Journal of Environmental Sciences-china最新文献

The copper complexing of dissolved organic matter released from hydrochar (HDOM) affects the former's environmental behavior. In this study, how hydrothermal temperatures (180, 220 and 260 °C) influence the molecular-level constitutions and Cu(II) binding features of HDOM were elucidated via fourier transform ion cyclotron resonance mass spectrometry and multi-spectroscopic analysis. The findings demonstrated that the almost HDOM molecules had the traits of lower polarity and higher hydrophobicity. As the hydrothermal temperature increased, the molecules with particularly high relative strength gradually disappeared, average molecular weight, percentages of CHON and aliphatic compounds of HDOM reduced while the percentages of CHO and aromatic compounds increased. In general, the fluorescence quenching of Cu(II) weakened as hydrothermal temperature rose and the Cu(II) binding stability constants of fluorophores in HDOM were 4.50–5.31. In addition, the Cu(II) binding order of fluorophores in HDOM showed temperature heterogeneities, and polysaccharides or aromatic rings of non-fluorescent substances had the fastest responses to Cu(II) binding. Generally, fluorescent components tend to bind Cu(II) at relatively trace concentrations (0–40 µmol/L), whereas non-fluorescent substances tend to the bind Cu(II) at relatively higher concentrations (50–100 µmol/L). This study contributed to the prediction of the potential environmental behaviors and risks of Cu(II) at the molecular level after hydrochar application.

Carbon dioxide (CO₂) mineralization technology has attracted significant attention, due to the synergistic terminal treatment of CO₂ and industrial waste. The combined CO₂ mineralization process with steel enterprises is a promising route to simultaneously address CO₂ emissions and SS treatment. Recently, a serial of the relevant work focus on a single type of steel slag (SS), and the understanding of CO₂ absorption by mineralization of various SS is very lacking. Meanwhile, it is urgent requirement for systematic summary and discussion on how to make full use of the mineralized products produced after the mineralization of CO₂ in SS. This review aims to investigate the progress of CO₂ mineralization using SS, including the potential applications of mineralization products, as well as the environmental impact and risk assessment of mineralization product applications. Currently, the application of SS mineralization products is primarily focused on their use as construction materials with low economic value. With usage of the mineralization products for ecological restoration (e.g. sandy soil remediation) was treated as an advanced route, but still remaining challenge in functional materials preparation, and its technical economy and possible hazards need to be further explored by long-term experimental tests.

Lead-free halide perovskite material has drawn fast-growing interest due to its superior solar-conversion efficiency and nontoxic nature. In this work, we have successfully fabricated cesium silver bismuth bromide (Cs₂AgBiBr₆) quantum dots utilizing the hot injection method. The as-synthesized quantum dots were characterized by combined techniques, which showed remarkable visible-light photocatalytic activity for organic dyes and antibiotic degradation in ethanol. Specifically, about 97% of rhodamine B and methyl orange may be removed within 10 min and 30 min, respectively. Additionally, 60% of antibiotic residue of tetracycline hydrochloride is degraded in 30 min which is 7 times more than that on commercial titania (P25). The reactive species for the photodegradation are determined through capture experiments, and a reaction mechanism is proposed accordingly. This work provides a novel photocatalyst for the selective removal of diverse organic contaminants in ethanol and an alternative for the potential application of lead-free halide perovskites.

Synthetic phenolic antioxidants (SPAs) are widely used in diverse industries due to their exceptional antioxidant characteristics. However, human exposure to SPAs may cause health problems. In this study, 226 dust samples were collected from 10 provinces in China, and six SPAs (three parent SPAs and their three transformation products) were analyzed. The concentrations of ∑₆SPAs (the sum of six target compounds) ranged from 15.4 to 3210 ng/g (geometric mean (GM): 169 ng/g). The highest concentration of ∑₆SPAs was found in Sichuan Province (GM: 349 ng/g), which was approximately 4 times higher than that in Hubei Province (81.6 ng/g) (p < 0.05). The concentrations of butylated hydroxytoluene (BHT), 2,2′-methylene bis (4-methyl-6‑tert-butylphenol) (AO2246), 2,6-di‑tert‑butyl‑1,4-benzoquinone (BHT-Q), 2,6-di‑tert‑butyl‑4-(hydroxymethyl) phenol (BHT-OH), and ∑p-SPAs were substantially higher in dust from urban areas than rural areas (p < 0.05). AO2246 concentration in dust from homes (GM: 0.400 ng/g) was about 4 times higher than that in workplaces (0.116 ng/g) (p < 0.01). Significantly higher ∑p-SPAs concentrations were found in dust from homes (GM: 17.5 ng/g) than workplaces (11.4 ng/g) (p < 0.01). The estimated daily intakes (EDIs) of ∑₆SPAs exposed through dust ingestion were 0.582, 0.342, 0.197, 0.076, and 0.080 ng/kg bw/day in different age groups, and exposed through dermal contact was 0.358, 0.252, 0.174, 0.167, and 0.177 ng/kg bw/day. EDIs showed that the exposure risks of SPAs decreased with age. This is the first work to determine SPAs in dust from 10 provinces in China and investigate the spatial distribution of SPAs in those regions.

Waterborne pathogens pose a lifelong threat, necessitating advanced disinfection systems with state-of-the-art materials. Laser-Induced Graphene (LIG), a 3-dimensional form of graphene, is a widely known electrode material for its electrically-induced antimicrobial properties. However, LIG surfaces exhibit antimicrobial properties exclusively in the presence of electricity. In this work, copper-doped LIG (Cu-LIG) composite electrodes and filters were developed with enhanced antimicrobial properties in single-step laser scribing. The work emphasizes the optimization of copper doping with LIG for both electrical and non-electrical-based disinfection. The copper doping was optimized to a minimal concentration (∼1%) just to enhance the electrochemical properties of LIG. Furthermore, the excess addition of copper was helpful towards non-electricity-based treatment without significant leaching. The prepared surfaces were tested in both electrodes and filter configuration and showed excellent antibacterial and antiviral activity against mixed bacterial culture and a model enteric virus, MS2 bacteriophage. On the application of 2.5 V with Cu-LIG electrodes, 6-log removal of bacteria and virus was achieved. Furthermore, the membrane-based electroconductive filters were tested in a flow-through configuration and demonstrated 6-log removal at 2.5 V with a flux of ∼ 500 L m² h⁻¹ with both bacteria and viruses at minimum energy expense. Additionally, reactive oxygen species scavenging and hydrogen peroxide generation experiments have confirmed the role of electrical effects and indirect oxidation on the inactivation mechanism. The prepared Cu-LIG composite surfaces showed potential for environmental remediation applications.

The MXenes, a new class of two-dimensional layered materials, have found extensive applications in water treatment for its excellent thermal stability, electrical conductivity, and excellent adsorption ability. Sulfidized nano zero-valent iron (S-nZVI) is a good reducing agent, however, the practical application of S-nZVI is currently restricted due to the tendency of nano materials to agglomerate. Herein, MXenes use as a support and in situ loading S-nZVI on it to prepare a new material (S-nZVI/Ti₃C₂T_x), and applied it to U(VI) removal in water treatment. The microscopic characterization proves that S-nZVI on Ti₃C₂T_x has good dispersion and effectively alleviates agglomeration. Batch experiments shown that S-nZVI/Ti₃C₂T_x has a very good effect on U(VI) removal, and the maximum adsorption capacity reaches 674.4 mg/g under the aerobic condition at pH=6.0. The pseudo-second-order kinetic model and the Langmuir isotherm model were found to be more appropriate for describing the adsorption behavior. This indicates that the removal process is a single molecular layer chemisorption. Moreover, the S-nZVI/Ti₃C₂T_x maintained a removal efficiency of over 85 % for U(VI) even after being reused five times, demonstrating its excellent reusability. It is worth noting that the material can remove 79.8% of 50 mg/L of U(VI) in simulated seawater, indicating that S-nZVI/Ti₃C₂T_x possessed an excellent uranium extraction performance from seawater. Experimental results and XPS analysis showed that U(VI) was removed by adsorption, reduction and co-precipitation. Moreover, S-nZVI/Ti₃C₂T_x was a low toxicity material to hyriopsis cumingii. Therefore, S-nZVI/Ti₃C₂T_x was expected to be a candidate as adsorbent with great potential in removal of uranium from wastewater and seawater.

The electrochemical corrosion of ductile pipes (DPs) in drinking water distribution systems (DWDS) has a crucial impact on cement-mortar lining (CML) failure and metal release, potentially leading to drinking water quality deterioration and posing a risk to public health. An in-situ scanning vibrating electrode technique (SVET) with micron-scale resolution, microscopic scale detection and water quality analysis were used to investigate the corrosion behavior and metal release from DPs throughout the whole CML failure process. Metal pollutants release occurred at three different stages of CML failure process, and there are potential risks of water quality deterioration exceeding the maximum allowable levels set by national standards in the partial failure stage and lining peeling stage. Furthermore, the effects of water chemistry (Cl⁻, SO₄²⁻, NO₃⁻, and Ca²⁺) on corrosion scale growth and iron release activity, were investigated during the CML partial failure stage. Results showed that the CML failure process in DPs was accelerated by the autocatalysis of localized corrosion. Cl⁻ was found to damage the uncorroded metal surface, while SO₄²⁻ mainly dissolved the corrosion scale surface, increasing iron release. Both the oxidation of NO₃⁻ and selective sedimentation of Ca²⁺ were found to enhance the stability of corrosion scales and inhibit iron release.

Disinfection of swimming pool water is critical to ensure the safety of the recreational activity for swimmers. However, swimming pools have a constant loading of organic matter from input water and anthropogenic contamination, leading to elevated levels of disinfection byproducts (DBPs). Epidemiological studies have associated increased risks of adverse health effects with frequent exposure to DBPs in swimming pools. Zhang et al. (2023b) investigated the occurrence of trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), and haloacetaldehydes (HALs) in eight swimming pools and the corresponding input water in a city in Eastern China. The concentrations of THMs, HAAs, HANs, and HALs in swimming pools were 1–2 orders of magnitude higher than those detected in the input water. The total lifetime cancer and non-cancer health risks of swimmers through oral, dermal, inhalation, buccal, and aural exposure pathways were assessed using the United States Environmental Protection Agency's (USEPA) standard model and Swimmer Exposure Assessment Model (SWIMODEL). The results showed that dermal and inhalation pathways were the most significant for the associated cancer and non-cancer risks. This article provides an overview and perspectives of DBPs in swimming pools, the benefits of swimming, the need to improve the monitoring of DBPs, and the importance of swimmers’ hygiene practices to keep swimming pools clean. The benefits of swimming outweigh the risks from DBP exposure for the promotion of public health.

Although air pollutant emissions have sharply reduced in recent years, the occurrence of PM_2.5 pollution events remains an intractable environmental problem in Beijing, and regional transport is the key influence factor. However, it has been difficult to identify regional transport characteristics and the main contributors to pollution events in recent years. In this study, the relative contribution of regional transport was quantified (61.3%) in PM_2.5 pollution events during 2018-2021 by the Community Multiscale Air Quality model embedded with the Integrated Source Apportionment Model (CMAQ-ISAM). The four regions with the largest fractional contributions to Beijing for all events were Shandong (7.7%), South Hebei (7.3%), Baoding (6.2%), and Langfang (5.8%). Pollution events were classified into the following types based on regional transport directions: local, southwest (SW), southeast (SE), south-mixed (SM), and others. Based on the transport distance, the SW, SE, and SM types can be subdivided into SW-short, SW-long, SE-short, SE-long, SM-short, SM-long distance from southwest, SM-long distance from southeast, and SM-long distance from southwest and southeast. SE-long was regarded as the most important type, with the highest relative frequency (20%). The transport directions were related to the southwest wind at 925 hPa and southeast wind at 1000 hPa in the south of the Beijing–Tianjin–Hebei (BTH) region, and the distance was mainly controlled by wind strength. The wind-field difference can be attributed to the low-pressure and high-pressure systems that control the BTH region. The results suggest that regional joint pollution control should be optimized based on the transport type.

Several studies have demonstrated that reintroducing crop straw to fields may intensify cadmium (Cd) contamination in agricultural soils. However, the specific effects of long-term straw management practices on Cd concentration and its bioavailability in soil-rice ecosystems remain unclear. In this context, to explore the influence of straw return (SR) and straw removal (NSR) on Cd accumulation in both soil and rice within a double-cropping system, we conducted a four-year field study. Our research study unveiled that NSR consistently decreased soil Cd concentration and its bioavailability by approximately 16.93%–27.30% and 8.23%–21.05% respectively across both study sites. Conversely, SR resulted in a substantial increase in soil Cd bioavailability, ranging from 38.64%–53.95%. Notably, compared to NSR, SR significantly increased total soil Cd by 5.47%–36.58% and increased Cd content in brown rice by 8.00%–100.24%. Remarkably, after four consecutive years of NSR, brown rice Cd concentration at the Changfeng site compiled with national safety standards (GB 2762–2022). Additionally, returning early rice straw significantly raised soil Cd bioavailability for the subsequent crop, more so than late rice straw did for the early rice the following year. The findings suggest that traditional double-cropping cultivation with straw removal can effectively mitigate Cd contamination risks in crops and farmland in Hunan Province.