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A highly efficient fluoride adsorbent Al2 O3 /CeO2 was synthesized in this work and used it to fluoride removal in the fixed-bed adsorption through changing the different experimental conditions (influent F- concentration, flow velocity, and bed heights). The adsorption capacity was 9.72 mg/g. In addition, the Adams-Bohart and Thomas models were used to fit and evaluate the column breakthrough curve of fluoride removal process by Al2 O3 /CeO2 , and the correlation coefficients (R2 ) of the Thomas model were close to 1 under all experimental conditions. The structure of Al2 O3 /CeO2 and the adsorption mechanism were confirmed by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), N2 adsorption and desorption isotherm, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Moreover, the adsorption of fluoride (F- ) was mainly through metal binding (MF) and hydroxyl binding (AlOH⋯F) on the surface of the Al2 O3 /CeO2 . Furthermore, the regeneration and coexisting anions studies of Al2 O3 /CeO2 were carried out, and the efficiency of adsorption was still above 70% after five cycles. PRACTITIONER POINTS: Removal of fluoride was studied by fixed-bed experiment, and the adsorption capacity of composite Al2 O3 /CeO2 was 9.72 mg/g. The metal complex played important role in fluoride removal and reusability makes a long-term application for fluoride adsorption. Fluoride wastewater is pumped to the fixed-bed column, and fluoride ions are absorbed by Al2 O3 /CeO2 through fluoride metal complex and aluminum hydrofluoride.

In recent years, many efforts have been made to modulate the interaction between carriers and nanoparticles under the integrity of the active site structure. Herein, SrFeO

Chlorinated polyfluoroalkyl ether sulfonate (F-53B) and perfluorooctanesulfonate (PFOS) are used and emitted as fog inhibitors in the chromium plating industry, and they are widely detected worldwide. To study the effects of F-53B and PFOS on the rhizosphere defense system, they were added at two levels (0.1 and 50 mg Lsup-1/sup) to the soil where different plants (Lythrum salicaria and Phragmites communis) were grown. In bulk soils, high concentrations of F-53B/PFOS resulted in significant increases in soil pH, NHsub4/subsup+/sup-N, and NOsub3/subsup-/sup-N (the effect of PFOS on NOsub3/subsup-/sup-N was not significant). Moreover, the extent of the effects of PFOS and F-53B on the physicochemical properties of bulk soils were different (e.g., PFOS caused an increase of NHsub4/subsup+/sup-N by 8.94%-45.97% compared to 1.63%-25.20% for F-53B). Root exudates and PFASs together influenced the physicochemical properties of rhizosphere soils (e.g., TOC increased significantly in contaminated rhizosphere soils but did not change in non-bulk soils). Under the influence of F-53B/PFOS, the root exudates regulated by plants were changed and weakened the effect of F-53B/PFOS on microbial community of rhizosphere soil. The rhizosphere defense systems of different plants have both similarities and differences in response to different substances and concentrations.

The increasing use of fluoroquinolone antibiotics, which are found in various environmental media, is a constant threat to ecological safety and human health. In this paper, SrFeO3@MoS2 heterogeneous catalyst was prepared to activate peroxymonosulfate (PMS) for the degradation of levofloxacin (LVO). The characteristics of SrFeO3@MoS2 samples were studied and the optimum conditions for the removal of LVO by SrFeO3@MoS2/PMS system were investigated. The removal of LVO by the SrFeO3@MoS2-0.3/PMS system could reach 96.06% within 20 min of reaction. The effect of inorganic anions (SO42−, Cl−, NO3− and H2PO4−) commonly found in actual water bodies on catalytic reaction was explored. The reusability investigation revealed that the catalyst could still remove 88.06% of LVO within 20 min after four cycles. Moreover, SO4•−, •OH and 1O2 were identified by Electron Paramagnetic Resonance (EPR) tests and scavenger experiments, where the SO4•− and •OH were dominant reactive species. Combining with the XPS characterisation, the activation mechanism of SrFeO3@MoS2-0.3/PMS was proposed, and the oxygen vacancies and transition metals on the sample surface were active sites of PMS activation. Furthermore, the possible degradation pathways of LVO were well-established based on the detected intermediates.

Sulfate aerosol is a major fraction of haze, playing an important role in aerosol formation and aging processes. In order to understand the mechanism of sulfate formations, the characteristics of sulfur isotope composition were determined during different heterogeneous oxidation reactions of sulfur dioxide. Although NH3 was more beneficial to the formation of sulfate, compared with NOX and O3, 34S tended to enrich the lighter sulfur isotopes in the presence of NH3. Furthermore, in consideration of the potential competitive effects of NOX, O3, and NH3 in the heterogeneous oxidation processes, the contributions of each gas were evaluated via Rayleigh distillation model. Notably, NOX oxidation contributed 67.5±10 % of the whole sulfate production, which is higher than O3 (13.3±10 %), and NH3 oxidation (19.2±10 %) on the basic of the average fractionation factor. The observed δ34S values of sulfate aerosols were negatively correlated with sulfur oxidation ratios, owing to the sulfur isotopic fractionations during the sulfate formation processes. Given the isotope mass balance, the overall δ34Ssulfate approached the δ34Semission as oxidation of SO2 progressed, suggesting that NOX played a major rather than a sole role in the different heterogeneous oxidation processes of SO2.

Sulfate as the major constituent of atmospheric aerosol plays a key role in aerosol formation and aging processes. However, little attention has been paid to the impacts of mineral dust on the oxidation of SO2, along with the effects of temperature, moisture, and light intensity. In this study, the influences of these parameters on the formation of sulfate and sulfur isotope composition were investigated in detail. Temperature promoted the heterogeneous oxidation of SO2 on the surface of hematite (α-Fe2O3), while excessive temperature was unfavorable for sulfate formation. Besides, the effect of temperature on sulfur isotope fractionation was not apparent. In addition, relative humidity (RH