While adsorption is a mainstream technique for Cr(VI) remediation, conventional iron-based powder materials suffer from agglomeration, passivation, and separation difficulties. The introduction of aluminum (Al) to construct Fe-Al bimetallic systems can effectively overcome the surface passivation barrier of single metals and induce interfacial synergistic effects. In this study, waste bamboo powder was employed as the carbon source, and Fe-Al bimetallic modified biochar beads (FeAlBCSA) with a three-dimensional porous cage-like structure were successfully fabricated via sodium alginate cross-linking encapsulation coupled with high-temperature pyrolysis. The results demonstrate that, at an initial concentration of 100 mg L-1, FeAlBCSA achieves nearly complete removal (similar to 100%) of Cr(VI) from aqueous solutions, with the effluent concentration below the limits specified in the Integrated Wastewater Discharge Standard. The maximum theoretical adsorption capacity of FeAlBCSA for Cr(VI) reaches 136.15 mg g-1, and exhibits strong resistance to oxidative deactivation of zerovalent iron (Fe0), maintaining stable Cr(VI) removal activity even after 30 days of air exposure. Characterization techniques, including XRD and XPS, reveal that the efficient removal of Cr(VI) by FeAlBCSA is governed by the synergistic interplay of interfacial reduction and adsorption processes. Specifically, the macroscopic bead structure facilitates direct physical solid-liquid separation, while the removal process is driven by electrostatic attraction, inner-sphere complexation, and the chemical reduction of Cr(VI) to Cr(III) by zerovalent iron (Fe0). This study effectively addresses the key limitations of conventional adsorbents, including rapid deactivation, limited adsorption capacity, and challenges in recovery.

Per- and polyfluoroalkyl substances (PFASs) are a class of highly persistent emerging pollutants frequently detected in various aquatic environments due to their widespread industrial applications and resistance to degradation. Adsorption holds great promise for removing PFASs, but its practical performance is constrained by insufficient selectivity for short-chain PFASs and difficulties in adsorbent regeneration. As an emerging separation technology, electrosorption removes charged species by adsorbing them in the electrical double layers forming at the interface between solution and the electrode, and has recently been applied to PFASs removal. Compared to traditional adsorption, electrosorption can regulate the capture and release of PFASs by adjusting the voltage, enabling electrode regeneration without using chemical regenerants. However, its performance strongly depends on the interfacial interactions between PFASs and electrode materials, as well as on electrode design. This paper reviews the adsorption mechanisms of PFASs, including hydrophobic interactions, electrostatic interactions, and fluorophilic interactions. It then summarizes the performance, removal mechanisms, and limitations of both conventional and novel adsorbents, including activated carbon, anion exchange resins, polymeric adsorbents, and porous framework materials. This paper focuses on recent research advances in electrosorption technology for PFASs separation and conducts a simplified techno-economic analysis of electrosorption materials. Using activated carbon and ion-exchange resins as benchmarks, it evaluates the cost of electrosorption materials and identifies their primary economic bottlenecks. Finally, this paper outlines future research directions to guide the continued optimization of PFASs adsorption and electrosorption separation technologies.

In recent years, the growing demand for functional textiles has propelled significant advancements in hydrophobic finishing technologies. Despite the exceptional performance of fluorinated hydrophobic materials, increasingly stringent environmental regulations targeting per- and polyfluoroalkyl substances (PFAS) have elevated fluorine-free alternatives to the forefront of research. This paper first systematically reviews the latest progress in typical fluorine-free hydrophobic materials, encompassing paraffin-based, acrylic-based, silicone-based, polyurethane-based, nano-silica modified materials, and bio-based materials, while analyzing their respective performance characteristics. Subsequently, the primary fabrication strategies for fluorine-free hydrophobic surfaces are elaborated, including impregnation, spraying, layer-by-layer self-assembly, electrospinning, sol-gel methods, plasma technology and vapor deposition. Building upon this foundation, the paper focuses on a comprehensive review of application studies involving the integration of multiple functionalities—such as self-cleaning, anti-icing, oil-water separation, and atmospheric water collection—on hydrophobic textile surfaces. Finally, the key challenges currently faced by fluorine-free hydrophobic materials are analyzed, and it is proposed that future research should prioritize the synergistic innovation of molecular design and finishing technologies to develop high-performance, multi-functional, sustainable, and cost-effective fluorine-free hydrophobic surfaces.

Soil degradation has become a pressing global issue, posing a significant threat to the soil environment, agricultural productivity, and food security. Factors such as nutrient depletion, erosion, and contamination have contributed to the declining health of soils worldwide. Biochar (BC) and phosphogypsum (PG) have shown great promise in improving soil fertility and quality, but their combined application and the full extent of their potential benefits and limitations remain underexplored and demand comprehensive attention. This review thoroughly assesses the individual applications of BC and PG as soil amendments, focusing on their respective physicochemical properties and their effects on soil structure, fertility, and plant growth. It also explores the synergistic effects of BC and PG when used in combination, emphasizing their potential to improve soil water retention, nutrient availability, and overall plant performance, thereby offering a promising solution for sustainable agriculture. Finally, the key considerations associated with the combined use of BC and PG, such as application rate, impact on soil health, and variability in soil types are addressed, while outlining future research directions to enhance their efficacy. In conclusion, the combined application of BC and PG contributes to impoved soil health and enhanced crop yields and promotes the integrated management of biomass waste and industrial byproducts such as PG, transforming agricultural and industrial waste streams into valuable resources, thus presenting a low-cost, environmentally sustainable approach to addressing soil degradation.

Increasing atmospheric CO2 levels necessitate the development of efficient capture and conversion technologies. Porous organic polymers (POPs) have emerged as promising candidates owing to their high surface area, structural tunability, and chemical stability. This review summarizes recent molecular engineering strategies for enhancing CO2 adsorption and electrochemical reduction (CO2RR), including heteroatom doping, post-synthetic functional group grafting, and integration with carbon-based materials. These approaches significantly enhance catalytic selectivity, stability, and conversion efficiency to value-added products, such as CO, formate, methanol, and ethanol, under mild conditions. Despite these advances, key challenges remain, including low intrinsic electrical conductivity, difficulties in scalable synthesis, and limited control over pore architecture. Future research should focus on developing dual-functional POPs capable of simultaneous CO2 capture and conversion, improving electrical conductivity, and establishing scalable and cost-effective fabrication strategies. The integration of computational design, in situ/operando characterization, and device-level optimization will be crucial for bridging the gap between laboratory-scale performance and practical industrial applications.

Soil acidification, salinization, and heavy metal pollution pose serious threats to global food security and sustainable agricultural development. Biochar, with its high porosity, large surface area, and abundant functional groups, can effectively improve soil properties. However, due to variations in feedstocks and pyrolysis conditions, it may contain potentially harmful substances. Industrial wastes such as fly ash, steel slag, red mud, and phosphogypsum are rich in minerals and show potential for soil improvement, but direct application may pose environmental risks. The co-application of biochar with these wastes can produce composite amendments that enhance pH buffering capacity, nutrient availability, and pollutant immobilization. Therefore, a review of biochar-industrial waste composites as soil amendments is crucial for addressing soil degradation and promoting resource utilization of wastes. In this study, the literature was retrieved from Web of Science, Scopus, and Google Scholar using keywords including biochar, fly ash, steel slag, red mud, phosphogypsum, combined application, and soil amendment. A total of 144 articles from 2000 to 2025 were analyzed. This review summarizes the physicochemical properties of biochar and representative industrial wastes, including pH, electrical conductivity, surface area, and elemental composition. It examines their synergistic mechanisms in reducing heavy metal release through adsorption, complexation, and ion exchange. Furthermore, it evaluates the effects of these composites on soil health and crop productivity, showing improvements in soil structure, nutrient balance, enzyme activity, and metal immobilization. Finally, it identifies knowledge gaps as well as future prospects and recommends long-term field trials and digital agriculture technologies to support the sustainable application of these composites in soil management.

Mercury pollution is becoming an increasingly serious issue in the ecological environment. Herein, two aminefunctionalized poly(pyrrole methane)s materials were synthesized from hydrazine for the efficient and selective removal of mercury ions in water. PPDHA and PPD12HA exhibit exceptional adsorption capacities of 1124 and 1080 mg center dot g-1 at 298 K, respectively, and achieve rapid adsorption equilibrium within 20 and 45 min, demonstrating their superior performance. Meanwhile, the two amine-functionalized poly(pyrrole methane)s have excellent adsorption selectivity, for distribution coefficient (Kd) values of Hg(II) greater than 5 x 105 mL center dot g-1, which is 103 (alpha s) times that of other divalent metal ions. Even after 10 adsorption-desorption cycles, the removal efficiency for 10 mg center dot L-1 of Hg(II) remained above 98 %. Additionally, the adsorption mechanism research reveals that amine groups serve as the primary adsorption sites for Hg(II) through infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculations. This study demonstrates the potential of amine-functionalized poly(pyrrole methane)s synthesized from hydrazine as highly efficient adsorbents for Hg(II) in water, providing a viable approach for further remediation of heavy metal-contaminated wastewater.

Designing phosphate adsorbents is often hindered by trial-and-error optimization that overlooks nonlinear coupling between preparation parameters and operational conditions. Here we present a unified, explainable machine-learning framework that links red mud modified biochar bead (RM/CSBC) preparation (red mud dosage, biomass dosage, and pyrolysis temperature) to operating variables (initial pH, reaction temperature, contact time, and initial phosphate concentration) and directly guides condition selection. Using 95 independent experiments, six regressors were trained and compared. Random Forest (RF) model demonstrated strong prediction accuracy, with R2 values of 0.916 for the training set and 0.892 for the test set. Support Vector Regression (SVR) model showed superior performance, achieving R2 values of 0.984 and 0.967 for training and test sets, respectively, with low RMSE (0.068 and 0.083) and PBIAS (5.41% and 6.86%). Feature importance analysis revealed red mud and biomass doses positively influenced phosphate adsorption, with surface active sites and phosphate concentration gradient playing significant roles. Experimental verification confirmed RF and SVR models provided accurate predictions under three representative conditions, with deviations between predictions and measurements of +0.66, +0.19, and −0.69 mg·g−1 for SVR and −1.08, −0.79, and −1.15 mg·g−1 for RF, offering reliable guidance for phosphate removal in wastewater using RM/CSBC. This work highlights the potential of using machine learning to optimize waste-based adsorbent materials for wastewater treatment, significantly reducing time and experimental costs.

This study investigates the use of struviterient-loaded magnesium-modified biochar beads (Ca/MgBC + NP) as a slow-release fertilizer and soil amendment, comparing its performance with commercially available slow-release fertilizers (SRF) in different soils and crop types. The results demonstrate that Ca/MgBC + NP exhibited satisfying swelling, water retention, and slow-release properties in all tested soils. In sandy soil, which showed the most significant differences (p < 0.05), Ca/MgBC + NP enhanced the growth of Brassica chinensis L. and Spinacia oleracea L. after 90 d, with shoot and root lengths, as well as fresh and dry weights, 1.25 2.84 times higher than those treated with SRF. The cation exchange capacity and organic carbon content of sandy soil were significantly improved (by 38.55

In this study, red mud (RM) was utilized as an iron and aluminum source, and reed biomass served as a carbon precursor to prepare red mud-modified biochar beads (RM/CSBC) via the gel-calcination method. Under a pyrolysis temperature of 900 °C and an RM/biomass dosage of 3 g each, RM/CSBC exhibited an optimal balance between adsorption performance and cost. Within typical pH range of 6–9 in wastewater, RM/CSBC maintained effective adsorption performance, while metal ion leaching (Fe ≤ 0.3 mg·L−1, Al ≤ 0.2 mg·L−1) complied with Class II surface water standards in China. Kinetic data were well fitted by the pseudo second-order model, supported by the Elovich model, indicating the involvement of both chemical and physical adsorption mechanisms. Isotherm results showed that the Langmuir model provided the best fit, indicating monolayer adsorption, with a maximum capacity of 85.16 mg·g−1 at 25 °C. XPS analysis revealed the formation of AlPO4 and FePO4 precipitates, confirming chemical precipitation as a key mechanism, along with electrostatic attraction and physical sorption. This study highlights the feasibility of RM/CSBC as an efficient and low-cost phosphate adsorbent and provides a theoretical basis for phosphorus removal and recovery from wastewater using waste-derived materials.

As the major form of antimony in the aqueous environment, the adsorption for the removal of Sb(OH)6- is a meaningful task. In this study, MgFe2O4-doped and iron(III) alginate cross-linked biochar ternary composite adsorbents, Fe/(MgFeO-BC) beads, were synthesized. The typical characterization analysis showed the successful synthesis of Fe/(MgFeO-BC) beads with the significant synergistic effect on the adsorption activity of MgFe2O4, the foaming effect of BC and the dispersing effect of the bead skeleton. The adsorption experiments showed significantly increased adsorption capacity of Fe/(MgFeO-BC) compared to the comparative adsorbent with Qm= 125.65 mg/g. The adsorption was able to reach equilibrium within 350 min. At low initial Sb(OH)6- concentration, the adsorption of Fe/(MgFeO-BC) can still achieve the standard antimony concentration (<= 0.02 mg/L), giving potential for practical applications. The introduction of MgFe2O4 enhanced the adsorption capacity while imparting magnetic properties of composite beads, resulting in significant improvement in separation efficiency. The -OH in the structure of MgFe2O4 is the adsorption active site of Fe/(MgFeO-BC), and the adsorption of Sb (OH)6- is accomplished mainly through ligand exchange and inner-sphere complexation. These results suggest that Fe/(MgFeO-BC) is a kind of promising Sb(OH)6- adsorbent with safe, green and recyclable properties, which provides a reference for the removal of Sb(OH)6- from wastewater, even at low concentrations.

A series of doped and dedoped polyphenol functionalized poly(pyrrole methane)s (234HBAs) were designed to investigate the impact of various dopants on mercury adsorption in water. The adsorption performance of dedoped 234HBAs showed no significant difference (ranging from 2961 to 3004 mgg(-1) at 318 K). However, the adsorption capacities of doped 234HBAs for mercury exhibited significant optimization and varied among different dopants (ranging from 3676 to 4103 mgg(-1) at 318 K). In addition to ultra-high adsorption capacity, 234HBAs also exhibited broad working pH range (2-11), fast kinetics (adsorption equilibrium within 10 min), good anti-ion interference and selectivity (K-d > 7.1 x 10(5) mLg(-1)), and excellent regeneration ability (little attenuation of adsorption capacity after 20 cycles). Furthermore, through characterization techniques (FT-IR, XPS) and the density functional theory (DFT) calculation, it was discovered that the presence of doped acid ions enhanced the capture and immobilization of mercury to varying extents besides the robust chelation binding of mercury by the adjacent phenolic hydroxyl groups. Among these ions, oxygen-containing citrate and sulfate exhibited a stronger ability to facilitate the removal of mercury compared with chloride ions. More importantly, this straightforward approach to fabricating functionalized adsorbents for the remediation of mercury-containing wastewater holds significant guiding implications for the treatment of other heavy metal and organic wastewater.

Ferrous modified biochar beads (Fe/SABC) with three-dimensional reed skeletal network uniformly dispersing Fe particles (FeO, Fe3O4 and Fe0) were developed by gelation-calcination method. Batch experiment results showed Fe/SABC could reach a phosphate recovery capacity of 52.92 mg/g, about 12 times that of unmodified biochar (BC) and twice that of ferrous modified biochar powder (Fe/BC). Fe/SABC exhibited better mass transfer performance than its powder form and maintained great phosphate recovery capacity within a wide initial pH range. Most co-existing metal ions enhanced phosphate recovery, while organic matters had little impacts. Characterization results indicated the main recovery mechanism was vivianite crystallization, with flower-like vivianite crystals (40-50 mu m in diameter) forming on both the surface and inside of Fe/SABC. During the phosphate recovery process, reductive Fe on Fe/SABC generated Fe2+ in situ and form vivianite nuclei with phosphate. Fe/ SABC provided attachment sites for vivianite nuclei and induced heterogeneous nucleation, consequently promoting vivianite auto-nucleation and growth. Furthermore, three-dimensional reed skeletal network within Fe/ SABC could create microdomain inert atmosphere to slow down reductive Fe and vivianite oxidation. The recovered products could be separated magnetically and had potential as slow-release fertilizers. In summary, this study confirms the feasibility of using Fe/SABC to recover phosphate via vivianite, providing new insights into phosphate recovery and future applications.

Phosphate and ammonia as important sources of eutrophication in water bodies, their removal and recovery are crucial for environmental management. In this study, magnesium-modified biochar beads (Ca/MgBC) capable of adsorbing PO3-4 and NH+4 simultaneously were prepared, the size of the biochar materials was successfully enlarged to realize recycling. Ca/MgBC has excellent simultaneous adsorption properties, compared to single PO3-4 or NH+4 solution, the adsorption capacity of PO3-4 was increased almost twice and that of NH+4 was increased almost 1.5 times in simultaneous adsorption solution. The Qmax, PO3-4 was 253.95 mg/g and Qmax, NH was 177.25 mg/g. Characterization results indicated that struvite crystallization was the main adsorption mechanism of PO3-4 and NH+4 in the simultaneous solution, which was also the reason for the promotion effect of simultaneous adsorption. Besides, ion exchange, surface precipitation and electrostatic attraction were also the other mechanisms for the adsorption. NP-loaded Ca/MgBC has a better slow-release potential of N and P under neutral condition. The adsorbed saturated Ca/MgBC still had good removal effects on seven common soil heavy metals (Cd, Hg, Cu, Pb, Cr, Zn and Ni). These results suggest that Ca/MgBC is a kind of promising adsorbent for phosphate and ammonia with safe, green, and sustainable properties, and offers the possibility of soil fertilization and remediation for carbon neutrality.

As the pollution and destruction of global water resources become more and more severe, the treatment of wastewater has attracted significant attention. The template method is a synthetic method in which the template is the main configuration to control, influence, and modify the morphology as well as control the dimensions of the material, thus achieving the properties that determine the material. It is simple, highly reproducible, and predictable, and more importantly, it can effectively control the pore structure, size, and morphology of the material, providing a novel platform for the preparation of adsorbent materials with excellent adsorption properties. This review focuses on the classification of the templates according to their properties and spatial domain-limiting capabilities, reviews the types of hard and soft template materials and their synthetic routes, and further discusses the modulation of the morphological structure of the materials by the introduction of templates. In addition, the application and adsorption mechanisms of heavy metal ions and dyes are reviewed based on the regulatory behavior of the template method.

Owing to the high concentration of swine wastewater produced via dry-wet separation, the cur-rent volume of discharge is difficult to process with biochemical treatments. Therefore, the primary enhanced flocculation pretreatments were conducted using both vermiculite and cationic poly-acrylamide (C-PAM). After adding 4 g/L vermiculite flocculant and 24 mg/L C-PAM, the turbid-ity, chemical oxygen demand, suspended substances, total phosphorus and NH4-N of the swine wastewater were 19.2 NTU, 454.5 mg/L, 34.0 mg/L, 5.5 mg/L, and 267.1 mg/L, respectively, with removal efficiencies of 95%, 66%, 87%, 86% and 10%. Under these conditions, the heavy metals in the flocculated supernatant and sediment met discharge standards. The vermiculite flocculant depended on the action of the dissolved substances in the vermiculite flocculant and the particulate substances. The dissolved species were dominated by electrical neutralization, forcing the colloids to destabilize. The destabilized colloids rely on van der Waals forces and the mass forces between the particulate part of the vermiculite flocculant and destabilized colloids to form flocs of differ-ent sizes. Therefore, the vermiculite flocculant exhibited a good sedimentation performance during flocculation. C-PAM swept and adsorbed flocs and organic pollutants to form larger secondary agglomerates, making them easier to settle and separate under particle gravity conditions. The elu-cidation of the synergistic effect of the vermiculite flocculant and C-PAM provides a strong scien-tific basis for the primary enhanced pretreatment of swine wastewater.

The reduction of fluoride concentrations in water is one of many concerns. Adsorption is the most widely used technology for fluoride removal and the center to development of adsorption technology is the improvement of adsorbents. This review classifies the typical fluoride removal adsorbents into four types: metal oxides/hydroxides, biopolymers, carbon-based, and other adsorbents. The exploitation of new materials and the synthesis of composite materials are two ways of developing new adsorbents. In comparison to the discovery of novel adsorbents for fluoride adsorption, research into the composite synthesis of different types of conventional adsorbents has proliferated in recent years. The traditional adsorbents used the earliest, metal oxides, can act as active centers in a wide range of applications for modifying and compounding with other types of adsorbents. This study emphasizes reviewing the research on fluoride removal by composite adsorbents synthesized from different types of metal-modified materials. Seven factors were compared in terms of material characterization, initial fluoride concentration, adsorbent dose, pH, temperature, reaction time, and maximum adsorption capacity. The modification of composite adsorbents is facile and the synergistic effect of the different types of adsorbents significantly improves fluoride adsorption capacity. Metal composite adsorbents are synthesized by facile coprecipitation, hydrothermal, or impregnation modification methods. The adsorption mechanisms involve electrostatic attraction, ion exchange, complexation, and hydrogen bonding. The fluoride adsorption capacity of composite adsorbents has generally improved, indicating that most modifications are successful and have application prospects. However, to achieve significant breakthroughs in practical applications, numerous issues such as cost, separation/regeneration performance, and safety still need to be considered.

In this study, water hyacinth was adopted to prepare biochar followed by modification using KMnO4. And the modified biochars were applied in Cd contaminated soil, exploring the effects of water hyacinth biochar on lettuce growth, Cd enrichment, soil enzyme activities and microbial changes by pot experiments. Modified biochar application significantly reduced the Cd accumulation in lettuce shoots and roots. Compared to the control, the application of water hyacinth biochar at 1% rate resulted in significant reduction of Cd contents by 40.7% and 33.7% in the shoots and roots of lettuce. Also, the reduction was 33.3% and 20.8% compared with the application rate of unmodified biochar. With the increase of biochar application, the amount of Cd was absorbed by lettuce shoots and roots showing significant reduction of plant Cd accumulation in response to the biochar application rate. Additionally, the lowest available Cd concentration in soil (1.34 mg kg-1) was obtained with the application of modified biochar at 1% rate, which might be the main reason for the lower Cd concentration in lettuce shoot and root parts. Furthermore, structural analysis showed that Cd was fixed on the modified biochar, in a passivated state, by larger specific surface area, more active sites and more stable covalent binding complexes leading to a strong decrease of the available Cd in the soil. Moreover, it was concluded that the increment of the enzyme activities in the soil was up to 2.51 times significantly following the application of modified water hyacinth biochar with 3% amount. Lastly, 16sRNA sequencing showed that biochar addition may lead to changes of microbial structure and abundance in soil.

The decrement of low concentration of fluoride to below standard (< 1 mg/L) is one of the current research hotspots. In this work, reed biochar beads cross-linked with cerium alginate were prepared by the gelationspheroidization-carbonization method to serve as an efficient fluoride adsorbent. The results of batch adsorption experiments showed that RBM-Ce (dosage of 1 +/- 0.01 g/L) could rapidly remove fluoride (concentration of around 10 mg/L) over a wide range of pH 3-9, and showed trace leaching amount of Ce ions during adsorption. The maximum adsorption capacity was 34.86 mg/g at normal temperature (20 degrees C), and the most consistent curve was Langmuir model in adsorption isotherms. In adsorption kinetics experiments, RBM-Ce showed a rapid adsorption rate capable of treating fluoride under certain standard within 15 min, and the fit was consistent with the pseudo-second order model. The SEM, EDS and XRD characterization indicated that CeO2 nanoparticles was dispersed and immobilized on the surface of biochar beads. From zeta potential, XPS, FTIR and Raman analyses, the adsorption mechanisms included ion exchange, electrostatic attraction, hydrogen bonding and complexation. All characterization and adsorption experiments pointed to RBM-Ce beads as promising adsorbents for fluoride removal.

Phosphorus (P) uptake from wastewater is a widespread concern due to the concurrent issues of P contamination and deficiency. A corn straw biochar-based eggshell bead composite (CS-E0.25-Ca(b)) was innovatively synthesized via a facile gelation-calcination method for efficient P recovery from urine solutions. Batch adsorption experiments showed that CS-E0.25-Ca(b) fabricated under optimal conditions exhibited a superior adsorption capacity (136.83 mg/g), which was 29.93 and 6.77 times that of pristine biochar (CSBC) and bead without the addition of eggshell respectively. CS-E0.25-Ca(b) exhibited favorable adsorption performance at pH 6.0-9.0 and in the presence of coexisting anion conditions, and showed good mass transfer performance in urine environment. Characterization results indicated that corn straw biochar matrix can lead to porous internal structure, which could facilitate better dispersion of CaO/Ca(OH)2 in eggshell to adhere on CS-E0.25-Ca(b). The comparison of FTIR and XPS analyses revealed that the surface precipitation with Ca-P products of hydroxyapatite (HAP) and amorphous calcium phosphate (ACP) was the predominant mechanism of phosphorus adsorption on CS-E0.25-Ca (b). In the slow-releasing experiment, the urine P-saturated CS-E0.25-Ca(b) displayed controllable and long-term slow-releasing property in neutral solution. Besides, CS-E0.25-Ca(b) after P release displayed favorable adsorption performance for common heavy metals, showing potential extra benefit for remediating heavy metal contaminated soils. All the results suggested that CS-E0.25-Ca(b) can realize superior P uptake from urine, also be potentially qualified as a promising slow-releasing fertilizer for soil P supply.