Search Results (2,713)

Conventional heavy metal remediation technologies are constrained by low efficiency, secondary pollution risks, and limited scalability. Dissolved organic matter (DOM), with its green, cost-effective complexation properties, has become a promising pathway for pollution control. Existing patent bibliometric studies in this field suffer from single-database bias, limited causal quantification of policy impacts, and incomplete depiction of global–local technological heterogeneity. To address these gaps, this study maps the technological innovation landscape of DOM interactions with four typical heavy metals (Cd, Pb, Cu, Zn) during 2004–2024, using a complementary dual-database framework combining Derwent and IncoPat. We integrate a three-dimensional “time–region–technology” analytical framework with interrupted time series analysis (ITSA), after standardized data processing including family deduplication and citation normalization. Cross-validation confirms that China contributes the largest share of global patent output (46.6% in Derwent, 55.0% in IncoPat). Three milestone environmental policies in China exert sequentially intensifying causal effects on patent growth (all p < 0.05), forming a closed-loop mechanism of policy orientation, funding support, technology transfer, and international diffusion. We identify a pronounced global–local technological divergence: global frontier innovation centers on digital basic research, whereas local innovation in China prioritizes engineering applications. Core patents advance the field through cross-domain technology adaptation, and the representative technical paradigm (exemplified by patent CN101168852A) has been industrially validated. These findings provide empirical support for engineering translation and policy optimization in DOM-based heavy metal remediation. Full article

Whether zinc (Zn) and copper (Cu) bioaccumulation in the Pacific oyster (Magallana gigas) reflects toxicological stress or is an incidental consequence of growth remains unclear. We cultured three commercial triploid M. gigas stocks for approximately one year, sampling gill and hepatopancreas at the start and end of this period, when Zn/Cu burden was naturally low and high, respectively. Pooled samples from both time points were profiled by whole-transcriptome sequencing, enzyme activity and oxidative damage assays, qPCR validation, and protein–protein interaction network analysis. Transcriptome-wide changes in both tissues tracked the culture period, but growth and Zn/Cu burden were too highly collinear (r = 0.92–0.98) to separate statistically. Critically, of the four metals measured (Zn, Cu, iron [Fe], and manganese [Mn]), only Zn and Cu increased with growth, whereas Fe and Mn did not, indicating metal-specific rather than generalized accumulation. Superoxide dismutase (SOD) activity and the transcript abundance of its copper/zinc isoform (Cu/Zn-SOD) increased with growth in both tissues, whereas catalase (CAT) activity was unchanged and glutathione peroxidase (GPX) activity rose only in gill. Malondialdehyde (MDA), a marker of oxidative damage, increased in both tissues. Gill mounted a broader response than hepatopancreas, including upregulation of KEAP1 alongside downregulation of detoxification, proteostasis, and ribosome-related genes. Stock-level qPCR further revealed stock-dependent regulation of antioxidant genes in hepatopancreas. Together, these results indicate that Zn/Cu bioaccumulation in M. gigas co-varies with growth in a metal-specific manner, consistent with cofactor demand for Cu/Zn-SOD. The accompanying oxidative and proteostatic changes therefore more plausibly reflect growth physiology than an independent pollutant signal. Full article

The disposal of stone mine tailings (SMTs) near agricultural lands has become a major environmental concern because of their elevated concentrations of environmentally hazardous metals (EHMs). The minimization of the potential detrimental effects of soil pollution on crop cultivation and food safety are the major concerns in modern agricultural practice. Vermitechnology has emerged as a sustainable bioconversion approach for biotically stabilizing mine tailings into a nature-friendly organic amendment. However, the agronomic potential and environmental safety of vermiprocessed stone mine tailings remain poorly understood. To fill this research gap, this study assessed the effectiveness of mine-tailing-derived vermicompost as an organic amendment for Solanum lycopersicum L. (tomato) cultivation. Vermicompost was prepared from both inorganic mine tailings and organic cow dung (1:1 and 2:1 ratios, w/w) together using earthworm Eisenia fetida species. The results demonstrated that the treatment amended with 1:1 vermicomposted tailings supplemented with the recommended dose of chemical fertilizer (T3) outperformed all other treatments by enhancing soil microbial activity, the concentration of bioavailable NPK, improved fruit yield, different biochemical parameters, and reduced post-harvest bioavailable Cr, Ni, Cu, Pb, and Cd concentration. Severity Adjustment Margin of Exposure (SAMOE) analysis indicated estimated dietary risk (Class 5) for Cr (VI) and Cd in tomatoes grown on untreated mine tailings, whereas vermicompost-amended treatments reduced the risk to low or negligible levels. Overall, the findings suggest that vermicomposted stone mine tailings emerged as a potential complementary soil amendment and an eco-friendly strategy which improve crop growth while reducing metal availability and its associated health risks. Full article

Cellulose acetate (CA) is a promising bio-derived membrane material for water treatment; however, its limited availability of active functional sites can restrict its affinity toward dissolved pollutants. In this study, a cellulose acetate membrane was fabricated by phase inversion and subsequently functionalized through novel direct graft copolymerization with bio-based itaconic acid (IA) using potassium persulfate (KPS) as an initiator in an aqueous medium. The grafting approach introduced carboxylic functional groups into the CA matrix, providing additional active sites for pollutant removal. The successful grafting was confirmed by UV–Vis and 1H NMR spectroscopy, while XRD indicated changes in the structural organization of the polymer matrix. SEM/EDS characterization further revealed morphological changes associated with grafting, and cross-sectional SEM showed the development of finger-like, continuous pore channels within the modified membrane. The effects of reaction time, IA concentration, and KPS concentration on the grafting percentage were systematically evaluated, with grafting increasing up to an optimum range before declining at excessive monomer or initiator concentrations. Thermal analysis demonstrated improved stability after grafting, with the 6.6% grafted CA-g-IA membrane exhibiting an initial decomposition temperature of 351 °C and a reduced weight loss of 85% at 500 °C, compared with 344 °C and 91%, respectively, for pristine CA. The 6.6% CA-g-IA membrane was subsequently evaluated for the removal of Cu(II) and methylene blue (MB) from aqueous solutions. Cu(II) uptake was strongly influenced by contact time, solution pH, initial concentration, and grafting percentage, with the highest performance observed around pH 6 and 240 min contact time. The membrane also maintained its Cu(II)-binding performance over four regeneration cycles following HNO₃ treatment. Overall, direct IA grafting provides a simple bio-based functionalization strategy for enhancing the pollutant-binding functionality of cellulose acetate membranes, demonstrating potential for the removal of metal ions and cationic dyes from contaminated water. Full article

Lake sediments act as important sinks for heavy metals and microplastics, yet the mechanisms governing their enrichment, coexistence, and combined ecological risks remain insufficiently understood. This study investigated sediments from Daihai Lake, China, systematically characterizing the occurrence features of microplastics (morphology, size, and composition) and their associated heavy metal contents. A composite pollution risk framework (Multi Feature Potential Ecological Risk Index) was developed to evaluate microplastics–heavy metals interactions using correlation analysis, principal component analysis, and cluster analysis. In addition, a two-dimensional pollution index was applied to assess combined ecological risks. Results showed that MP abundance ranged from 6.60 to 26.80 n·g⁻¹, with a decreasing trend from southwest to northeast. Microplastics were dominated by fragments, with a high proportion of small particles (<0.25 mm), and were mainly composed of polyethylene terephthalate and polypropylene. The average concentrations of heavy metals in sediments were ranked as follows: Mn (863 ± 78 mg·kg⁻¹); Cr (124 ± 28 mg·kg⁻¹); Zn (86 ± 17 mg·kg⁻¹); Ni (43 ± 10 mg·kg⁻¹); Cu (36 ± 0.1 mg·kg⁻¹); Pb (23 ± 5 mg·kg⁻¹); As (15 ± 4 mg·kg⁻¹); and Cd (0.20 ± 0.04 mg·kg⁻¹). The two-dimensional comprehensive index values ranged from 124 to 1032, with an average value of 365.0, exceeding the risk threshold (>100). Approximately 70% of sampling sites exhibited high composite pollution risks. Small-sized and fibrous microplastics showed significant positive correlations with multiple heavy metals, indicating strong carrier effects. Full article

The concentrations of 18 chemical elements were determined in the upper soil horizons within the landscapes of river basins in the Eastern Caucasus, using the Ulluchay, Sulak, Sunzha, Samur, Shuraozen (Russia), Karachay, and Atachay (Azerbaijan) rivers as case studies. This research aims to provide an ecological and geochemical assessment of soil conditions in the mountain river basins of the Eastern Caucasus. The ecological status of the soils is largely governed by elevated concentrations of such elements as Zn, Ni, Cu, Mo, As, and Cr, which exhibit both accumulation tendencies and potential toxicity. Environmentally unfavorable areas were identified through an integrated scoring assessment that incorporates the values of four ecological and geochemical indices: the modified contamination factor (mCf), the Pollution Load Index (PLI), the Potential Ecological Risk Index (PERI), and the total contamination index (Zc). According to each index, more than half of the study area is classified as uncontaminated. Low PLI values were recorded for 54% of the sampling sites, and low mCf values for 63%. Based on PERI and Zc, 82% of the sampling sites are categorized as uncontaminated. The integral scoring assessment enabled the delineation of more than a dozen environmentally unfavorable areas, with the highest concentrations observed in the Atachay and Karachay basins, spatially extensive in the Sunzha basin. The formation of environmentally unfavorable zones in terms of soil contamination is primarily driven by natural factors, including lithological conditions, climatic features, complex topography, and the directions of waterborne and mechanical migration. Anthropogenic factors contribute to a lesser extent to the development of high-contamination zones and exert only localized influences near major settlements. The results can be applied to mitigate public health risks and to promote sustainable development of mountain river basins. Targeted measures are proposed for the sustainable management of contaminated areas, including restrictions on agricultural activities and the use of drinking water sources. Full article

Agricultural soils in arid regions require assessment approaches that separate local element enrichment from actual ecological and human health relevance. Here, a site-prioritization framework is applied to potentially toxic elements (PTEs) in agricultural soils from Onaizah, central Saudi Arabia. The approach combines contamination indices, ecological-risk screening, deterministic health-risk estimates, Monte Carlo resampling, and relative ranking of management priorities. A total of 33 surface-soil samples collected from cultivated farms were examined for As, Co, Cr, Cu, Mn, Ni, Pb, V, and Zn. The measured concentration ranges (mg/kg) were 1–5 (As), 1–12 (Co), 10–53 (Cr), 4–38 (Cu), 107–541 (Mn), 6–54 (Ni), 2–23 (Pb), 8–47 (V), and 11–168 (Zn). Based on their mean concentrations, the investigated elements decreased in the following sequence: Mn > Zn > Cr > Ni > V > Cu > Pb > Co > As. The P_N values ranged from 0.127 to 1.339, indicating 27 safe sites, 2 warning-line sites, and 4 slightly polluted sites, mainly controlled by localized Zn enrichment and, in one case, Pb. In contrast, mCd values of 0.099–0.676 indicated nil to very low contamination, while RI values of 2.743–15.701 confirmed low ecological risk across all samples. Non-carcinogenic risk was generally below the threshold of concern, with HI values of 0.204–1.018 for children and 0.024–0.119 for adults. Only one site showed a marginal child HI exceedance, emphasizing localized rather than widespread health concern. Children showed approximately 8.6-fold higher non-carcinogenic risk than adults, with Mn, Cr, As, and V as the main contributors. The total LCR values for As, Cr, and Pb ranged from 7.79 × 10⁻⁶ to 4.07 × 10⁻⁵ for children and from 3.48 × 10⁻⁶ to 1.82 × 10⁻⁵ for adults, within the commonly tolerable range of 1 × 10⁻⁶ to 1 × 10⁻⁴. Chromium was the dominant contributor to LCR. Monte Carlo resampling supported the deterministic risk classification, with only a 3.1% probability of child HI exceeding 1 and no simulated exceedance of the LCR threshold for either children or adults. From the standpoint of sustainable soil management, site 7 should undergo further health-risk assessment, while sites 30 and 33 require source verification and periodic monitoring before any remediation action is considered. Full article

This study provides baseline information for environmental assessment in North Riyadh, Saudi Arabia. It assessed the concentrations of eight heavy metals, namely cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), lead (Pb), vanadium (V), and zinc (Zn), in 28 surface soil samples collected across the area. Pollution status was evaluated using the contamination factor (CF), geoaccumulation index (Igeo), enrichment factor (EF), pollution load index (PLI), and degree of contamination (DC), while Pearson correlation, principal component analysis (PCA), and standardized hierarchical cluster analysis (HCA) were applied to identify the possible sources of these metals. Iron was the most abundant element (mean 8482.14 mg kg⁻¹), consistent with its role as a major crustal constituent. Co, Cr, Fe, Ni, and V showed low contamination (CF < 1) and a predominantly geogenic origin, reflected in strong inter-element correlations and a dominant rotated principal component explaining 54.8% of the total variance; Cu, Pb, and, in particular, Zn departed from this pattern, loading together on a distinct secondary component (32.1% of variance) and showing localized enrichment at a small number of sites. None of the 28 samples exceeded the pollution threshold for PLI (all < 1) or DC (all < 8), indicating that the soils of North Riyadh remain overall unpolluted with respect to these eight metals. These findings provide an early geochemical baseline for the district and identify Cu–Pb–Zn enrichment near construction and traffic corridors. Full article

In the present work, polyvinylpyrrolidone (PVP) was selected as the primary raw material and fully dissolved in N,N-dimethylformamide (DMF) solvent. Hydroxymethyl cellulose (HMC), acrylic acid (AA) monomer with outstanding chelating performance, and UR were added in sequence. On this basis, composite nanofiber membrane substrates of PVP/AA/HMC/UR were fabricated by means of electrospinning. Afterwards, silane coupling agent KH-560 was blended with polylactic acid (PLA). A uniform PLA/KH-560 functional coating was covered on the surface of the as-prepared nanofiber membrane via microfluidic coating treatment, and the target composite nanofiber adsorbent was ultimately obtained. Relevant performance characterization results indicated that moderate addition of HMC could greatly optimize the tensile strength of the membrane material, whereas excessive HMC dosage would cause a deterioration in mechanical strength. Moreover, the breaking elongation presented a slight declining trend, and the integrated mechanical stability of the membrane could fully meet the service demands for cyclic reuse. As a functional monomer, acrylic acid effectively boosted the material’s adsorption performance toward typical heavy metal ions, including Zn²⁺, Cu²⁺ and Pb²⁺. In simulated acidic wastewater generated from rare earth mining and extraction (pH = 3 and pH = 6.5), the removal efficiency of the as-prepared material for the three heavy metal ions all exceeded 95%. Even after being soaked in strong acid solution at pH 2 for 8 h, its adsorption rate was still maintained at 88.5%. In the cyclic experiment, the adsorption efficiency stayed above 75% after two recycling runs, decreased to roughly 55% in the third cycle, and dropped below 30% at the fourth reuse stage. The introduction of UR imparted remarkable acid-resistant structural stability to the composite material. The membrane structure remained complete without damage after long-term immersion in a pH 2 strong acid environment, and high-efficiency heavy metal removal capability could be guaranteed when the solution pH was not lower than 3. Targeting the practical treatment dilemma of acidic heavy metal-containing wastewater from rare earth exploitation and extraction, this research successfully developed a novel eco-friendly adsorbent featuring superior acid resistance, high adsorption performance and certain recyclability. This newly designed material makes up for the deficiencies in traditional adsorbents represented by activated carbon, including poor heavy metal removal ability in acidic media and secondary pollution risks resulting from disposable use. The research findings can offer a novel technical reference and feasible approach for the purification of acidic rare earth wastewater in practical engineering applications. Full article

Heavy metal wastewater, characterized by high toxicity, poor biodegradability, and strong bioaccumulation potential, poses a serious threat to the ecological environment and human health. Conventional chemical treatment methods are costly and prone to secondary pollution. In contrast, using solid waste to prepare environmental functional materials for “waste control by waste” has emerged as a research hotspot in the field of synergistic water pollution control and resource recovery. This review systematically consolidates the sources, physicochemical properties, and compositional characteristics of typical industrial solid wastes—including red mud, electroplating sludge, fly ash, copper slag, and blast furnace slag—and elucidates how compositional variations constrain the selection of functionalization pathways. On this basis, key preparation techniques, namely hydrothermal synthesis, surface modification/impregnation, thermal treatment, geopolymerization, and sol–gel/polymerization, are critically reviewed and compared in terms of product structural regulation, process complexity, and engineering scale-up potential. Subsequently, the adsorption performance of the resultant materials toward heavy metals such as Pb²⁺, Cu²⁺, Cr(VI), As(VI), Cd²⁺, Ni^2+, and Zn²⁺ is discussed, with particular emphasis on the pronounced effects of pH, temperature, initial concentration, coexisting ions, and adsorbent dosage on adsorption capacity. Notably, Pb²⁺ exhibits the highest adsorption capacity, whereas the removal of Cr(VI) and As(V) is strongly governed by the positive charge density and reduction efficiency of the material surface. In quinary heavy metal competitive systems, marked differences in the affinity of adsorption sites toward distinct metal ions have been observed. Mechanistic analysis identifies ion exchange, surface complexation, electrostatic attraction, and redox reactions as the predominant removal pathways. This review further incorporates engineering-oriented assessments, including multi-component competitive adsorption, fixed-bed column operation, and regeneration stability, and identifies the critical bottlenecks currently impeding the transition from laboratory-scale research to practical implementation—namely, performance instability arising from feedstock variability, attenuation of adsorption capacity during prolonged operation (with a 10–40% decline over 5–10 cycles), underdeveloped regeneration and recovery routes, and a systemic deficiency in techno-economic analysis and life-cycle assessment data. Finally, future research directions are proposed, emphasizing the development of low-carbon and energy-efficient preparation technologies, the promotion of synergistic valorization of multiple solid wastes alongside critical metal recovery, and the advancement of this field toward engineering applications through artificial intelligence-assisted design and life-cycle assessment, thereby furnishing theoretical references and technical support for the integrated management of industrial solid waste resource utilization and heavy metal wastewater treatment. Full article

Biogas slurry can enhance soil fertility, but the heavy metals it contains may pose potential ecological risks to soil-crop systems. To mitigate heavy metal pollution resulting from the application of biogas slurry to soil, this study investigated potential remediation strategies through the use of blended biochar application. In this study, soil incubation experiments were conducted to evaluate the immobilization performance of cow dung biochar (CB), corn straw biochar (SB), and blended biochar (cow dung + corn straw) (C3S7, C5S5, and C7S3) toward Pb, Zn, Ni, Cr, Cu, As, and Cd under different biogas slurry ratios (Z0, Z1:8, and Z1:4). The results concluded that immobilization efficiency consistently followed the order C7S3 ≥ C5S5 > C3S7 > CB ≈ SB, indicating that the blended biochar generally outperformed the two single biochar in the biogas slurry-irrigated soil system. Batch adsorption experiments showed that adsorption of all metals was better described by the pseudo-second-order model (R² > 0.94). Isotherm fitting further indicated that Zn, Ni, Cr, Cu, and Cd were better fitted by the Langmuir model, whereas Pb and As were better fitted by the Freundlich model. Physicochemical characterization, scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM–EDS), and Fourier transform infrared spectroscopy (FTIR) analyses collectively suggested that the superior performance of blended biochar was associated with the integration of mineral-related characteristics from CB and surface chemical properties from SB, which together enhanced the synergistic fixation of coexisting metals. Consistently, biochar application reduced the potential ecological risk index (RI) of bioavailable heavy metals in soil, with blended biochar showing lower RI values than CB and SB. C7S3 exhibited the best performance in all treatments, highlighting the potential of blended biochar as an effective amendment for mitigating multi-metal pollution risks with biogas slurry utilization. Full article

Industrial parks are hotspots of potentially toxic element (PTE) pollution, yet single-medium assessments fail to capture atmospheric contamination and source-specific risks. This study integrated soil–leaf analysis with quantitative source apportionment to evaluate PTE pollution in a chemical industrial park in China’s lower Yangtze River region. Soil and Photinia serratifolia leaf samples from 31 sites were analyzed for eight PTEs using the Pollution Load Index (PLI), Enrichment Factor (EF), Bioconcentration Factor (BCF), and Foliar Capture Rate (FCR). Principal Component Analysis–Multiple Linear Regression quantified source contributions to concentrations and risks. Results revealed moderate soil contamination (PLI = 1.43) with localized enrichment of As, Cd, Cu, and Zn (EF > 5). Element-specific pathways differed markedly: Cd, Zn, and Cu showed patterns consistent with relatively greater soil-related uptake contributions (BCF = 0.85–1.12; FCR < 25%), whereas As, Cr, Ni, and Pb exhibited patterns suggestive of stronger atmospheric deposition influences (BCF < 0.5; FCR = 54–78%). Four sources were identified, with chemical manufacturing contributing 53% of the ecological risk and 55% of the carcinogenic risk and thermal power generation accounting for 67% of the non-carcinogenic risk. Ecological risk was low (Risk Index = 113) and non-carcinogenic risk was negligible (Hazard Index = 0.0646), but carcinogenic risk was non-negligible (Carcinogenic Risk = 1.43 × 10⁻⁵). This study demonstrates that foliar bioindicators can provide indicative evidence of atmospheric contamination and that source contributions to risk differ substantially from mass contributions, providing a methodological framework for targeted pollution control. Full article

Heavy metal/loid (HM) pollution of soils, primarily as a consequence of mining and ore-processing activities, poses significant risks to ecosystems and human health. Soil microbial communities play essential roles in maintaining key ecosystem functions, including nutrient cycling, carbon sequestration, and soil stability. The purpose of this study was to characterize the taxonomic composition and diversity of bacterial communities and evaluate their functional adaptation to heavy metal stress in soils affected by long-term gold–copper mining activities in Bulgaria. Ten soil samples representing a Cu pollution gradient (53–860 mg kg⁻¹) were categorized into five pollution classes. High-throughput sequencing of 16S rRNA gene amplicons revealed the dominance of the phyla Pseudomonadota (mean relative abundance 32%), Acidobacteriota (22%), and Actinomycetota (16%). At the class level, Alphaproteobacteria (18%), Terriglobia (16%), and Gammaproteobacteria (14%) were the most abundant taxa, indicating their adaptation to long-term heavy metal contamination. The genus Z2-YC6860 exhibited significant tolerance to Cu, whereas Bradyrhizobium_503372 was negatively associated with As and Zn concentrations. Functional predictions suggested enrichment of key pathways related to heavy metal resistance, including efflux systems and detoxification. The study design spans a broad Cu pollution gradient across river-associated and industrially impacted sites, providing an ecologically relevant framework for evaluating microbial responses to long-term metal stress. Full article

The Murmansk Region (the Russian Arctic) faces severe environmental degradation due to heavy metal (HM) pollution from copper–nickel smelting, resulting in vast industrial barrens with elevated concentrations of copper (Cu) and nickel (Ni). Conventional phytostabilization methods are often ineffective or costly, necessitating alternative bioremediation strategies. This study evaluates the potential of microalgae and cyanobacteria for revegetating HM-contaminated substrates. Six strains of Nostoc-like morphotypes and three green microalgae were tested for Cu²⁺ tolerance (0.5–15 mg/L). While most strains exhibited growth inhibition at ≥3 mg/L Cu²⁺, Atlanticothrix sp. KPABG-154445, isolated from Tolbachik Volcano, showed positive growth at 2 mg/L Cu²⁺ under the tested conditions and recovering metabolic activity post-exposure. In sorption experiments, non-viable biomass achieved 68% Cu²⁺ removal at 2 mg/L, outperforming actively growing cultures. A microcosm experiment using copper-spiked nepheline slime (simulating mining waste) revealed Atlanticothrix sp. KPABG-154445’s ability to colonize nutrient-poor substrates, forming biocrusts covering 42% of the surface within one month, even under Cu²⁺ contamination (10 mg/kg). These findings highlight cyanobacteria, particularly strains such as KPABG-154445, as promising agents for the bioremediation of Arctic industrial barrens, leveraging their dual capacity for heavy metal tolerance and biocrust formation. Full article

4-Chlorophenol (4-CP) is a persistent and highly toxic pollutant commonly found in groundwater. However, its efficient degradation remains challenging due to the rapid agglomeration of conventional zero-valent iron (ZVI) nanoparticles, their narrow pH operating range, and the environmental risks associated with synthetic chelating agents. To address these limitations, this study presents a rationally designed catalytic system integrating cyclodextrin polymer (CDP)-supported bimetallic Cu-Fe nanoparticles (Cu-Fe-CDP) with citric acid (CA) as a green complexing agent. The porous CDP matrix effectively mitigates nanoparticle agglomeration and provides abundant active sites, while the Fe-Cu bimetallic coupling accelerates electron transfer and iron corrosion. Critically, CA acts as a biocompatible ligand that sustains Fe(II)/Fe(III) redox cycling, expands the effective pH range, and enhances hydroxyl radical (·OH) generation. The system achieves 92.13% degradation of 4-CP within 80 min at pH 9.0 and nearly complete removal at pH values between 3.0 and 7.0. Mechanistic studies, including electron paramagnetic resonance (EPR) spectroscopy and radical quenching tests, confirm the dominance of ·OH radicals (82.67% inhibition by TBA) and the essential role of surface Fe(II)/Fe(III) cycling. The catalyst exhibits excellent reusability, broad-spectrum activity toward multiple pollutants, and sustained performance in real water matrices and long-term column tests with minimal metal leaching. This work demonstrates a chemically robust strategy for chlorophenol remediation using green citric acid and biodegradable CDP without exogenous oxidant addition, showing promise for further development toward practical applications. Full article