Journal of hazardous materials letters最新文献

Graphitic carbon nitride (g-C₃N₄) has garnered significant attention due to its low cost, ease of preparation, high chemical stability, and non-toxicity. Nevertheless, pristine g-C₃N₄ faces challenges in simultaneously achieving a broad absorption range, high stability, efficient charge separation, and strong redox capability, which hampers its practical applications. Recently, g-C₃N₄-based Z-scheme photocatalysts have emerged as research hotspots owing to their robust redox ability, effective charge carrier separation, and capacity to harness visible light for degradation of tetracyclines (TCs) in waters. This review delves into the fundamental photocatalysis, and application of g-C₃N₄-based Z-scheme photocatalysts for the degradation of TCs pollutants. The review concludes with final remarks and a concise discussion on the prospects of g-C₃N₄-based Z-scheme photocatalysts.

Since 2007, the market for e-cigarettes has resulted in increasing demand for newer technologies and flavorings contributing to the complexity of these products. As a result, methodologies for e-cigarette aerosol capturing and testing have become a necessity in understanding the toxicities surrounding e-cigarette products. This study tests an alternative aerosol capture method followed by toxicity testing of the sample collected on a lung in vitro model.

The separation and recovery of Fe(III) in heavy metal mixtures is a great challenge due to its strong ion exchange property. In this study, we developed a novel cinnamon-like blended fiber (PAN/PEG) using electrostatic spinning and dissolution post-treatment, which exhibited highly selective separation properties and satisfactory adsorption capacity for Fe(III). Owing to the preferential coordination of Fe(III) with both cyanide and hydroxyl groups, PAN/PEG possessed such excellent adsorption capacity as 1.12 mmol/g. Notably, the infinite selective separation coefficient between Fe(III) and other heavy metal ions (HMIs) achieved even from the octa-mixed metal systems. Furthermore, PAN/PEG demonstrated good anti-interference ability against coexisting inorganic salts. In addition, PAN/PEG was highly effective in removing lower concentration Fe(III) from complex PTA wastewater with super-high selectivity, which enabled the subsequent purification of Co(II) and Mn(II). Overall, PAN/PEG could be prepared and recovered facilely, and had great potential in the exclusive separation of Fe(III).

Per and polyfluoroalkyl substances (PFAS) have been shown to be ubiquitous in the environment, and one issue of critical concern is the leaching of PFAS from soil to groundwater. The risk posed by contaminants present in soil is often assessed in terms of the anticipated impact to groundwater through the determination of soil screening levels (SSLs). The U.S. Environmental Protection Agency (EPA) established a soil screening model for determining SSLs. However, the model does not consider the unique retention properties of PFAS and, consequently, the SSLs established with the model may not represent the actual levels that are protective of groundwater quality. The objective of this work is to revise the standard EPA SSL model to reflect the unique properties and associated retention behavior of PFAS. Specifically, the distribution parameter used to convert soil porewater concentrations to soil concentrations is revised to account for adsorption at the air-water interface. Example calculations conducted for PFOS and PFOA illustrate the contrasting SSLs obtained with the revised and standard models. A comparison of distribution parameters calculated for a series of PFAS of different chain length shows that the significance of air-water interfacial adsorption can vary greatly as a function of the specific PFAS. Therefore, the difference between SSLs calculated with the revised versus standard models will vary as a function of the specific PFAS, with greater differences typically observed for longer-chain PFAS. It is anticipated that this revised model will be useful for developing improved SSLs that can be used to enhance site investigations and management for PFAS-impacted sites.

Synopsis

The widely used EPA SSL model is revised for PFAS applications to account for adsorption at the air-water interface.

The paper presents the results of the application of raw phosphogypsum as an adsorbent for the preliminary treatment of coke-chemical wastewater with an initial concentration of phenol 395 mg/L. Studies in batch mode have proved that phenol removal is promoted by increasing the adsorbent dose and effluent temperature, the optimal phosphogypsum dose was found to be 5 g/L. The adsorption kinetics follows a pseudo-first-order model, the maximum adsorption capacity of phosphogypsum reaches 85 mg/g, which provides purification from phenol at the level of 85–90%. The process is spontaneous and endothermic. In column mode, at an effluent flow rate of 3 mL/min and the height of the fixed bed of 15 mm adsorbent dynamic capacity reached 124 mg/g. The obtained data indicate that raw phosphogypsum, available in huge quantities in the dumps of phosphoric acid plants, can be effectively used for the pretreatment of phenolic wastewater before biological treatment.

In advanced oxidation processes with metal-containing catalysts, metal dissolution usually leads to reduced efficiency and biotoxicity. Therefore, it is very important to find efficient non-metallic materials. In this work, a metal-free mesoporous tubular g-C₃N₄ was fabricated using melamine and urea mixed according to the mass ratios of 1:12 (TPCN₁₂) by a facile one-step thermal polymerization method. Mesoporous tubular TPCN₁₂ was proved to be successfully synthesized by scanning electron microscope (SEM) and X-ray diffraction (XRD). Then the degradation of carbamazepine (CBZ) by activating peroxymonosulfate (PMS) of TPCN₁₂ under visible light was investigated. It was found that degradation rate constant of CBZ in TPCN₁₂/Vis/PMS system (0.0939 min⁻¹) exhibited great superiority over that in TPCN₁₂/Vis system (0.0149 min⁻¹) and in TPCN₁₂/PMS system, which indicated TPCN₁₂, Vis and PMS had a synergistic effect. The dominant role of the electron transfer and the primary contribution of the holes (h⁺) and •O₂⁻ reactive species were revealed in TPCN₁₂/Vis/ PMS system. Furthermore, the system showed sufficient advantages over a wide pH range and high resistance to inorganic anions. In general, the TPCN₁₂/Vis/PMS system was capable of high stability and recyclability. This metal-free mesoporous tubular catalyst was proposed to achieve efficient and green elimination of pharmaceutical organic pollutants.

Many environmental factors affect the breakdown of plastics in aquatic environments, including exposure to ultraviolet (UV) irradiation and elevated environmental temperatures. More studies are needed to understand how these stressors contribute to plastic degradation, resulting in the release of smaller plastic particles. We studied the impact of environmentally relevant UV and temperature (37 °C) weathering of four high-production volume plastics (polystyrene, polypropylene, low-density polyethylene, and high-density polyethylene) suspended in water. Particle release was detected, characterized by scanning electron microscopy (SEM), and nanoparticles were quantified by nanoparticle tracking analysis (NTA). Weathering resulted in the release of micro- and nanoparticles that exhibited a plastic signature corresponding to the parent microplastic. Nanoparticle release is broadly correlated with an increase in the carbonyl index of the parent microplastic. Aged microplastics were characterized for physical and chemical changes. The impact of weathering on microplastic surface hardness and polymer oxidation depended on material type and environmental factors. Few to no particles were observed in controls, including controls that contained microplastics at 4 °C in dark conditions, highlighting the importance of weathering stimuli in particle release. These results show that plastic degradation needs to consider both the parent microplastic and the smaller particles that are formed.