Rapid and reliable identification of multivariate geochemical anomalies is critical for delineating prospective mineralized zones and reducing uncertainty in mineral exploration targeting. Extended isolation forest (EIF) is a powerful unsupervised ensemble learning algorithm that efficiently isolates anomalies from high-dimensional geochemical datasets using randomly oriented hyperplane partitions. Previous studies have demonstrated the effectiveness of EIF in multivariate geochemical anomaly detection and mineral potential modeling. However, its performance can be significantly affected by stochastic variability arising from random partitioning and random subsampling during isolation tree construction, which may result in unstable anomaly patterns and inconsistent exploration targets in complex geological environments. To mitigate this limitation, we developed a robust unsupervised framework for the identification of multivariate geochemical anomalies associated with gold mineralization in the Southwestern Yilgarn Craton, Australia. The proposed framework integrates robust factor analysis (RFA), a Jaccard-based stability index and EIF to enhance the reliability and reproducibility of anomaly detection. RFA was first applied to compositional soil geochemical data to identify the most significant pathfinder elements associated with gold mineralization, which were subsequently used as input variables for the EIF model. The model was then optimized using a Jaccard-based stability criterion to ensure consistent anomaly detection across repeated independent runs. Model performance was assessed using area under the receiver operating characteristic curve (AUC). The obtained AUC value of 0.82 indicates strong predictive capacity, confirming that the generated anomaly map effectively delineates mineralization-related geochemical patterns and provides a reliable proxy for mineral prospectivity mapping. Overall, the proposed framework offers a robust and reproducible unsupervised approach for multivariate geochemical anomaly detection with strong applicability in both greenfield and brownfield mineral exploration settings.
Water conservancy and hydropower projects enhance regional climate resilience and watershed water security yet inevitably trigger large-scale involuntary reservoir resettlement. As representative involuntarily displaced populations, reservoir resettlees' social identity directly impacts local social stability and regional sustainable socioeconomic development. Based on a ten-year longitudinal qualitative investigation including in-depth interviews and participant observation in Village Y of Wuxikou Reservoir, Jiangxi Province, this paper divides the entire resettlement process into three stages: relocation, stabilization and development. From the dual perspectives of host community identity and out-groups identity, this study explores the dynamic evolutionary rules of resettlees' social identity. The results indicate that resettlees sequentially develop alienated identity, superficial adaptive identity and segregated identity across different phases. On this basis, the core concept of differential identity is proposed, which features a dual structure of vertical temporal differentiation and horizontal spatial differentiation. This paper expands the applicable scope and explanatory power of the “differential mode of association” and social identity theory in involuntary resettlement contexts. Grounding on the differential identity framework, this paper puts forward targeted integrated governance solutions to break intergroup segregation, facilitate cross-group integration and build resilient resettlement communities consistent with Sustainable Development Goals (SDGs) 11 and 13.
The discrimination of ore deposit types is primarily based on geological, geochemical, and isotopic characteristics. Conventionally, these types are identified using specific element diagrams. However, traditional geochemical methods often fail to determine scheelite deposit types of the complex Xuefengshan Sb-Au-W metallogenic belt in China, where mineralization resulted from the superposition of multiphase geological events. Machine learning (ML) methods, have been increasingly applied to identify deposit genesis by establishing relationships between deposit characteristics and genetic types using extensive datasets. However, inaccurate data labels, the limitations of single models, and poor model interpretability lead to decreased accuracy. This study proposes a ML framework based on interpretable ensemble learning. We collects geochemical element data from typical orogenic and magmatic-hydrothermal scheelite deposits globally. Deep clustering is used to filter data and overcome the subjectivity of original data labels. An ensemble learning model is used to construct a classifier to improve the model's robustness and generalization ability. An interpretable model is introduced to analyze the contribution of individual feature elements, revealing the metallogenic genesis. This method demonstrates high accuracy on the test set. According to this method, the scheelite deposit type of the Xuefengshan metallogenic belt is primarily magmatic-hydrothermal in origin, with orogenic superposition. This helps resolve a long-standing controversy in the region and establishes a repeatable and interpretable new paradigm for ML-based discrimination of ore deposit genetic types.
Though volcanogenic massive sulfide (VMS) deposits are major global sources of indium (In), the physicochemical mechanisms and key factors controlling its significant enrichment remain poorly understood. To address the issue, this study investigates the Tiemurt VMS Pb-Zn-Cu deposit, utilizing detailed petrography, in-situ LA-ICP-MS analysis, and thermodynamic modeling to reveal the In enrichment mechanisms in VMS deposits. Petrographic observations identified two distinct generations of sphalerite corresponding to different mineralization stages. The early-stage sphalerite (Sp1) is euhedral-subhedral, associated with pyrite, and displays darker colors (red to brown), whereas the late-stage sphalerite (Sp2) is anhedral, intimately intergrown with chalcopyrite, and shows lighter colors (mainly yellow). The trace element results demonstrate that Sp1 has a significantly higher In content (average 317 ppm) than Sp2 (average 220 ppm). Additionally, In concentrations positively correlate with Fe contents. Because Fe is the primary chromophore that darkens sphalerite, this strong coupled enrichment mechanism allows macroscopic sphalerite color (red > brown > yellow) to serve as a reliable indicator for In concentration. Crystallization temperatures calculated using the GGIMFis thermometer range from 344 to 382 °C for Sp1 and 312 to 355 °C for Sp2, indicating a cooling trend during fluid evolution. Thermodynamic modeling data showed that in the early-stage hydrothermal fluids (≥360 °C), Zn2+ preferentially complexes with Cl−, leaving InCl2+ or In3+ as unstable species, and In efficiently precipitates into Sp1 under the environment of log fO2 = −32 to −26 and pH = 6–8. As the fluids cool at ~340 °C, weakened Zn2+ competition allows In3+ to form stable InCl3, and In precipitates into Sp2 under the conditions of log fO2 = −42 to −32 and pH = 5.5–11. We therefore conclude that the key factor controlling the difference in In content between Sp1 and Sp2 is the precipitation mechanism rather than migration capacity. This may be different from the In enrichment mechanism associated with magmatic hydrothermal systems, where In is mainly present as InCl3 complexes with strong migration capacity. These new findings enable us to understand how the physicochemical conditions of fluids control the enrichment of In in VMS deposits, and also highlight that the color of sphalerite can be used to target potential In resources in PbZn deposits.
Electrochemically mediated atom transfer radical polymerization (eATRP) has evolved rapidly since its introduction in 2011, becoming one of the most precise and versatile controlled polymerization methods. This review highlights key developments in the last ten years that have advanced eATRP in mechanistic understanding, technological implementation, and materials applications. Significant progress has been made in kinetic modeling, which now incorporates electrochemical parameters to more accurately describe eATRP activation–deactivation dynamics. Strategies to overcome mass-transfer limitations, particularly through modulation of current-delivery patterns, have further improved control. New mechanistic insights have broadened the scope of viable initiating systems, including pseudohalide and sacrificial initiators, while hybrid approaches integrating electrolysis with external stimuli have expanded operational flexibility. Technological advances increasingly emphasize simplicity and scalability, exemplified by “plug-and-play” eATRP platforms and successful upscaling to liter-scale reactors. These developments strengthen the potential of this concept as an industrially relevant technique. Sustainability considerations have also shaped recent research, with iron-catalyzed ATRP emerging as a promising green alternative. In parallel, the method’s utility in producing diverse polymer architectures, including linear, star, and brush polymers, has enabled the fabrication of functional materials for advanced applications. All developments indicate that since 2017, eATRP has evolved from a proof-of-concept electrochemical variant of ATRP into an increasingly scalable platform for low-catalyst polymer synthesis and surface functionalization, in which mass and charge transports are engineered by the waveform applied. Therefore, this review provides an up-to-date summary of mechanistic advances, technological innovations, and the expanding role of this technique in sustainable polymer and materials synthesis.
The Qukulekedong Au–Sb deposit, located in the western East Kunlun Orogenic Belt, contains resources of 21.5 t Au and 73 kt Sb and has been interpreted as an intrusion-related Au–Sb system. However, the timing and exploration significance of deep, proximal skarn mineralization remain poorly constrained. Here, we present new petrographic, mineralogical, mineral geochemical, and UPb geochronological data for the intrusive rocks and newly identified deep skarn. Zircon UPb dating yielded crystallization ages of 211.5 ± 1.9 Ma for the diorite porphyry and 211.7 ± 1.1 Ma for the gabbro diorite, indicating broadly coeval Late Triassic magmatism. Garnet UPb dating of the deep skarn yielded ages of 208.4 ± 5.8 Ma and 208.2 ± 4.8 Ma, directly constraining a Late Triassic skarn mineralization event. The deep skarn is characterized by grossular-rich garnet, diopside, actinolite, vesuvianite, epidote, chlorite, pyrite, arsenopyrite, and pyrrhotite, and was subsequently overprinted by quartz–sulfide and quartz–stibnite–carbonate veins. Zircon and amphibole mineral chemistry indicate that the Late Triassic intrusions crystallized from relatively hot, hydrous magmas under near-FMQ to slightly reduced conditions. Trace-element variations in garnet record progressive fluid evolution from Grt-a, characterized by high HFSE, HREE, V, and Cr contents and high Th/U ratios, to Grt-b, characterized by lower REE and HFSE contents and a closer association with hydrous alteration minerals. These results indicate that the deep skarn represents a proximal, high-temperature component of the Qukulekedong intrusion-related Au–Sb system, thereby expanding exploration targets from shallow Au–Sb veins to deep contacts between intrusions and carbonate-bearing strata, fault-intersection zones, and skarn zones containing Grt-a-type garnet.
Reservoir resettlement is a complex, and long-term recovery process. It involves more than physical relocation, extend to livelihood reconstruction, improvement of living conditions, and psychological recovery. To design post-resettlement policies, it is crucial to understand how these areas interact. This study develops an integrated system dynamics and agent-based simulation (SD-ABS) framework to examine the multidimensional recovery trajectories of resettlers affected by the Yangtze-to-Huaihe Water Diversion Project in China. The framework captures the co-evolution of production recovery, living recovery, and psychological recovery, as well as the feedback mechanisms linking individual behaviors and system-level changes. The model is parameterized and validated using from official monitoring reports, statistical yearbooks, and household surveys. Results show production recovery strongly depends on employment opportunities, skills training, and policy timing. Growth type policies yield better long-term employment outcomes than decrease type approaches. Living recovery can be accelerated by increased investment, however the effectiveness of investment depends on its alignment with resettlers' actual needs. Psychological recovery lag behind other trends and is strongly shaped by kinship and rebuilding social network. These findings show that post-resettlement recovery is dynamic and shaped by nonlinear economic, living, and psychological factors. The proposed SD-ABS framework provides a novel way to analyze long-term recovery. The study offers practical policy insights for employment support, targeted investments, and community integration. The findings help improve resettlement management for large-scale water infrastructure projects.
This review aims to present polytetrafluoroethylene (PTFE), its recent syntheses and processes, properties, applications, and its position in the per- and polyfluoroalkyl substances (PFAS) context. It is the most widely produced fluoropolymer, with production volumes increasing every year. In this review, this specialty polymer is described as endowing exceptional characteristics (chemical, thermal, UV, and aging resistance, waterproofness, rheological, mechanical, tribological, surface properties, and moisture vapor permeability). These outstanding features are well explained by numerous studies linking them to their crystallinity and packing structure, which are closely associated with a constantly evolving chemical synthesis process (fluorinated surfactants are no longer used nowadays). Moreover, the high molar mass of PTFE (several million g.mol-1) prevents its penetration through the human membrane, in addition to its insolubility in all solvents, non-toxicity, and non-bioaccumulation, showing its safe behavior (i.e., biocompatible) and Food and Drug Administration (FDA) approval. Furthermore, although considered a PFAS, this material meets the 13 Organization for Economic Co-operation and Development (OECD) polymer of low concern (PLC) criteria and, so far, is not subject to regulatory restrictions. Because of such features, PTFE can be used in many advanced applications satisfying stringent requirements (in terms of durability, safety, operational efficiency, and sustainability). Then, PTFE is a must-have material in the medical field and in transportation (aerospace, aircraft, railway, and automotive). It is also essential in electronics, the Internet of Things, clean energy storage and conversion, and other high-tech applications, making it an irreplaceable material in many areas of daily life.
Manganese carbonates can be formed via either diagenetic reduction of Mn oxides from hydrothermal and marine environments by organic matter, or direct growth on calcite or dolomite in anoxic environments. The Triassic Heqing manganese carbonate ores in the Heqing basin, Yunnan Province, South China provides an excellent case to show they form by redox between Mn oxides and methane during diagenesis in a low sulfate freshwater environment. The manganese ores are hosted by limestones and predominantly composed of micro-to fine-crystalline rhodochrosite and massive hausmannite. An oxic depositional environment is indicated by the bulk rocks showing negative Ce anomalies (Ce/Ce* = 0.36–1.59, average = 0.89) from which the hausmannite was deposited, and subsequently replaced or encrusted by rhodochrosite. The manganese ores exhibit no significant Eu anomaly (Eu/Eu* = 0.72–1.18, average = 1.01), and are plot on hydrogenous area of SiO2 versus Al2O3 diagram, reflecting that the manganese was supplied dominantly from chemical weathering. A low sulfate freshwater sedimentary and early diagenetic environment is indicated by low Y/Ho and La/La* ratios for the bulk rocks or Mn carbonates, the absence of pyrite and sulfate minerals. Under such an environment, hausmannite was reduced by biogenic methane and organic matter to generate rhodochrosite as shown by two mixing trends with endmember δ13C values lighter than −70‰ and − 25‰, respectively. We report a rare case showing that strongly 13C-depleted Mn carbonate ore was formed in a freshwater lacustrine environment and can serve as a methane sink.
The trace element composition of galena provides important constraints on the genetic classification of Zn-Pb deposits. However, conventional binary discrimination diagrams are limited in complex multi-element geochemical signatures and often result in ambiguous interpretations. In this study, we compiled a global dataset comprising 1649 LA-ICP-MS analyses of galena from five major genetic types of Zn-Pb deposits, including skarn, epithermal, Mississippi Valley-type (MVT), volcanogenic massive sulfide (VMS), and sedimentary exhalative (SEDEX). Eight trace elements, including Zn, Cd, Cu, Ag, Sn, Sb, Tl, and Bi, were selected to construct a machine learning classification framework. The Random Forest machine learning model achieves a macro-averaged F1-score of 0.82, demonstrating good predictive performance. The SHapley Additive exPlanations (SHAP) analysis reveals that Tl, Bi, Sn, and Ag exert the greatest influence on model predictions, highlighting their diagnostic significance. The trained model was applied to three deposits with debated genetic affinities. The Huayangchuan and Xiyi deposits are classified as SEDEX type, whereas the Shuangjianzishan deposit is epithermal type, consistent with the geological characteristics of the deposits. The results of this study demonstrate that the galena trace element compositions are effective in Zn-Pb deposit classification.
The water-level-fluctuation zone (WLFZ) of reservoirs is a critical hotspot for cadmium (Cd) accumulation, yet the stabilization kinetics of exogenous labile Cd in these periodically inundated soils remain poorly understood, limiting accurate ecological risk assessment. This study integrated long-term field monitoring, laboratory incubation, and multi-model simulations in the Xiangxi River WLFZ of the Three Gorges Reservoir to investigate soil Cd dynamics and develop a predictive model for Cd stabilization. Results revealed pronounced spatial heterogeneity in soil properties and Cd distribution, with total Cd concentrations ranging from 0.31 to 2.06 mg/kg (mean: 0.64 mg/kg), nearly five times the local background value. The mean geo-accumulation index (1.61) indicated light-to-moderate pollution, primarily from historical agricultural non-point sources, though their relative contribution has declined. Spiked Cd bioavailability decreased in three stages, accurately described by a pseudo-second-order kinetic model (R2 > 0.90 for 86.4% of samples). By coupling this kinetic equation with a Gradient Boosting algorithm, a hybrid predictive model was developed that robustly simulated exogenous Cd stabilization (R2 = 0.862, RMSE = 0.024). This study clarifies the key drivers of Cd fate in WLFZ soils and provides a quantifiable tool to support long-term risk assessment and targeted management of Cd contamination.
Constraining the physicochemical conditions that govern lithium (Li) enrichment and the formation of Li-bearing clay minerals is critical for understanding the genesis of clay-type Li deposits. However, these conditions remain difficult to define because Li-bearing clay minerals commonly form through multistage fluid–rock interaction, and direct evidence for Li-bearing fluids is rarely preserved in clay-rich systems. To address this issue, this study investigates the hydrothermal fluid–rock interaction responsible for Li enrichment and Li-bearing clay formation in the Mesoproterozoic Wumishan Formation, through thermodynamic modeling using GEM-Selektor. Based on recalculated clay-mineral structural formulas and custom thermodynamic data, titration and leaching models were performed at 200 °C, 220 °C, 240 °C, and 260 °C and 1000 bar to evaluate the effects of temperature, fluid/rock ratio, and host-rock buffering. The results show that Li enrichment was controlled by staged hydrothermal alteration in a carbonate-dominated host system, governed by temperature, fluid/rock ratio, and carbonate buffering. In both models, mineral assemblages evolved systematically with reaction progress, and pH was strongly buffered by the carbonate host rocks. Li-rich smectite-rich illite/smectite mixed-layer (Li-I/smectite) formation was closely linked to pH evolution and occurred within a specific pH window of approximately 7.6–8.8 during fluid–rock interaction. Li-I/smectite was the only Li-bearing clay phase consistently resolved in both models, suggesting preferential stabilization within a restricted hydrothermal-geochemical window. These results provide a thermodynamic perspective on the favorable conditions for Li-bearing clay formation and offer a new approach for evaluating the ore-forming environment of clay-type lithium deposits.
Lead‑zinc mineralization in South China is commonly associated with Mid-Late Jurassic (∼170–150 Ma) magmatic activity. However, the genesis of many deposits lacking direct magmatic connections remains poorly constrained owing to limited geochronological data. The Hengyang Basin, located within the Qin-Hang Metallogenic Belt (QHMB, South China), hosts numerous PbZn deposits whose origins remain debated, with proposed models including magmatic-hydrothermal and Mississippi Valley-type (MVT) styles. The Liushutang deposit (1.36 Mt at 0.85% Pb and 4.49% Zn) is a representative example. Its mineralization comprises three stages: (I) quartz-pyrite, (II) quartz-pyrite-chalcopyrite-galena-sphalerite (main ore stage), and (III) quartz-barite-sphalerite. Integrated geological, mineralogical, and isotopic evidence, including fault-hosted vein geometry, pervasive silicification, a quartz-barite-sulfide assemblage with chalcopyrite and tetrahedrite, magmatic-like HO isotopic signatures, and extremely high Rb/Sr ratios (mean 839) of hydrothermal roscoelite, collectively points to a magmatic-hydrothermal origin for Liushutang. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) data show that Ga enrichment in sphalerite (up to 857 ppm) results primarily from lattice incorporation via Cu-coupled substitution under high-salinity conditions associated with phase separation triggered by rapid fluid depressurization. The Stage II roscoelite RbSr isochron age of 105.8 ± 5.4 Ma (MSWD = 1.3) constrains the timing of PbZn mineralization and clearly distinguishes it from the ∼158 Ma Mid-Late Jurassic magmatic-hydrothermal PbZn deposits (e.g., Kangjiawan and Shuikoushan) in the Hengyang Basin. Although no coeval intrusions are exposed at Liushutang, geophysical data indicate the presence of concealed intrusions beneath the deposit. This ∼106 Ma age coincides with a regional extensional tectonic regime (ca. 135–80 Ma) that caused lithospheric thinning, asthenospheric upwelling, and the formation of NE-trending pull-apart basins, collectively providing the thermal driver and structural permeability for ore formation. Consequently, the Hengyang Basin records two distinct episodes of magmatic-hydrothermal PbZn mineralization: Mid-Late Jurassic and Early Cretaceous, with the Liushutang deposit exemplifying the latter. This finding reveals a previously underrecognized Early Cretaceous magmatic-hydrothermal metallogenic episode in the QHMB and provides a valuable framework for regional exploration by highlighting the roles of concealed intrusions and extensional tectonic settings in PbZn ore formation and critical metal (Ga) enrichment.
The Carajás Mineral Province in the Amazonian Craton hosts the world's oldest known world-class IOCG deposits (ca. 2.72–2.68 and 2.55 Ga). At the northern part of the province, iron-rich rocks containing magnetite and a distinctive CaFe- and KFe-rich silicate assemblage (garnet, amphibole, and biotite) envelop the copper‑gold ore within the IOCG deposits that are hosted by the Cinzento Shear Zone (e.g., Salobo, GT-46, QT-02, Furnas). Although these Fe-rich assemblages clearly predate IOCG mineralization, their origin remains debated, with interpretations attributing its formation to either ore-forming hydrothermal processes or metamorphism. This study integrates petrography, electron probe microanalysis, δ18O and δD isotopes, and LuHf and SmNd garnet geochronology to unravel the processes responsible for iron-rich rocks within the IOCG deposits along the Cinzento Shear Zone. The results indicate that early metasomatic minerals (spessartine, Ca-amphibole, Ti-rich biotite, and sillimanite) formed prior to the Fe-rich assemblage observed today. Garnet LuHf apparent ages of ca. 2.64 Ga in Salobo and GT-46 indicate crystallization prior to the main IOCG mineralizing event, whereas ca. 2.55 Ga SmNd data record complete isotopic resetting by IOCG fluids. At QT-02, similar LuHf (2546 ± 19 Ma) and SmNd dates (2527 ± 38 Ma) suggest syn-shear garnet growth at limited fluid circulation. The presence of spessartine, representative of primary garnet compositions, meta-BIFs, tourmaline-rich zones and garnet-sillimanite-rich rocks, together with the record of fluids derived from mixed magmatic and seawater sources, suggest the development of ancient exhalative systems within the Carajás Province. The early metasomatic paragenesis formed through the modification of subseafloor Fe-Mn-rich sediments and phyllic/argillic hydrothermal halos. This modification resulted from a combination of thermal input from the emplacement of sublithospheric melts, widespread magmatism and early IOCG-related fluids (ca. 2.72 Ga). Subsequently, hot (640 °C to 350 °C) K- and Fe-rich IOCG hydrothermal fluids at ca. 2.55 Ga, lead to the formation of substantial volumes of almandine-grunerite and Fe-biotite zones, which are recognized in these IOCG deposits as characteristic ore envelopes. The protracted thermal evolution of the province culminated in lithospheric weakening and strain localization, which facilitated the development of large-scale structures such as the Cinzento Shear Zone. These structures, in turn, channeled hydrothermal fluid and exerted primary control over the distribution of IOCG mineralization.
The development of safe, high-energy-density solid-state lithium metal batteries is a paramount goal in energy storage research. Solid polymer electrolytes (SPEs) play a pivotal role in this endeavor. Still, they are fundamentally constrained by the intrinsic limitations of conventional homopolymers, such as poly(ethylene oxide), which suffer from low ionic conductivity and poor electrode-electrolyte interfacial stability. In contrast to the solvation engineering paradigm effective for liquid electrolytes, a transformative strategy for SPEs lies in the topological engineering of the polymer host. This review systematically elaborates how controlled/living polymerization techniques, such as reversible addition-fragmentation chain-transfer polymerization, atom transfer radical polymerization, ring-opening (co)polymerization, and click chemistry, enable the precise synthesis of polymers with well-defined topologies, including linear, graft, star, hyperbranched, and crosslinked networks. Specifically, linear and block architectures enable sequence-controlled organization and microphase-separated ion pathways; graft and star polymers suppress crystallization and increase free volume and segmental mobility; hyperbranched structures provide dense coordination sites and short transport distances; and crosslinked networks reinforce the electrolyte and stabilize interfaces while preserving continuous ion-conducting domains. We provide an in-depth analysis of how these tailored architectures synergistically enhance ionic conductivity, Li+ transference number, and electrochemical stability by suppressing crystallization, inducing nanoscale microphase separation to form continuous ion-conduction pathways, and directly modulating the Li+ coordination environment. A special focus is placed on the role of topological design in stabilizing the solid-solid interface. Furthermore, we detail the integration of these synthetic methodologies via in-situ polymerization, a transformative strategy that concurrently constructs tailored topological structures within the battery cell and dramatically reduces interfacial impedance. Finally, we highlight some of the exceptional electrochemical performance SPEs from the fast charging and long-term cycling to the intrinsic safety, which employ this topological engineering, and we conclude with perspectives on future research directions, thereby providing a clear blueprint for designing next-generation polymer electrolytes from molecular architecture to device application.
Increasing environmental concerns highlight the need to transition from petroleum to renewable, sustainable resources for the fabrication of carbon-neutral products. Cellulose, the most abundant natural polysaccharide on Earth, serves as a fundamental structural component in plants and offers immense potential for a wide range of human applications. Moving beyond conventional dissolution-regeneration processes, the ionic modification of cellulose has emerged as a key strategy to enhance its functionality. This approach yields derivatives that can be categorized into anionic, cationic, and zwitterionic/amphoteric types, many of which are already widely commercialized. Beyond differences in the polarity of the charged groups, variations in their interactions with ions and molecules confer distinct functionalities. Therefore, this review systematically summarizes the types and structures of various ionic cellulose derivatives (including nanocellulose), outlining typical ionic modification routes including oxidation, esterification, etherification, and grafting reactions that target hydroxyl groups on the cellulose backbone. We further examine the charge-governed properties of these materials, such as biological activity, surface wettability, stimulus responsiveness, ion exchange capacity, ion regulation, and energy dissipation. Notably, this review places emphasis on analyzing how these properties determine performance across diverse applications, including biomedical engineering, energy storage/conversion, environmental remediation, sensors, and actuators. Finally, we identify current challenges in the field and outline future opportunities for the rational design and advanced application of ionic cellulose derivatives. We hope this review will bridge the gap between ionic cellulose derivatives and their practical applications.
Excessive amounts of ammonium (NH4+) can trigger the occurrence of eutrophication, algal blooms and diseases. Hence, identifying the causes of NH4+ pollution is crucial for protecting water resources and the ecological environment. Although the causes of high NH4+ concentrations have been extensively studied, whether the dissimilatory nitrate reduction to ammonium (DNRA)-mediated conversion of nitrate (NO3−) to NH4+ results in ammonium pollution remains uncertain. In this work, the source of NH4+ in groundwater of the Yangtze Estuary was identified through the integration of nitrogen isotopic abundance, microbial communities and nitrogen (15N) isotope tracer analysis techniques. The contributions of introduced NO3− to NH4+ via DNRA were simulated through labelling experiments. Our results revealed that the DNRA rates in groundwater ranged from 0.261 to 0.362 μmol/L/h and exceeded those of nitrification, denitrification and anammox. Both the isotopic abundance and microbial communities indicated that DNRA is a critical factor contributing to the NH4+ concentration in groundwater of the Yangtze Estuary. The results of a simulation experiment revealed that the proportions of the DNRA rate to the total NO3− reduction and accumulation rates of NH4+ at different concentrations of K15NO3 (0.5, 1, 5, 10, 30 and 60 μmol/L) ranged from 67.04% ~ 80.78% and 0.163–0.506 μmol/L/h, respectively. Therefore, introduced NO3− could significantly contribute to NH4+ via DNRA in groundwater of the Yangtze Estuary. Notably, the contribution increased (y = 2.318ln(x) + 70.424, R2 = 0.782) with increasing NO3− input concentration. The input of NO3− in global DNRA-active areas should be considered, especially inputs from anthropogenic activities. Our results could advance our understanding of anthropogenic influences on groundwater contamination.
