Molecular composition and characteristics of Sediment-adsorbed Dissolved Organic Matter (SDOM) along the coast of China.

Sediment-adsorbed Dissolved Organic Matter (SDOM) in coast plays a crucial role in the terrestrial and marine carbon cycle processes of the global environment. However, understanding the transport dynamics of SDOM along the coast of China, particularly its interactions with sediments, remains elusive. In this study, we analyzed the δ13C and δ15N stable isotopic compositions, as well as the molecular characteristics of SDOM collected from coastal areas spanning the Bohai Sea (BS), Yellow Sea (YS), East China Sea (ECS), and South China Sea (SCS), by using isotope ratio mass spectrometry and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS). We identified the predominant sources of carbon and nitrogen in coastal sediments, revealing terrigenous origins for most C and N, while anthropogenic sources dominated in the SCS. Spatial variations in SDOM chemodiversity were observed, with diverse molecular components influenced by distinct environmental factors and sediment sources. Notably, lignins and saturated compounds (such as proteins/amino sugars) were the predominant molecular compounds detected in coastal SDOM. Through Mantel tests and Spearman's correlation analysis, we elucidated the significant influence of spatial environmental factors (temperature, DO, salinity, and depth) and sediment sources on SDOM molecular chemodiversity. These findings contribute to a more comprehensive understanding of the carbon cycle dynamics along the Chinese coast.

Local Structure and Crystallization Transformation of Hydrous Ferric Arsenate in Acidic H2O-Fe(III)-As(V)-SO42- Systems: Implications for Acid Mine Drainage and Arsenic Geochemical Cycling.

Hydrous ferric arsenate (HFA) is a common thermodynamically metastable phase in acid mine drainage (AMD). However, little is known regarding the structural forms and transformation mechanism of HFA. We investigated the local atomic structures and the crystallization transformation of HFA at various Fe(III)/As(V) ratios (2, 1, 0.5, 0.33, and 0.25) in acidic solutions (pH 1.2 and 1.8). The results show that the Fe(III)/As(V) in HFA decreases with decreasing initial Fe(III)/As(V) at acidic pHs. The degree of protonation of As(V) in HFA increases with increasing As(V) concentrations. The Fe K-edge extended X-ray absorption fine structure and X-ray absorption near-edge structure results reveal that each FeO6 is linked to more than two AsO4 in HFA precipitated at Fe(III)/As(V) < 1. Furthermore, the formation of scorodite (FeAsO4·2H2O) is greatly accelerated by decreasing the initial Fe(III)/As(V). The release of As(V) from HFA is observed during its crystallization transformation process to scorodite at Fe(III)/As(V) < 1, which is different from that at Fe(III)/As(V) ≥ 1. Scanning electron microscopy results show that Oswald ripening is responsible for the coarsening of scorodite regardless of the initial Fe(III)/As(V) or pH. Moreover, the formation of crystalline ferric dihydrogen arsenate as an intermediate phase at Fe(III)/As(V) < 1 is responsible for the enhanced transformation rate from HFA to scorodite. This work provides new insights into the local atomic structure of HFA and its crystallization transformation that may occur in AMD and has important implications for arsenic geochemical cycling.

Simultaneous stabilization of particulate and bioavailable arsenic in soils from the realgar mining area by polyacrylamide, nano-SiO2, and ferrihydrite composite materials.

Arsenic (As) contamination in realgar mining areas poses a severe environmental and health risk, highlighting the critical need for effective strategies to manage As migration, particularly in its particulate and bioavailable states. Soil erosion and water leaching serve as significant pathways for spreading As, emphasizing the imperative to curtail its mobility. In the present study, we proposed an effective strategy that combines the utilization of polyacrylamide (PAM), nano-SiO2 (NS), and ferrihydrite (Fh) to elevate the stability of As in soils from a realgar mining area. The results show that this composite material demonstrates the capability to concurrently regulate soil erosion and mitigate the leaching of bioavailable As. The combination of the three materials in the proportion of 0.5 % PAM +0.1 % NS + 1.0 % Fh can reduce the soil particulate and bioavailable As content by 99.11 % and 93.98 %, respectively. The unconfined compressive strength of the soil can be increased by about 30 % under this condition. The SEM analyses show that the addition of PAM and NS can significantly enhance the aggregation of soil particles and then reduce the soil erosion rate. These findings highlight the significant potential of the proposed approach in mitigating As contamination in soil within mining environments. The approach offers a sustainable and comprehensive solution to address the transport of heavy metal contaminants in both particulate and bioavailable states in mining areas.

Reorganization of structural brain networks in Parkinson's disease with postural instability/gait difficulty.

The Postural Instability/Gait Difficulty (PIGD) subtype of Parkinson's disease (PD) has a faster disease progression, a higher risk of cognitive and motor decline, yet the alterations of structural topological organization remain unknown. Diffusion Tensor Imaging (DTI) and 3D-TI scanning were conducted on 31 PD patients with PIGD (PD-PIGD), 30 PD patients without PIGD (PD-non-PIGD) and 35 Healthy Controls (HCs). Structural networks were constructed using DTI brain white matter fiber tractography. A graph theory approach was applied to characterize the topological properties of complex structural networks, and the relationships between significantly different network metrics and motor deficits were analyzed within the PD-PIGD group. PD-PIGD patients exhibited increased shortest path length compared with PD-non-PIGD and HCs (P < 0.05, respectively). Additionally, PD-PIGD patients exhibited decreased nodal properties, mainly in the cerebellar vermis, prefrontal cortex, paracentral lobule, and visual regions. Notably, the degree centrality of the cerebellar vermis was negatively correlated with the PIGD score (r = -0.390; P = 0.030) and Unified Parkinson's Disease Rating Scale Part III score (r = -0.436; P = 0.014) in PD-PIGD patients. Furthermore, network-based statistical analysis revealed decreased structural connectivity between the prefrontal lobe, putamen, supplementary motor area, insula, and cingulate gyrus in PD-PIGD patients. Our findings demonstrated that PD-PIGD patients existed abnormal structural connectomes in the cerebellar vermis, frontal-parietal cortex and visual regions. These topological differences can provide a topological perspective for understanding the potential pathophysiological mechanisms of PIGD in PD.

Tuning the Electrolyte and Interphasial Chemistry for All-Climate Sodium-ion Batteries.

Sodium-ion batteries (SIBs) present a promising avenue for next-generation grid-scale energy storage. However, realizing all-climate SIBs operating across a wide temperature range remains a challenge due to the poor electrolyte conductivity and instable electrode interphases at extreme temperatures. Here, we propose a comprehensively balanced electrolyte by pairing carbonates with a low-freezing-point and low-polarity ethyl propionate solvent which enhances ion diffusion and Na+-desolvation kinetics at sub-zero temperatures. Furthermore, the electrolyte leverages a combinatorial borate- and nitrile-based additive strategy to facilitate uniform and inorganic-rich electrode interphases, ensuring excellent rate performance and cycle stability over a wide temperature range from -45 °C to 60 °C. Notably, the Na||sodium vanadyl phosphate cell delivers a remarkable capacity of 105 mAh g-1 with a high rate of 2 C at -25 °C. In addition, the cells exhibit excellent cycling stability over a wide temperature range, maintaining a high capacity retention of 84.7 % over 3,000 cycles at 60 °C and of 95.1 % at -25 °C over 500 cycles. The full cell also exhibits impressive cycling performance over a wide temperature range. This study highlights the critical role of electrolyte and interphase engineering for enabling SIBs that function optimally under diverse and extreme climatic environments.

Research progress on the mechanism of common inflammatory pathways in the pathogenesis and development of lymphoma.

In recent years, the incidence and mortality rates of lymphoma have gradually increased worldwide. Tumorigenesis and drug resistance are closely related to intracellular inflammatory pathways in lymphoma. Therefore, understanding the biological role of inflammatory pathways and their abnormal activation in relation to the development of lymphoma and their selective modulation may open new avenues for targeted therapy of lymphoma. The biological functions of inflammatory pathways are extensive, and they are central hubs for regulating inflammatory responses, immune responses, and the tumour immune microenvironment. However, limited studies have investigated the role of inflammatory pathways in lymphoma development. This review summarizes the relationship between abnormal activation of common inflammatory pathways and lymphoma development to identify precise and efficient targeted therapeutic options for patients with advanced, drug-resistant lymphoma.

Inflammatory pathways directly or indirectly regulate the TME and are closely related to the development of lymphoma.This review was conducted to elucidate the connection between inflammatory pathways and the tumorigenesis and drug resistance of several common lymphomas.Overall, targeting abnormally activated molecules upstream and downstream of lymphoma inflammatory pathways in the future is expected to be a new target for lymphoma treatment.

Topological alteration of the brain structural network in Parkinson's disease with apathy.

BACKGROUND: Apathy is a common neuropsychiatric manifestations in Parkinson's disease (PD), but neural network mechanisms still remain elusive. We aim to investigate the topological alteration of the brain structural network in PD with apathy. METHOD: In the present study, a total of 47 apathetic PD (aPD) patients, 37 non-apathetic PD (naPD) patients, and 40 healthy controls (HCs) were enrolled. Diffusion tensor imaging (DTI) in conjunction with graph-theoretic approaches were used to explore the alterations of topological properties of the WM structural network arising from apathy in PD. One-way analysis of covariance and post hoc analyses were performed to explore differences among the three groups. Correlations were ascertained to examine relationships between the Starkstein Apathy Scale (AS) scores and significantly different network metrics among the three groups. RESULTS: Both aPD and naPD patients remained small-world topology. However, compared with the naPD patients, aPD patients showed increased clustering coefficient (Cp) at the global level. At the regional level, aPD exhibited decreased nodal properties, mainly in the right dorsolateral prefrontal cortex (DLPFC), the right caudate nucleus (CAU), the right hippocampus, and the right superior parietal gyrus. Further, AS scores were negatively correlated with degree centrality of the right DLPFC (r = -0.254, p = 0.020) and the right CAU ( r = -0.357, p = 0.001) in the pooled patients with PD. CONCLUSIONS: The findings suggested that apathy in PD presented relatively optimized global topological properties of the brain structural network and disrupted topological organization of the regional network, particularly involving the fronto-striatal-limbic circuits. The altered topological properties of abnormal brain regions might be used to understand the physiopathologic mechanism of the neural network in aPD patients.

Bacterial community in the metal(loid)-contaminated marine vertical sediments of Jinzhou Bay: Impacts and adaptations.

Metal(loid) discharge has led to severe coastal contamination; however, there remains a significant knowledge gap regarding its impact on sediment profiles and depth-resolved bacterial communities. In this study, geochemical measurements (pH, nutrient elements, total and bioavailable metal(loid) content) consistently revealed decreasing nitrogen, phosphorus, and metal(loid) levels with sediment depth, accompanied by reduced alpha diversity. Principal coordinate analysis indicated distinct community compositions with varying sediment depths, suggesting a geochemical influence on diversity. Ecological niche width expanded with depth, favoring specialists over generalists, but both groups decreased in abundance. Taxonomic shifts emerged, particularly in phyla and families, correlated with sediment depth. Microbe-microbe interactions displayed intricate dynamics, with keystone taxa varying by sediment layer. Zinc and arsenic emerged as key factors impacting community diversity and composition using random forest, network analysis, and Mantel tests. Functional predictions revealed shifts in potential phenotypes related to mobile elements, biofilm formation, pathogenicity, N/P/S cycles, and metal(loid) resistance along sediment profiles. Neutral and null models demonstrated a transition from deterministic to stochastic processes with sediment layers. This study provides insights into the interplay between sediment geochemistry and bacterial communities across sediment depths, illuminating the factors shaping these ecosystems.

Iodide and sulfite synergistically accelerate the photo-reduction and recovery of As(V) and As(III) in sulfite/iodide/UV process: Efficiency and mechanism.

Photo-reduction of arsenic (As) by hydrated electron (eaq-) and recovery of elemental arsenic (As(0)) is a promising pathway to treat As-bearing wastewater. However, previously reported sulfite/UV system needs large amounts of sulfite as the source of eaq-. This work suggests a sulfite/iodide/UV approach that is more efficient and consumes much less chemical reagents to remove As(III) and As(V) and recover valuable As(0) from wastewater, hence preventing the production of large amounts of As-containing hazardous wastes. Our results showed that more than 99.9% of As in the aqueous phase was reduced to highly pure solid As(0) (>99.5 wt%) by sulfite/iodide/UV process under alkaline conditions. Sulfite and iodide worked synergistically to enhance reductive removal of As. Compared with sulfite/UV, the addition of iodide had a substantially greater effect on As(III) (over 200 times) and As(V) (approximately 30 times) removals because of its higher absorptivity and quantum yield of eaq-. Furthermore, more than 90% of the sulfite consumption was decreased by adding a small amount of iodide while maintaining similar reduction efficiency. Hydrated electron (eaq-) was mainly responsible for As(III) and As(V) reductions and removals under alkaline conditions, while both SO3•- and reactive iodine species (e.g., I•, I2, I2•-, and I3-) may oxidize As(0) to As(III) or As(V). Acidic circumstances caused sulfite protonation and the scavenging of eaq- by competing processes. Dissolved oxygen (O2) and CO32- prevented As reduction by light blocking or eaq- scavenging actions, but Cl-, Ca2+, and Mg2+ showed negligible impacts. This study presented an efficient method for removing and recovering As from wastewater.

Rapid-charging aluminium-sulfur batteries operated at 85 °C with a quaternary molten salt electrolyte.

Molten salt aluminum-sulfur batteries are based exclusively on resourcefully sustainable materials, and are promising for large-scale energy storage owed to their high-rate capability and moderate energy density; but the operating temperature is still high, prohibiting their applications. Here we report a rapid-charging aluminium-sulfur battery operated at a sub-water-boiling temperature of 85 °C with a tamed quaternary molten salt electrolyte. The quaternary alkali chloroaluminate melt - possessing abundant electrochemically active high-order Al-Cl clusters and yet exhibiting a low melting point - facilitates fast Al3+ desolvation. A nitrogen-functionalized porous carbon further mediates the sulfur reaction, enabling the battery with rapid-charging capability and excellent cycling stability with 85.4% capacity retention over 1400 cycles at a charging rate of 1 C. Importantly, we demonstrate that the asymmetric sulfur reaction mechanism that involves formation of polysulfide intermediates, as revealed by operando X-ray absorption spectroscopy, accounts for the high reaction kinetics at such temperature wherein the thermal management can be greatly simplified by using water as the heating media.

Divergent adaptation strategies of abundant and rare bacteria to salinity stress and metal stress in polluted Jinzhou Bay.

Understanding how abundant (AT) and rare (RT) taxa adapt to diverse environmental stresses is vital for assessing ecological processes, yet remains understudied. We collected sediment samples from Liaoning Province, China, representing rivers (upstream of wastewater outlet), estuaries (wastewater outlets), and Jinzhou Bay (downstream of wastewater outlets), to comprehensively evaluate AT and RT adaptation strategies to both natural stressors (salinity stress) and anthropogenic stressors (metal stress). Generally, RT displayed higher α- and ß-diversities and taxonomic groups compared to AT. Metal and salinity stresses induced distinct α-diversity responses in AT and RT, while ß-diversity remained consistent. Both subcommunities were dominated by Woeseia genus. Metal stress emerged as the primary driver of diversity and compositional discrepancies in AT and RT. Notably, AT responded more sensitively to salinity stress than RT. Stress increased topological parameters in the biotic network of AT subcommunities while decreasing values in RT subcommunities, concurrently loosening interactions of AT with other taxa and strengthening interactions of RT with others in biotic networks. RT generally exhibited greater diversity of metal resistance genes compared to AT. Greater numbers of genes related to salinity tolerance was observed for the RT than for AT. Compared to AT, RT demonstrated higher diversity of metal resistance genes and a greater abundance of genes associated with salinity tolerance. Additionally, deterministic processes governed AT community assembly, reinforced by salinity stress. However, the opposite trend was observed in the RT, where the importance of stochastic process gradually increased with metal stresses. The study is centered on exploring the adaptation strategies of both AT and RT to environmental stress. It underscores the importance of future research incorporating diverse ecosystems and a range of environmental stressors to draw broader and more reliable conclusions. This comprehensive approach is essential for gaining a thorough understanding of the adaptive mechanisms employed by these microorganisms.

Electrolyte Engineering with Tamed Electrode Interphases for High-Voltage Sodium-Ion Batteries.

Sodium-ion batteries (SIBs) hold great promise for next-generation grid-scale energy storage. However, the highly instable electrolyte/electrode interphases threaten the long-term cycling of high-energy SIBs. In particular, the instable cathode electrolyte interphase (CEI) at high voltage causes persistent electrolyte decomposition, transition metal dissolution, and fast capacity fade. Here, this work proposes a balanced principle for the molecular design of SIB electrolytes that enables an ultra-thin, homogeneous, and robust CEI layer by coupling an intrinsically oxidation-stable succinonitrile solvent with moderately solvating carbonates. The proposed electrolyte not only shows limited anodic decomposition thus leading to a thin CEI, but also suppresses dissolution of CEI components at high voltage. Consequently, the tamed electrolyte/electrode interphases enable extremely stable cycling of Na3V2O2(PO4)2F (NVOPF) cathodes with outstanding capacity retention (>90%) over 3000 cycles (8 months) at 1 C with a high charging voltage of 4.3 V. Further, the NVOPF||hard carbon full cell shows stable cycling over 500 cycles at 1 C with a high average Coulombic efficiency (CE) of 99.6%. The electrolyte also endows high-voltage operation of SIBs with great temperature adaptability from -25 to 60 °C, shedding light on the essence of fundamental electrolyte design for SIBs operating under harsh conditions.

The fate of arsenic during the crystallization process of FeIII oxyhydroxides: Effect of reaction media, pH value, and Fe/As molar ratio under relatively low arsenic loading.

Understanding the nature of arsenic (As) adsorbed on FeIII oxyhydroxides, and the subsequent behavior of As during the crystallization process, is critical to predicting its fate in a range of natural and engineered settings. In this work, As adsorbed on FeIII oxyhydroxides formed in the different reaction media at different pH values were characterized with X-ray diffraction (XRD), Raman spectra, transmission electron microscopy (TEM), and extended X-ray absorption fine structure spectroscopy (EXAFS) to determine how As is redistributed during the crystallization process. Results showed that at pH 12, a quarter of the added As was still left in the liquid phase with the formation of goethite and hematite as the major and minor product. The concentration of As was found to be the lowest at pH 4 which is independent of the reaction media, indicating the importance of pH value in the crystallization process of the As adsorbed FeIII oxyhydroxides. Under acidic conditions, sulfate and chloride media favored the formation of goethite and hematite, respectively. Arsenic can indeed be incorporated into the structure of the formed goethite at pH 4. The morphology of the formed products changed to rhombus-like particles if both goethite and hematite appeared as the later as the dominant product.

Direct immobilization of Se(IV) from acidic Se(IV)-rich wastewater via ferric selenite Co-precipitation.

The attenuation of acidic Se(IV)-rich wastewater, including those associated with acid mine drainage (AMD) and nonferrous metallurgical wastewater (NMW), presents a serious environmental challenge. This study investigates the effects of diverse factors from pH values to Se(IV)/Fe(III) molar ratios, initial Se(IV) concentrations, and alkali neutralization agents on the direct co-precipitation of ferric selenites in AMD and NMW systems involving different orders of Fe(III) and alkali addition. Our results show that amorphous sulfate-substituted ferric (hydrogen) selenite and Se(IV)-bearing ferrihydrite-schwertmannite are the major Se(IV)-attenuation solids except that gypsum is an additional phase in the NMW system with Ca(OH)2 neutralization. Produced ferric selenites achieve 98-99.8% of Se(IV) immobilization under optimal conditions of pH 4.5, Se(IV)/Fe(III) molar ratios of 0.0625-0.5, and initial Se(IV) concentrations of 0.15-1.3 mmol·L-1. Moreover, completing FeSO4+ and FeHSeO32+/FeSeO3+ complexes as well as different ferric selenite co-precipitates are shown to collectively control aqueous Se(IV) remaining. Specifically, three distinct trends of aqueous Se(IV) concentrations separately correspond to changes in the four factors. The co-precipitation in the NMW system via pH adjustment followed by Fe(III) addition is more efficient for Se(IV) fixation than that in the AMD system because of minimal complexation, concurrent Fe(III) hydrolysis, and enhanced ferric selenite co-precipitation in the former.

Enhancement of arsenic uptake and accumulation in green microalga Chlamydomonas reinhardtii through heterologous expression of the phosphate transporter DsPht1.

Arsenate (AsV) is a predominant arsenic contaminant in aerobic water. Microalgae have been recently used in the phytoremediation of arsenic-contaminated water. However, the amount of AsV uptake in microalgae is limited, which hinders the application of microalgae in arsenic-contaminated water treatment. Here, we found that the expression of a novel phosphate transporter DsPht1 in Dunaliella salina was highly upregulated after AsV exposure. Fluorescent protein-tagging analysis showed the plasma membrane location of DsPht1. Furthermore, DsPht1 was overexpressed in a model microalga Chlamydomonas reinhardtii. The DsPht1 transgenetic lines accumulated up to 6.4-fold higher total arsenic than the untransformed line, and the AsV amount in total arsenic increased by 8.3-fold. Moreover, the organoarsenic content was also higher in the transgenetic lines. Overall, the DsPht1 transformants generated in this study increased arsenate uptake and transformation, which are promising for the effective phytoremediation of arsenic-contaminated water.

A solution-to-solid conversion chemistry enables ultrafast-charging and long-lived molten salt aluminium batteries.

Conventional solid-to-solid conversion-type cathodes in batteries suffer from poor diffusion/reaction kinetics, large volume changes and aggressive structural degradation, particularly for rechargeable aluminium batteries (RABs). Here we report a class of high-capacity redox couples featuring a solution-to-solid conversion chemistry with well-manipulated solubility as cathodes-uniquely allowed by using molten salt electrolytes-that enable fast-charging and long-lived RABs. As a proof-of-concept, we demonstrate a highly reversible redox couple-the highly soluble InCl and the sparingly soluble InCl3-that exhibits a high capacity of about 327 mAh g-1 with negligible cell overpotential of only 35 mV at 1 C rate and 150 °C. The cells show almost no capacity fade over 500 cycles at a 20 C charging rate and can sustain 100 mAh g-1 at 50 C. The fast oxidation kinetics of the solution phase upon initiating the charge enables the cell with ultrafast charging capability, whereas the structure self-healing via re-forming the solution phase at the end of discharge endows the long-term cycling stability. This solution-to-solid mechanism will unlock more multivalent battery cathodes that are attractive in cost but plagued by poor reaction kinetics and short cycle life.

Diversity, functional potential, and assembly of bacterial communities in metal(loid)-contaminated sediments from a coastal industrial basin.

A comprehensive understanding of ecological processes related to bacterial communities in these ecosystems is critical for improving the sustainability of estuarine-coastal ecosystem functions. However, the community composition, functional potential, and assembly mechanisms of bacterial community in metal(loid)-contaminated estuarine-coastal habitats remain poorly understood, especially along lotic systems extending from rivers to estuaries and to bays. Here, we collected sediment samples associated with sewage outlets from rivers (upstream/midstream of sewage outlet), estuaries (sewage outlets), and Jinzhou Bay (downstream of sewage outlets) within Liaoning Province, China in order to evaluate the relationships between microbiome and metal(loid) contamination. Sewage discharge markedly increased the concentrations of metal(loid)s in sediments, including of As, Fe, Co, Pb, Cd, and Zn. Significant discrepancies in alpha diversity and community composition were observed among the sampling sites. The above dynamics were primarily caused by salinity and metal(loid) concentrations (i.e., of As, Zn, Cd, and Pb). Furthermore, metal(loid) stress significantly increased abundances of metal(loid)-resistant genes, but decreased abundances of denitrification genes. Dechloromonas, Hydrogenophaga, Thiobacillus, and Leptothrix were denitrifying bacteria present within sediments of this estuarine-coastal ecosystem. Moreover, the stochastic processes dominated the community assembly in estuary offshore sites, while deterministic processes dominated river community assembly mechanisms. Salinity and total nitrogen concentration, rather than metal(loid) concentrations, governed the assembly processes in these sites. Overall, these elucidate mechanisms involved in constructing community diversities, functional potential, and assembly.

Anthropogenic perturbation enhances the release of geogenic Mn to groundwater: Evidence from hydrogeochemical characteristics.

High geogenic Mn groundwater is widespread around the world and has also proved to be harmful to human health, especially to the IQ of Children. The natural release of Mn from aquifer sediments in slightly reducing condition is believed to be the primary cause. However, there isn't enough evidence to prove that anthropogenic activities promote the reductive release of Mn. Here a Historical Petrochemical Waste Storage Site (HPWSS) was studied to evaluate its impact on groundwater quality. Significantly elevated Mn, as well as elevated TDS, anionic surfactants, and organic pollutants, were found in the shallow aquifer (9-15 m) groundwater compared to the surrounding area. The Mn was believed to be generated in-situ, while others are caused by anthropogenic pollution. The good correlations between Mn and NH4+, HCO3-, I, As, Co, V, Ti, respectively, showed the Mn mobilization was mainly attributed to the reductive dissolution of Mn oxides/hydroxides. The potential processes leading to this enhanced Mn release are discussed, including 1) the infiltration of high salinity water which solubilized sediment organic matter (OM); 2) the anionic surfactants that promoted the dissolution and mobilization of surface-derived organic pollutants as well as sediment OM. Any of these processes may have provided a C source to stimulate the microbial reduction of Mn oxides/hydroxides. This study showed the input of pollutants could change the redox and dissolution conditions of the vadose zone and aquifer, causing a secondary geogenic pollution risk in groundwater. Since Mn is easily mobilized in suboxic condition as well as its toxicity, the enhanced release due to anthropogenic perturbation merits more attention.

All-in-one strategy to prepare molded biochar with magnetism from sewage sludge for high-efficiency removal of Cd(â ¡).

Biochar in powder could lead to the separation difficulties after using and easy dispersion by wind with non-necessary consumption during the practical application. The current method for preparing molded biochar is multi-step, tedious, and required exogenous reagents. Moreover, the dehydration of sewage sludge with high water content (>85%) causes expensive production cost, limiting its secondary utilization. Therefore, an "all-in-one" strategy was developed to prepare molded biochar with magnetism by using sewage sludge as endogenetic binder, water source, carbon source, as well as magnetic source, and biomass wastes as water moderator and pore-forming agent. The molded biochar showed high removal capacity towards Cd(Ⅱ) of 456.2 mg/g, which was 6 times higher than the commercial activated carbon in powder (69.1 mg/g). The excellent removal performance of the molded biochar was in linear correlation the O/C ratio (R2 =0.855), resulting in the complexation with Cd(Ⅱ). DFT calculations indicated the amounts and species of oxygen changed the electron distribution and electron-donation properties of biochar for Cd(Ⅱ). Moreover, the Na+ exchanges with Cd(Ⅱ) were also an important removal mechanism. This study provided a novel synthesis strategy for the molded biochar with both high particle density and high adsorption capability.

Exogenous-organic-matter-driven mobilization of groundwater arsenic.

The potential release capacity of arsenic (As) from sediment was evaluated under a high level of exogenous organic matter (EOM) with both bioreactive and chemically reactive organic matters (OMs). The OMs were characterized by FI, HIX, BIX, and SUVA254 fluorescence indices showing the biological activities were kept at a high level during the experimental period. At the genus level, Fe/Mn/As-reducing bacteria (Geobacter, Pseudomonas, Bacillus, and Clostridium) and bacteria (Paenibacillus, Acidovorax, Delftia, and Sphingomonas) that can participate in metabolic transformation using EOM were identified. The reducing condition occurs which promoted As, Fe, and Mn releases at very high concentrations of OM. However, As release increased during the first 15-20 days, followed by a decline contributed by secondary iron precipitation. The degree of As release may be limited by the reactivity of Fe (hydro)oxides. The EOM infiltration enhances As and Mn releases in aqueous conditions causing the risk of groundwater pollution, which could occur in specific sites such as landfills, petrochemical sites, and managed aquifer recharge projects.