Interface optimization by impedance spectroscopy and photoelectrocatalytic degradation of clofibric acid

Performance, community structure, metabolic pathway, and mechanism in a three-dimensional electrocatalytic biofilter (3DEBF) for the degradation of multiple concentrations of clofibric acid (CA)

A three-dimensional electrocatalytic biofilter (3DEBF) was constructed to remove clofibric acid (CA). This study compared the effectiveness of 3DEBF and biological aerated filter (BAF) in the removal of refractory CA, examined the effects of influent CA concentrations (0.1, 0.3, 0.5, 0.7, and 1.0 mg/L) on microbial community, and proposed a possible 3DEBF degradation mechanism. Results indicated that the average removal efficiency of 3DEBF reached a peak (76.09%) at 0.7 mg/L, which was 14.43% higher than that of BAF. Based on the microbial community analysis, the significant enrichment of Rhodobacter, Mycobacterium, and Sphingopyxis in 3DEBF was associated with the effect of the CA concentration and the electric field. The degradation pathway indicated that xenobiotics biodegradation and metabolism, membrane transport and replication and repair related genes were upregulated in 3DEBAF. Moreover, CA degradation is based on a combination of adsorption, electrochemical oxidation, and biodegradation.

Effects of various alcohol sacrificial agents on hydrogen evolution based on CoS2@SCN nanomaterials and its mechanism

Visible light induced photocatalysis converted solar energy to chemical energy in the form of hydrogen. g-C₃N₄ modified by thermal oxidation etching, doped S, and nonprecious metal cocatalyst CoS₂ (CoS₂@SCN) were used for photocatalytic hydrogen production. And then the charge transfer behavior and mechanism of various alcohol sacrificial agents on hydrogen evolution was analyzed by optical characterization, impedance analysis, Mott-Schottky, and photocurrent tests. The relationship between the structure and catalytic performance was also explored using characterization methods. The results showed that CoS₂ significantly improved the light absorption of g-C₃N₄, and carrier migration and separation. And when the sacrificial agent was triethanolamine, the nanocomposite CoS₂@SCN exhibited best catalytic performance with the highest hydrogen activity of 223.6 μmol g^-1 h^-1, the minimum volume in-phase charge transfer resistance with 55.19 Ω and the maximum photocurrent and photocurrent density with 5.5 μA cm^-2 and 0.63 mA cm^-2. The more negatively charged surface of organic alcohols were, the easier they were to react with holes, thus enhanced charge transfer and hydrogen production efficiency. This report provides guidance for the selection of hydrogen producing sacrificial agents and preparation of highly charge-efficient catalysts. And it also provides a theoretical basis for hydrogen production from wastewater and environmental remediation.