Nanohydroxyapatite (nHA) is a highly promising candidate for sustainable agriculture due to its excellent biocompatibility and environmental friendliness. However, their practical application has long been hindered by poor dispersibility. Herein, we develop an in situ approach that couples phosphorylated carbon sphere (PCS) formation from waste orange peels with concurrent nHA nucleation, creating nHA/PCS composites as a root exudate-triggered nanofertilizer. Density functional theory (DFT) calculations show weak binding energy at the nHA/PCS-nHA interface, thereby inhibiting nHA nanorods agglomeration. Compared to commercial nanohydroxyapatite (nCHA), nHA/PCS demonstrates superior interface stability and sustained-release properties. The nHA/PCS treatment significantly enhances lettuce seedling growth by improving root architecture and stimulating oxalic acid secretion, increasing leaf fresh weight by 60.95% compared to that with nCHA treatments. As a scaffold, the PCS matrix chemically anchors nHA nanorods for a controlled release in response to root exudates. This work presents an innovative strategy for engineering stable nanofertilizer delivery systems.

LiMnxFe1-xPO4 are considered highly promising cathode materials for next-generation lithium-ion batteries due to its high operating voltage, high energy density, excellent thermal stability, and environmental friendliness. To address the intrinsic limitations of LiMnxFe1-xPO4 cathode materials, including poor electronic conductivity and limited cycling stability, a Co and Ti co-doped LiMn0.6Fe0.4PO4 material with a gradient co-doping structure (denoted as LMFP-Co@Ti) was successfully synthesized via a two-step carbothermal reduction process. The Ti-rich outer layer effectively suppresses Mn dissolution and mitigates Jahn-Teller distortions, while the Co-doped inner layer enhances electronic conductivity and Li+ diffusion kinetics, achieving an optimized balance between electrochemical activity and structural integrity. Electrochemical evaluations demonstrate that the LMFP-Co@Ti electrode delivers an initial discharge capacity of 137.67 mAh g-1 at 1C and retains 80.5 % of its capacity after 500 cycles, markedly outperforming pristine LiMn0.6Fe0.4PO4 (LMFP) and the uniformly co-doped a uniformly co-doped sample LiMn0.6Fe0.36Co0.01Ti0.03PO4/C (LMFP-CoTi). Even under high-rate conditions (10C), the LMFP Co@Ti maintains an impressive discharge capacity of 100.94 mAh g-1, confirming its superior rate capability and long-term cycling stability. This work provides new insights into the rational design of dual-doped olivine-type cathodes, demonstrating that the gradient structure can effectively balance high-rate performance and longterm structural stability for next-generation lithium-ion batteries.

Excessive fluorspar mining has underscored the urgency of recovering fluorine from fluorine-enriched phosphate waste. In this work, a novel method was proposed to recovering fluorine from fluorine-enriched phosphate waste and convert it into advanced fertilizers via roasting. The thermodynamics were systematically studied using the Factsage 8.0 software and HSC Chemistry 6.0. The effects of the roasting temperature and time on the defluorination rate and weight-average degree of polymerization (DPw) were investigated. The results showed that the defluorination rate keep increasing, while the weight-average degree of polymerization first increased and then decreased as the temperature increased. The reaction process was systematically analyzed using XRD, FT-IR, SEM-EDS, TG-IR-MS and XPS, and the reaction mechanism of defluorination and polymerization was elucidated through density functional theory (DFT) calculation and kinetic studies. Additionally, the performance of the fertilizer was verified through slow-release and sulfuric acid curing experiments. The DPw of a calcium polyphosphate slow-release fertilizer was 1.28, the defluorination rate reached 31.3%, and after 30 days, 97.0% and 84.9% of the phosphorus and calcium were released, respectively. After curing the defluorination rate increased to 70.2%, and the proportions of available phosphorus and calcium content were 90.3% and 80.3%. This work demonstrates a green, pollution-free strategy for the separation and recovery of fluorine and for valorizing fluorine-enriched phosphate waste.

In this study an electro-deionization (EDI) technology employing α-zirconium hydrogen phosphate (α-ZrHP) inorganic ion-exchange resins is investigated for purifying ⁶⁰Co-containing low-level radioactive NaNO₃ wastewater. Special focus is given to the scale-up effects from lab to miniature pilot-scale operation. The influence of key process parameters including voltage, solution flow rate and volume ratio, as well as feed concentration on NaNO₃ desalination performance and water dissociation behavior was studied. Under optimal conditions, the system achieved a treatment capacity of 9.53 L/h, a water recovery rate of 81.8%, a specific energy consumption of 1.73 kWh/m³ , and a removal rate exceeding 99% for both NaNO₃ and Co (NO₃) ₂. The EDI process demonstrated superior performance compared to electrodialysis (ED), and the transfer behavior of Co²⁺ was revealed. The treatment of genuine low-level radioactive wastewater resulted in a 97.55% removal of 60Co β-radioactivity. The results confirm that the inorganic resin-packed EDI system, leveraging the exceptional radiation resistance of the inorganic material and efficient desalination capability, is a promising technology for radioactive wastewater treatment. The successful lab to miniature pilot scale-up provides valuable insights for future industrial implementation of this technology.

The treatment of biomass waste and remediation of environmental pollution caused by heavy metal ions have become critical concerns in environmental science. Herein, an innovative approach was developed to substitute conventional phosphoric acid modification of ready-made biochar. Waste bagasse was treated in situ with wet-process phosphoric acid(WPPA) to prepare a novel biochar material for Cr (VI) removal from industrial wastewater. The adsorption efficiency of Cr (VI) was systematically investigated using biochar pyrolyzed at various temperatures. Furthermore, comparative analyses were conducted to evaluate the structural properties of biochar before and after WPPA modification, along with their corresponding Cr (VI) adsorption performances. The GW400 biochar, modified with WPPA and pyrolyzed at 400 degrees C, demonstrated significantly enhanced characteristics, including abundant surface functional groups, larger specific surface area (SSA) and higher carbon yield. This in situ modification consequently achieved Cr (VI) adsorption rate of 96% with a maximum adsorption capacity of 97.38 mg/g. Kinetic studies revealed rapid adsorption characteristics, with the pseudo-second-order model indicating that 90% of the total adsorption capacity could be achieved within the initial 10 min. The results of adsorption experiments and DFT calculations jointly demonstrated that the main adsorption mechanisms involve electrostatic attraction, redox and surface complexation. This work presents an efficient, economical and green way of water treatment based on the principle of waste for waste.

The bulk chemical fertilizer industry is highly sensitive to costs, with raw material input often being decisive. Herein, we propose a strategy for using low-cost citrate-soluble ammonium phosphates to produce the water-soluble fertilizer of ammonium polyphosphates (APP, (NH4)(n+2)PnO3n+1, n < 20). Citrate-soluble traditional process monoammonium phosphate (T-MAP) and urea undergo polycondensation in a 400 L kneading reactor. Resulting APP powder (T-MAP-APP) obtains less water-insoluble of 0.57% than that of T-MAP (11.18%). Impurities in T-MAP are regulated, in which metal ions cap P-OH to raise melting point (>200 degrees C, enabling solidification), while SO42- disrupts crystals for better solubility. Pilot-scale preparation (100 kg/batch, 10 repetitions) shows stable weight-average polymerization degree (PD) of 2.79-2.97 and water-insoluble of merely 0.42-0.55%. As a promising industrial route, T-MAP-APP achieves a cost reduction of 22%, which is expected to substitute the water-soluble monoammonium phosphate (W-MAP) as raw material, thereby driving the APP market as water-soluble fertilizers.

Compared with conventional phosphate rock (PR), middle-phosphate rock (MPR) shows a significant reduction in P2O5 content, coupled with elevated concentrations of SiO2 and sesquioxides (R2O3). The mineralogical composition, silicon speciation, and structural characteristics of MPR were characterized using an integrated suite of analytical techniques, including inductively coupled plasma atomic emission spectrometer (ICP-AES), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), polarized light microscopy (PLM), and mineral liberation analysis (MLA). Based on these compositional and structural characteristics of MPR, a methodology for grinding and classification was proposed. Through precise blending and fine beneficiation, the MPR blending ratio [m(MPR)/m(total PR) & times; 100%] achieved 32.21 wt %, ensuring operational stability in WPA production. This integrated approach successfully produced 16667.90 tons of 60 wt % (N+P2O5) powdered monoammonium phosphate (MAP) and 222312.44 tons of 64 wt % (N+P2O5) granular diammonium phosphate (DAP) superior products.

Aligning with sustainable agricultural needs, amino acid-enhanced monoammonium phosphate (MAP) shows strong potential for improving nutrient utilization efficiency which is vital for increasing crop yields while reducing environmental impacts. But the lack of a clearly green production process hinders its large-scale production and application. This study investigated the effects of amino acid addition stage (before or after ammoniation) and dosage on the manufacturing process, MAP product properties, and agronomic performance. Results showed that adding 1.0% amino acids before ammoniation reduced water-insoluble substances by 11.93% through chelation with Mg2+, thereby lowering slurry viscosity and regulating particle size distribution, which reduced resistance loss and ultimately decreased carbon emissions. Meanwhile, threonine/serine esterification with phosphoric acid decreased free amino acids in the final product, but it increased MAP fertilizer utilization by 32.67% while simultaneously decreasing phosphorus accumulation in agriculture, resulting in notable economic and environmental benefits. Thus, adding 1.0% amino acids before ammoniation is the preferred green method for producing enhanced MAP. This study provides crucial insights for efficient-enhanced fertilizers production and can advance the sustainable development of industrial and agricultural chains.

Sodium manganese fluorophosphate (Na2MnPO4F), as a novel fluorophosphate-based cathode material, has attracted widespread attention in the scientific community in recent years due to its high theoretical specific capacity, low cost, and eco-friendliness. However, this material has problems such as poor electronic conductivity and obvious capacity fading during cycling, which limit its practical application. Transition metal cation doping and carbon coating modification represent common yet effective strategies for enhancing the electrochemical properties of phosphate-based materials. In this study, Na2MnPO4F/C composites and Na2Mn0.98M0.02PO4F/C composites (where M = Fe2+, Co2+, Ni2+) were synthesized via a wet ball milling and in situ pyrolytic carbon coating procedure to investigate the influence of transition metal cation doping on the structural and electrochemical properties of Na2MnPO4F as a cathode in lithium-ion batteries. The phase constituents, morphological structure, and electrochemical performance of the as-obtained materials were examined using various characterization techniques. The results indicate that the introduction of a small amount of transition metal cations does not alter the crystal structure of Na2MnPO4F; all samples maintain a well-crystallized monoclinic phase with the P2(1/n) space group. The samples exhibit a micro-scale aggregate architecture with varying degrees of aggregation, composed of primary nanoparticles measuring approximately 10 to 50 nm. When utilized as cathode materials in lithium-ion batteries, the electrochemical performances of the metal ion-doped Na2MnPO4F/C composites is enhanced compared to the undoped variant. Notably, Na2Mn0.98Ni0.02PO4F/C demonstrates the best comprehensive electrochemical performance, achieving a high initial specific discharge capacity of 116.9 mAh & centerdot;g(-1) with no significant capacity decay observed after 50 cycles at a charge-discharge current density of 10 mA & centerdot;g(-1) within a voltage range of 1.5 V to 4.8 V.

Metallic Li is considered a promising anode material for high-energy batteries due to its extremely high theoretical capacity and lowest electrochemical potential. However, the commercialization of lithium metal batteries faces significant challenges, primarily due to uncontrollable growth of lithium dendrites and substantial volume changes during charge and discharge, which result in poor safety, low stability, and limited cycle life. Here, a spinel-type Li4Ti5O12 (LTO) coating was prepared by a simple high-temperature solid-phase method and attached to the separator surface of lithium metal batteries as a coating through a mechanical coating approach. Benefiting from its improved electrolyte wettability and high ionic conductivity of the modified coating, it exhibited a low interfacial resistance, enabling lithium ions to rapidly penetrate the coating and maintaining a uniform lithium-ion flux at the electrode interface. It alleviated the growth of Li dendrites caused by the uneven distribution of lithium ions and mitigated the volume change. This composite coating achieves excellent cycling performance in half-cells, symmetric cells and button-type full cells. At a current density of 0.5 mA cm-2 and a capacity of 1 mAh cm-2, the Li/PP@LTO||Cu battery achieves stable cycling for over 180 cycles with a Coulombic efficiency maintained at 98%. At current densities of 1 mA cm-2 and capacity of 1 mAh cm-2, the Li/PP@LTO||Li/PP@LTO composite symmetric battery can stably cycle for 900 h with a polarization voltage stabilized at 25 mV. This work demonstrates a straightforward approach to develop dendrite-free lithium metal anodes, addressing the critical challenges of interface instability in lithium metal batteries.

The effects of ammonium polyphosphate (APP, (NH4)(n+2)PnO3n+1, n < 20) on soil phosphorus (P) availability vary depending on polymerization distributions and the soil type, yet the mechanisms driving these differences remain unclear. This study explored the availability and transformation of P affected by APP1 (P species of P-1-P-2) and APP2 (P species of P-1-P-7) in two different soils, in comparison with conventional ammonium phosphates (APs). APP application increased Olsen-P by 10.7-24.8% in calcareous soil, but decreased it by 2.6-10.8% in acid soil relative to APs. In calcareous soil, APP significantly increased soluble-P, adsorbed-P, and Fe-associated P, as reflected by CaCl2, NaHCO3, and NaOH extractable Ps, while decreased more stable Ca-associated P and occluded P indicated by NH4Ac and Na3C6H5O7-Na2S2O4-NaOH extractable Ps. The changes in the composition of CaCO3 and Fe/Al oxides together with/without the reduced organic carbon loss mainly contributed to the decrease in P sorption/precipitation and the increase in P desorption/dissolution. In acid soil, APP significantly increased microbial biomass P, leading to reduced labile inorganic P and elevated labile organic P. Meanwhile, APP increased both oxalate-extractable and complex Fe/Al oxides, which affected P adsorption-desorption to a certain extent. Compared to APP1, APP2 resulted in P existing in a more labile adsorbed state, thereby increasing P availability in both calcareous and acid soils. The main processes affecting P availability in the calcareous soils were abiotic transformations, while biotic transformations played the key role in the acid soils.

Sodium-ion batteries (SIBs) are promising candidates for large-scale energy storage, yet their development is hindered by sluggish kinetics and severe polarization of cathode materials. Prussian blue analogues (PBAs), despite their open frameworks, suffer from weak -C≡N- covalency and highly localized electronic states, leading to structural instability during Na+ insertion/extraction. Herein, entropy engineering is employed to regulate the electronic structure of PBAs by constructing a series of high-entropy Prussian blue analogues (HEPBAs) (HE-FeMnCoMCu, M = Ni, V, Ti, Zn) with a fixed Fe-Mn-Co-Cu backbone and systematically varied fifth metal. We demonstrate that the N-coordination energy levels critically determine the degree of electronic delocalization across the -C≡N- bridges. Among the investigated systems, Ni2+ exhibits the optimal energy-level alignment with the C≡N π* states, significantly strengthening metal-ligand-metal electronic coupling and promoting ligand-to-metal and metal-metal charge transfer (LMCT/MMCT). Consequently, the Ni-containing sample shows the strongest and broadest LMCT/MMCT absorption in ultraviolet-visible-near-infrared (UV-vis-NIR) spectra and a more complex local electronic environment in X-ray photoelectron spectroscopy (XPS) analysis. Benefiting from enhanced electronic delocalization, HE-FeMnCoNiCu exhibits reduced polarization, the lowest charge-transfer resistance, and accelerated Na+ diffusion kinetics. As a result, it delivers a high reversible capacity of 87.21 mAh g-1 at 1 A g-1 and retains 85.45% of its capacity after 1000 cycles at 500 mA g-1. This work reveals that entropy-driven modulation of N-coordination energy levels fundamentally governs the electronic delocalization and electrochemical kinetics of PBAs, offering a rational design strategy for high-performance SIBs.

Silicon has emerged as one of the most promising anode materials for next-generation lithium-ion batteries due to its exceptional specific capacity and abundant resources. However, its widespread application is hindered by structural deformability and low intrinsic conductivity. By strategically integrating a conductive carbon matrix with silicon, it becomes feasible and efficient to enhance the electrical conductivity of silicon and accommodate the stress-induced volume expansion during battery operation. In this study, a series of silicon/graphite/amorphous carbon (Si/G/C) composites were prepared using mechanical milling and carbothermal reduction. The study focused on two main aspects: the effect of the ratio of micro-sized silicon to flake graphite on the properties of the composite and the compatibility of different-scale silicon particles (micro-sized silicon and nano-sized silicon) and different kinds of natural graphite (flake graphite and cryptocrystalline graphite). The results reveal that when micro-sized silicon and flake graphite are combined, the graphite is fragmented more thoroughly, resulting in smoother surfaces and reduced aggregation of secondary particles. The composites with a mass ratio of 7:3 micro-sized silicon to flake graphite have the smallest specific surface area and pore size, homogeneous distribution, and stable structure. This exceptional carbon-to-silicon ratio endows the Si/G/C composite with rapid reaction kinetics, enabling a specific discharge capacity of 854.1 mAh g(-1) after 200 cycles at 1A g(-1). The findings offer valuable insights into the design and optimization of silicon-based anode materials for next-generation lithium-ion batteries.

Fluorine resources mainly occur in fluorspar and phosphate rock and recovery of fluorine from the phosphorus chemical industry has become increasingly significant because of the excessive exploitation of fluorspar resources. In this study, a new method was proposed to prepare the calcium magnesium polyphosphate (CMPP) and recover the fluorine by using the fluorine-containing phosphoric acid residue and phosphate tailings as the raw materials. The effect of reaction temperature, time and material ratio on the defluorination rate, as well as the degree of polymerization distribution and polymerization ratio of the resultant CMPP were investigated systematically. The total defluorination rate was 64.64%, and the weight-average degree of polymerization and polymerization ratio of CMPP were 2.98 and 86.82% under the optimal conditions. The reaction process of CMPP preparation was systematically analyzed based on 19F NMR, TG-IR, XRD, SEM, XRF, and TGRS characterization, and the mechanism of fluorine escape and phosphorus polymerization was elucidated. This work provides a new promising method for fluorine recovery and the resourceful utilization of solid waste from the phosphorus chemical industry.

Dense polymeric blends with (transiently) fixed positive charges are ideal as anion exchange membranes (AEMs) for treating acidic wastewater with salts via diffusion dialysis. Pyrrolidone from vinylpyrrolidone (VP) copolymers offers a unique chemistry compared to conventional quaternary ammonium, enabling greener and more efficient membrane synthesis. The hydrophobic/hydrophilic characteristics and the miscibility of copolymers with membrane materials determine the microstructure and consequent membrane properties. Here, a commercial copolymer, poly(vinylpyrrolidone-co-vinyl acetate) (P(VP-VAc)), was blended with membrane material polyether sulfone (PES) to prepare PES-P(VP-VAc) blend membranes. The influence of VP content in the copolymers, casting solution composition, and membrane microstructure on the physicochemical properties, mass transfer performance, and stability of the membranes was systematically investigated. It was found that the copolymers (63.8-73.2 wt % VP content, similar to 80 kDa) were partially miscible with PES, resulting in microphase-separated membranes. With the VP mass fraction in the blend membranes increased, both the membrane mass increase and volume swelling degree in water and acid increased. When the membrane VP mass fraction reached 41.5 wt %, the permeability coefficients of sulfuric acid and ferrous sulfate increased rapidly. The PES-P(VP-VAc 6/4) blend membrane, containing 41.5 wt % VP, exhibited sulfuric acid and ferrous sulfate permeability coefficients of 228.5 and 4.1 x 10-9 m2/h, respectively. By simply blending two commercial polymers, this study successfully prepared PES-P(VP-VAc) blend AEMs with a microphase-separated structure, and their application in sulfuric acid recovery through diffusion dialysis was evaluated.

To achieve the upcycling of annually upsurging lignocellulosic wastes, the artificial humification of furfural residue is investigated under hydrothermal conditions with the objective of producing a high-concentration nitrogen-phosphorus-potassium (NPK) suspension fertilizer. Through orthogonal analysis, process conditions are optimized as a liquid-to-solid (aqueous KOH to furfural residue) ratio of 15, a reaction time of 5 h and a hydrothermal temperature of 160 degrees C. Subsequently, we screen out a formulation of suspension agents to stabilize the alkaline leachate, in which 0.50% sodium lignosulfonate, 0.20% xanthan gum and 0.05% potassium sorbate are incorporated via wet ball-milling. The Herschel-Bulkley equation well fits the rheological characteristics of the resulting suspension fertilizer with R2 value exceeding 0.99. This suspension system is thus determined as one pseudoplastic non-Newtonian fluid. Due to higher static viscosity, it demonstrates superior anti-agglomeration capacity within a temperature range of 15-55 degrees C, while flowing smoothly through pipes during high-speed spraying onto the soil relied on its shear thinning. These findings provide novel insights for the high-value utilization of bio-waste and the development of new fertilizers with less consumption of energy and water.

Prussian blue analogues (PBAs) are promising cathode materials for sodium-ion batteries (SIBs). However, conventional co-precipitation synthesis using soluble salts often results in rapid reaction kinetics, leading to lattice vacancies and residual coordinated water in PBAs. Although chelating agents can slow reaction rates, they increase production costs. Additionally, pure iron-based PBAs suffer from low capacity, while pure manganese-based PBAs exhibit poor cycling stability. To address these challenges, this study focuses on iron-manganese-based PBAs (Fe-MnHCF) synthesized via the solubility product principle. By selecting insoluble salts (FeC2O4/MnC2O4) to control reaction kinetics without chelators, the method reduces lattice defects and coordinated water content of Fe-MnHCF materials. Building upon this technology, MnCl2 is incorporated into the electrolyte to suppress Mn dissolution from Fe-MnHCF materials during the electrochemical sodium-storage cycling process. Through a combination of experimental characterization, theoretical analysis, and numerical simulation, this study systematically investigates the effects of synthesis parameters, component optimization, and electrolyte modification of the fabricated materials. The optimized Fe-MnHCF electrode delivers a high capacity of 115.7 mAh g-1 and retains 90.5% of its reversible capacity after 1500 cycles at 10C in the electrolyte containing 0.5 wt% MnCl2, demonstrating superior rate capability and long-term stability. This work provides a cost-effective strategy for defect engineering in PBAs and offers valuable insights into electrolyte optimization for high-performance SIBs.

High capacity, selective recovery and separation of precious metals from complex aqueous solutions is essential but remains a challenge in practical applications. Here, we prepared a thiophene‐modified aromatic porous organic cage (T‐PAC) with high stability for precise recognition and recovery of gold. T‐PAC exhibits an outstanding gold uptake capacity of up to 2260 mg/g with fast adsorption kinetics and high adsorption selectivity. It's also used to selectively recover gold from a variety of complex aqueous solutions in a stable and efficient manner. The theoretical calculations and dedicated experiments suggest that anion‐π interactions between the [AuCl4]‐ and TFP fractions on T‐PAC cooperated with S/N boning and redox effects play the decisive role in the highly efficient gold recovery performance.