dyes. The structure of as-prepared nZVI/PANI/APT was characterized by various test methods. The removal property and degradation mechanism for azo (alizarin yellow R, methyl red, chrome black T, methyl orange) and non-azo (methylene blue, rhodamine B) dyes in aqueous solution were investigated. The presence of PANI/APT can decrease the aggregation of nZVI particles with maintenance of reactivity and improving adsorption capacity for degradation azo dye. The experiment results showed that the removal property of the composite materials on azo dyes is obviously better than that on non-azo dyes. The varying removal efficiencies of dyes depend on the different degradation mechanisms. Azo dyes removal by nZVI/PANI/APT was mainly due to the reductive cleavage of the N = N of nZVI, while non-azo dyes removal mainly contributes to the adsorption of PANI/APT. The study demonstrated that nZVI/PANI/APT has potential applications for the removal of azo dyes from wastewaters.