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Fast degradation and complete mineralization of herbicide dalapon (DPN) as the target pollutant has been investigated for the first time by the heterogeneous photoelectro-Fenton (hPEF) process using a nitrogen doped reduced graphene oxide (NrGO) modified carbon felt (CF) cathode (NrGO@CF) and a ternary nanocomposite catalyst (TNC) based on reduced graphene oxide (rGO), Fe3O4, and TiO2to maintain high yield generation of H2O2and •OH. The effects of main variables, including the catalyst composition and amount, applied current, and initial pH of the solution, were investigated. The as-synthesized nanomaterials exhibit significant improvements thanks to their high specific surface area, increased H2O2production, catalytic activity, and the possibility to work in a wide pH range. This system also promotes photoreduction and photooxidation reactions by increasing photon absorption. By combining highly conductive carbon materials and the photoexcited electrons from TiO2, redox cycling between ≡FeIIand ≡FeIIIwas facilitated, thus improving the process performance. Catalytic stability measurements show that the use of a NrGO@CF cathode, an equimass rGO-Fe3O4-TiO2TNC and boron doped diamond (BDD) anode trio resulted in the fast degradation and complete mineralization of DPN within 30 and 60 minutes, respectively, after five consecutive cycles under UV light irradiation, 500 mA current intensity, 0.1 g L−1catalyst concentration and pH 6 conditions. Moreover, intermediate products of DPN oxidation were identified. Therefore, this study highlights an efficient and stable cathode and catalyst duo for the removal of a short chain halogenated aliphatic herbicide from aqueous media.

Pharmaceuticals constitute one of the more widely reported anthropogenic micropollutants, and their removal usually requires a specific treatment method. The oxidative degradation and mineralization of molnupiravir (MNP), a novel antiviral drug used for COVID treatment, were investigated for the first time by EF processes using both raw carbon felt (CF) and modified dual-function CF cathodes. The classical electro-Fenton (CEF) process using CF cathode has significant challenges, including a narrow pH range and a lack of ability to reuse the catalyst. To overcome these limitations, a dual-function FeIIFeIIIlayered double hydroxide modified carbon felt (FeIIFeIIILDH@CF) cathode was developed using a hydrothermal method. The FeIIFeIIILDH@CF cathode was characterized using BET, FTIR, SEM, cyclic, and linear sweep voltammetry. The efficiency of FeIIFeIIILDH@CF cathode for the removal of MNP compared with that of raw carbon felt (CF) cathode, including the effects of operating parameters. The heterogeneous electro-Fenton (HEF) process with FeIIFeIIILDH@CF cathode allowed an almost complete mineralization (98.08 % TOC removal) of 0.1 mM MNP solution. The mineralization ability of the FeIIFeIIILDH@CF cathode was more than 95 % after 5 cycles, suggesting a good reusability of the synthesized cathode. The absolute rate constant for the oxidation of MNP with ●OH (2.22 ± 0.03 ×109M−1s−1) was also determined for the first time. In addition, the modified LDH cathode has the advantage of being effective over a wide pH range while avoiding the use of an iron salt as a catalyst.

In this work, the removal results of the application of sequential chemical precipitation (CP) and coagulation (CC) over boron-containing industrial wastewater were presented. Effect of amount of Ca(OH)2/B2O3concentration ratio, initial pH and Al2(SO4)3∙18H2O concentration on B2O3removal was investigated using Box–Behnken based custom experimental design. Response surface methodology (RSM) was used to evaluate the effect of process variables and their interactions on boron removal. Results show that selected operational parameters and obtained regression model were statistically significant. The coefficient of determination was found as 0.9846, indicating that the model has a good fit with experimental data. Water has been obtained in a dischargeable quality according to Water Pollution Control Regulation of Turkish Authorities with 95% B2O3removal from an initial concentration of 13.23 g/L under optimum operating conditions of 2.01 g Ca(OH)2/1 g/L B2O3ratio, pH 8.12 and 13.5 g/L Al2(SO4)3∙18H2O.