Selective Adsorption Of Phosphate Research Articles

Carboxymethyl cellulose/ microfibrillated cellulose hydrogel beads for phosphate recovery: Templating effects of in situ-grown CaCO3 nanoparticles from CO2

Carboxymethyl cellulose (CMC) hydrogel is a promising adsorbent. However, its weak chemical interaction with phosphate restricts the adsorption capacity and selectivity for nutrient recovery. In this study, CaCO3 nanoparticles were grown with microfibrillated cellulose using CO2 before crosslinking CMC into hydrogel beads to improve phosphate adsorption through chemical interactions. Scanning electron microscope showed the rough surface with wrinkles and the slightly porous surface after removing CaCO3. Fourier-transform infrared spectroscopy confirmed calcite formation in CMC hydrogel and the removal through chelation based on the calcite peak at 852 cm−1. However, the calcite crystallinity was absent in the X-ray diffraction analysis due to the hindrance of the amorphous hydrogel. The phosphate adsorption capacity was increased to 109.87 mg/g by growing CaCO3 nanoparticles instead of blending. After removing CaCO3 nanoparticles, the phosphate adsorption capacity was further raised to 132.21 mg/g due to the increment of active sites and surface area. The adsorption was stable between pH 3 and pH 7, and it was only significantly affected by HCO3- due to alkalinity changes. The selective phosphate adsorption was driven by chemical interaction, as proven by the pseudo-second-order kinetic model and Langmuir isotherm. After 6 cycles, the adsorption capacity was maintained more than 80 %.

La-doped CeO2/rGO hybrid with high oxygen vacancy to enhance phosphorus adsorption by capacitive deionization

Cerium oxide is one of the most attractive electrode materials in capacitive deionization (CDI) technology for selective phosphate adsorption due to the specific interaction. However, Ce3+/Ce4+ ratio and material conductivity of cerium oxide electrode determine the adsorption performance. Herein, a dual strategy was exploited with polyol-solvothermal reaction in the presence of graphite oxide and cerium salt followed by hydrothermal La-doping to obtain the three-dimensional (3D) assembly of La-doped CeO2 at the reduced graphene oxide (La-CeO2/rGO). The as-prepared La-CeO2/rGO hybrid exhibited interconnected structure with CeO2 uniformly distributed on the rGO support. La3+, by partially replacing Ce4+ in the lattice, was evenly fused into CeO2 nanosphere, enhancing the content of Ce3+ and oxygen vacancies and inhibiting lattice distortion. As a CDI positive electrode, the La0.15-CeO2/rGO with optimal La doping achieved the maximum theoretical adsorption capacity of 118.7 mg P/g with high separation factor (αSO42-P = 13.9), superior to the CeO2/rGO (67.8 mg P/g, αSO42-P = 10.1). In addition, the La-CeO2/rGO electrode is extremely robust, with excellent adsorption performance in wide pH range and good regeneration ability, compared to CeO2/rGO. This work proves that the synergy of trace La doping and 3D rGO support effectively improves the adsorption performance of La-CeO2/rGO electrodes and enhances the cycling stability of CDI devices. The corresponding adsorption mechanism was demonstrated.

Lanthanum-modified tobermorite synthesized from fly ash for efficient phosphate removal.

Phosphate removal from water by lanthanum-modified tobermorite synthesized from fly ash (LTFA) with different lanthanum concentrations was studied. LTFA samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and Brunauer‒Emmett‒Teller specific surface area analysis. The results showed that the LTFA samples were mainly composed of mesoporous tobermorite-11Å, and LTFA1 with a lanthanum concentration of 0.15M had a high specific surface area (83.82 m2/g) and pore volume (0.6778 cm3/g). The phosphate adsorption capacities of LTFA samples were highest at pH 3 and gradually decreased with increasing pH. The phosphate adsorption kinetics data on LTFA samples were most accurately described by the Elovich model. The adsorption isotherms were in the strongest agreement with the Temkin model, and LTFA1 showed the highest phosphate adsorption capacity (282.51mg P/g), which was higher than that of most other lanthanum-modified adsorbents. LTFA1 presented highly selective adsorption of phosphate with other coexisting ions (HCO3-, Cl-, SO42-, and NO3-). In addition, phosphate was adsorbed onto LTFA samples by forming inner-sphere phosphate complexes and amorphous lanthanum phosphate. This study provides technical support for development of efficient fly ash-based phosphate adsorbents.

Emulsion synthesis of cellulose/lanthanum alginate /La (Ⅲ) composite microspheres for efficient and selective adsorption of phosphate

Phosphorus exceeding the standard will destroy the ecological environment of the freshwater resources and endanger the survival of aquatic animals. Due to the intrinsic complexation between La(Ⅲ) and alginate, in this study, lanthanum hydroxide was first prepared from lanthanum nitrate, the chemical crosslinking agent was replaced by La(Ⅲ), and cellulose/lanthanum alginate/La(OH)3 composite microspheres (CSPGs-La) were synthesized using polyethyleneimine (PEI) as a crosslinking agent through the emulsification process in one pot. In comparison, the adsorption capacity of 80 mg L−1 PO43− treated with CSPGs-La, CSPGs-Ech (Samples where the chemical crosslinking agent was not replaced by La(Ⅲ)) and La(OH)3 was 159.5 mg g−1, 57.51 mg g−1 and 137.4 mg g−1, respectively. CSPGs-La has good swelling performance, unique three-dimensional structure and mass transfer efficiency, which are the important reasons for its strong ability to capture phosphate. In the presence of coexisting anions, CSPGs-La can still accurately adsorb PO43−, showing good adsorption selectivity. Intra-surface spherical complexation and electrostatic adsorption play an important role. When the dose of CSPGs-La is 1.35 g L−1, the phosphorus pollutants in the actual domestic sewage can be reduced to 10 μg L−1 below. After five adsorption cycles, the retention rate of phosphorus removal performance is 87.7 %. This study provides a green, easy to implement, and promising solution for the preparation of efficient and selective phosphorus removal adsorbent.

Selective Phosphate Adsorption Using Topologically Regulated Binary-Defect Metal-Organic Frameworks: Essential Role of Interfacial Electron Mobility.

Metal-organic framework (MOF)-modified biochars (BC) have gained recognition as potent adsorbents for phosphate. However, essential insights into the electronic interfacial state of the MOFs remain lacking. In this study, we propose a novel topological transformation strategy to directionally regulate the interfacial electronic states of BC/MOFs composites. The optimized BC/MOFs exhibited an excellent selective phosphate adsorption capacity of 188.68 mg·g-1, coupled with rapid sorption kinetics of 6.81 mg·(g·min0.5)-1 in simulated P-laden wastewater. When challenged with real bioeffluent, such efficacy was still maintained (5 mg·L-1, 25.92 mg·g-1). This superior performance was due to the Fe(III) → Fe(II) transition, promoting electron mobility and leading to the anchoring of Mg(II) to form specific coordination unsaturated sites (Mg-CUS) for phosphate adsorption. Importantly, the simultaneous regulation of binary defects further enhances electron mobility, resulting in the formation of sp3 unequal hybrid orbitals with a stronger internal coupling capability between Mg 3s in Mg-CUS and O 2p in phosphate. Furthermore, the high electron affinity of Mg effectively promotes electron cycling, endowing BC/MOFs with a distinct self-healing capability to facilitate phosphate desorption. The outcomes of this study provide novel perspectives for electronic regulated phosphate adsorption.

Incorporation of La/UiO66-NH2 into cellulose fiber for efficient and selective phosphate adsorption

The pollution resulting from excessive phosphorus usage has garnered significant attention. In this study, the cellulose composite fiber was fabricated by immobilizing La doped UiO66-NH2 nanoparticles onto cellulose fiber through a facile in-situ hydrothermal synthesis method. Nanosized UiO66-NH2 particles were uniformly distributed on the CCF, and La doping induced defects in the crystal structure of UiO66-NH2, which provided active sites for phosphate absorption. The composite cellulose fiber materials exhibited fast (1 h) and effective (7.6 mg g−1) adsorption properties to phosphate compare to other adsorption materials. Moreover, the adsorption process for phosphorus were spontaneous and endothermic, which accorded with pseudo-second-order kinetic and Langmuir isotherm models. FTIR and XPS analyses elucidate that chemical bond and electrostatic attraction between Zr/La-O-P play pivotal roles in phosphate capture mechanism. The adsorption was driven by two interaction, namely electrostatic interaction between -NH2 and phosphate and chemical bond of Zr-O-P and La-O-P. Notably, the composite fiber exhibited effective adsorption ability within a wide pH range of 3–7, and excellent selectivity to phosphate under common interfering ions such as SO42-, NO3-, and Cl-. Overall, this research has provided new thinking of La-UiO66-NH2/CCF as a promising phosphate adsorbent possessing favorable adsorption properties, which will facilitate the utilization of cellulose composite fibers in wastewater treatment.

Al(iii)-based MOF for the selective adsorption of phosphate and arsenate from aqueous solutions

Schematic representation of the application of DUT-5 to remove phosphate and arsenate from aqueous solutions.

Oxygen-vacancy abundant δ-Bi2O3@PCNF anode for selective phosphate removal with exceptional capacity

Excessive phosphate concentration in waterbody will lead to eutrophication and deterioration of water quality. Capacitive deionization (CDI) is an environmental-friendly technique for ion removal, and the phosphate ions can be selectively removed and accumulated by designing the CDI electrode materials with specific phosphate bonding capability. Herein, a δ-Bi2O3-modified porous carbon nanofiber (δ-Bi2O3@PCNF) was constructed by solvothermal reaction in the presence of polyhydric alcohols. Due to abundant oxygen vacancies and high flexibility, the δ-Bi2O3@PCNF was used directly as a self-supporting CDI anode for selective phosphate adsorption. Under the optimized conditions, the adsorption capacity of phosphate arrived at 99.6 mg P/g in 50 mg P/L solution, and the adsorption maximum of 127.5 mg P/g was achieved according to Langmuir adsorption model. In the dual-anion solution containing PO43– and Cl–, the δ-Bi2O3@PCNF electrode still maintains the high selectivity, with a P separation factor of 22 (CPO43–/CCl– = 1:5, molar ratio) in PO43–/Cl– mixture. By using the δ-Bi2O3@PCNF-based CDI device, the actual paddy drainage has realized the ultralow phosphate concentration down to 0.03 mg P/L. The related mechanisms involved in phosphate adsorption on δ-Bi2O3@PCNF were proposed. This work demonstrates the great potential of CDI technology for low-concentration phosphorus recovery, owing to the high selectivity of the δ-Bi2O3@PCNF electrode material.

Natural Vermiculite Slice Modified by CTAB and Zirconium for Selective Adsorption of Phosphate

Natural Vermiculite Slice Modified by CTAB and Zirconium for Selective Adsorption of Phosphate

Environmentally friendly crab shell waste preparation of magnetic biochar for selective phosphate adsorption: Mechanisms and characterization

It is important to address the issues of fishery waste treatment and integrated pollutant removal in environmental remediation. In this study, FeSO4·7H2O was used for the first time to combine with fishery waste crab shells for the preparation of magnetic biochar in a practical and effective manner (FBC600) for the selective adsorption of phosphate. FBC600 was prepared by the one-pot dipping method and the features of its phosphate adsorption were studied. The outcomes demonstrate that pseudo-second-order kinetics and the Langmuir model effectively describe the adsorption process. The maximum adsorption capacity was 149.27 P mg/g. The adsorption capacity of FBC600 at equilibrium was 2.13 times higher than that of unmodified biochar BC. FBC600 is pH-adaptable from 3 to 10 and has excellent anti-interference capabilities. FTIR and XPS investigations revealed that electrostatic adsorption, ion exchange, ligand exchange, and chemical precipitation are the primary processes of FBC600 phosphate adsorption. The P-loaded FBC600 promoted the germination index (GI: 290.17%-314.51%) and root growth (root length: 1.54 cm-2.27 cm) of maize seeds better than other liquid substrates (20 p mg/L, 100 p mg/L). Therefore, P-loaded FBC600 is anticipated to have agricultural use as a phosphate fertilizer for plant growth.

Novel Y2O3 based calcium-alginate beads for highly selective adsorption of phosphate from aqueous solution.

Recently, selective phosphorus removal from aqueous solution has been a highly desirable strategy to combat eutrophication due to the increasingly stringent phosphorous emission standards. However, conventional adsorbents pose the limitations in phosphate removal suffering from lack of selectivity and stability under complicated condition and poor separation. In this study, novel Y2O3 based calcium-alginate (Y2O3/SA) beads of feasible stability and highly selectivity towards phosphate by encapsulating Y2O3 nanoparticles inside calcium-alginate beads via Ca2+ controlled gelation process was synthesized and characterized. The phosphate adsorption performance and mechanism were investigated. In general, a high selectivity among co-existing anions was found with co-existing anion concentration up to 62.5 times of the phosphate concentration. Additionally, phosphate adsorption by Y2O3/SA beads exhibited stable performance over a wide pH range between 2 and 10, while reaching the maximum adsorption capacity at pH 3 (48.54mg-P/g). The value of point of zero charge (pHpzc) of Y2O3/SA beads was approximately 3.45. Pseudo-second-order and Freundlich isotherm models can well accord with kinetics and isotherms data. The FTIR and XPS characterizations analyzed that inner-sphere complexes were proposed to be the major contributor of Y2O3/SA beads for phosphate removal. In conclusion, Y2O3/SA beads as the mesoporous material exhibited excellent stability and selectivity towards phosphate removal.

High Purity Struvite Recovery from Hydrothermally-Treated Sludge Supernatant Using Magnetic Zirconia Adsorbent.

Recovery of phosphorus from sludge will help to alleviate the phosphorus resource crisis. However, the release of phosphorus from sludge is accompanied by the leaching of large amounts of coexisting ions, i.e., Fe, Al, Ca, and organic matter, which decreases the purity of sludge-derived products. In this study, an adsorption-desorption process using magnetic zirconia (MZ) as the adsorbent is proposed to obtain a high purity recovery product. The process involves selective adsorption of phosphate from the hydrothermally treated sludge supernatant (HTSS) using MZ, followed by desorption and precipitation to obtain the final product: struvite. The results indicated that at a dosage of 15 g/L, more than 95% of phosphorus in the HTSS could be adsorbed by MZ. Coexisting ions (Ca2+, Mg2+, Fe3+, Al3+, SO42−, NO3−, Cl−, etc.) and organic matter (substances similar to fulvic and humic acid) in the HTSS had a limited inhibitory effect on phosphate adsorption. Using a binary desorption agent (0.1 mol/L NaOH + 1 mol/L NaCl), 90% of the adsorbed phosphorus could be desorbed. Though adsorption-desorption treatment, struvite purity of the precipitated product increased from 41.3% to 91.2%. Additionally, MZ showed good reusability, maintaining a >75% capacity after five cycles. X-ray photoelectron spectroscopy (XPS) indicated that MZ adsorbed phosphate mainly by inner-sphere complexation. This study provided a feasible approach for the recovery of phosphorus from sludge with high purity.

A simple polypropylene fiber membrane embedded with clean La(OH)3 nanoparticles for highly efficient phosphate anions removal

Lanthanide materials are attracting increasing attention owing to their ability to strongly bind with phosphorus (P). In this paper, a novel method of producing clean lanthanum nano-aerosols by spark ablation is proposed, the particles are uniformly deposited on a cheap and readily available Polypropylene(PP) fiber membrane in a special gas environment, and combined with water (solvent) for hydrothermal synthesis of the new material, PP-La. Material characterization confirmed that the formation of La(OH)3 nanoparticles and ligand exchange plays an important role in the phosphorus adsorption process, extended X-ray absorption spectroscopy demonstrated that phosphate was bound to the lanthanum site. The adsorption capacity of PP-La for phosphate is 188.6 mg P/g La, and the cost index (capacity/synthesis cost) is 132.54 mg P/USD. In addition, unlike most sorbents, PP-La has the advantage of being easily separated from water. This synthesis method is green and simple, the lanthanum is not toxic, the Polypropylene fiber membrane is cheap and has better mechanical strength, and the application prospect is very broad. Our results provide a new strategy for the development of efficient adsorbents and the treatment of eutrophication by selective adsorption of phosphate in lakes, reservoirs, rivers, and other water bodies.

Nanoscale Zero-Valent Iron Confined in Anion Exchange Resins to Enhance Selective Adsorption of Phosphate from Wastewater

The removal and recovery of phosphorus from wastewater are crucial for reducing eutrophication and alleviating phosphate rock depletion. In this study, nanoscale zero-valent iron (nZVI) confined in Alfa Aesar Amberlite IRA-402 (Cl) anion exchange resin composite adsorbents was developed by in situ reduction and deposition (denoted as nZVI-402-Cl) to remove phosphate from simulated and real wastewater. Surface and structure characterizations revealed that nZVI particles with a partially oxidized surface were loaded on the surface and inside the anion exchange resin. The phosphate adsorption capacity of nZVI-402-Cl was found to be high over a wide pH range (3.0–11.0), with a maximum adsorption capacity of 56.27 mg P/g at pH 7.2. Despite the presence of interfering sulfate and nitrate anions, nZVI-402-Cl maintained its high phosphate adsorption capacity owing to its excellent selectivity. The confinement of nZVI in anion exchange resins, in particular, could reduce the negative effects of humic acid on phosphate removal. After five regeneration/use cycles, the phosphate removal of nZVI-402-Cl was maintained close to 95%. In column mode tests, the nZVI-402-Cl column process generates ∼1850 bed volume (BV) clean water ([phosphorus] < 0.1 mg/L) from the wastewater treatment plant effluents. In contrast, the value of the IRA-402 column is only ∼900 BV. nZVI-402-Cl has proven to be an efficient and selective adsorbent for practical phosphate removal and recovery in different water environments.

Development of novel ZnZr-COOH/CNT composite electrode for selectively removing phosphate by capacitive deionization

The discharge of phosphate from sewage water can lead to water eutrophication and endanger the aquatic ecosystem. Capacitive deionization (CDI) has displayed great potential for salt removal and nutrient recovery due to its excellent performance such as environmental friendliness and energy efficient. In this study, the terephthalic acid intercalated carbon nanotube composite material (ZnZr-COOH/CNT) was developed as an anode and its selective removal of phosphate in CDI was investigated. At a applied voltage of 1.2 V, ZnZr-COOH/CNT electrode exhibited great adsorption capacity of phosphate with low concentration (∼10 mg/L) at a wide range of pH (3 – 10), with the equilibrium concentration as low as 0.3 mg/L which was less than the national first-class emission standard (0.5 mg/L). Moreover, the adsorption of phosphate by ZnZr-COOH/CNT composite electrode was mildly disturbed by the coexisting ions (Cl−, NO3–, SO42− and HCO3–). X-ray Photoelectron Spectroscopy (XPS) analysis indicated that the zirconium and zinc were coordinated with phosphate to form inner sphere complex, and the hydrogen bond was formed between the hydroxyl group of phosphate and the carboxyl group of electrode material, which enhanced the selective adsorption of phosphate. Furthermore, the energy consumption of CDI dephosphorization was calculated as low as 0.0075 kWh/g P and 0.043 kWh/m3 water at 1.2 V. This study was expected to provide the potential electrode materials and theoretical basis for the application of CDI dephosphorization.

Understanding Competitive Phosphate and Silicate Adsorption on Goethite by Connecting Batch Experiments with Density Functional Theory Calculations.

Despite the biogeochemical importance of phosphate fate and transport in aquatic environments, little is known about how competition with other common aqueous oxyanions affects its retention by mineral surfaces. Here, we examined the competitive uptake of phosphate and silicate on goethite over a wide pH range, using batch measurements supported by DFT calculations. The results show selective adsorption of phosphate at pH < 4 and silicate at pH > 10 with little to no competitive effect. However, between 4 < pH < 10, the total phosphate and silicate loading was found to be almost equal to that of silicate loading from single-component solution, revealing a proportionate competition for surface site types and a competitive effect controlling their mutual retention. DFT-calculated adsorption energies and charge density redistributions for various surface complexes on different charged (101) and (210) facets are consistent with the trends observed in batch measurements, suggesting that the observed behavior reflects the primary controlling influence of goethite surface chemistry at the molecular scale. An important implication is that at the circumneutral pH in most environmental systems, where iron oxyhydroxides comprise much of the reactive interfacial area, unbound phosphate concentrations may be strongly controlled by dissolved silicate concentration, and vice versa.

Structural insight into the alginate derived nano-La(OH)3/porous carbon composites for highly selective adsorption of phosphate

In this study, a novel nano-La(OH)3/porous carbon composites derived from La alginate xerogel with egg-box structure had been successfully synthesized by a gradient heat treatment in nitrogen atmosphere. This facile fabrication strategy can be easily employed to considerably encapsulate La(OH)3 nanoparticles uniformly into the porous carbon matrix derived from the alginate macromolecule framework. The optimized sample, labeled as LS-550(N), exhibited extremely high phosphate uptake and great selectivity. The adsorption kinetic process dramatically followed pseudo-second-order model. The Langmuir model fitted maximum equilibrium adsorption capacity is 133.58 mg·g−1. The phosphate adsorption mechanisms could be consist of electrostatic interaction, complexation and ligand exchange interaction on the surface of LS-550(N). The prominent practical applicability of LS-550(N) in the regeneration test suggests that the LS-550(N) could be a potential adsorption candidate for the decontamination of phosphate-containing natural water bodies.

Removal of Nitrogen and Phosphorus in Synthetic Stormwater Runoff by a Porous Asphalt Pavement System with Modified Zeolite Powder Porous Microsphere as a Filter Column

Porous asphalt pavement (PAP) system is a widely used treatment measure in sustainable stormwater management and groundwater recharge, but their variable performance in nitrogen (N) and phosphorus (P) removal requires further reinforcement prior to widespread uptake. Two laboratory-scale PAP systems were developed by comparing limestone bedding and zeolite incorporated into modified zeolite powder porous microsphere (MZP-PM) as a filter column under a typical rainfall. The PAP system of zeolite bedding incorporated into MZP-PM (a weight less than 5% of zeolite) removed 74.5% to 90.6% of ammonium (NH4+-N) and 72.9% to 92.4% of total phosphate (TP) from the influent, as compared with 25.7% to 62.7% of NH4+-N and 32.6% to 56.4% of TP by that of the limestone as bed material. This improvement was presumably due to MZP-PM’s high adsorption capacity and surface complexation. The formation of ≡(La)(OH)PO2 was verified to be the dominant pathway for selective phosphate adsorption by MZP-PM and ion-exchange was proved to be the main removal process for ammonium. This study provides promising results for improving N and P removal by modifying a porous asphalt pavement system to include an MZP-PM adsorbent column as a post-treatment.

Selective adsorption of phosphate by carboxyl-modified activated carbon electrodes for capacitive deionization.

Capacitive deionization (CDI) has been considered as a promising technology for removing phosphate from water but suffer inferior selectivity and electrosorption performances for phosphate of current carbon electrodes in CDI. Herein, we achieved highly selective phosphate removal from a ternary effluent of Cl-, PO43-, and SO42- by using nitric acid-treated activated carbon (AC) with various modification times and pure AC as the anode and cathode, a novel phosphate selective asymmetric CDI reactor. The results showed that carboxyl groups greatly grafted on the materials after modification (varying from 0.00084 to 0.0012 mol g-1). The phosphate selectivity of the present research was higher than that of unmodified CDI, and it increased with the increase of carboxyl groups content. The highest phosphate selectivity (2.01) in modified materials is almost six times higher than that of pure AC. Moreover, the modified electrodes exhibited good regenerative ability with a phosphate desorption efficiency of around 72.12% during the adsorption/desorption process and great stability during the cycling experiment. These results demonstrated that the innovative application of nitric acid-modified AC can effectively selectively remove phosphate from mixed anion solution, opening a hopeful window to selective adsorption in water treatment by CDI.

Selective and superior capture of phosphate by using bimetallic bismuth-based metal-organic frameworks

In order to mitigate the negative impact of aquatic organism eutrophication and maintain the balance of the water ecosystem, the removal of phosphate has become an urgent need. Herein, we prepared two kinds of high-performance bismuth-based metal-organic frameworks (Bi-MOFs) for phosphate treatment, namely, original Bi-MOF (CAU-17) and lanthanum-doped bimetallic Bi-MOF (La-CAU-17). The maximum adsorption capacity of as-made CAU-17 attains 186.57 mg/g. Noticeable, the maximum adsorption capacity of La-CAU-17 is up to 216.07 mg/g due to the doping of lanthanum. The experimental result shows that La-CAU-17 has a better affinity for phosphate and maintains a higher adsorption capacity in a wide pH range (7–12). Mechanistic studies supported by fourier transform infrared spectroscopy (FTIR) have shown that the binder BTC3− and La3+ could coordinate during the doping process, thus exposing more central metal (Bi) as the adsorption sites. Furthermore, density functional theory (DFT) calculation demonstrates that La-CAU-17 has more negative adsorption energy, which is more conductive to phosphate adsorption. In conclusion, bimetallic Bi-MOF (La-CAU-17) has a synergistic effect on phosphate adsorption and provides a candidate method for efficient and selective adsorption of phosphate.