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[Display omitted] • Non-antibiotic pharmaceuticals have higher risk than antibiotics in landfill leachates. • Population size contributed to the regional differences of pharmaceuticals in leachates. • Solid waste composition and loading affect pharmaceutical concentrations in leachate. • High level of pharmaceuticals was observed in the leachate of residual/food waste. Municipal solid waste (MSW) landfill sites have been identified as a significant source of pharmaceuticals in the environment because unused or expired pharmaceuticals are discarded into MSW, which eventually percolate into leachates. However, the contamination of pharmaceuticals in landfill leachate in China is not comprehensively understood. Previous research into factors influencing pharmaceutical concentrations focused on a limited number and type of target pollutants or restricted study area. In the present study, 66 pharmaceuticals were analyzed (including 45 antibiotic and 21 non-antibiotic pharmaceuticals, also categorized as 59 prescription and 7 non-prescription pharmaceuticals) in leachate samples from landfill sites with various characteristics in different regions of China. The results indicated that non-antibiotic pollutants were present at significantly higher concentrations than antibiotic pollutants, with median concentrations of 1.74 μg/L and 527 ng/L, respectively. Non-antibiotic pollutants also presented a higher environmental risk than antibiotic pollutants, by 2 to 4 orders of magnitude, highlighting that non-antibiotic pharmaceuticals should not be overlooked during the assessment of landfill leachate. Pharmaceutical concentrations in landfill leachate samples exhibited regional differences; the population size served by the landfills was the dominant factor contributing to the observed differences. In addition, landfill characteristics such as the solid waste composition and MSW loading can also affect pharmaceutical concentrations in landfill leachate. Despite the implementation of the classification and disposal policy of MSW in Shanghai, China since July 2019, specifying that unused or expired pharmaceuticals should be discarded as hazardous waste, high levels of pharmaceutical contaminations were detected in leachate from the main components of classified MSW (i.e., residual and food waste). These findings emphasize the importance of pharmaceutical management in solid waste systems. [ABSTRACT FROM AUTHOR]

Iron sludge generation poses a challenge to the application of Fenton/Fenton-like processes in wastewater treatment. In this study, sulfidated nano zero-valent iron (S-nZVI) was introduced to enhance the activation of sodium percarbonate (SPC) by Fe(III), mitigating the generation of iron sludge by promoting the Fe(III)/Fe(II) cycle. The proposed technique efficiently removed 94.3 % fluoranthene (FLT) in which HO• acted as the major reactive oxygen species responsible for FLT degradation. Toxicity analysis revealed phthalic acid and 1-phenylnaphthalene as FLT degradation intermediates which finally converted to CO 2 and H 2 O. Similarly, the luminous bacteria experiment also showed that the FLT degradation process was environmentally benign. The support of S-nZVI to the Fe(III)/Fe(II) cycle was determined by analyzing the morphology and characterization of S-nZVI. The removal of FLT reached more than 80 % at pH ranging from 3.0 to 10.0, and the detrimental effects of low concentrations of Cl− were mitigated. SPC/S-nZVI/Fe(III) process showed good removal of FLT (90 %) in both real groundwater and river simulation experiments. Furthermore, SPC/S-nZVI/Fe(III) process was successfully applied in soil slurry media with around 90 % FLT degradation in 12 h. The influence of the soil/water ratio on FLT removal was found to be negligible. SPC/S-nZVI/Fe(III) process was superior for the removal of mixed FLT, naphthalene, and phenanthrene contamination. In conclusion, the SPC/S-nZVI/Fe(III) system exhibits enormous potential in the remediation of polycyclic aromatic hydrocarbons (PAHs) contaminated sites. [Display omitted] • The desired FLT removal was obtained both in aqueous solution and soil slurry. • HO• was the dominant ROS for FLT degradation. • Fe(III)/Fe(II) cycle was promoted by S-nZVI. • The effective pH of SPC/S-nZVI/Fe(III) process was 3.0–10.0. • Simulation of FLT degradation in actual groundwater experiments was conducted. [ABSTRACT FROM AUTHOR]

In the advanced oxidation process for the remediation of organic contaminated water and soil, sodium percarbonate (SPC) is regarded as a potential oxidant. Iron sulfide (FeS) was chosen as an activator in this work for assisting fluoranthene (FLT) removal, with Fe(III) addition overcoming the solution pH constraint on FLT removal in the SPC/FeS process. At the optimal chemical dosages, SPC/FeS (pH = 3.0) and SPC/FeS/Fe(III) (pH = 5.7) processes removed approximately 100% and 92.8% of FLT, respectively. Based on the results of scavenging trials and electron paramagnetic resonance analysis, HO• was the dominant reactive oxygen species in FLT removal by SPC/FeS and SPC/FeS/Fe(III) processes. Dissolved oxygen (DO) played a crucial role in FLT removal, and SPC/FeS/Fe(III) process was more dependent on DO than SPC/FeS process. Both processes overcame the limitation of Cl– on the application of SPC-induced oxidation process. In actual groundwater experiments, 95.5% of FLT was removed in SPC/FeS/Fe(III) process at an initial solution pH of 5.0. In soil slurry trials, 12 h was the optimal reaction time for FLT removal, and the SPC/FeS and SPC/FeS/Fe(III) processes degraded 85.6% and 86.7% of FLT, respectively. In conclusion, the FeS-activated SPC-induced oxidation process offers perspectives for PAHs contaminated field decontamination and contributes to the optimization of modern oxidation methods. [Display omitted] • Fe(III) could overcome the solution pH constraint on FLT removal in SPC/FeS process. • FLT degradation in aqueous solution and soil slurry by SPC/FeS and SPC/FeS/Fe(III) processes was investigated. • HO• was the dominant ROS for FLT degradation. • The degradation pathways of FLT were proposed. • The adverse effect of Cl– on FLT removal was surmounted. [ABSTRACT FROM AUTHOR]

• nCaO 2 performed better for TCE degradation than conventional CaO 2. • Citric acid significantly enhanced TCE degradation. • HO was the primary ROSs in CaO 2 /Fe(II) and CaO 2 /Fe(II)–CA systems. • Cl− and HCO 3 − inhibited TCE degradation at different levels. • Effective degradation of TCE in actual groundwater was achieved. In this study, nCaO 2 was synthesized successfully and applied in the Fe(II)-based catalytic environments in investigating trichloroethylene (TCE) removal performance. nCaO 2 with the particle sizes in the range of 50–200 nm was prepared, and it performed better for TCE removal when compared to the conventional CaO 2. Further experimental results showed that 70.4% of TCE could be removed in 180 min at the nCaO 2 /Fe(II)/TCE molar ratio of 1/2/1, while this data was elevated to 86.1% in the presence of citric acid (CA) at the nCaO 2 /Fe(II)/CA/TCE molar ratio of 1/2/2/1 in the same test period. Probe compound tests, specifically designed for free radicals confirmation, demonstrated the presence of HO and O 2 − . Moreover, scavenging tests indicated that HO was the major radical responsible for TCE degradation but O 2 − promoted the removal of TCE in both nCaO 2 /Fe(II) and nCaO 2 /Fe(II)-CA system. In addition, the effects of initial solution pH and anions (Cl−, HCO 3 −) were also evaluated. The performance of TCE degradation in actual groundwater demonstrated that both nCaO 2 /Fe(II) and nCaO 2 /Fe(II)-CA systems can be applicable for TCE removal in ISCO practice and the nCaO 2 /Fe(II)-CA system is much promising technique. These fundamental data strongly confirmed the feasibility and potential of nCaO 2 based technique in the remediation of TCE contaminated groundwater. [ABSTRACT FROM AUTHOR]

Due to the fast and high oxidation efficiency for organic pollutants, it is extremely challengeable to develop efficient catalysts for peroxymonosulfate (PMS) to enhance the removal efficiency of pollutants. Herein, we fabricated a bimetallic MOF (CuCo-ABDC) by a facile hydrothermal process, which displayed 2D nanosheets structure and rich active sites. The characterization results showed that CuCo-ABDC-4 with Cu:Co ratio of 1:1 synthesized via temperature gradient ((100 ℃, 24 h) + (150 ℃, 12 h)) had low-crystalline but high catalytic performance towards PMS. With orange G (OG) as the model organic pollutant, CuCo-ABDC-4 displayed the highest catalytic activity for activation of PMS, where 96.4% of OG removal efficiency was achieved within 60 min via a rate constant of 0.052 min−1. The excellent catalytic activity can be attributed to the high density and uniformly distributed unsaturated Co(II) which was considered to be the main active site, and the interaction between Co and Cu species in the bimetallic MOF. The quenching experiments indicated the production of SO 4 •−, · OH, and 1O 2 in CuCo-ABDC-4/PMS system and 1O 2 acted as the predominant reactive species for degradation of OG. Moreover, the presence of NO 2 −, H 2 PO 4 −, SO 4 2−, HCO 3 − and HA exhibited evident inhibition on the OG degradation rate. On the contrary, the existence of CO 3 2− could promote the OG degradation due to the production of carbonate radical. This work introduces a novel and facile fabrication strategy to attain 2D nanosheets structure bimetallic catalysts with high catalytic performance for activation of PMS in wastewater treatment. [Display omitted] • MOFs with rich active sites was prepared by temperature gradient method for the first time. • CuCo-ABDC-4 displayed high catalytic activity for activation of PMS. • 1O2 was the major species coexistence with SO4•− and · OH in CuCo-ABDC-4/PMS system. • Uniformly distributed unsaturated Co(II) and Cu(II), and their interaction effect contributed to catalytic activity. • The existence of CO32− could promote the OG degradation rate [ABSTRACT FROM AUTHOR]