Hydrogen-Donor-Controlled Polybrominated Dibenzofuran (PBDF) Formation from Polybrominated Diphenyl Ether (PBDE) Photolysis in Solutions: Competition Mechanisms of Radical-Based Cyclization and Hydrogen Abstraction Reactions.

Polybrominated dibenzofurans (PBDFs) are characteristic dioxin-like products of polybrominated diphenyl ether (PBDE) photolysis. In this study, competition mechanisms of radical-based cyclization and hydrogen abstraction reactions are proposed in PBDF formation. Commonly, the ortho C-Br bond dissociation during photolysis generates aryl radicals, which undergo intramolecular cyclization to form PBDFs or hydrogen abstraction with hydrogen donors (such as organic solvents and water) to form lower brominated PBDEs. By using 2,4,4'-tribromodiphenyl ether (BDE-28) as the model reactant, the experimental PBDF formation ratios in various solutions are explained quantitatively by the calculated rate constants of cyclization and hydrogen abstraction reactions using the density functional theory (DFT) method. The solvent effect of pure and mixed solvents on PBDF formation is illustrated successfully. The structure-related hydrogen donation ability for hydrogen abstraction controls the bias of competition reactions and influences PBDF formation. Water resulted to be the most significant generation of PBDFs. Fulvic and humic acid display higher hydrogen donation ability than small-molecule organics due to the partitioning effect in aqueous solution. Quantitative structure-activity relationship (QSAR) models of the calculated rate constants for 512 cyclization and 319 hydrogen abstraction reactions using 189 PBDEs as the initial reactants in water are established, revealing the high risk of PBDF formation in aqueous solution.

Adsorption behavior of hierarchical porous biochar from shrimp shell for tris(2-chloroethyl) phosphate (TCEP): Sorption experiments and DFT calculations.

Tris(2-chloroethyl) phosphate (TCEP) as a new type of flame retardant exists in various water environments, causing great risks to humans and the environment. In this study, shrimp shell was used to prepare an economical and environmental-friendly adsorbent for the efficient removal of TCEP. The systematic studies including characterization, removal performance, and adsorption mechanism of shrimp shell biochar toward TCEP were carried out. Adsorption kinetics and thermodynamics showed that fast equilibrium reached within 30 min, the maximum adsorption capacity qm was 108 µmol g-1 at 298 K, and the adsorption process is spontaneous and exothermic. The environmental factor, such as temperature, pH, inorganic anions and organic matter hardly affected the adsorption performance. Structural characterization indicated that the hierarchical porous structure of shrimp shell biochar is the key to excellent adsorption performance. The adsorption mechanisms were further revealed using density functional theory (DFT) calculations, and the hydrogen bond, van der Waals interactions, Cl-H interactions, and pi-H interactions were identified as potential interaction mechanisms between TCEP and specific biochar structures. The calculated binding energy between TCEP and simplified biochar structure suggested that oxygen-containing groups especially carboxyl, hydroxyl and aldehyde facilitate the adsorption. Our work not only provides a novel strategy for the quick remediation of organophosphate-contaminated water environments but also offers new opportunities for crustacean waste biomass valorization.

Efficient removal of polybrominated diphenyl ethers from soil washing effluent by dummy molecular imprinted adsorbents: Selectivity and mechanisms.

Surfactant enhanced elution is an effective method for removing hydrophobic organic pollutants from soils. The key to the development of leaching technology is selective removal of targeted pollutants in soil washing effluent and recycling of surfactant solutions. In this study, a molecular imprinting technique was applied to selectively sorb polybrominated diphenyl ethers (PBDEs) in soil washing effluent. The novel molecular imprinted polymers (MIPs) using different template molecules were synthesized by precipitation polymerization. Adsorption behaviors and mechanisms of MIPs were studied through experiments and theoretical calculations. The results show that 4-bromo-4'-hydroxybiphenyl and toluene can be effective imprinting molecule for MIPs synthesis. The maximal adsorption capacity of selected dummy molecular imprinted polymer (D1-MIP) was 1032.36 µmol/g, and that of part molecular imprinted polymer (P-MIP) was 981.13 µmol/g. Their imprinting factors in 5 PBDEs adsorption ranged from 2.13 to 5.88, the recovery percentage of Triton X-100 can reach 99.09%, confirming the feasibility of reusing surfactant. Various PBDEs could be removed by MIPs, and Quantitative Structure Property Relationship analysis revealed that PBDEs' molecular volume, planarity, polarity, and hydrophobicity have major influences on their adsorption performance. DFT calculation revealed that Van der Waals force and hydrogen bonding played important roles during selective adsorption. These results can provide effective theoretical guidance for surfactant enhanced soil elution in practical engineering applications.

Spatial and temporal variations of metal fractions in paddy soil flooding with acid mine drainage.

Environmental release of acid mine drainage (AMD) poses a potential threat to the environment and human health due to its high content of heavy metals. The impact of AMD flooding on unpolluted soil leads to serious pollution over time via a complex process, related to the geochemical behavior of toxic metals that so far has only been partially investigated. Here, a soil column study was conducted to investigate the migration of Cu and Cd fractions in unpolluted paddy soil following treatment with AMD collected from the Dabaoshan Mining area. Tessier's sequential extraction was performed to fractionate the metals at various depths over time. After 160 days of experimental flooding, the soil pH stabilized at 2.52 at a column depth of 5 cm. The fractions of Cu and Cd that were highly mobile increased significantly during AMD flooding. For Cd, the latter already occurred on day 67. At a depth of 20 cm, the total content of Cu maximally increased from initially 26.89 mg kg-1 to 696.96 mg kg-1 on day 160, while the content of Cd maximally increased from 0.22 mg kg-1 to 391.30 mg kg-1 on day 67. Reduced partition index analysis conformed that the mobility of both Cu and Cd significantly increased in contaminated soil during continuous AMD flooding. Scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) identified a changed distribution of the elements in the soil, with Fe appearing to have aggregated. The correlation analysis between Cu and Cd in pore water and in different fractions in the soil's solid phase identified a dynamic distribution of these metals in certain geochemical components during their migration. The results of this study contribute to a scientific foundation to describe the geochemical behavior of heavy metals in soil subject to AMD flooding.

Remediation of Cd-, Pb-, Cu-, and Zn-contaminated soil using cow bone meal and oyster shell meal.

To understand the environmental friendliness and high efficiency of organic materials during remediating soil polluted by heavy metals by assessing the feedback of soil ecosystems after organic materials were put into polluted soil. Incubation research was undertaken to examine the impact of amendments ranging from 0.1% to 3.0% (w/w), including single cow bone meal (BM), single oyster shell meal (OS), and a composite of 50% BM mixed with 50% OS (BO) on soil biochemical properties. The findings revealed that the implementation of BM and OS increased soil pH, the content of certain nutrients, and the activities of catalase (S-CAT), and urease (S-UE) while decreasing the availability of Cd, Pb, Cu, and Zn. Overall, the immobilization effect on Cd and Zn after a 108-day incubation was ranked as follows: BM group > OS group ≥ BO group, and the order of the immobilization effect of Pb and Cu was OS group > BO group > BM group. In addition, the dominant bacterial community flora shifted toward alleviating the re-dissolution of metal ions from the soil and promoting nutrient recycling in soil within 108 days of cultivation. RNA analyses showed that the strongest determinants for microbial communities between BM application and OS application at the genus level were soil pH, CEC, and heavy metal (Cd, Pb). These results increase our understanding of the leaching performance of Cd, Pb, Cu and Zn and the evolution trend of microorganisms when organic amendments remediate heavy metal contaminated soil.

Synergistic Pd Single Atoms, Clusters, and Oxygen Vacancies on TiO2 for Photocatalytic Hydrogen Evolution Coupled with Selective Organic Oxidation.

Developing efficient photocatalysts for synchronously producing H2 and high value-added chemicals holds great promise to enhance solar energy conversion. Herein, a facile strategy of simultaneously engineering Pd cocatalyst and oxygen vacancies (VO s) on TiO2 to promote H2 production coupled with selective oxidation of benzylamine is demonstrated. The optimized PdSA+C /TiO2 -VO photocatalyst containing Pd single atoms (SAs), clusters (C), and VO s exhibits much superior performance to those of TiO2 -VO and PdSA /TiO2 -VO counterparts. The production rates of H2 and N-benzylidenebenzylamine over PdSA+C /TiO2 -VO are 52.7 and 1.5 times those over TiO2 -VO , respectively. Both experimental and theoretical studies have elucidated the synergistic effect of Pd SAs, clusters, and VO s on TiO2 in boosting the photocatalytic reaction. The presence of Pd SAs facilitates the generation and stabilization of abundant VO s by the formation of PdOTi3+ atomic interface, while Pd clusters promote the photogenerated charge separation and afford the optimum active sites for H2 evolution. Surface VO s of TiO2 guarantee the efficient adsorption and dissociation/activation of reactant molecules. This study reveals the effect of active-site engineering on the photocatalysis and is expected to shed substantial light on future structure design and modulation of semiconductor photocatalysts.

Off-label use of antipsychotic medications in psychiatric inpatients in China: a national real-world survey.

BACKGROUND: The off-label use of antipsychotic medications is common in many countries, and the extent of such use in psychiatric inpatients in China has not been sufficiently studied. The purpose of this study was to survey the incidence and examine the correlates of off-label antipsychotic use in a large, nationally-representative sample in China. METHODS: This study included discharged psychiatric patients between March 19 and 31, 2019 from 41 tertiary psychiatric hospitals across 29 provinces in China. Their socio-demographic and clinical data were collected and analyzed. RESULTS: After excluding patients with schizophrenia spectrum disorder or bipolar disorder, 981 patients were included in the analysis. Overall, antipsychotics were prescribed to 63.2% (95%CI 60.2-66.2%) of the sample. Antipsychotics were used in a wide spectrum of psychiatric disorders, with the rate being the highest among patients with dissociative (conversion) disorders (89.9, 95%CI 83.0-94.8%), organic mental disorders (81.7, 95%CI 73.1-88.7%), dementia (79.0,95%CI 67.8-87.9%), obsessive-compulsive disorder (77.8, 95%CI 55.7-92.5%), mental disorders due to psychoactive substances (75.3,95%CI 64.7-84.2%), behavioural and emotional disorders with onset usually occurring in childhood and adolescence (71.4, 95%CI 45.5-90.1%), somatoform disorders (63.2, 95%CI 40.8%-82..2%), major depression disorder (53.7,95%CI 48.8-58.6%), anxiety disorder (38.8,95%CI 30.5-47.7%), and insomnia (25.0, 95%CI 8.5-28.9%). The top three most commonly used antipsychotics were olanzapine (29.1%), quetiapine (20.3%) and risperidone (6.8%), and their corresponding average doses were 9.04 ± 5.80 mg/day, 185.13 ± 174.72 mg/day, and 2.98 ± 1.71 mg/day, respectively. A binary logistic regression showed that younger age, having the Employee Health Insurance or Residents Health Insurance, having psychotic symptoms and requiring restraint during hospitalization were significantly associated with off-label use of antipsychotics. CONCLUSION: Off-label use of antipsychotics is very common in psychiatric inpatients in China, mainly with moderate-dose use of single agents. However, the efficacy and safety of this practice is uncertain for many diagnoses and for the elderly. Clinicians should be cautious about this practice while waiting for more research data.

Integrated ecological risk assessment of heavy metals in an oil shale mining area after restoration.

Although the mining area has been restored, the environmental problems caused by years of large-scale oil shale mining are still continuing, coupled with the intensive distribution of the surrounding petrochemical industry, posing a serious threat to the local ecological environment. In this study, we investigated eight heavy metals (Cu, Ni, Pb, Cd, As, Cr, Mn and Zn) contamination and distribution around mining area, evaluated the potential risks of environment, identified the main sources of metal pollution and performed source apportionment. The results showed that the original north and south dumps were seriously polluted, and the CF values were significantly higher than other sampling sites. Ni, Zn and Mn have high coefficients of variation, which may be greatly affected by human factors and especially the waste slag piled up. The concentration of heavy metals in the water was lower than in the soil; soil particles, pH, Eh and acid mine drainage influence the variation of heavy metal concentrations. As and Cd have very high RAC values, and accordingly they were mainly present in the exchangeable and reduced fractions. Mn was exposed to higher ecological risks, followed by Pb, although there were high loads on carbonate bound and oxidizable fractions. APCS-MLL receptor model was used to identify and apportionment three main sources of contamination. The mean contribution rates of industrial activity, atmospheric deposition and mixed sources accounted for 39.77%, 22.24% and 37.99%, respectively. Cluster analysis further classified the metal pollution sources according to the spatial distance of sampling points.

Anchoring Positively Charged Pd Single Atoms in Ordered Porous Ceria to Boost Catalytic Activity and Stability in Suzuki Coupling Reactions.

Single-atom (SA) catalysis bridging homogeneous and heterogeneous catalysis offers new opportunities for organic synthesis, but developing SA catalysts with high activity and stability is still a great challenge. Herein, a heterogeneous catalyst of Pd SAs anchored in 3D ordered macroporous ceria (Pd-SAs/3DOM-CeO2 ) is developed through a facile template-assisted pyrolysis method. The high specific surface area of 3DOM CeO2 facilitates the heavily anchoring of Pd SAs, while the introduction of Pd atoms induces the generation of surface oxygen vacancies and prevents the grain growth of CeO2 support. The Pd-SAs/3DOM-CeO2 catalyst exhibits excellent activity toward Suzuki coupling reactions for a broad scope of substrates under ambient conditions, and the Pd SAs can be stabilized in CeO2 in long-term catalytic cycles without leaching or aggregating. Theoretical calculations indicate that the CeO2 supported Pd SAs can remarkably reduce the energy barriers of both transmetalation and reductive elimination steps for Suzuki coupling reactions. The strong metal-support interaction contributes to modulating the electronic state and maintaining the stability of Pd SA sites. This work demonstrates an effective strategy to design and synthesize stable single-atom catalysts as well as sheds new light on the origin for enhanced catalysis based on the strong metal-support interactions.

Dissimilatory iron and sulfate reduction by native microbial communities using lactate and citrate as carbon sources and electron donors.

The bacterial (dissimilatory) iron and sulfate reduction (BIR and BSR) are intimately linked to the biogeochemical cycling of C, Fe, and S in acid mine drainage (AMD) environments. This study examined the response of native microbial communities to the reduction of iron and sulfate in bench experimental systems. Results showed that the reduction of ferric iron and sulfate took place when the electron acceptors coexist. Existence of Fe(III) can postpone the reduction of sulfate, but can enhance the reduction rate. Cultures grown in the presence of 10 mM iron can reach the final level of sulfate bio-reduction rate (~100%) after 35 days incubation. 16 S rDNA -based microbial community analysis revealed that the three genera Anaeromusa, Acinetobacter and Bacteroides were dominated in the ferric-reducing conditions. SRB (Desulfobulbus, Desulfosporosinus and Desulfovibrio) were dominated in the sulfate reduction process. Results in this study highlighted the highly coupled nature of C, Fe, and S biogeochemical cycles in AMD and provided insights into the potential of environmental remediation by native microbial.

Degradation of tris(2-chloroethyl) phosphate (TCEP) in aqueous solution by using pyrite activating persulfate to produce radicals.

Organophosphorus esters (OPEs), as one kind of emerging and toxic contaminant are ubiquitous in various environments. This study investigated the degradation of tris(2-chloroethyl) phosphate (TCEP) as a category OPEs by pyrite (FeS2)-activated persulfate (PS). The result shows that near-100% degradation of TCEP was achieved after 120 min in FeS2-PS system. The important role of Fe2+ in the activation mechanism was confirmed by the introduction of Fe2+ into the PS only system. Radical scavengers experiment and electron paramagnetic resonance (EPR) confirmed the presence of SO4·- and ·OH，which revealed that ·OH and SO4·- played major roles in TCEP degradation. The effect of various environmental factors, including pyrite and oxidant dosage, inorganic ions and pH were investigated. The result indicated that Fe3+ and Cl- can accelerate the degradation rate of TCEP and the reaction between TCEP and FeS2-PS favors acidic conditions (pH>9). In addition, due to the acidification of pyrite, this system can be applied with a wide pH range. Besides, two oxidation products, C4H9Cl2O4P and C2H6ClO4P were identified, which suggest that hydroxylation was probably the main mechanism. This study greatly improves our understanding on TCEP removal in FeS2-PS system.

Rate constants for the reaction of hydroxyl and sulfate radicals with organophosphorus esters (OPEs) determined by competition method.

Advanced oxidation processes (AOPs), such as hydroxyl radical (•OH) and sulfate radical (•SO4-) mediated oxidation, are proved to be effective methods to remove the organophosphorus esters (OPEs) in wastewater effluents. However, few studies have reported about the bimolecular reaction rate constants between free radicals (•OH and •SO4-) and OPEs. This issue was solved by selecting three OPEs as model compounds, the oxidation of these OPEs in UV/H2O2 and UV/K2S2O8 process were studied. Tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCPP), and tris(2,3-dichloropropyl) phosphate (TDCPP) can hardly be oxidized through direct irradiation methods using UV lamp, with the oxidation rate less than 30% after 7 h' irradiation. However, TCEP, TCPP, and TDCPP undergo degradation via UV/H2O2 and UV/K2S2O8 processes easily, the oxidation rates increased with increasing H2O2 and K2S2O8 dosage. The oxidation rates of three OPEs have been studied using competition experiments in the UV/H2O2 and UV/K2S2O8 processes. The bimolecular reaction rate constants of TCEP, TCPP and TDCPP with •OH were 2.50 × 1010, 3.95 × 1010 and 2.94 × 1010 respectively; while •SO4- were 3.00 × 107, 1.82 × 107 and 2.06 × 107 respectively. Results showed that the simplified kinetic model involves only steady state concentration of free radicals and the molecular reaction rate contents are available for calculating the oxidation rates of OPEs in ultrapure water.

Migration and fate of metallic elements in a waste mud impoundment and affected river downstream: A case study in Dabaoshan Mine, South China.

Fate of metallic elements and their migration mechanisms in a waste mud impoundment and affected downstream were assessed. Physicochemical and mineralogical methods combined with PHREEQC calculation, statistical analysis and review of relevant literatures were employed. Results showed that the waste in mud impoundment had been severely weathered and acidized. Metallic elements exhibited high mobility and activity, with a mobility ranking order of Cd > Zn > Mn > Cu ≈ Cr > As ≈ Pb. Hydraulic transportation originating from elevation variation was the most important driving force for metallic elements migration. Although damming standstill was considered as an effective strategy for controlling coarse suspended particulate pollutants, metallic elements were still transported to the Hengshi River in both dissolved phase and fine suspended particle phase accompanied by the overflow of acid mine drainage. The concentrations of dissolved metallic elements were attenuated significantly along the Hengshi River within 41 km stretch. Precipitation/ co-precipitation of iron oxyhydroxides, especially schwertmannite, ferrihydrite and goethite minerals, were established as the most critical processes for metallic elements attenuation in river water. Accompanied by metals migration in the river, two pollution sensitive sites with notably high content of metals in the stretch of S6-S8 and S10, were identified in gently sloping river stretch.

Effects of nano bamboo charcoal on PAHs-degrading strain Sphingomonas sp. GY2B.

Nano bamboo charcoal (NBC) has been commonly used in the production of textiles, plastics, paint, etc. However, little is known regarding their effects towards the microorganisms. The effects of NBC on phenanthrene degrading strain Sphingomonas sp. GY2B were investigated in the present study. Results showed that the addition of NBC could improve the phenanthrene removal by Sphingomonas sp. GY2B, with removal efficiencies increased by 10.29-18.56% in comparison to the control at 24h, and phenanthrene was almost completely removed at 48h. With the presence of low dose of NBC (20 and 50mgL(-1)), strain GY2B displayed a better growth at 6h, suggesting that NBC was beneficial to the growth of GY2B and thus resulting in the quick removal of phenanthrene from water. However, the growth of strain GY2B in high dose of NBC (200mgL(-1)) was inhibited at 6h, and the inhibition could be attenuated and eliminated after 12h. NBC-effected phenanthrene solubility experiment suggested that NBC makes a negligible contribution to the solubilization of phenanthrene in water. Results of electronic microscopy analysis (SEM and TEM) indicated NBC may interact with the cell membrane, causing the enhanced membrane permeability and then NBC adsorbed on the membrane would enter into the cells. The findings of this work would provide important information for the future usage and long-term environmental risk assessment of NBC.

Optimization and verification of selective removal of organophosphate esters from wastewater by molecularly imprinted adsorbent.

Tributyl phosphate (TNBP), a new type of flame retardant, is an emerging pollutant and has been frequently detected in various matrices such as wastewater. Efficient removal of TNBP is critical for wastewater treatment. In this study, molecularly imprinted polymer (MIP) was prepared using precipitation polymerization for selective adsorption of TNBP. The results showed that MIP had a porous structure and formed effective imprinting cavities, which was primarily responsible for its superior adsorption ability. The adsorption of TNBP by MIP was carried out following both the pseudo-secondary kinetic model and the Langmuir isothermal adsorption model. MIP adsorbed TNBP rapidly and reached adsorption equilibrium within 30 min with 923 µmol g-1 at 298 K. The adsorption capacity and adsorption rate of MIP were respectively 2 and 5.49 times those of non-molecularly imprinted polymers. In addition, MIP could effectively counter disturbances from external parameters like temperature and pH, exhibiting strong environmental flexibility. MIP can specifically adsorb organophosphate esters, and can selectively adsorb TNBP under the interference of coexisting contaminants such as1,3-diphenylguanidine and isazofos. In actual bodies of water, MIP's highly selective adsorption of TNBP retains its advantage. The selective adsorption of MIP was mainly due to the common phosphate skeleton, and the specific substituent of organophosphate esters played an important role in the imprinting process. Hydrogen bonding might be involved in the polymerization process of TNBP with acrylamide and the adsorption process of TNBP by MIP.MIP exhibited good reuse efficiency, the total adsorption capacity decreased by no more than 25% after 7 reuse cycles. This study provides a simple and efficient method for selective removal of organophosphate from wastewater.

Divergent redistribution behavior of divalent metal cations associated with Fe(II)-mediated jarosite phase transformation.

The Fe(II)/Fe(III) cycle is an important driving force for dissolution and transformation of jarosite. Divalent heavy metals usually coexist with jarosite; however, their effects on Fe(II)-induced jarosite transformation and different repartitioning behavior during mineral dissolution-recrystallization are still unclear. Here, we investigated Fe(II)-induced (1 mM Fe(II)) jarosite conversion in the presence of Cd(II), Mn(II), Co(II), Ni(II) and Pb(II) (denoted as Me(II), 1 mM), respectively, under anaerobic condition at neutral pH. The results showed that all co-existing Me(II) retarded Fe(II)-induced jarosite dissolution. In the Fe(II)-only system, jarosite first rapidly transformed to lepidocrocite (an intermediate product) and then slowly to goethite; lepidocrocite was the main product. In Fe(II)-Cd(II), -Mn(II), and -Pb(II) systems, coexisting Cd(II), Mn(II) and Pb(II) retarded the above process and lepidocrocite was still the dominant conversion product. In Fe(II)-Co(II) system, coexisting Co(II) promoted lepidocrocite transformation into goethite. In Fe(II)-Ni(II) system, jarosite appeared to be directly converted into goethite, although small amounts of lepidocrocite were detected in the final product. In all treatments, the appearance or accumulation of lepidocrocite may be also related to the re-adsorption of released sulfate. By the end of reaction, 6.0 %, 4.0 %, 76.0 % 11.3 % and 19.2 % of total Cd(II), Mn(II), Pb(II) Co(II) and Ni(II) were adsorbed on the surface of solid products. Up to 49.6 %, 44.3 %, and 21.6 % of Co(II), Ni(II), and Pb(II) incorporated into solid product, with the reaction indicating that the dynamic process of Fe(II) interaction with goethite may promote the continuous incorporation of Co(II), Ni(II), and Pb(II).

Non-targeted screening and photolysis transformation of tire-related compounds in roadway runoff.

Roadway runoff serves as a crucial pathway for transporting contaminants of emerging concern (CECs) from urban environments to receiving water bodies. Tire-related compounds originating from tire wear particles (TWPs) have been frequently detected, posing a potential ecological threat. Yet, the photolysis of tire-related compounds within roadway runoff remains inadequately acknowledged. Addressing this deficit, our study utilized high-resolution mass spectrometry (HRMS) to characterize the chemical profile of roadway runoff across eight strategically selected sites in Guangzhou, China. 219 chemicals were identified or detected within different confidence levels. Among them, 29 tire-related contaminants were validated with reference standards, including hexa(methoxymethyl)melamine (HMMM), 1,3-diphenylguanidine (DPG), dicyclohexylurea (DCU), and N-cyclohexyl-2-benzothiazol-amine (DCMA). HMMM exhibited with the abundance ranging from 2.30 × 104-3.10 × 106, followed by DPG, 1.69 × 104-8.34 × 106. Runoff sample were exposed to irradiation of 500 W mercury lamp for photodegradation experiment. Photolysis results indicated that tire-related compounds with a low photolysis rate, notably DCU, DCMA, and DPG, are more likely to persist within the runoff. The photolytic rates were significantly correlated with the spatial distribution patterns of these contaminants. Our findings underscore TWPs as a significant source of pollution in water bodies, emphasizing the need for enhanced environmental monitoring and assessment strategies.

Efficient removal of heavy metals in water utilizing facile cross-link conjugated linoleic acid micelles.

Micellar-enhanced ultrafiltration (MEUF) technology is an effective method to treat low-concentration heavy metal wastewater. However, the leakage of surfactants in the ultrafiltration (UF) process will inevitably cause secondary pollution. In this study, a biosurfactant of conjugated linoleic acid (CLA) with conjugated double bonds was selected to bind its micelles by simple thermal crosslinking to obtain morphologically stable stearic acid (SA) nanoparticles. The pure SA nanoparticles were obtained by repeated dialysis. The stability of the SA nanoparticles was verified by comparing the particle size distribution and solubility of the materials before and after crosslinking at different pH levels. The effectiveness of SA nanoparticle-enhanced UF in removing heavy metals was verified by exploring the adsorption performance of SA nanoparticles. The dialysis device was used to simplify the UF device, wherein SA nanoparticles were assessed as adsorbents for the elimination of Cu2+, Pb2+, and Cd2+ ions from aqueous solutions under diverse process parameters, including pH, contact time, metal ion concentration, and coexisting ions. The findings indicate that the SA nanoparticles have no evidence of secondary contamination in UF and exhibit compatibility with a broad pH range and coexisting ions. The maximum adsorption capacities for Cu2+, Pb2+, and Cd2+ were determined to be 152.77, 403.56, and 271.46 mg/g, respectively.

Arsenic redistribution associated with Fe(II)-induced jarosite transformation in the presence of polygalacturonic acid.

Jarosite exists widely in acid-sulfate soil and acid mine drainage polluted areas and acts as an important host mineral for As(V). As a metastable Fe(III)-oxyhydoxysulfate mineral, its dissolution and transformation have a significant impact on the biogeochemical cycle of As. Under reducing conditions, the trajectory and degree of abiotic Fe(II)-induced jarosite transformation may be greatly influenced by coexisting dissolved organic matter (DOM), and in turn influencing the fate of As. Here, we explored the impact of polygalacturonic acid (PGA) (0-200 mg·L-1) on As(V)-coprecipitated jarosite transformation in the presence of Fe(II) (1 mM) at pH 5.5, and investigated the repartitioning of As between aqueous and solid phase. The results demonstrated that in the system without both PGA and Fe(II), jarosite gradually dissolved, and lepidocrocite was the main transformation product by 30 d; in Fe(II)-only system, lepidocrocite appeared by 1 d and also was the mainly final product; in PGA-only systems, PGA retarded jarosite dissolution and transformation, jarosite might be directly converted into goethite; in Fe(II)-PGA systems, the presence of PGA retarded Fe(II)-induced jarosite dissolution and transformation but did not alter the pathway of mineral transformation, the final product mainly still was lepidocrocite. The retarding effect on jarosite dissolution enhanced with the increase of PGA content. The impact of PGA on Fe(II)-induced jarosite transformation mainly was related to the complexation of carboxyl groups of PGA with Fe(II). The dissolution and transformation of jarosite drove pre-incorporated As transferred into the phosphate-extractable phase, the presence of PGA retarded jarosite dissolution and maintained pre-incorporated As stable in jarosite. The released As promoted by PGA was retarded again and almost no As was released into the solution by the end of reactions in all systems. In systems with Fe(II), no As(III) was detected and As(V) was still the dominant redox species.

Determination of decabrominated diphenyl ether in soils by Soxhlet extraction and high performance liquid chromatography.

This study described the development of a method based on Soxhlet extraction combining high performance liquid chromatography (Soxhlet-HPLC) for the accurate detection of BDE-209 in soils. The solvent effect of working standard solutions in HPLC was discussed. Results showed that 1:1 of methanol and acetone was the optimal condition which could totally dissolve the BDE-209 in environmental samples and avoid the decrease of the peak area and the peak deformation difference of BDE-209 in HPLC. The preliminary experiment was conducted on the configured grassland (1 µ g/g) to validate the method feasibility. The method produced reliable reproducibility, simulated soils (n = 4) RSD 1.0%, and was further verified by the analysis e-waste contaminated soils, RSD range 5.9-11.4%. The contamination level of BDE-209 in burning site was consistent with the previous study of Longtang town but lower than Guiyu town, and higher concentration of BDE-209 in paddy field mainly resulted from the long-standing disassembling area nearby. This accurate and fast method was successfully developed to extract and analyze BDE-209 in soil samples, showing its potential use for replacing GC to determinate BDE-209 in soil samples.