Iron oxyhydroxide catalyzes production of artificial humic substances from waste biomass.

Production of artificial humic substances (AHS) from waste biomass will contribute to environmental protection and agricultural productivity. However, there is still a lack of a faster, more efficient and eco-friendly way for sustainable production. In this study, we proposed a method to accelerate the production of AHS from cotton stalks by mild pyrolysis and H2O2 oxidation in only 4 hours, and investigated the formation of AHS during biomass transformation. We found that the process increased the aromatic matrix and facilitated biomass transformation by enhancing the depolymerization of lignin into micromolecular phenolics (e.g., guaiacol, p-ethyl guaiacol, etc.). The optimum conditions of pyrolysis at 250 °C and oxidation with 6 mL H2O2 (5 wt%) yielded up to 19.28 ± 1.30 wt% artificial humic acid (AHA) from cotton stalks. In addition, we used iron oxyhydroxide (FeOOH) to catalyze biomass transformation and investigated the effect of FeOOH on the composition and properties of AHS. 1.5 wt% FeOOH promoted the increased content of artificial fulvic acid (AFA) in AHS from 10.1% to 26.5%, eventually improving the activity of AHS. FeOOH raised the content of oxygen-containing groups, such as carboxylic acids and aldehyde, and significantly increased polysaccharide (10.94%-18.95%) and protein (1.95%-2.18%) derivatives. Polymerization of amino acid analogs and many small-molecule carbohydrates (e.g., furans, aldehydes, ketones, and their derivatives) promoted AFA formation. Finally, carbon flow analysis and maize incubation tests confirmed that AHS were expected to achieve carbon emission reductions and reduce environmental pollution from fertilizers. This study provides a sustainable strategy for the accelerated production of AHS, which has important application value for waste biomass resource utilization.

Enhancing the extracellular electron transfer ability via Polydopamine@S. oneidensis MR-1 for Cr(VI) reduction.

Microbial reduction of hexavalent chromium (Cr (VI)) shows better efficiency and cost-effectiveness. However, immobilization of Cr (III) remains a challenge as there is a limited supply of electron donors. A greener and cleaner option for donating external electrons was using bioelectrochemical systems to perform the microbial reduction of Cr(VI). In this system, we constructed a polydopamine (PDA) decorated Shewanella oneidensis MR-1 (S. oneidensis MR-1) bioelectrode with bidirectional electron transport, abbreviated as PDA@S. oneidensis MR-1. The conjugated PDA distributed on the intracellular and extracellular of individual S. oneidensis MR-1 has been shown to accelerate electron transfer by outer membrane C-type cytochromes and flavin-bound MtrC/OmcA pathway by various electrochemical analyses. As expected, the PDA@S. oneidensis MR-1 biofilm achieved 88.1% Cr (VI) removal efficiency (RE) and 58.1% Cr (III) immobilization efficiency (IE) within 24 h under the autotrophic conditions at the optimal voltage (-150 mV) compared with the control potential (0 mV). The PDA@S. oneidensis MR-1 biofilm showed increased RE activity was attributed to the shortening of the distance between individual bacteria by PDA. This research provides a viable strategy for in situ bioremediation of Cr(VI) polluted aquatic environment.

Preparation of copper-based catalysts from electroplating sludge by ultrasound treatment and their antibiotic degradation performance.

The recovery of heavy metals from electroplating sludge is important for alleviating heavy metal pollution and recycling metal resources. However, the selective recovery of metal resources is limited by the complexity of electroplating sludge. Herein, CuFe bimetallic Fenton-like catalysts were successfully prepared from electroplating sludge by a facile room-temperature ultrasonic-assisted co-precipitation method. The prepared CuFe-S mainly consisted of nanorods with diameters of 20-30 nm and lengths of 100-200 nm and a small number of irregular particles. Subsequently, we performed tetracycline (TC) degradation experiments, and the results showed that the product CuFe-S had very good performance over a wide pH range (2-11). At an initial pH = 2, CuFe-S could degrade 91.9% of 50 mg L-1 TC aqueous solution within 30 min, which is better than that of a single metal catalyst. Free radical scavenging experiments and electron paramagnetic resonance (EPR) tests revealed that ·OH was the main active species for the degradation of TC by CuFe-S. In conclusion, a CuFe bimetallic Fenton-like catalyst was developed for the catalytic degradation of antibiotics, which provides a novel technical route for the resource utilization of electroplating sludge and shows an important practical application prospect.

Boosting Electroreduction Kinetics of Nitrogen to Ammonia via Atomically Dispersed Sn Protuberance.

Atomically dispersed metal catalysts show potential advantages in N2 reduction reaction (NRR) due to their excellent activity and efficient metal utilization. Unfortunately, the reported catalysts usually exhibit unsatisfactory NRR activity due to their poor N2 adsorption and activation. Herein, we report a novel Sn atomically dispersed protuberance (ADP) by coordination with substrate C and O to induce positive charge accumulation on Sn site for improving its N2 adsorption, activation and NRR performance. The extended X-ray absorption fine structure (EXAFS) spectra confirmed the local coordination structure of the Sn ADPs. NRR activity was significantly promoted via Sn ADPs, exhibiting a remarkable NH3 yield (RNH3 ) of 28.3 µg h-1 mgcat -1 (7447 µg h-1 mgSn -1 ) at -0.3 V. Furthermore, the enhanced N2 Hx intermediates was verified by in situ experiments, yielding consistent results with DFT calculation. This work opens a new avenue to regulate the activity and selectivity of N2 fixation.

Hydrothermal Synthesis of WO3·0.33H2O Nanorod Bundles as a Highly Sensitive Cyclohexene Sensor.

In this paper, WO3·0.33H2O nanorods were prepared through a simple hydrothermal method using p-aminobenzoic acid (PABA) as an auxiliary reagent. X-ray diffraction (XRD) and transmission electron microscopy (TEM) images showed that the products with PABA addition were orthorhombic WO3·0.33H2O, which were mainly composed of nanorods with different crystal planes. The sensing performance of WO3·0.33H2O nanorod bundles prepared by the addition of PABA (100 ppm cyclohexene, Ra/Rg = 50.6) was found to be better than the WO3 synthesized without PABA (100 ppm cyclohexene, Ra/Rg = 1.3) for the detection of cyclohexene. The new synthesis route and sensing characteristics of as-synthesized WO3·0.33H2O nanorods revealed a promising candidate for the preparation of the cost-effective gas sensors.

Iron-Based Metal-Organic Frameworks as Catalysts for Visible Light-Driven Water Oxidation.

The development of earth-abundant, active, and stable catalysts is important for solar energy conversion. Metal-organic frameworks (MOFs) have been viewed as a promising class of porous materials, which may have innovative application in photocatalysis. In this paper, three types of Fe-based MOFs and their aminofunctionalized derivatives have been fabricated and systematically studied as water oxidation catalysts (WOCs) for oxygen evolution under visible light irradiation. MIL-101(Fe) possesses a higher current density and earlier onset potential and exhibits excellent visible light-driven oxygen evolution activity than the other Fe-based catalysts. It speeds up the oxygen evolution reaction rate with the higher initial turnover frequencies value of 0.10 s(-1). Our study demonstrates that Fe-based MOFs as efficient WOCs are promising candidates for photocatalytic water oxidation process.

Strongly Coupled CoCr2 O4 /Carbon Nanosheets as High Performance Electrocatalysts for Oxygen Evolution Reaction.

A strongly coupled CoCr2 O4 /carbon nanosheet composite is concurrently grown via a facile one-step molten-salt calcination approach. The strong coupling between carbon and CoCr2 O4 has improved the electrical conductivity and preserved the active sites in catalysts. These results may pave the way to improve the performance of spinel oxides as electrocatalysts for oxygen evolution reactions.

DIET-like and MIET-like mutualism of S. oneidensis MR-1 and metal-reducing function microflora boosts Cr(VI) reduction.

Microbial treatment of Cr(VI) is an environmentally friendly and low-cost approach. However, the mechanism of mutualism and the role of interspecies electron transfer in Cr(VI) reducing microflora are unclear. Herein, we constructed an intersymbiotic microbial association flora to augment interspecies electron transfer via functionalizing electroactive Shewanella oneidensis MR-1 with metal-reducing microflora, and thus the efficiency of Cr(VI) reduction. The findings suggest that the metal-reducing active microflora could converts glucose into lactic acid and riboflavin for S. oneidensis MR-1 to act as a carbon source and electron mediator. Thus, when adding initial 25 mg/L Cr (VI), this microflora exhibited an outstanding Cr (VI) removal efficiency (100%) at 12 h and elevated Cr (III) immobilization efficiency (80%) at 60 h with the assistance of 25 mg/L Cu(II). A series of electrochemical experiments proved this remarkable removal efficiency were ascribed to the improved interspecies electron transfer efficiency through direct interspecies electron transfer and riboflavin through mediated interspecies electron transfer. Furthermore, the metagenomic analysis revealed the expression level of the electron transport pathway was promoted. Intriguing high abundance of genes participating in the bio-reduction and biotransformation of Cr(VI) was also observed in functional microflora. These outcomes give a novel strategy for enhancing the reduction and fixation of harmful heavy metals by coculturing function microflora with electrogenic microorganisms.

Upcycling of Cr-Containing Sulfate Waste into Efficient FeCrO3/Fe2O3 Catalysts for CO2 Hydrogenation Reaction.

Upcycling Cr-containing sulfate waste into catalysts for CO2 hydrogenation reaction benefits both pollution mitigation and economic sustainability. In this study, FeCrO3/Fe2O3 catalysts were successfully prepared by a simple hydrothermal method using Cr-containing sodium sulfate (Cr-SS) as a Cr source for efficient conversion and stable treatment of Cr. The removal rate of Cr in Cr-SS can reach 99.9% at the optimized hydrothermal conditions. When the synthesized catalysts were activated and used for the CO2 hydrogenation reaction, a 50% increase in CO2 conversion was achieved compared with the catalyst prepared by impregnation with a comparable amount of Cr. According to the extraction and risk assessment code (RAC) of the Reference Office of the European Community Bureau (BCR), the synthesized FeCrO3/Fe2O3 is risk-free. This work not only realizes the detoxification of the Cr-SS but transfers Cr into stable FeCrO3 for application in a catalytic field, which provides a strategy for the harmless disposal and resource utilization of Cr-containing hazardous waste.

Formation mechanism of persistent free radicals during pyrolysis of Fenton-conditioned sewage sludge: Influence of NOM and iron.

The present study provided an innovative insight into the formation mechanism of persistent free radicals (PFRs) during the pyrolysis of Fenton-conditioned sludge. Fenton conditioners simultaneously improve the dewatering performance of sewage sludge and catalyze the pyrolysis of sewage sludge for the formation of PFRs. In this process, PFRs with a total number of spins of 9.533×1019 spins/g DS could be generated by pyrolysis of Fenton-conditioned sludge at 400°C. The direct thermal decomposition of natural organic matter (NOM) fractions contributed to the formation of carbon-centered radicals, while the Maillard reaction produced phenols precursors. Additionally, the reaction between aromatic proteins and iron played a crucial role in the formation of phenoxyl or semiquinone-type radicals. Kinetics analysis using discrete distributed activation energy model (DAEM) demonstrated that the average activation energy for pyrolysis was reduced from 178.28 kJ/mol for raw sludge to 164.53 KJ/mol for Fenton conditioned sludge. The reaction factor (fi) indicated that the primary reaction in Fenton-conditioned sludge comprised of 27 parallel first-order reactions, resulting from pyrolysis cleavage of the NOM fractions, the Maillard reaction, and iron catalysis. These findings are significant for understanding the formation process of PFRs from NOM in Fenton-conditioned sludge and provide valuable insight for controlling PFRs formation in practical applications.

Efficient removal and transformation of Cr(VI) from alkaline wastewater to form a ferrochromium spinel multiphase via a modified ferrite process.

Chromium-containing wastewater causes serious environmental pollution due to the harmfulness of Cr(VI). The ferrite process is typically used to treat chromium-containing wastewater and recycle the valuable chromium metal. However, the current ferrite process is unable to fully transform Cr(VI) into chromium ferrite under mild reaction conditions. This paper proposes a novel ferrite process to treat chromium-containing wastewater and recover valuable chromium metal. The process combines FeSO4 reduction and hydrothermal treatment to remove Cr(VI) and form chromium ferrite composites. The Cr(VI) concentration in the wastewater was reduced from 1040 mg L-1 to 0.035 mg L-1, and the Cr(VI) leaching toxicity of the precipitate was 0.21 mg L-1 under optimal hydrothermal conditions. The precipitate consisted of micron-sized ferrochromium spinel multiphase with polyhedral structure. The mechanism of Cr(VI) removal involved three steps: 1) partial oxidation of FeSO4 to Fe(III) hydroxide and oxy-hydroxide; 2) reduction of Cr(VI) by FeSO4 to Cr(III) and Fe(III) precipitates; 3) transformation and growth of the precipitates into chromium ferrite composites. This process meets the release standards of industrial wastewater and hazardous waste and can improve the efficiency of the ferrite process for toxic heavy metal removal.

Boosting bioelectricity generation in microbial fuel cells via biomimetic Fe-N-S-C nanozymes.

Anode performance has been regarded as a crucial factor determining long-term stability and electricity generation of microbial fuel cells (MFCs), which restricts by the difficult extracellular electron transfer (EET) on the microbe/anode interface. Herein, inspired by biological enzyme systems, this study synthesized the biomimetic nanozymes with Fe-N-S-C active sites as the anode materials of MFCs, which was similar to the hemes of c-type cytochromes (c-Cyts) for boosting EET process. As excepted, an obviously faster start-up and a much higher power density were achieved by the MFCs equipped with Fe-N-S-C nanozymes (startup time, 3.5 d; power density, 2366 ± 34 mW m-2) than that based on traditional carbon cloth (startup time, 5.6 d; power density, 1009 ± 26 mW m-2). Such unique features of Fe-N-S-C nanozymes anode not only greatly favored the bacterial adhesion and the electroactive bacteria enrichment on the anode surface, but also efficiently facilitated the EET process between the electroactive bacteria and anode surface. This study provided a feasible strategy for designing the novel MFC anode materials from the perspective of bionic enzyme.

Influence of pyrolysis temperature on sludge biochar: the ecological risk assessment of heavy metals and the adsorption of Cd(II).

Pyrolysis of sludge to biochar can not only reduce the sludge volume, toxic organic compound, and pathogens, but also be applied as effective adsorbents. However, the immobilization of heavy metals in the sludge and the properties of the biochar greatly rely on the pyrolysis temperature. In this paper, municipal sludge biochar (SBC) was prepared from 400 to 1000 °C. Pyrolysis immobilized heavy metals in sludge and the potential ecological risk of heavy metals significantly decreased to low level at temperature above 500 °C. At 700 °C, the adsorption capacity of Cd(II) reached a maximum (120.24 mg·g-1). The Cd(II) adsorption fitted the Pseudo-second-order model, indicating the existence of chemical adsorption. The adsorption capacity increased along with the initial pH and slowed down after pH reached 5.5. The existence of coexisting cations (Ca2+ and Na+) and anions (SO42- and NO3-) displayed different degree of inhibitory action on Cd(II) adsorption. The SEM, XRD, FTIR, and XPS analysis of sludge biochar before and after adsorption revealed that there were CdCO3, CdSO4, Cd2SiO4, Cd3(PO4)2, and Cd9(PO4)6 appearing on the surface of sludge biochar, suggesting that the adsorption of Cd(II) by SBC included co-precipitation, ion exchange, coordination with π electrons, and complexation. It was confirmed that different properties formed by pyrolysis temperature made a difference in adsorption mechanism of sludge biochar.

Highly Efficient Adsorption of Pb(II) by Functionalized Humic Acid: Molecular Experiment and Theoretical Calculation.

Environmental pollution has been widely considered by researchers, especially the heavy metals damage to the human and ecological environment is irreversible. Adsorption is an important method to remove heavy metal ions from the environment. In this paper, humic acid (HA) was functionalized by the improved Hummers method, and its adsorption capacity for Pb(II) was studied. The results of scanning electron microscope (SEM), X-ray diffraction (XRD), Roman, and Brunauer-Emmett-Teller (BET) showed that the thickness of irregular particles decreases to a layered structure during the transformation process. In addition, X-ray photoelectron spectroscopic (XPS) and Fourier transform infrared spectra (FT-IR) spectra showed that the surface of oxidized-biochar (OBC) was rich in reactive oxygen species, which was conducive to the formation of coordination bonds with Pb(II). Further adsorption experiments showed that it was a spontaneous monolayer chemisorption. The results of the DFT calculation showed that -COOH had the lowest adsorption energy for Pb(II), and it was easier to form stable chemical bonds than -OH, -C=O, and -C-O-C-. Because those oxygen-containing functional groups not only can promote electrostatic attraction but also are more favorable for forming a covalent bond with Pb(II). This study had guiding significance for the deep modification and application of weathered coal as a heavy metal ion adsorbent or cation exchanger.

Study on adsorption of hexavalent chromium by composite material prepared from iron-based solid wastes.

A new adsorbent with chromium removal function was synthesized by carbon thermal method using iron-containing waste Fenton sludge and carbon-containing solid waste fly ash to treat high pH scoring wastewater generated from industrial processes. The results showed that the adsorbent used T = 273.15 K, pH = 10, t = 1200 min, C0 = 100 mg/L, had a removal rate of Cr(VI) of more than 80%, and the adsorption capacity could reach 393.79 mg/g. The characterization results show that the synthesized mesoporous nitrogen-doped composite material has a large specific surface area and mesoporous structure, and the surface of the material is rich in oxygen-containing functional groups and active sites. Compared with other studies, the adsorption capacity of the material is larger, which indicates that the removal effect of Cr(VI) in this study is better. The adsorption kinetic results show that the adsorption follows a pseudo second kinetic model, and the adsorption process is a chemisorption involving electron sharing or electron exchange. This experiment designed a simple method to synthesize mesoporous nitrogen-doped composites using industrial solid waste, with raw materials from cheap and easily available industrial solid waste, and solved the dual problems of heavy metals in wastewater and solid waste, providing a new idea for the resource utilization of Fenton sludge while not producing secondary pollution.

Approaches for filtrate utilization from synthetic gypsum production.

Waste recycling and industrial wastewater treatment have always been of interest. A green approach was developed for the filtrate of synthetic gypsum production from water treatment coagulation sediments and spent sulfuric acid. Due to the high concentration of iron sulfate, concentrated filtrate showed good coagulation results, which were 5% lower than pure iron sulfate. In addition, a high concentration of iron facilitates its use as a precursor for synthesizing magnetic sorbents and photocatalysts. Such materials were synthesized by the solution combustion synthesis method. Oil sorption capacity reached 1.8 g/g, comparable to some synthetic materials and higher than sorption materials based on natural materials. Photodegradation of acid telon blue dye after 90 min of irradiation time was 82.7% with catalyst derived from filtrate compared to the just dye solution with 17.6% efficiency. The reaction rate constant for the photocatalyst sample was up to 11.4-fold higher compared with only UV treatment. The neutralized filtrate containing sulfur, calcium, magnesium, and sodium has been tested as a complex fertilizer. The results of bioindication for oil radish showed up to a 15% increase in the shoot length. A number of techno-economic indicators show that such an approach is advantageous from a technological, environmental, and economic point of view.

Iron-calcium reinforced solidification of arsenic alkali residue in geopolymer composite: Wide pH stabilization and its mechanism.

Arsenic-alkali residue (AAR) from antimony production can pose significant health and environmental hazards due to the risk of arsenic (As) leaching. In this study, geopolymer composite synthesized from fly ash (FA) was investigated for efficient stabilization of high-arsenic-containing AAR (As2O3 of 22.74 wt%). Two industrial wastes, e.g., granulated blast furnace slag (GBFS) with active calcium composition and water-quenched slag (WQS) from lead-zinc smelting with active iron composition, were investigated for the reinforcement of AAR geopolymer solidification. A wide pH stabilization (from pH = 3-pH = 12) of AAR with the geopolymer composite was successfully achieved, and As leaching concentration of geopolymer with the addition of 5 wt% AAR was significantly reduced from 2343.73 mg/L (AAR) to that below 0.18 mg/L, which successfully meet the regulatory limit of Chinese domestic waste landfill (GB, 18598-2019, 1.2 mg/L) and hazardous waste landfill (GB16889-2008, 0.3 mg/L). Johnbaumite (Ca5(AsO4)3(OH)) was formed in geopolymer composite and leached samples with initial pH from 2.6 to 6 (final pH from 5.54 to 13.15). Magnetite and iron hydroxide phases with strong adsorption and/or As co-precipitation capability were also observed. As stabilization was also achieved with iron oxidation from As(III) to As(V). This study solves the problem of unstable As leaching at different pH for the solidification of arsenic-bearing solid waste, and provides a promising and practical strategy for efficient solidification/stabilization of AAR as well as other similar arsenic-bearing solid wastes with geopolymer composite.

Recovery of carbon from spent carbon cathode by alkaline and acid leaching and thermal treatment and exploration of its application in lithium-ion batteries.

The spent carbon cathode (SCC) is a hazardous solid waste from aluminum production. It has an abundant carbon source and a unique graphitic carbon layer structure, making it a valuable waste for recycling. This paper uses alkaline and acid leaching methods to report a straightforward way of extracting recovered carbon (RC) from SCC as anode material for lithium-ion batteries (LIBs). The results show that alkaline and acid leaching conditions at 70 °C with 1 M NaOH and HCl solution individually in 6 h and a liquid-solid ratio of 20:1 can result in RC with up to 94.63% carbon content than 49.38% in SCC, exhibiting a typical graphite structure. SCC and RC materials are obtained after calcination at 400 °C in an inert atmosphere and used as anode materials (SCC-400 and RC-400). In this paper, The initial charging specific capacities are 490.0 mA h g-1, 195.4 mA h g-1, and 423.2 mA h g-1and initial coulombic efficiencies (ICE) are 67.8%, 78.9%, and 72.0% of RC-400, SCC, and SCC-400. RC-400 also shows excellent capacity retention and impedance values. This exciting finding provides a viable, non-hazardous, and resourceful method for treating and disposing of SCC from aluminum electrolysis.

Fe/C materials prepared by one-step calcination of acidified municipal sludge and their excellent adsorption of Cr(VI).

Biochar derived from municipal sludge can be applied to adsorption. But it usually requires activation and pickling due to the generation of impurities such as metal oxide particles, which is uneconomical. Here, a facile strategy, acidification-one-step calcination, was developed and sludge-based Fe-C materials with good Cr(VI) removal effect were obtained by regulating the amount of hydrochloric acid. The results show that the adsorption capacity of Fe/C-5 (the best sample) for Cr(VI) was 150.84 mg g-1. According to the Langmuir isotherm and pseudo-second-order kinetic model, the removal of Cr(VI) by Fe/C-5 is spontaneous and endothermic chemisorption process. In addition, Fe/C-5 has good ability to remove Cr(VI) under the interference of coexisting ions, and has good cycle stability. The removal of Cr(VI) by Fe/C-5 is considered to be synergistic process of adsorption and reduction. The Fe atoms were highly dispersed in Fe/C-5 and tightly bonded with C atoms, which not only strengthened the Cr(VI) adsorption by electrostatic attraction, but also activated the C atoms in the biochar material, so that the C atoms can reduce Cr(VI) to Cr(III) under acidic conditions. This may be due to the fact that acid pretreatment converted the iron in municipal sludge in the form of Fe-O/OH to free Fe3+ and entered the C lattice during the calcination process. In this work, Fe-C materials with excellent Cr(VI) adsorption capacity were prepared by one-step calcination method, which has important reference significance for the resource utilization of municipal sludge.

Modification of sludge-based biochar using air roasting-oxidation and its performance in adsorption of uranium(VI) from aqueous solutions.

Modification methods for sludge-based biochar are often complex and generally ineffective. In this study, sludge-based biochars were prepared at low cost using a simple air roasting-oxidation modification method and the adsorption performance on U(VI) was investigated. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) results together indicated that more carbon-oxygen functional groups were formed on the surface of oxidized biochar (OBC) compared to unoxidized biochar (BC). The adsorption performance of 550-OBC (biochar oxidized at 550 °C) on U(VI) was explored in batch experiments. The maximum adsorption capacity was up to 490.2 mg/g at 25 °C and pH 6, exceeding most of the reported biochars. 550-OBC also showed good adsorption performance at low U(VI) concentration, with 96% removal at pH 6 and an initial U(VI) concentration of 1 mg/L. Density functional theory (DFT) calculations indicated that the H-bond length between the solvated U(VI) and functional groups on the OBC was about 1.7 Å, which forms stronger H-bonds between them compared to that between U(VI) and BC (4.21 Å), and the adsorption energy value for this complex was highly negative -31.82 kcal/mol. In addition, 550-OBC exhibited high selectivity for U(VI) adsorption and excellent regeneration performance, making it a cost-effective and high-performance adsorbent.