The widespread presence of Cu(II) in the environment poses a significant threat to ecosystems, driving the need for efficient removal technologies. Adsorption using low-cost biochar offers a promising approach. In this study, a magnetic biochar composite (MGBC) was synthesized from Ginkgo biloba leaves via high-temperature pyrolysis combined with KOH activation and Fe3O4 magnetization. Its performance in removing Cu(II) from aqueous solution was systematically evaluated. Characterization by SEM-EDS, BET, FT-IR, and XRD showed that MGBC possesses more oxygen-containing functional groups, a higher specific surface area and pore volume, and a smaller pore size than the non-activated biochar (GBC). Consequently, MGBC improved the Cu(II) removal rate by 65.34 % relative to GBC. After five cycles of magnetic recovery, MGBC retained a high removal rate of 73.01 +/- 0.52 %. The adsorption process followed the pseudo-second-order kinetic and Langmuir isotherm models, indicating monolayer chemisorption. The maximum theoretical adsorption capacity at 318 K was 64.66 +/- 3.99 mg/g. Thermodynamic analysis confirmed that the process was spontaneous and endothermic. Owing to its high saturation magnetization (17.55 emu/g), MGBC could be readily separated from solution. Mechanistic analysis, supported by XPS, revealed that removal occurred through pore filling, electrostatic attraction, complexation, and redox reactions. Thus, MGBC is a simple, eco-friendly, highly effective, and recyclable adsorbent with strong potential for heavy metal remediation in wastewater.

The herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA) poses a significant threat to aquatic organisms and human health due to its resistant biodegradability. It is urgent to develop efficient removal methods for MCPA, especially advanced oxidation technologies based on metal organic frameworks (MOFs) catalysts. This study aims to remove MCPA by catalyzing peroxymonosulfate (PMS) with Co@MOF-808(C) and optimizing the catalytic degradation conditions with the Central Composite Design (CCD) of Response Surface Methodology (RSM). In addition, the reusability of Co@MOF-808(C) and the mineralization effect of MCPA, along with the potential degradation pathway of MCPA and the ecotoxicity of the degradation intermediates, were investigated. Results revealed that temperature, catalyst concentration, and PMS had significant impacts on MCPA degradation, and the optimal conditions were Co@MOF-808(C) 625mg·L⁻¹, PMS 5.85mM, pH 4.0, 45 ℃ and rotate speed 236rpm. The total organic carbon removal efficiency of 85.9% and MCPA degradation rate of 98.1% were oobtained under the optimal conditions, and the degradation rate remained as high as 94.4% when the catalyst was reused five times. The contribution rate of reactive oxygen species (ROS) for MCPA degradation was SO4·− (77.8%) > ·OH (18.5%) > O2·− (3.7%), and the degradation pathways included decarboxylation, hydroxylation and ring opening. Moreover, the ecotoxicity of MCPA was significantly reduced after the degradation by Co@MOF-808(C)/PMS system. In consequence, the Co@MOF-808(C)/PMS process may be an efficient alternative for treating MCPA wastewater.

The development of efficient and recoverable materials for synergistic purification represents a key challenge in treating toxic dye wastewater. Herein, a magnetic biochar (Fe-GBC) was synthesized from ginkgo leaf waste via K2FeO4 impregnation and pyrolysis, and then composited with g-C3N4 through ball-milling to obtain Fe-GBC/gC3N4 composites. Their structure, morphology, and photoelectrochemical properties were systematically characterized. The composites demonstrated remarkable synergistic adsorption-photocatalysis for Acid Fuchsin (AF) degradation under simulated sunlight. Fe-GBC with nano-flake morphology was uniformly dispersed on g-C3N4, forming a tight heterojunction that promoted charge separation. At a Fe-GBC to g-C3N4 mass ratio of 1:1, the composite showed optimal performance, following pseudo-first-order kinetics and achieving a 79.9% removal after 120 min dark adsorption and 150 min irradiation. The composite significantly outperformed its individual components, confirming a synergy between adsorption and photocatalysis. It also exhibited excellent magnetic recoverability and stability over five reuse cycles. AF removal was influenced by initial concentration, pH, and catalyst dosage. Radical trapping indicated center dot O2- and center dot OH as the main active species. The enhancement mechanism is attributed to biochar acting as an electron acceptor, suppressing electron-hole recombination. This work provides a novel magnetically recyclable photocatalyst for pollutant removal and a green strategy for valorizing ginkgo leaf waste.

The rising frequency of marine oil spills and industrial oily wastewater discharge necessitates superhydrophobic materials for efficient oil-water separation, environmental resilience, and operational flexibility. Conventional absorption materials suffer from poor cycle stability, limited functionality, and complex preparation. To address these limitations, this study proposes a multifunctional modification strategy using a melamine sponge (MS) substrate. A superhydrophobic MS (SiO2-Fe3O4-PDMS@PDA/MS) was successfully synthesized. Biomimetic polydopamine (PDA) modification created a robust adhesion interface. Synergistic incorporation of SiO2 nanoparticles and Fe3O4 magnetic particles established a hierarchical rough structure, followed by low surface energy modification with polydimethylsiloxane (PDMS). The material exhibits excellent superhydrophobicity (water contact angle = 153.4 degrees). The strong interfacial adhesion of PDA and the micro-nano structure significantly enhance stability of the coating. Functional advantages include: Magnetic nano-Fe3O4 enables capabilities of directional control for precise absorption of magnetic oil pollutants. The synergy of PDMS and SiO2 maintains strong hydrophobicity (WCA >142 degrees) after immersion in solutions of acid, alkali, or salt, and mechanical wear. It demonstrates high capacity for absorption of various oils and organic solvents (25.7-72.9 g/g) and efficiency of oil-water separation (98.2%), with a retention rate of performance >83% after 10 cycles. Combined with technology of vacuum-assisted continuous separation, it enhances treatment of complex oil-water systems. Furthermore, the material exhibits characteristics of photothermal conversion, rapidly heating to 110.7 degrees C under illumination of 1.0 kW/m(2), significantly boosting absorption capacity for oils of high viscosity. The process of preparation is straightforward and uses environmentally friendly raw materials. Possessing capabilities of magnetic responsiveness, flame retardancy, and photothermal conversion, SiO2-Fe3O4-PDMS@PDA/MS offers an efficient, sustainable solution for recovery of marine oil spills, treatment of industrial oily wastewater, and control of high-viscosity oil pollution.

In this paper, the novel electrochemical in situ synthesis process for H2O2, in which oxygen is in situ generated from water electrolysis powered by photovoltaic renewable energy and Mg2+ ions is added, is constructed by an ordinary Pt anode and a graphite or carbon felt cathode in a green, safe, low-cost, and high-yield way. The results show that the yields of hydrogen peroxide (YHP) for Mg(NO3)2 and MgSO4 are all higher than that for light MgO and are above 19.8 mg/L. The optimal Mg2+ concentration of 30 mg/L, pH of 1, current density of 30 mA/cm2, and cathodic immersion depth of 50 mm is determined, respectively. For solutions containing Mg2+, their YHPs are consistently higher than that of the Mg2+-free solution and properly adding Mg2+ into solutions can improve YHP. YHP for carbon felt cathodes is much higher than that for graphite plates, and the fluffy spatial structure of the cathode is beneficial to synthesis of H2O2. Additionally, YHP for pure oxygen blown into solution is the highest and 494.2 mg/L. Even if solar illumination intensity is very low, its YHP can reach to the same yield as high solar illumination intensity, too. In the meantime, the in situ synthesizing mechanism of H2O2 is suggested. Finally, their energy consumption and actual energy utilization efficiency are analyzed. The used method is feasible for the novel in situ synthesis of hydrogen peroxide.

A Co@Cu-MOF(C) catalyst was synthesized and evaluated for doxycycline (DOX) degradation via peroxymonosulfate (PMS) activation. Under the optimal conditions (catalyst dosage: 400 mg L-1; PMS concentration: 2 mM; pH: 9.0; temperature: 30 degrees C), 99.3% of DOX (20 mg L-1) was removed within 40 min. The Co@Cu-MOF (C)/PMS system maintained favorable degradation performance within the investigated pH range and in the presence of common inorganic anions, indicating promising matrix tolerance under the tested conditions. Most operational parameters mainly affected the early-stage degradation behavior, whereas the removal efficiencies became relatively similar in the later stage. Quenching experiments combined with electron paramagnetic resonance (EPR) measurements confirmed that center dot OH, SO4 center dot-, O2 center dot- , and 1O2collectively contributed to DOX transformation, with the 1O2-dominated non-radical pathway playing a dominant role. X-ray photoelectron spectroscopy (XPS) analysis further indicated that surface redox cycling of Co2+/Co3+ (together with Cu+/Cu2+) promoted PMS activation and the generation of reactive oxygen species. HPLC-MS identified the major degradation intermediates, and the proposed degradation route involved sequential demethylation/dehydration, ring-opening, fragmentation, and deep oxidation reactions. Moreover, T.E.S.T. suggested that, compared with the parent DOX, the major intermediates exhibited an overall reduction in mutagenicity risk and a decreasing trend in developmental-toxicity-related endpoints, implying partial mitigation of potential ecological and health hazards during the degradation process. Overall, these results highlight the scientific significance of constructing a Co/Cu bimetallic MOF-derived catalyst for PMS activation and provide new insight into the dominant 1O2-mediated non-radical pathway for antibiotic-contaminated water treatment

Nitrogen (N) and phosphorus (P) play pivotal roles in water eutrophication. Effective removal of N and P from water is a crucial approach to mitigating eutrophication. In the present study, pyrolyzed shell powder (PSP) and its silicon composite (CPSP-Si) were used for the simultaneous removal of N and P. Sodium silicate was added to PSP, which solidified PSP and thus reduced the loss of metal oxides contained in PSP during sintering, and enhanced the adsorption capacity for N and P. Kinetic test results revealed that simultaneous removal of N and P by PSP was 12.424 and 2.0 times higher than the removal of only N and only P systems, respectively. Adsorption isotherms showed that the maximum adsorption capacities of PSP for N and P in the N and P system were 433.15 mg N/g and 623.77 mg P/g , respectively. X-ray diffraction (XRD) analysis indicated that the products included conventional compounds such as calcium phosphate and magnesium phosphate, as well as struvite, swaknoite, and dittmarite. The fixed-bed column experiments revealed the breakthrough bed volume (BV) points for PSP at 259 BV and 778 BV, and for CPSP-Si at 1,156 BV and 1,203 BV, corresponding to N and P, respectively. Furthermore, the N and P adsorption efficiencies of CPSP-Si were significantly higher than those of PSP. Our results also showed that breeding wastewater treated with CPSP-Si significantly inhibited the growth of Chlorella vulgaris. Additionally, the maize pot experiment indicated that CPSP-Si enriching N and P has promising potential as a soil amendment in agricultural fields.

The increasing prominence of Cu(II) pollution in water bodies has driven the development of efficient and easily recoverable adsorbents. In this study, M-CBC was prepared from waste coffee grounds via pyrolysis and ball milling. Ball milling significantly increased the specific surface area and introduced abundant oxygen-containing functional groups. The loaded Fe3O4 provided favorable superparamagnetism (saturation magnetization: 8.87 emu/g), enabling rapid magnetic separation. Batch adsorption experiments showed that under optimal conditions (pH 5.0, dosage 0.8 g/L, time 180 min), the actual adsorption capacity for Cu(II) reached 23.54 +/- 0.23 mg/ g, representing an approximately 66% enhancement compared to unmodified biochar. The adsorption process followed the pseudo-second-order kinetic model and the Langmuir isotherm model, with a theoretical maximum adsorption capacity of 49.06 +/- 1.36 mg/g at 25 degrees C, suggesting predominantly monolayer adsorption behavior on relatively homogeneous active sites. Thermodynamic analysis revealed that the adsorption process exhibited spontaneous and temperature-dependent characteristics, indicating the possible coexistence of multiple adsorption interactions. After five consecutive adsorption-desorption cycles, M-CBC retained 71.4% of its initial capacity, demonstrating excellent regeneration stability. Mechanistic analysis revealed that surface complexation with oxygen-containing groups played a dominant role, while the redox activity of Fe3O4 provided synergistic enhancement. The combined effects of ball milling and Fe3O4 loading effectively improved the adsorption performance, magnetic recoverability, and structural stability of the biochar. This work offers a resource-efficient approach to valorize waste coffee grounds and highlights the promising potential of M-CBC for treating Cu(II)containing industrial wastewater due to its high efficiency and easy recoverability.

Photocatalysis is a promising strategy for environmental remediation but is commonly limited by inefficient charge separation and slow interfacial reaction kinetics. Herein, an aerosolized microdroplet-coupled semiconductor photocatalytic system is developed to enhance photocatalytic performance through interfacial microenvironment regulation. Dispersing TiO₂ nanoparticles into aerosolized microdroplets enables synergistic coupling between the strong built-in electric field at the gas-liquid interface and the localized interfacial electric field at the semiconductor-water interface, which significantly promotes photogenerated charge separation and hydroxyl radical generation. The microdroplet-assisted system achieved a •OH generation rate of 0.31 min⁻¹ within 60 min and a methylene blue degradation rate of 0.16 min⁻¹ within 20 min, markedly outperforming the bulk-phase photocatalytic system (0.17 and 0.11 min⁻¹, respectively). The enhancement strategy was further validated using multiple semiconductor photocatalysts, including ZnO, CuO, Fe₂O₃, and ZrO₂, all of which exhibited improved photocatalytic activity under microdroplet-assisted conditions. In addition, efficient pollutant degradation was achieved in real river water samples, demonstrating good system stability and practical applicability. This work highlights microdroplet-induced interfacial electric field coupling as an effective approach for boosting photocatalytic efficiency, offering new insights for the design of advanced photocatalytic systems for environmental applications.

Currently, within the framework of China’s “dual carbon” goals—aiming to reach a carbon peak by 2030 and achieve carbon neutrality by 2060—agriculture plays a dual role as both a carbon source and a carbon sink. It holds significant potential for carbon sequestration and emission reduction. Therefore, studying the spatial and temporal evolution patterns and driving factors of regional agricultural carbon emission efficiency (ACEE) is crucial for advancing low-carbon agricultural development. This study analyzes agricultural carbon emission data from the Yangtze River Delta (YRD) region spanning the years 2001 to 2020. It utilizes the Super-SBM model and the Global Malmquist-Luenberger (GML) index to investigate the temporal and spatial characteristics of ACEE from both static and dynamic perspectives. Furthermore, the Tobit model is employed to identify the key factors influencing ACEE. The results confirmed that: (1) From the perspective of static efficiency, the average ACEE value from 2001 to 2020 was 0.83, with the ACEE values ranked from highest to lowest as follows: Jiangsu, Shanghai, Zhejiang, and Anhui. (2) From the perspective of dynamic efficiency, the ACEE exhibits an upward trend, with an average annual growth rate of 2.10

Microplastics (MPs) carry and spread environmental pollutants far and wide. The surface structure of MPs changes when MPs are exposed to light, and which influences the adhesion of MPs to pollutants. In this study, ultraviolet (UV) irradiation (1000 W mercury lamp, 80W/cm2) was utilized to simulate the aging of PVC MPs in natural environments. The adsorption and desorption behaviors of PVC MPs on tildipirosin were investigated. Furthermore, Escherichia coli was used for antibiotic stress experiments. The results revealed that aged PVC MPs exhibited a new oxygen-containing absorption peak at 1736 cm−1, attributing to the stretching of a C = O. Notably, tildipirosin adsorption by the pristine PVC MPs conformed to the pseudo-first-order kinetic model (R2 = 0.975), while the aged PVC MPs followed the pseudo-second-order kinetic model. The adsorption process followed the Langmuir thermodynamic equation. Furthermore, the desorption rates of the pristine, 6-day-aged, and 12-day-aged PVC MPs were determined to be 24.2

Water‐solid contact electrification (CE) is a common physical phenomenon. The electron transfer during water‐solid CE can mediate the redox reactions at the interface, however, the effect of different surface functional groups on this physicochemical process and its mechanism are limited in understanding. Here, we have regulated the redox reactions caused by CE between water and florine‐doped tin oxide (FTO) with various functional groups, as well as their electron transfer processes during the contact. It is revealed that the ‐COOH FTO sample has a larger work function than the no functional group FTO and ‐OH FTO samples and can easily accept electrons to promote electron transfer from water‐solid heterojunctions in CE by density functional calculation. The nitrate reduction and nitrite oxidation experiments showed that the redox capacity of the water – FTO heterojunction with ‐COOH is much more than that of the water – FTO heterojunction with ‐OH or fewer functional groups in the CE process. The redox capacity of the water‐FTO CE originates from reduction and oxidation species, which was confirmed by the electron transfer and active species detection analysis. These findings deepen our understanding of the correlation between surface functional groups and redox capacity in the CE process.

Comprehensive utilization of phosphorus slag (PS) is crucial to achieve sustainable resource utilization. However, only few systematic studies have been conducted on returning PS to fields. In this study, effects of PS on the soil microenvironment and planting were investigated in detail using simulations of returning PS to fields. The results showed that returning PS to fields would not cause heavy metal pollution in the soil. At the end of the experiment, the soil physicochemical properties revealed that PS addition (5% and 20% mass ratio) resulted in a slight increase in soil pH, which indicated that PS amendment decreased the acidity of the soil sample. Compared with a control sample, the available nitrogen decreased (about 10.64% to 25.53%) in the amended soil, and which was positively related to the added content of PS. Conversely, the available phosphorus content increased (from 87.64% to 192.43%) with the increase of PS content added to soil. Moreover, the PS addition to the soil altered the microbial composition. The top six genera in soil microbial community were Bryobacter (1.59%), Geobacter (1.54%), Haliangium (1.51%), Nitrospira (1.19%), Candidatus Udaeobacter (1.14%), and Sphingomonas (1.12%). The activity of urease, phosphatase, and cellulase increased, and the abundance of functional genes related to nitrogen (ureC, amoB, nirS, and nirK) and phosphorus (ppx, pqqC, and phoD) also increased after PS addition. In a pot experiment, the addition of PS to soil promoted the growth of crops. In summary, proper addition of PS to agricultural soil is beneficial for both the soil environment and the growth of crops.

Marine oil spills and the illegal discharge of industrial wastewater have resulted in significant environmental and ecological pollution. Consequently, it is essential to develop multifunctional oil-water separation materials that are abundant in raw materials, environmentally friendly, easily operable in complex environments, and fully recyclable. In this study, inspired by lotus leaves and mussels, a low-cost commercial polyurethane (PU) sponge was utilized as the substrate. Hydrophobic SiO2 and magnetic Fe3O4 nanoparticles were modified by coating with self-polymerized dopamine to enhance surface roughness. The surface was chemically treated with fluorine-free, green, low-surface-energy polydimethylsiloxane (PDMS). Thus, a sponge exhibiting both superhydrophobic and superoleophilic properties was synthesized via impregnation technology. The results indicated that the modified PU sponge exhibited a water contact angle of 151.3 degrees. The sponge demonstrated significant adsorption capacity for various oils and organic solvents, ranging from 20.55 to 33.63 times its own weight. The adsorption capacity remained stable after 10 separation cycles. Using gravity-driven flow or a peristaltic pump, the modified PU sponge achieved continuous oil-water separation with efficiency exceeding 97 %. The modified PU sponge demonstrated effective separation of toluene-in-water emulsions. It exhibited outstanding magnetic responsiveness, enabling rapid oil adsorption under magnetic guidance, and showed excellent flame retardancy to mitigate fire risks. This multifunctional polyurethane sponge, developed through synergistic modification, demonstrated significant potential for oil-water separation and environmental remediation applications.

The widespread availability of glyphosate in shallow lakes is of significant concern. Glyphosate is an organophosphorus pesticide that can affect the phosphorus cycle and microbial communities in lakes. However, the effects of glyphosate on lakes in different geographical locations remain unclear. This study not only investigated glyphosate and aminomethylphosphonic acid (AMPA) residues in sediments from rural and urban lakes, but also examined differences in the effects of these substances on lake microbial communities and phosphorus cycles. Glyphosate and AMPA were detected in 100% of sediments from the three rural and three urban lakes surveyed. Glyphosate concentrations were not significantly different among all lake sediments; however, AMPA concentrations were significantly higher in rural lake sediments than in urban lake sediments (P < 0.05). The abundance of the glpC gene, encoding an organophosphorus-degrading enzyme, and the abundance of Luteitalea sp. TBR-22, which is enriched for the glpC gene, were significantly different between rural and urban lake sediments (P < 0.05). Notably, the abundance of glpC and Luteitalea sp. TBR-22 was significantly and positively correlated with AMPA concentration (P < 0.05). In addition, the AMPA concentration was significantly and positively correlated with the O-bonded inorganic phosphate (Pi) content (P < 0.05). These results suggest that high AMPA concentrations in rural lake sediments may increase the production of O-bonded Pi in lake sediments by controlling the expression of glpC in Luteitalea sp. TBR-22, leading to higher concentrations of O-bonded Pi in the rural lake sediments than in the urban lake sediments.

The shale gas flowback wastewater (SGFW) contains abundant dissolved organic matter (DOM), including some refractory DOM which are difficult to be biodegraded, and the removal and transformation of these refractory DOM have attracted global attentions. In this study, the DOM molecular transformation for SGFW during ozonation treatment was investigated based on the fluorescence excitation-emission matrix-parallel factor analysis (EEM-PARAFAC) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Results revealed that the DOM in SGFW was autochthonous and mainly derived from microbial sources with low humification extent, and four fluorescent components were categorized as fulvic acid-like/ humic acid-like substances (C1, 240(320)/400 nm), soluble microbial by-product-like substances (C2, 250(300)/350 nm; C4, 280/316 nm), and humic acid-like substances (C3, 270(370)/452 nm). The ozonation (120 min) for SGFW obtained a removal efficiency of 68.0 %, 58.4 %, 78.1 %, and 47.3 % for chemical oxygen demand (CODCr), dissolved organic carbon (DOC), ultraviolet absorbance at 254 nm (UV254), and specific UV absorbance at 254 nm (SUVA254), respectively. In addition, both C3 and C4 were decreased by 32.5 % and 50.7 %, along with the decrease of H/Cwa and O/Cwa. The CHO compounds were degraded/transformed into other molecule substances and 22 CHO compounds were classified as resistant molecules after ozonation for 120 min, with the contribution of 91.7 % for resistant molecules; on the contrary, the CHONS compounds were completely removed after ozonation. The ozonation also reduced the molecular numbers of the lipids, proteins, carbohydrates, and lignins, corresponding to the decreased organic contents (CODCr and DOC) of SGFW. Correlation analysis indicated that both the fluorescent components (four components) and DOM molecules (four classes) had strong correlations with water quality indexes. These results further conforming that DOM molecules from SGFW could be partially transformed into micromolecules after ozonation.

The photocatalytic generation of hydrogen peroxide (H2O2) using artificial synthetic methods is promising. However, the sluggish hole-induced water oxidation half-reaction that hinders charge separation severely limits H2O2 generation efficiency. This study used the oxidation half-reaction of tetracycline (C22H24N2O8, TC) to accelerate charge separation over GaOOH/In(OH)(3) composites with Type II heterojunctions under sunlight irradiation to increase the H2O2 generation efficiency. The results demonstrated that the H2O2 generation efficiency significantly increased from 74.7 to 389.8 mu mol L(-1)h(-1) as the TC degradation efficiency increased from 0.02 to 0.37 mg L(-1)h(-1). Radical quenching experiments further indicated that TC degradation consumed holes, increasing the electron formation rate and enhancing H2O2 generation. A comparison with density functional theory calculations revealed that H2O2 generation was a one-step 2-electron route (O-2 + 2e(-) + 2H(+) -> H2O2). These findings are expected to provide new strategies for promoting photocatalytic synthesis of H2O2.

Traditional fluorescent probes have challenges, including aggregation-induced quenching, biological incompatibility, and suboptimal selectivity. In this study, we developed a novel probe derived from natural rutin featuring an aggregation-induced emission (AIE) effect. Through hydroxy engineering of rutin, the optimized probe enables precise detection of Fe3+ via 2:1 stoichiometric coordination. The probe demonstrates remarkable analytical performance, with a detection limit as low as 0.22 mu M. Concentration-dependent responses were observed within 0-20 mu M, with significant linearity (R-2 > 0.99) in the 0-10 mu M range. Density functional theory calculations reveal that the binding of Fe3+ effectively suppresses intramolecular charge transfer. The hydroxy-engineered modification plays a pivotal role in facilitating complexation for bond formation and providing appropriate steric hindrance. This research establishes a new benchmark for natural product-based AIE probes and deepens understanding of the structure-activity relationships governing flavonoid-metal recognition.

The persistent presence of refractory antibiotics in the environment poses significant systemic risks to both ecosystems and public health. This study developed magnetic pomegranate peel biochar (MPBC) via KOH/Fe3O4 coimpregnation and pyrolysis to address norfloxacin (NOR) pollution. Characterized by a heterogeneous structure, MPBC exhibited a high surface area (895.43 m2/g) and magnetization (14.8 emu/g), enabling rapid magnetic separation. Batch experiments demonstrated that the adsorption kinetics and thermodynamic behavior of MPBC on NOR conformed more closely to the pseudo-second-order kinetic model and the Langmuir isotherm model. The maximum theoretical adsorption capacity, estimated using the Langmuir isotherm model, was 61.9 mg/g, which is 5.9 times greater than that of PBC. Through the characterization and analysis of the materials, the adsorption mechanism was investigated. It was found that the adsorption process primarily involved electrostatic interactions, π-π interactions, hydrogen bonding, and pore filling. MPBC retained 76.7% adsorption efficiency after five magnetic recovery cycles, showcasing robust reusability. In addition, economic analysis indicates that MPBC has a high cost-effectiveness ratio, with its comprehensive preparation cost ranging from $14.3-20.0/kg, which is comparable to that of commercial activated carbon. As a sustainable adsorbent derived from agricultural waste, MPBC combines high antibiotic removal efficiency with environmental remediation benefits. Its recyclability and magnetic separation capability offer a practical solution for mitigating refractory antibiotic pollution, aligning with circular economy principles and organic wastewater treatment needs.

Metal (hydro)oxide particles with efficient phosphate removal properties are widely used in the treatment of eutrophic waters (mainly phosphorus). However, the disadvantages of easy agglomeration and difficult separation limit their application. In this study, a polyurethane sponge (PU) was coated with sodium carboxymethyl cellulose (CMC-Na) to anchor FeO(OH) to prepare a novel functional composite (CFe@PU), which overcame the disadvantages of metal (hydro)oxide particles. The results revealed that the coating process of CMC-Na on the PU surface contributed to loading of FeO(OH) and enhanced the affinity for phosphate. The maximum adsorption capacity of CFe@PU was 21.22 mg phosphate-P per g, which was 1.74 times that of Fe@PU, and the effect of the coating process was significant (P = 0.01). The material displayed remarkable selectivity when exposed to a diverse array of anions and within the pH range of 4-8. The phosphorus removal efficiency by CFe@PU was >71.34% after three regeneration cycles. Investigating the adsorption mechanisms revealed that electrostatic attraction and inner-sphere ligand exchange were involved in the adsorption process. In a lake water experiment, the phosphorus in the CFe@PU treated group decreased from 0.2 mg L-1 to 0.004 mg L-1, limiting algae growth significantly. These results indicated that CFe@PU was a potential adsorbent in controlling eutrophication.