Journal of hazardous materials最新文献

The Laizhou Bay (LZB) is of ecological and fishery importance. The discharge of effluents containing numerous pollutants into the LZB via rivers poses significant risks to ecosystem and human health. Estuarine biomonitoring is therefore crucial for assessing the contribution of rivers to coastal pollution and their impacts on species. Estuarine oyster Crassostrea gigas is a preferable bioindicator to pollution conditions. This study measured accumulation of contaminants and expression levels of gene biomarkers in the LZB and Northern Shandong Peninsula (NSP) oysters. The LZB oysters accumulated higher levels of brominated flame retardants (BFRs) and poly- and perfluoroalkyl substances (PFAS), while NSP oysters exhibited greater accumulation of heavy metals. Decabromodiphenyl ethane was the dominant BFR, while perfluorooctanoic acid and perfluoro-2-methoxyacetic acid were the dominant PFASs in oysters. The expression of gene biomarkers effectively distinguished the LZB and NSP oysters, with CYP2 subfamilies expression correlating with BFRs and PFASs and metallothionein expression indicating heavy metals. The reproductive endocrine and neuroendocrine-immune systems in oysters might be the targets of BFRs and heavy metal pollution, respectively. The negative correlation between contaminant accumulation and gene expression might be explained by adaptive evolution, emphasizing the need to consider genetic diversity in ecological risk assessments.

To develop an energy-efficient system for the removal of chlorinated organic pollutants, Fe-Ni/reduced graphite oxide/polymerized polypyrrole@nickel foam was constructed as a catalytic cathode for pulsed electrocatalytic degradation, where cathode-catalyzed production of hydrogen radicals (H*) and hydroxyl radical (·OH) generated at the anode led to dechlorination of 4-chlorophenol (4-CP), and dechlorination products were mineralized and degraded under the action of·OH. When energy was continuously supplied to the reaction system in the constant potential mode, the 4-CP concentration near the electrode was insufficient, limiting the reaction rate. Conversely, in the square-wave pulsed potential mode, mass transfer limitations were mitigated, significantly enhancing reaction efficiency and reducing energy consumption. At -1.2 V (vs. Ag/AgCl), the 4-CP removal efficiency reached 93.79 % in the pulsed potential mode, surpassing the constant potential mode's performance of 81.40 %. The synergistic periodic oscillation of the potential, direct electron transfer, and catalytic generation of active free radicals in the pulsed potential mode reduced intermediate concentrations and increased 4-CP mineralization, while the degradation pathway remained unchanged. This research presents a method for the efficient treatment of chlorinated organic pollutants in water using pulsed electrocatalytic degradation.

In this study, we investigated the potential benefits of L-Fucose administration to pregnant mice exposed to Ochratoxin A (OTA), a widespread mycotoxin, producing ovarian damage in offspring. The results showed that administration of 3.5 μg/d OTA induced alterations in intestinal tissues and gut microbiota of pregnant mice, leading to heightened local and systemic inflammation. This inflammatory affected the ovaries of their 3 dpp offspring, in which elevated levels of LPS and ROS were found associated to significant decreased oocyte count and impaired primordial follicle assembly. Moreover, mRNA-Seq analysis showed significant changes in ovarian transcriptomes linked to various GO terms and KEGG pathways, notably ferroptosis, a recognized form of cell death observed. Interestingly, administration of 0.3 g/kg b. w. L-Fucose following OTA exposure mitigated these effects on intestinal tissues and gut microbiota in mothers and on the offspring's ovaries. Similar benefits were obtained by gut microbiota transplantation from L-Fucose-treated pregnant females into OTA-exposed mothers. These findings suggest that inflammatory impact of OTA on maternal intestine/gut can pass to the fetus causing offspring ovary defects and support the use of L-Fucose as adjuvant to counteract the adverse effects of mycotoxins on the gut microbiota, particularly reference to those affecting reproductive organs.

Ferrous iron (Fe(II)) produced by microbial Fe(III) reduction and reactive oxygen species (ROS) generated from aerobic Fe(II) oxidation can mediate iodate (IO₃^-) reduction and iodide (I^-) oxidation, respectively. Nevertheless, how Fe redox cycling under redox fluctuating conditions drives transformation of iodine species remain unclear. In this study, Shewanella oneidensis MR-1 wildtype (WT) and its mutant △dmsEFAB, which lost the ability to enzymatically reduce IO₃^-, were chosen to conduct ferrihydrite/goethite/nontronite culture experiments under consecutive cycles of anoxic reduction of Fe(III) and re-oxidation of Fe(II) by O₂ to reveal the role of Fe redox cycling in the transformation of iodine species. The results showed that both surface-adsorbed and mineral structural Fe(II) chemically reduced IO₃^-. Chemical IO₃^- reduction by biogenic Fe(II) was slower than enzymatic IO₃^- reduction by WT. Compared to △dmsEFAB cultures, WT cultures all showed higher Fe(II) concentrations under anoxic conditions but lower cumulative •OH under oxic conditions, which imply the chemical reaction between I^- and ROS. I^- oxidation by ROS, however, did not lead to a significant production of IO₃^- compared with I^- formed under anoxic conditions. Consequently, Fe redox cycling successively reduced IO₃^- to I^-, which highlights vital roles of Fe(III)-reducing bacteria in I^- formation and mobilization in environments.

How the anion ligands of manganese precursors affect the catalytic activity of amorphous manganese oxides (MnOx) in Fenton-like process is poorly understood. Here, five amorphous MnOx synthesized by Mn(II) precursors with different ligands were characterized and adopted to activate peracetic acid (PAA) for bisphenol A (BPA) degradation. Although > 90 % BPA removal was achieved in the five MnOx/PAA processes via both adsorption and oxidation, the oxidation k_obs greatly differentiates by the ligands types with the order of MnOx-N > MnOx-S > MnOx-Cl > MnOx-AA > MnOx-OA. Ligands types would affect the specific surface area of MnOx and their ability to adsorb BPA, however which is not the decisive factor in determining the contaminant oxidation efficiency. Multiple experimental results indicate that the generation of oxygen vacancies induced by the ligands alters the Mn(III)/Mn(IV) ratio, ultimately contributing to the different efficiency of BPA oxidation driven by the direct electron transfer mechanism. Moreover, amorphous MnOx holds the promise of practical applications in catalytic PAA of various micropollutants with good stability. This study advances the fundamental understanding of ligand-regulated amorphous MnOx-catalyzed PAA process.

The efficient treatment of phenol wastewater is of great necessity since it induces serious pollution of water and soil ecosystems. Using biochar-immobilized functional microorganisms can innovatively and sustainably deal with the existing problem. In this study, we utilized response surface methodology (RSM) combined with life cycle assessment (LCA) to improve phenol biodegradation rate through a novel separated alkali-resistant and thermophilic strain Bacillus halotolerans ACY. Bioinformatic analysis revealed the genetic foundation of ACY to adapt to harsh environments. The characteristics of pig manure biochar (PMB) produced at varying pyrolysis temperatures (300-700 ℃) and adsorption experiment were investigated, immobilization of the phenol-degrading ACY on PMB600 under alkaline and high pollution load promoted phenol removal and extreme environment resistance, and the phenol removal rate reached 99.5 % in 7d in actual phenol wastewater, which increased compared with those achieved by PMB (50.6 %) and free bacteria (80.5 %) alone. Scanning Electron Microscope (SEM) and Fourier transform infrared spectrometry (FTIR) observations indicated the successful bacterial immobilization on PMB600. Reusability and economic cost study further demonstrated PMB600 as an excellent carrier for wastewater treatment. LC-MS, toxicology and carbon footprint analyses demonstrated that bacterial metabolism exerted synergy with adsorption for phenol removal, while biodegradation exerted the predominant impact on the immobilized bacterial system. This study provides an eco-friendly and effective approach to treat phenol wastewater.

Antimony(V) mobility in acid mine drainage (AMD) is often controlled by sorption and coprecipitation with schwertmannite - a poorly-ordered Fe(III) oxyhydroxysulfate mineral. However, due to its metastable nature, schwertmannite transforms over time to more thermodynamically stable Fe(III) phases, such as goethite. This study examines how transformation of Sb(V)-bearing schwertmannite to goethite impacts Sb(V) mobility, while also assessing the role that Sb(V) may play in stabilizing schwertmannite against such transformation. To address these aims, Sb(V)-free, Sb(V)-sorbed and Sb(V)-coprecipitated schwertmannite were allowed to undergo partial transformation to goethite under acid sulfate conditions. Iron K-edge EXAFS spectroscopy revealed that sorbed and coprecipitated Sb(V) partly stabilized schwertmannite against transformation. The onset of schwertmannite transformation to goethite was found to drive clear mobilization of Sb(V) into solution, regardless of the Sb(V) loading or whether Sb(V) was initially sorbed or coprecipitated with the precursor schwertmannite. This initial phase of Sb(V) mobilization was followed by subsequent solid-phase recapture of the released Sb(V), with Sb K-edge EXAFS spectroscopy revealing that this process involved Sb(V) incorporation into the newly-formed goethite. Our findings show that, although schwertmannite transformation to goethite is partially inhibited by co-existing Sb(V), the initial stage of this transformation process drives significant Sb(V) mobilization in AMD systems.

It has been reported that tripolyphosphate (TPP) can effectively enhance the activation of O₂ by Fe(II) to remove organic pollutants in the environment. However, the influence of solution pH on the generation and conversion of reactive oxygen species (ROS) and their degradation of pollutants in the Fe(II)/O₂/TPP system needs further investigation. In this study, we demonstrated that O₂^•- and •OH were the main ROS responsible for degradation in the system at different pH conditions, and their formation rates were calculated using a steady-state model. Experiments combined with density functional theory (DFT) calculations showed that the p-nitrophenol (PNP) degradation pathway in the Fe(II)/O₂/TPP system is regulated by solution pH. Specifically, at pH = 3, the existence of Fe(II) in the solution is dominated by [Fe(II)(HTPP)₂]^2-, which leads to a rapid conversion from O₂ and HO₂• to generate •OH, and PNP is primarily oxidatively degraded. However, at pH = 5/7, [Fe(II)(TPP)₂]^4- is taking the lead with which O₂^•- is accumulated in the solution due to the slow conversion to •OH in this condition, and the PNP is mainly reductively degraded. This study proposes a new strategy to achieve the targeted oxidative/reductive removal of different types of pollutants by simply varying the solution pH in the Fe(II)/O₂/TPP system.

This study systematically explored the role of Mn(II) in the removal of 4-chlorophenol (4-CP) by electro-oxidation (EO) employing anodes with low oxygen evolution potential (OEP), i.e., Ti/RuO₂-IrO₂, Ti/Pt, and Ti/Ti₄O₇, as well as anodes with high OEP, namely, Ti/PbO₂, Ti/SnO₂, and boron-doped diamond (Si/BDD). Mn(II) significantly promoted 4-CP removal on the anodes with low OEP at fairly low current density (0.04 to 1 mA/cm²), but had minimal to negative impact on those with high OEP. Cyclic voltammetry and X-ray photoelectron spectra revealed that Mn(II) was oxidized to Mn(III), then to Mn(IV) on the anodes with low OEP, whereas its was oxidized directly to Mn(IV) on those with high OEP. Deposition of manganese oxide on the anodes with low OEP suppressed oxygen evolution reaction (OER) in EO process, but enhanced OER on those with high OEP. Quenching and spectral results consistently indicated that Mn(III) and Mn(IV) were the primary species responsible for enhancing 4-CP removal on the anodes with low OEP. These findings provide mechanistic insights into the redox transformation of Mn(II) in EO and the theoretical basis for a novel strategy to boost pollutant degradation in EO systems using low OEP anodes through coupling with the redox chemistry of manganese.

The composition of dissolved black carbon (DBC) could be influenced by adsorption on minerals, subsequently affecting DBC's photoactivity and the photoconversion of contaminants. This study investigated the changes in photoactivity of DBC after absorption on ferrihydrite at Fe/C ratios of 0, 1.75, 7.50, and 11.25, compared the influences of DBC₀ and DBC_7.50 on the photodegradation of four typical antibiotics (AB) including sulfadiazine, tetracycline, ofloxacin, and chloramphenicol. The selective adsorption led to the compounds with high aromaticity, high oxidation states, and more oxygen-containing functional groups being more favorably adsorbed on ferrihydrite, further causing the steady-state concentrations of ³DBC*, ¹O₂, and •OH respectively to drop from 1.83 × 10^-13 M, 7.45 × 10^-13 M, and 3.32 × 10^-16 M in DBC₀ to 1.22 × 10^-13 M, 0.93 × 10^-13 M and 2.30 × 10^-16 M in DBC_11.25, while the light screening effect factor increased from 0.740-0.921 in DBC₀ with above four antibiotics to 0.775-0.970 for that of DBC_11.25. Unexpectedly, DBC after adsorption played a dual role in the photodegradation of various antibiotics. This difference might be caused by antibiotics' chemical composition, functional groups interacting with reactive intermediates, and the overlap in UV-vis spectra between antibiotics and DBC. Our data are valuable for understanding the dynamic roles of DBC in the photodegradation of antibiotics.