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• A novel technology for simultaneous soil SMZ degradation and N supply was developed. • The technology involves FB-catalyzed oxidation combined with UHP application. • Pot test confirmed FB-UHP is a promising technology for agricultural soil remediation. This study developed a novel remediation technology based on urea-hydrogen peroxide (UHP) activated by a synthesized Fe-impregnated biochar (FB). The technology can simultaneously degrade sulfamethoxazole (SMZ) and supply nitrogen nutrition in cropland soil. Experimental results showed that 97.56% of SMZ was removed in the FB-UHP system within 24 h, whereas 7.12% and 14.65% were removed in the individual application of FB and UHP. Chemical probe and scavenger test results demonstrated that SMZ degradation mainly occurred through oxidation of hydroxyl radicals generated from the activation of UHP by FB. The effects of FB pyrolysis temperature, initial pH, and reaction temperature were investigated. The combination of UHP and FB led to efficient SMZ degradation at a wide pH range of 2–10. Catalytic durability test results showed that FB exhibited good stability even after four uses. A soil column leaching experiment showed that the addition of FB-UHP reduced the SMZ leaching from the soil by 95.06%, increased the nitrogen content on surface soil by approximately 2.5 times, and decreased the nitrogen leaching by 97.57%. Early-stage seedling growth bioassay confirmed that FB-UHP significantly enhanced the SMZ degradation, increased the soil nitrogen content, and improved the lettuce plant growth. Therefore, application of FB-activated UHP is a promising technology for agricultural soil remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] • The catalyst with Co/Mg molar ratio of 1/200 rapidly activated PMS to remove CQP. • CoO nanoparticles were wrapped by MgO in catalyst, limiting cobalt ion leaching. • MgO accelerated the formation of Co-OH complex and redox cycle of Co2+- Co3+- Co2+. • Activation mechanism of PMS by the catalyst was analyzed in depth. Cobalt oxide could be used to activate peroxymonosulfate (PMS) for removal of contaminants, while its use was restricted due to low catalytic activity by limited active sites and the risk of cobalt ion leaching. This study investigated chloroquine phosphate (CQP) degradation by Co-Mg mixed metal oxides with highly dispersed minute quantities of CoO nanoparticles to activate PMS. It was demonstrated that the Co/Mg optimal molar ratio of catalyst was 1/200, and by characterization of catalysts and their effects on degradation of CQP, CoO nanoparticles could be widely dispersed and wrapped by MgO support. In the catalyst/PMS system, degradation of CQP could accelerate with the increase of catalyst dosage, PMS concentration and temperature and the addition of C l - , H P O 4 2 - and H 2 P O 4 - , but decrease with the addition of Mg2+, N O 3 - , H C O 3 - and nature organic matter (NOM). By quenching experiments of active radicals, it was illustrated that S O 4 · - and O 2 · - made more significant contributions than H O · in this system for CQP degradation. The activation mechanism of PMS by the catalyst with good repeatability and stability was explained that MgO could effectively adsorb hydroxy groups, promoting the formation of Co-OH complex and accelerating the redox cycle of Co2+- Co3+- Co2+ in the catalyst. The strong interaction between CoO and MgO prevented cobalt ion leaching and enhanced catalyst activity over the wide pH range (5–10). And proposed intermediates and degradation pathways of CQP were analyzed. [ABSTRACT FROM AUTHOR]

[Display omitted] • The catalyst with optimized Cu/Mg molar ratio rapidly activated PMS to remove TAP. • MgO wrapped CuO nanoparticles in the catalyst and limited copper ion leaching. • MgO promoted the formation of Cu-OH complex and redox cycle of Cu+-Cu2+-Cu+. • Activation mechanism of PMS and degradation pathways of TAP were proposed. Copper-base catalysts with high load content of CuO were commonly utilized to activate peroxymonosulfate (PMS) for removal of contaminants but limited catalytic efficiency and increased risk of copper ion leaching restricted their use. In this paper, Cu-Mg mixed metal oxides with highly dispersed minute quantities of CuO were successfully prepared by one-pot synthesis for efficiently activating PMS to remove thiamphenicol (TAP), which was economical and environmentally friendly. The catalytic activities of catalysts with different molar ratios of Cu and Mg for PMS and their characteristics were evaluated, illustrating the optimal molar ratio of Cu and Mg (1:15, named CuMg-MMO) in the catalyst. For the CuMg-MMO catalyst, MgO widely dispersed and wrapped CuO nanoparticles, minimized the copper ion leaching and promoted the generation of Cu-OH complex and non-radical species. In the CuMg-MMO/PMS system, the influence factors for TAP degradation were analyzed, including different systems, catalyst dosages, PMS concentrations, temperatures, initial pH values, TAP concentrations, anions (N O 3 - , H C O 3 - , C l - , H P O 4 2 - and H 2 P O 4 -) and natural organic matter (NOM) concentrations. Under the optimal conditions (i.e., [catalyst]: 75 mg/L, [PMS]: 0.3 mM, temperature: 30 °C and initial pH: 6.5), TAP removal efficiency obtained by this system was 99.9%. S O 4 · - , · O 2 - and 1O 2 played more important roles than H O · in TAP degradation. Four successive repeated experiments indicated that CuMg-MMO possessed good reusability and stability. PMS decomposition, mineralization of TAP, the activation mechanism of PMS and possible degradation pathways of TAP were analyzed. [ABSTRACT FROM AUTHOR]

[Display omitted] • It was firstly demonstrated that the synergistic activation of PMS by MoS 2 @PANI and Cu(II). • High removal rate of sulfathiazole (≥85 %) achieved within a wide range of pH (3–10) in Cu(II)/MoS 2 @PANI/PMS. • H O ∙ , Cu(Ⅲ) and 1 O 2 were generated in Cu(II)/MoS 2 @PANI/PMS, while SO 4 ∙ - was negligible. • Compared with Fe(II), Cu(II) improved reusability and applicability of MoS 2 @PANI in activation of PMS. • The absorption of Cu(II) on MoS 2 @PANI improved the stability of MoS 2 @PANI. This paper synergistically combined MoS 2 @PANI (coating MoS 2 on polyaniline (PANI)) with Cu(II) to obtain effective activation of PMS in a wide range of pH (3–10). The removal rate of sulfathiazole (ST) in Cu(II)/MoS 2 @PANI/PMS (98 %) in 60 min was higher than in Cu(II)/PMS (50 %) and MoS 2 @PANI/PMS (70 %). Besides, the PMS consumption rate was 100 % within 30 min in Cu(II)/MoS 2 @PANI/PMS. Different concentrations of Cl - and HCO 3 - promoted the degradation of ST in varying degrees. And NO 3 - slightly inhibited the degradation of ST (removal rate more than 84 %). Notably, Cu(II)/MoS 2 @PANI/PMS could remove more than 80 % ST in different water bodies. The special structure of MoS 2 @PANI increased many activity sites of Mo(IV) to promote the cycle of Cu(II)/Cu(I) for activating PMS which generated H O ∙ , Cu(III) and 1 O 2. Twenty-seven degradation intermediates were identified and four possible degradation paths of ST were proposed. Moreover, Cu(II)/MoS 2 @PANI/PMS possessed a good non-selectivity for various organic pollutants. After three consecutive cycles, the removal rate still retained more than 90 % in Cu(II)/MoS 2 @PANI/PMS system. Compared with Fe(II), MoS 2 @PANI was more stable in Cu(II)/MoS 2 @PANI/PMS. The synergy of Cu and Mo broke the limitation of PMS activation under environmental aquatic conditions. Given that Cu(II) widely existed in wastewater, the new research strategy increased the application scope for homogeneous PMS activation with inherently Cu(II) in wastewater in environmental remediation. [ABSTRACT FROM AUTHOR]