Haibin Ma

In this study, an electrochemically coupled micro-electrolytic technology–enhanced soil infiltration system (E-ME-SIS) was proposed to address the problem of the high cost of traditional soil infiltration system (SIS) and the difficulty of removing imidacloprid (IMI) wastewater efficiently by a single treatment process. Micro-electrolytic ceramic substrates (MECS) were prepared from iron, activated carbon, aluminum, and fly ash and combined with an external power source to optimize the electrochemical and micro-electrolytic synergy and investigate their effectiveness in treating IMI wastewater. The results showed that MECS had a rough surface with a specific surface area of 2.682 m²/g, combining strong adsorption capacity (maximum adsorption of 1.149 mg/g) and wear resistance (24 h wear rate of 6.4%). The removal of total nitrogen (TN), total phosphorus (TP), and IMI by E-ME-SIS was stabilized at 99%, 98%, and 98%, respectively, at a current density (CD) of 0.625 mA/cm² and influent C/N (COD/N) = 5. This study significantly enhanced the removal of difficult-to-degrade pollutants by SIS through an electrochemically enhanced micro-electrolysis reaction, which provides an energy-saving and stable technical reference for the efficient treatment of IMI wastewater with a potential for engineering applications.

In view of the flue gas characteristics of cement kilns in China, the development of low-temperature denitrification catalysts with excellent anti-poisoning performance has important theoretical and practical significance. In this work, a series of MnCeO_x@TiO₂ and tourmaline-containing MnCeO_x@TiO₂-T catalysts was prepared using a chemical pre-deposition method. It was found that the MnCeO_x@TiO₂-T2 catalyst (containing 2% tourmaline) exhibited the best low-temperature NH₃-selective catalytic reduction (NH₃-SCR) performance, yielding 100% NO_x conversion at 110 °C and above. When 100–300 ppm SO₂ and 10 vol.% H₂O were introduced to the reaction, the NO_x conversion of the MnCeO_x@TiO₂-T2 catalyst was still higher than 90% at 170 °C, indicating good anti-poisoning performance. The addition of appropriate amounts of tourmaline can not only preferably expose the active {001} facets of TiO₂ but also introduce the acidic SiO₂ and Al₂O₃ components and increase the content of Mn⁴⁺ and O_α on the surface of the catalyst, all of which contribute to the enhancement of reaction activity of NH₃-SCR and anti-poisoning performance. However, excess amounts of tourmaline led to the formation of dense surface of catalysts that suppressed the exposure of catalytic active sites, giving rise to the decrease in catalytic activity and anti-poisoning capability. Through an in situ DRIFTS study, it was found that the addition of appropriate amounts of tourmaline increased the number of Brønsted acid sites on the catalyst surface, which suppressed the adsorption of SO₂ and thus inhibited the deposition of NH₄HSO₄ and (NH₄)₂HSO₄ on the surface of the catalyst, thereby improving the NH₃-SCR performance and anti-poisoning ability of the catalyst.