Search Results (131)

Iopamidol (IPM), as a typical recalcitrant emerging pollutant and precursor of iodinated disinfection by-products (I-DBPs), is unsuccessfully removed by conventional wastewater treatment processes. This study comprehensively evaluated the ozone/peracetic acid (O₃/PAA) process for IPM degradation, focusing on degradation kinetics, environmental impacts, transformation products, ecotoxicity, disinfection byproducts (DBPs), and microbial inactivation. The O₃/PAA system synergistically activates PAA via O₃ to generate hydroxyl radicals (^•OH) and organic radicals (CH₃COO^• and CH₃CO(O)O^•), achieving an IPM degradation rate constant of 0.10 min⁻¹, which was significantly higher than individual O₃ or PAA treatments. The degradation efficiency of IPM in the O₃/PAA system exhibited a positive correlation with solution pH, achieving a maximum degradation rate constant of 0.23 min⁻¹ under alkaline conditions (pH 9.0). Furthermore, the process demonstrated strong resistance to interference from coexisting anions, maintaining robust IPM removal efficiency in the presence of common aqueous matrix constituents. Furthermore, quenching experiments revealed ^•OH dominated IPM degradation in O₃/PAA system, while the direct oxidation by O₃ and R-O^• played secondary roles. Additionally, based on transformation products (TPs) identification and ECOSAR predictions, the primary degradation pathways were elucidated and the potential ecotoxicity of TPs was systematically assessed. DBPs analysis after chlorination revealed that the O₃/PAA (2.5:3) system achieved the lowest total DBPs concentration (99.88 μg/L), representing a 71.5% reduction compared to PAA alone. Amongst, dichloroacetamide (DCAM) dominated the DBPs profile, comprising > 60% of total species. Furthermore, the O₃/PAA process achieved rapid 5–6 log reductions of E. coli. and S. aureus within 3 min. These results highlight the dual advantages of O₃/PAA in effective disinfection and byproduct control, supporting its application in sustainable wastewater treatment. Full article

The deep defluorination of water remains a significant environmental challenge. In this work, aluminum was loaded onto the bifunctional resin S957 containing a phosphoric-sulfonic acid difunctional group for efficient fluoride removal. Al-S957 demonstrated excellent fluoride removal performance across a broad pH range. When anions and organics coexisted, Al-S957 exhibited significantly better fluoride adsorption performance compared to aluminum-loaded monofunctional resins. The adsorption followed an endothermic chemisorption process on a monolayer surface. FTIR and XPS analyses further revealed that fluoride removal relied on a ligand exchange mechanism. Column adsorption conducted over five cycles highlighted the strong practical potential of Al-S957. The results suggested that Al-S957 exhibits significant potential for practical applications. Full article

Nowadays, some amorphous and microcrystalline solid-state electrolytes (SSEs) with dual anions have attained high ionic conductivity and good compatibility with electrodes in all-solid-state lithium-ion batteries (ASSLIBs). In this work, crystalline SSEs of series A (Li_1+xTaO_1+xCl_4−x, −0.70 ≤ x ≤ 0.50) and B (LiTaO_2+yCl_2−2y, −1.22 ≤ y ≤ 0), having great application potential well over ambient temperatures, were prepared at 260–460 °C for 2–10 h using Li₂O, TaCl₅, and LiTaO₃ as the raw materials. The three-phase coexisting samples attained high σ values ranging from 5.20 to 7.35 mS cm⁻¹, which are among the reported high values of amorphous co-essential SSEs and other alloplasmatic crystalline ones. It is attributed to the synergistic effect of the polyanion trans-[O₂Cl₄] and cis-[O₄Cl₂] octahedra framework. Full article

In this study, a Bi₂O₃-TiO₂/PAC ternary composite photocatalyst was successfully synthesized via a hydrothermal method, employing powdered activated carbon (PAC) as the support and using bismuth nitrate and tetrabutyl titanate as raw materials. The external morphology, microstructure, elemental composition, and optoelectronic properties of the catalyst were characterized by XRD, SEM, TEM, XPS, UV-Vis DRS, and BET analyses. The photocatalytic activity of the composite toward the degradation of malachite green (MG) was systematically evaluated under various conditions. The results revealed that the composite exhibited excellent photocatalytic activity, achieving a degradation efficiency of up to 99%. Apart from extremely acidic or alkaline conditions, MG removal efficiency increased with a rising solution pH. Moreover, the photocatalyst exhibited excellent adaptability and stability in the presence of coexisting inorganic anions and humic substances, indicating its broad potential for practical applications. Reactive-species-trapping experiments indicated that superoxide radicals (·O₂⁻) were the primary active species in the degradation process, with hydroxyl radicals (·OH) and photogenerated holes (h⁺) acting synergistically. Moreover, the catalyst maintained over 90% removal efficiency after five consecutive cycles, demonstrating its excellent stability and reusability. This work provides a promising strategy and theoretical foundation for the efficient photocatalytic treatment of MG-contaminated wastewater. Full article

Wastewater involving nitrogen-containing emerging contaminants is always accompanied by ammonia nitrogen. In this study, the 254 nm UV light activating peroxymonosulfate (PMS) process was investigated based on its performance and mechanisms for the simultaneous removal of carbamazepine (CBZ) and ammonia nitrogen. The results showed that both CBZ and ammonia could be simultaneously removed from water by the UV/PMS process, which was mainly attributed to the oxidation of SO₄^•− and •OH, respectively. Solution pH did not significantly affect CBZ degradation, but was a crucial factor for the removal of ammonia, and only the alkaline condition was effective for ammonia removal. The steady-state concentration of SO₄^•− (4.37 × 10⁻¹¹ M) at pH 10.5 was determined as 32 times that of •OH (1.35 × 10⁻¹² M), which made CBZ more competitive than ammonia in competing for radicals and more adaptable to coexisting anions. An appropriate increase in PMS concentration and light intensity could improve the removal of ammonia more significantly than that of CBZ, but an over-intense reaction could accelerate the decrease in solution pH, resulting in a plateau in ammonia removal. Moreover, the formation of nitrate and nitrogen gas was the primary transformation route of ammonia in the UV/PMS process. With the optimum PMS concentration of 2 mM, about 50% of the total nitrogen could be removed. The results of this study may provide some insights into applying the UV/PMS process for the simultaneous removal of emerging contaminants and ammonia nitrogen. Full article

In recent years, the rapid development of industry has led to the discharge of large quantities of pollutants, including harmful dyes, into water sources, thereby posing potential threats to human health and the environment. FeOCl and biochar have their own shortcomings as a mediator in the heterogeneous Fenton process. To make both materials useful, FeOCl supported on bamboo biochar (FeOCl/BC) was prepared by calcination using FeCl₃·6H₂O and bamboo powder as raw materials, and the composite’s catalytic activities were explored with acid orange II (AO-II) as the target pollutant. The degradation efficiency of FeOCl/BC composites on AO-II was determined by testing the mass ratio of FeOCl and BC, initial pH, temperature, H₂O₂ concentration, catalyst addition, addition of coexisting inorganic anions, and natural organic matter. The addition of biochar to FeOCl increased the activation of H₂O₂ to generate •OH for the removal of AO-II and accelerated the cycle of Fe³⁺/Fe²⁺. The removal rate of AO-II by the Fe₁C_0.2 composite was 97.1% when the mass ratio of FeOCl and BC was 1:0.2 (Fe₁C_0.2), which was higher than that of the pure components (FeOCl or BC) at pH = 6.1. Moreover, after five reuses, the Fe₁C_0.2 composite still showed high degradation activity for AO-II, with 83.3% degradation and low activity loss. The capture experiments on the active material showed that the removal of AO-II by the Fe₁C_0.2 composite was mainly dominated by •OH; however, •O₂⁻ and h⁺ played minor roles. The synthesized Fe₁C_0.2 composite could be applied for organic contaminants such as AO-II with high removal efficiency. Full article

The excessive utilization and emission of waste plastics have caused serious damage to the environment, and it is of great significance to explore high-value utilization methods for these waste plastics. To address this challenge, functional nano cobalt-loaded porous carbon materials (CoPC) with excellent antibiotic wastewater removal properties were prepared by one-step pyrolysis using waste PET plastics as a carbon source, a process described in this paper. Characterization revealed that the obtained CoPC-2 catalysts had a high degree of defects, a large specific surface area (343.41 m²/g), and an abundant pore structure. Degradation results displayed that CoPC-2 removed 87.93% of 20 mg/L tetracycline with a reaction rate constant of 0.0668 min⁻¹. Moreover, CoPC-2 exhibited excellent degradation performance for tetracycline over a wide range of pH levels (4–10) and in coexistence with multiple inorganic anions. Electron paramagnetic resonance and radical quenching experiments revealed that radicals (·OH, and SO₄·⁻) and non-radicals (¹O₂) pathway participated in tetracycline degradation, with the non-radical pathway being dominant. This study not only offers promising prospects for resource utilization of waste plastics, but also provides novel approaches for the design of functional nanomaterials for antibiotic wastewater treatment. Full article

This study was carried out to appraise the groundwater fluoride removal effectiveness of Al-Fe oxide-infused diatomaceous earth (DE) in a continuous-flow fixed-bed column. The adsorbent was optimally synthesized and then characterized. A glass column designed for the experiment was packed with the test adsorbent at specific doses. The effects of flow rate, influent fluoride concentration and bed height (adsorbent dose) on fluoride removal were evaluated by fixing the value of a parameter while varying the others. The breakthrough volume was the volume of treated water obtained until the concentration of fluoride in the treated water reached 1.5 mg/L, which is the World Health Organization’s maximum limit of fluoride in drinking water. The maximum breakthrough volume obtained in this study was 118.2 mL under the optimum conditions of influent F⁻ concentration = 5 mg/L, 1 g of adsorbent with an initial bed height = 7.5 cm and a flow rate = 1.97 mL/min. Channeling and the presence of $\mathrm{P}{\mathrm{O}}_4^{3-}$ as a co-existing anion were limiting factors for the attainment of the breakthrough volume for groundwater defluoridation. Further work is encouraged to investigate a suitable binder that can hold the adsorbent particles firmly together, is not water-soluble, but remains water-permeable when dry. The resulting solid mass could then be pulverized into granules whose weight and rigidity would make them less susceptible to the channeling effect in the column. Full article

The extensive release of water contaminated with lead (Pb(II)) and antimony (Sb(V)) constitutes a serious threat to the human living environment and public health, necessitating immediate attention. In this study, a novel MnFe@SBA composite was synthesized using the hydrothermal method through the in situ growth of MnFe₂O₄ on SBA-15. The MnFe@SBA exhibits an amorphous structure with a high specific surface area of 405.9 m²/g and pore sizes ranging from 2 to 10 nm. Adsorption experiments demonstrated that MnFe@SBA removed over 99% of Pb(II) and 80% of Sb(V) within 120 min at initial concentrations of 10 mg/L, whereas both MnFe₂O₄ and SBA-15 exhibited poor adsorption capacities. Additionally, the MnFe@SBA displayed excellent tolerance towards coexisting cations, including Na⁺, K⁺, Mg²⁺, Ca²⁺, Zn²⁺, Ni²⁺, and Cd²⁺, as well as anions such as Cl⁻, NO₃⁻, CO₃²⁻, and PO₄³⁻. The adsorption behavior of Pb(II) onto MnFe@SBA was satisfactorily described by the pseudo-second-order kinetic model and the Freundlich isotherm, while the adsorption of Sb(V) was well-fitted by the pseudo-second-order kinetic model and the Langmuir isotherm. At 318 K, the maximum adsorption capacities of MnFe@SBA for Pb(II) and Sb(V) were determined to be 329.86 mg/g and 260.40 mg/g, respectively. Mechanistic studies indicated that the adsorption of Pb(II) and Sb(V) onto MnFe@SBA involved two primary steps: electrostatic attraction and complexation. In conclusion, the MnFe@SBA is anticipated to serve as an ideal candidate for efficient removal of Pb(II) and Sb(V) from contaminated water. Full article

This study investigates the potential of wood ash (WA), a by-product of wood-based energy production, as an eco-friendly alternative for removing fluoride from water. Kinetic analysis revealed that WA enables rapid fluoride removal, reaching equilibrium within 1 h (112.09 ± 3.9 mg/g). Equilibrium analysis demonstrated that WA exhibits a Langmuir maximum capacity of 157.34 mg/g, indicating a high adsorption capacity that ranks within the top 10% of reported adsorbents (34th out of 328). According to thermodynamic analysis, the adsorption process appears to be both endothermic and spontaneous at elevated temperatures. pH dependence studies showed that while the fluoride adsorption capacity of WA peaked under acidic conditions, it remained relatively stable (116.01 ± 0.8 mg/g) over a wide range of pH levels (5 to 11). An optimal dosage of 6.67 g/L achieved a greater than 98% fluoride removal rate. Coexisting anions affected the fluoride adsorption capacity of WA, with the order of influence being PO₄³⁻ > CO₃²⁻ >> SO₄²⁻ > NO₃⁻ ≈ Cl⁻. Mechanistic analyses confirmed the surface precipitation of CaF₂ as the primary mechanism responsible for fluoride removal. With a Ca content of over 66 wt.%, WA facilitates enhanced fluoride removal. Overall, this study highlights the efficacy of WA as a sustainable adsorbent for the removal of fluoride from water, contributing to the valorization of WA in wastewater treatment applications. Full article

Diethyl phthalate (DEP) is a commonly utilized plasticizer that has gained significant attention due to its widespread occurrence in the environment and its harmful impact on human health. The primary objective of this study was to evaluate and compare several (ultraviolet) UV-(peracetic acid) PAA advanced oxidation processes based on hydroxyl radicals to degrade DEP. The effect of UV-LEDs incorporating PAA at different UV ranges (UV-A, λ = 365 nm; UV-C, λ = 254 nm and VUV, λ = 254 nm) was evaluated. The results demonstrated that DEP was successfully degraded in both the UVC/PAA (removal rate 98.28%) and VUV/PAA (removal rate 97.72%) processes compared to the UVA/PAA process (removal rate of 2.71%). The competitive method evaluated the contribution of R-O•, which were 24.08% and 33.92% in UVC/PAA and VUV/PAA processes, respectively. We also evaluated the effects of peroxymonosulfate (PMS) dosages, UV irradiation, pH and anion coexistence on the removal of DEP. In the UVC/PAA system, DEP degradation was particularly effective (removal rate about 95.52%) over a wider pH range (3–9). As the concentration of HCO₃⁻ ions increased, there may have been some inhibition of DEP removal. The inhibitory effect of HA and Cl⁻ ions on DEP removal were negligible. Analysis of the intermediates revealed that DEP degradation primarily occurred via two pathways: hydrolysis and hydroxylation reactions. This study presents a potential mnethod for the removal of phthalates and offers some guidance for the selection of appropriate disinfection technologies in drinking water treatment. Full article

A carbon-based material was synthesized using potato peels (BPP) and banana pseudo-stems (BPS), both of which were modified with manganese to produce BPP-Mn and BPS-Mn, respectively. These materials were assessed for their ability to activate peroxymonosulfate (PMS) in the presence of MnCO₃ to degrade acetaminophen (ACE), an emerging water contaminant. The materials underwent characterization using spectroscopic, textural, and electrochemical techniques. Manganese served a dual function: enhancing adsorption properties and facilitating the breaking of peroxide bonds. Additionally, carbonate ions played a structural role in the materials, transforming into CO₂ at high temperatures and thereby increasing material porosity, which improved adsorption capabilities. This presents a notable advantage for materials that have not undergone de-lignification. Among the materials tested, BPS exhibited the highest efficiency in the carbocatalytic degradation of ACE, achieving a synergy index of 1.31 within just 5 min, with 42% ACE degradation in BPS compared to BPS-Mn, which achieved 100% ACE removal through adsorption. Reactive oxygen species such as sulfate, hydroxyl, and superoxide anion radicals were identified as the primary contributors to pollutant degradation. In contrast, no degradation was observed for BPP and BPP-Mn, which is likely linked to the lower lignin content in their precursor material. This work addressed the challenge of revalorizing lignocellulosic waste by highlighting its potential as an oxidant for emerging pollutants. Furthermore, the study demonstrated the coexistence of various reactive oxygen species, confirming the capacity of carbon-based matrices to activate PMS. Full article

Two new compounds, (NH₄)₄[Cu₇(Hmesox)₆(H₂O)₈]∙10H₂O (1) and [Ru(bpy)₃]₄[Cu₇(Hmesox)₆Cl₂]Cl₂∙2CH₃CN∙12H₂O (2), were prepared and their structures were solved by single-crystal X-ray diffraction (mesoxalic acid = dihydroxypropanedioic acid, H₄mesox). The triply deprotonated mesoxalate anion acts as a chelating and bridging ligand with its carboxylate and alkoxide groups, forming the anionic heptanuclear copper(II) clusters [Cu₇(Hmesox)₆(H₂O)₈]⁴⁻ and [Cu₇(Hmesox)₆Cl₂]⁶⁻ in 1 and 2, respectively. Variable temperature magnetic studies revealed antiferromagnetic interactions in 1 and the coexistence of ferro and antiferromagnetic interactions in 2. The [Ru(bpy)₃]²⁺ cations provided luminescent properties to compound 2. Full article

The adsorption of toxic metals onto iron oxides is a prevalent geochemical process in natural environments. Organic acids are known to modify the adsorption features of toxic ions through either competitive or cooperative effects. Nowadays, the toxic metal adsorption influenced by organic acids on iron oxides with varying facet exposures is not fully understood. This study explored how L-Aspartic acid (LA) influences Cr(VI) adsorption on two different exposure facets of lepidocrocite through batch adsorption experiments, in situ ATR-FTIR spectroscopy, and 2D-COS analysis. The results reveal that LA competes for available binding sites on lepidocrocite, consequently inhibiting the adsorption of Cr(VI). Rod-shaped lepidocrocite (R-LEP) owns more (001) facets and shows stronger Cr(VI) adsorption and LA competition than plate-like lepidocrocite (P-LEP), which mainly has (010) facets. The data for Cr(VI) uptake on both P-LEP and R-LEP within the effect of LA are well-fitted by the pseudo-second-order kinetics and the Freundlich isotherm model, suggesting chemical interaction as the dominant process for Cr(VI) coordination on lepidocrocite. Cr(VI) ions favor interaction with R-LEP over P-LEP, forming inner-sphere complexes on (001) facets. Concurrently, LA’s carboxyl groups can compete for the active sites on the lepidocrocite surfaces, engaging in anion exchange with hydroxyl groups, and forming outer-sphere and inner-sphere structures. This competitive effect is particularly pronounced in the R-LEP system. The current findings are expected to broaden insights into how the exposed facets of lepidocrocite influence the fate of Cr(VI) in the organic acid coexistence environment. Full article

Phosphorus mainly exists in the form of phosphate in water. Excessive phosphorus can cause eutrophication, leading to algae reproduction and the depletion of oxygen in water, destroying aquatic ecology. This study prepared quaternized polyaniline (PN) and quaternized polyaniline with lanthanum hydrate (HLO-PN), and a new nanocomposite for removing phosphate from wastewater was proposed. The results of adsorption experiments show that HLO-PN can effectively remove phosphate in the range of pH 3~7; the maximum adsorption capacity is 92.57 mg/g, and it has excellent anti-interference ability against some common coexisting anions (${\mathrm{F}}^{-},$ ${\mathrm{C}\mathrm{l}}^{-},$ ${\mathrm{NO}}_3^{-},$ ${\mathrm{SO}}_4^{2-}$) other than ${\mathrm{CO}}_3^{2-}$. After five adsorption–desorption cycles, the phosphate adsorption capacity (60 mg/g) was still 74.28% of the initial adsorption capacity (80.85 mg/g), indicating that the HLO-PN nanocomposites had good reusability and recovery of phosphorus. The characterization results show that phosphate adsorption is realized by electrostatic adsorption and ligand exchange. Full article