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Electro-activated persulfate has displayed good performance in the oxidation of antibiotic pollutants in wastewater. However, high power consumption and the introduction of excessive sulfate ions hinder the application of this technology. This research provided a novel strategy for the applications of small power supply and simple devices in antibiotic pollutant treatment. It has been confirmed that sulfate radical ( SO 4 ∙ - ) could be generated at the boron-doped diamond (BDD) anode in both low and high current conditions. This study proposed a novel low current density electrochemical technology assisted by peroxymonosulfate (PMS) for the degradation of antibiotics. Adding 1 mg/L PMS at current density as low as 1.25 mA/cm2 increased the electro-oxidation rates of ciprofloxacin 5-fold from 1.92 ± 0.67 h−1to 9.70 ± 0.10 h−1. According to the Butler-Volmer equation, the introduction of PMS changed the mechanism of electrode reactions, thermodynamic properties of the system therefore changed. The electron spin resonance (ESR) test has confirmed that hydroxyl radical (•OH), SO 4 ∙ - , and singlet oxygen (1O2) are all generated in low current electrochemical systems. Quenching experiments illustrate that both radical and non-radical ways play essential roles in electro-oxidation processes. The contribution rates of •OH, SO 4 ∙ - , and 1O2 were 15.6%, 33.2%, and 40.5%, respectively. An oxidation peak was observed in cyclic voltammetry (CV) around +1.2 V, indicating that PMS electrolyte may drive oxidation at this potential. Besides, the reaction pathways of ciprofloxacin were speculated. Four transformation pathways including stepwise piperazine ring cleavage, OH/F substitution, cyclopropane ring cleavage, and decarboxylation were proposed for ciprofloxacin degradation. [ABSTRACT FROM AUTHOR]

Due to the annual increase in wastewater treatment in most Chinese cities, a major environmental issue has arisen: safe treatment, disposal, and recycling of municipal sludge. Municipal sludge has a high content of carbon and essential nutrients for plant growth; hence, it has gained interest among researchers as a soil fertilizer. This study discusses the potential usage of municipal sludge as soil fertilizer (indicators include nitrogen (N), phosphorus (P), and trace elements) along with its shortcomings and drawbacks (potentially toxic elements (PTEs), organic matter (OM), pathogens, etc.) as well as reviews the latest reports on the role of municipal sludge in land use. The use of municipal sludge as a soil fertilizer is a sustainable management practice and a single application of sludge does not harm the environment. However, repeated use of sludge may result in the accumulation of harmful chemicals and pathogens that can enter the food chain and endanger human health. Therefore, long-term field studies are needed to develop ways to eliminate these adverse effects and make municipal sludge available for agricultural use. [ABSTRACT FROM AUTHOR]

In this paper, a ruthenium/titanium dioxide (Ru/TiO2) composite photocatalyst was successfully prepared with the sol–gel method. The composite catalysts were characterised by UV–Vis diffuse reflectance spectroscopy, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and transmission electron microscopy. After being immobilised, the photocatalyst showed good photocatalytic activity and removed the ammonia molecules in the ultraviolet visible light region. The experimental results of ammonia nitrogen removal showed that the Ru/TiO2 photocatalyst removes ammonia molecules with high efficiency under UV irradiation at a wavelength of 365 nm. Finally, through experimental analysis of NO2− and NO3− production in the process of photocatalytic oxidation, the mechanism of ammonia nitrogen removal and the reduction of nitrate nitrogen in the process of photocatalytic oxidation are proposed. Under high-intensity light, NH4+ can be effectively removed, while photogenerated electrons have a reduction effect on NO3− and the generation of NO3− can be controlled. [ABSTRACT FROM AUTHOR]