Phosphoric Acid Concentration Research Articles

Study of the Effect of Magnesium Sulfate and Ammonium Nitrate on the Chemical Activity of Solutions of Phosphoric Acid

The present study aimed to study the effect of magnesium sulfate and ammonium nitrate on the chemical activity of phosphoric acid solutions. The results of studies on increasing the chemical activity of extractive phosphoric acid from Central Kyzylkum and Karatau phosphorites due to the concentration of the first hydrogen ions and the pH of the medium are presented. It has been shown that introducing magnesium sulfate heptahydrate into the acid reduces the concentration of the first hydrogen ions. Adding an amount of ammonium nitrate increases the concentration of the first hydrogen ions even higher than in the acid without magnesium. It has been established that the solubility of magnesium hydrophosphate increases with an increase in the content of P2O5 phosphoric acid, dihydrogen phosphate decreases as a result of dissociation with the formation of a hydrophosphate ion, and phosphoric acid dissociates with the formation of a dihydrophosphate ion, which binds with hydrogen ions, forming a dihydrophosphate ion.

Selectivity and competitive mechanism of cation exchange resin for Fe, Mg, and Al ions in phosphoric acid

AbstractThe presence of iron, magnesium, and aluminum elements as the primary impurities in wet‐process phosphoric acid (WPA) adversely affects the industrial phosphoric acid and subsequent phosphorus chemical products. This study aims to investigate the selectivity and competition mechanism of Sinco‐430 cation exchange resin for Fe, Mg, and Al ions in phosphoric acid solution. By studying the effects of different process conditions on the removal efficiency, the suitable conditions for the static removal of metal ions from Fe‐Mg, Al‐Mg, and Fe‐Al binary systems were determined: solid–liquid mass ratio (S/L) of 0.3, phosphoric acid concentration of 27.61 wt.%, system temperature of 50°C, and rotational speeds of 200, 400, and 200 rpm, respectively. By calculating the selectivity coefficients of the resin for metal ions under different experimental conditions and mutual replacement experiments, the semi‐empirical formulas for the selectivity coefficients were derived and order of selectivity was determined as follows: Mg2+ > Fe2+ > Al3+. Visual MINTEQ 3.1 software and density functional theory (DFT) calculations demonstrated that at low pH, the main forms of Fe, Mg, and Al present in phosphoric acid were FeH2PO4+, Mg2+, and AlH2PO42+, respectively. This finding explained the differences in selectivity of the resin for Fe, Mg, and Al. The dynamic removal of metal ions from phosphoric acid was investigated. The order of metal ion selectivity of the resin by the dynamic method is the same as that of the static method, and the dynamic exchange behaviour was most consistent with the Yan model.

Adsorption of Methyl Red on porous activated carbon from agriculture waste: Characterization and response surface methodology optimization

Activated carbon is an internationally recognized adsorbent substance that removes contaminants from industrial discharges. In this study, we evaluate the capacity of Activated carbon produced by the chemical carbonization of Rosemary root, considered agricultural waste, by using phosphoric acid as an activator to adsorb Methyl Red (MR) from aqueous solutions. To identify the optimum conditions for the carbonization process, the effects of several factors on the removal of methyl red were examined. These parameters included carbonization time, temperature, phosphoric acid concentration, and contact time, with the help of experimental design. We found that 550 °C is the optimal temperature for carbonization of rosemary root, and the concentration of H3PO4 was discovered to be 5.5 mol/l. What about the times we determined for contact time and carbonization time, which were 30 min and 120 min, respectively. The resulting Activated Carbon of Rosemary Root (ACRR) material was then characterized using XRD, FTIR, Boehm titration, SEM/EDX, RAMAN, and Zeta potential. A batch system is used to perform our adsorption. In addition to pH effects, initial MR concentration, contact time, and masse effect were examined, and all the results were confirmed via experimental design using full factorial. In the present study, 15 mg of the adsorbent exhibited an adsorption capacity of 154.53 mg/g at pH 3.25 and a temperature of 328.15 k at a concentration of dye 50 mg/l. The adsorption results of methyl red onto ACRR powder showed that the adsorption process was best correlated with Freundlich isotherm and pseudo-second-order kinetic. According to the thermodynamic study, the system is exothermic. In order to understand the activated sites presented on MR and the mechanism of adsorption, density functional theory (DFT) using the B3LYP/6-311G base was used. Furthermore, the experimental results agree with the results of the computational model.

Enhancing thermal insulation with phosphate washing sludge waste as an inorganic foaming agent in porous acid-based geopolymers: Formulation and processing optimization

This study explores the potential utilization of phosphate washing sludge (PWS), a calcium carbonate-rich by-product of phosphate mining, as an inorganic foaming agent in the production of porous acid-based geopolymers. The investigation focused on evaluating the impact of various factors, including phosphoric acid concentration (ranging from 8 M to 12 M), liquid/solid (L/S) ratio (0.8 to 1.2), and the amount of PWS added (ranging from 0 wt% to 50 wt%), on the properties of the resulting geopolymers, such as porosity, density, thermal conductivity, and compressive strength. To optimize the formulation and processing parameters of porous acid-based geopolymers, a surface response methodology using statistical modeling was employed. This approach facilitated a systematic examination of the different factors influencing the properties of geopolymers. The raw materials involved in the study, namely kaolinitic clay, PWS, and the produced geopolymers, were characterized using various techniques such as X-ray Diffraction (XRD), X-ray Fluorescence (XRF), Scanning Electron Microscope coupled with Energy Dispersive X-Ray (SEM/EDX), laser particle size analysis, and mapping. The results revealed that the combination of a phosphoric acid concentration of 10 M, a L/S ratio of 0.88, and the addition of 16 wt% PWS yielded the best performance in terms of porosity, compressive strength, and thermal conductivity, with values of 29.4 %, 13.8 MPa, and 0.0931 W/m.K, respectively. Additionally, a mathematical model was developed to predict optimal parameter combinations for desired performance characteristics. This research holds promise for the development of cost-effective thermal insulation materials for building applications.

Effect of H3PO4 content and processing temperature on the structure and mechanical properties of porous Si3N4

Open-porous silicon nitride ceramics have been fabricated via low-temperature processing at 1200 °C using phosphoric acid as an inorganic binder and pore-forming agent. A detailed study of the effect of phosphoric acid content on the microstructure development and an in-depth analysis of the influence of the porosity and pore morphology on compressive strength, flexural strength, and notch-root radius corrected fracture toughness has been performed. Further, the progressive evolution of porosity and the amount and type of crystalline phases as a function of processing temperature were studied by intermittent XRD analysis. For the first time, a detailed analysis of the pore structure evolution on the longitudinal elastic constant of the porous samples was studied using a non-destructive ultrasonic technique. The critical H3PO4 content of 40 vol% yielded a homogeneous nanoporous structure that resulted in the best mechanical properties – compressive strength >120 MPa, flexural strength >70 MPa, and a notch-root radius corrected KIC ∼1 MPa m1/2. Despite the low fabrication temperature and economic processing route, the mechanical properties of the fabricated porous samples are comparable to the values for porous Si3N4 reported in the literature.

Solubility Studies of Sulfates of Copper, Zinc and Cobalt in Phosphoric Acid at 30 ºC

Present study reports the isothermal experiments conducted at 30 ºC to ascertain the solubility of copper, zinc and cobalt sulfates in phosphoric acid. The solubility diagram of CuSO4-H3PO4-H2O system is shown to have one branch, this is equivalent to the discharge of copper sulfate pentahydrate into the equilibrium solid phase. The solubility diagrams of zinc and cobalt sulfates have two branches of salt crystallization, corresponding to the release of hexahydrates and monohydrates of zinc and cobalt with increasing phosphoric acid content, saturated solutions in the ZnSO4-H3PO4-H2O and CoSO4-H3PO4-H2O systems become more viscous and denser, reaching a maximum at the transition point, while these indicators in the CuSO4-H3PO4-H2O system only increase.

Effect of Magnesium Carbonate and Phosphoric Acid Concentration on Microstructure and Corrosion Behavior of Magnesium Phosphate Coating

Effect of Magnesium Carbonate and Phosphoric Acid Concentration on Microstructure and Corrosion Behavior of Magnesium Phosphate Coating

Behavior of VOCs competitive adsorption with water vapor in a slit-shaped phosphoric acid mesoporous activated carbon model

Pistachio shells were activated with H3PO4, and mesoporous activated carbon (AC) was pyrolyzed and prepared at high temperature. The impacts of phosphoric acid concentrations on the structure, physicochemical properties, and VOC adsorption performance of ACs were investigated. The results indicated that the specific surface area, average pore size, and surface P content of 20% phosphoric acid AC reached 1031.8 m2·g−1, 4.16 nm, and 3.87%, respectively. With increasing phosphoric acid concentration, the microporosity and graphitization of the ACs decreased, and the average pore size and P content of the ACs increased. The adsorption performance of PSAC-1P and PSAC-2P for VOCs in high-humidity exhaust gas was the most favorable. grand canonical Monte Carlo (GCMC) calculations revealed that at a relative humidity of 80%, water molecules and VOCs were adsorbed on the graphite-structured carbon surface in turn. The larger the pore size, the easier it was for water molecules to aggregate, and the adsorption sites were occupied by water molecules. P-functional groups effectively inhibited water molecular clusters from forming water clusters, benefitting from the mesopore adsorption of VOCs in competition with water vapor. The findings provide significant support for the effective adsorption treatment of VOCs in high-humidity exhaust gas.

Application Of The Sol-Gel Hydroxhapatite Synthesis Method From Green Clam Shell

Hydroxyapatite is the main mineral that makes up bones and teeth so that it has a level of similarity with the mineral parts of bones and can be used as an alternative bone substitute material. As an alternative material for bone substitution, hydroxyapatite has a fairly high economic value and is still dominated by imports from foreign countries. In an effort to reduce the level of imports of hydroxyapatite, research was carried out on green mussel shells as a source of calcium for the synthesis of hydroxyapatite. The synthesis of hydroxyapatite was carried out using the sol-gel method with raw materials for calcium precursors obtained from green mussel shells and varied concentrations of phosphoric acid (0.1 M, 0.5 M, 1 M; 1.5 M; and 2 M). Based on the analysis of the hydroxyapatite product produced using Atomic Absorption Spectrophotometry analysis, it was found that the ratio of Calcium-Phosphate (Ca/P) for H3PO4 concentrations was 0.1 M, 0.5 M, 1 M; 1.5M; and 2 M respectively by 1.73; 1.70; 1.67; 1.63; and 1.61. In addition, based on the results of the Fourier Transform Infra Red analysis, a random sample also found a Ca-O group; PO43; and OH- which is the main group of Hydroxyapatite and from SEM analysis the crystal morphology is known to be spherical, uneven and agglomerated so that in this study the synthesis of Hydroxyapatite using the sol-gel method was successfully carried out..

Influence of the concentration of phosphoric acid (H3PO4) on the Ca/P ratio in obtaining hydroxyapatite (HAp) from eggshell

The objective of this research was to evaluate the influence of the concentration of phosphoric acid in the impregnation to obtain hydroxyapatite (HAp) from the recycling of the eggshell reduce the residues formed in conventional synthesis; in addition to evaluating the Ca/P ratio in the type of HAp obtained, in order to test the material in the removal of dyes. The material obtained was characterized by Scanning Electron Microscopy, Energy Dispersive Spectroscopy (EDS) to obtainmorphology and elmental composition, Fourier Transform Infrared and Raman Spectroscopy, to determine functional groups and crystalline phases respectively. A carbonated HAp was obtained, increasing the concentration of phosphoric acid (0.5M, 1M, 1.5M, 2M and 2.5M) increases the presence of the phosphate group in the material; therefore, the presence of carbonates decreases. It is important to highlight that by Raman it was not possible to find the presence of phosphates, it is necessary to analyze the material by other characterization techniques. Although, with the other techniques used, it was possible to determine the presence of this in the material.

Magnetic properties of phosphoric acid passivated Fe-Si-B amorphous magnetic powder core

The magnetic properties of Fe-Si-B amorphous soft magnetic powder cores (SMCs) passivated by phosphoricacid are investigated in this work. Effects of phosphoric acid content and annealing temperature at different frequencies on permeability and magnetic loss of SMCs have been studied, too. Electronic microscope pictures and results of B-H analyzer show that the surface of Fe-Si-B SMCs is coated with a layer of dense phosphate. Experimental results show that Fe-Si-B SMCs with the best comprehensive magnetic properties (μe = 23.71; Pcv = 470.6 mW•cm−3 measured at 1000 kHz, 20 mT) can be obtained by adding 0.8 wt% phosphoric acid at the annealing temperature of 480 °C.

NMR investigation of proton transport in polybenzimidazole/polyphosphoric acid membranes prepared via novel synthesis route

Here we present a molecular-level view of the structural changes in polybenzimidazole (PBI) membranes doped with phosphoric acid (PA) generated by a novel membrane fabrication technique. The modified PA doped membranes displayed unprecedented ionic conductivity at elevated temperatures, comparable to the starting PBI gel membranes prepared by the commonly used PPA process, while also exhibiting enhanced mechanical properties. To elucidate the cause of these effects, we used multi-nuclear (1H, 13C, 31P) 1D PFG, MAS and CPMAS, and 2D HETCOR magnetic resonance (NMR) techniques to characterize the structure and dynamics of the modified film and the original gel PBI membranes. 1H diffusivity measurements show significantly enhanced proton diffusivity, both in magnitude and in lower activation energy, which were consistent with its high ionic conductivity despite the lower PA content compared to the original gel membrane. CPMAS experiments further substantiated that the location of these distinct phosphate environments as being close to the polymer network. Finally, the phosphate groups in the modified membrane were revealed to be strongly bounded to each other and to the PBI polymer backbone in contrast to the combination of weakly and strongly bounded groups of the original gel membrane.

Prediction of Water Resistance of Magnesium Oxychloride Cement Concrete Based upon Hybrid-BP Neural Network.

To obtain the magnesium oxychloride cement concrete (MOCC) ratio with excellent water resistance quickly and accurately, a BP neural network (BPNN) model with a topology structure of 4-10-2 was designed, and the PSO (particle swarm optimization), GWO (gray wolf optimization), and WOA (whale optimization algorithm) algorithms were used to optimize the model. The input layer parameters of the model above were n(MgO/MgCl2), Grade I fly ash, phosphoric acid (PA), and phosphate fertilizer (PF) content, and the output layer was the MOCC's compressive strength and softening coefficient. The model had a dataset of 144 groups, including 100 training set data, 22 verification set data, and 22 test set data. The results showed that the PSO-BPNN model had the highest predictive accuracy among the four models, with a mean R2 of 0.99, mean absolute error(MAE) of 0.52, mean absolute percentage error(MAPE) of 0.01, and root mean square error (RMSE) of 0.73 in predicting compressive strength, and a mean R2 of 0.99, MAE of 0.44, MAPE of 0.01, and RMSE of 0.62 in predicting the softening coefficient. The results showed that using the PSO-BPNN to predict the compressive strength and softening coefficient of MOCC is feasible and can provide theoretical guidance for designing the MOCC mix.

Preparation of polyphosphoric acid and recovery of valuable fluorine resources though a microwave intensification flash evaporation process

Traditional evaporators for the concentration of wet process phosphoric acid (WPA) suffer from concentration, corrosion, and low fluorine yield (less than 40 wt.%). Based on the excellent heating and permittivity properties of phosphoric acid in microwave fields, a microwave intensification flash evaporation (MFE) system is proposed to concentrate highly corrosive WPA for preparing polyphosphoric acid (PPA) and efficiently recovering valuable fluoride resources. A polytetrafluoroethylene tank in a microwave resonant cavity coupled with a vacuum pump is used to facilitate boiling and evaporation. This study reports the evolution of the PPA preparation process by flash evaporation, defluorination, and the boiling phenomenon. In addition, the influencing mechanism of pressure and temperature on PPA preparation and fluorine recovery are investigated. The experimental results indicate the successful preparation of PPA with a P2O5 content higher than 75 wt.% and the cost is considerably much lower than the traditional method. Meanwhile, the recovery yield of fluorine exceeds 90 wt.%, alleviating the depletion of strategic natural resources and potential risk of environmental pollution. This study provides a basis for the efficient preparation of PPA and recovery of fluorine resource from WPA. It is also potentially significant to industries such as metallurgy and sewage treatment.

Properties and microstructure of total tailings cemented paste backfill material containing mining and metallurgical solid waste

Introduction: In order to improve the utilization efficiency of industrial waste discharged in the process of iron and steel metallurgy, a kind of material that can replace cement for mine filling is sought. In the test, steel slag (SS) and vanadium-titanium slag (VTS) were used as the primary raw materials to prepare cementing agents (CA). Then, combine it with vanadium-titanium iron ore tailings (VTIOTs) to make mine cemented paste backfill material (CPBM).Methods: The composition, properties and hydration mechanism of CPBM are studied through various tests, in-cluding mechanical property test, hydration heat test, X-ray diffraction (XRD), scanning electronic mi-croscopy (SEM), and fourier transform-infrared spectroscopy (FT-IR).Results: The results show that when the following conditions are met, the slump is 216 mm, and the 28-day flexural strength and compressive strength of CPBM reach 4.25 and 9.41 MPa, respectively, which meets the requirements of Chinese National Standard GB/T 39489-2020 Technical specification for the total tailings paste backfill: the mass percentage SS: VTS: phosphogypsum (PG): dicyandiamide waste slag (DWS) = 31:59:6:4; the content of compound phosphoric acid (CPA) accounts for 4% of the dry material; the cement sand ratio of CPBM is 1:4; the paste mass concentration (PMC) is 80%; and the content of water reducing agent (WRA) is 0.18%.Discussion: Mechanism studies show that the hydration product of the CA is mainly ettringite (AFt) and C-S-H gel. The addition of CPA promotes the hydration of active minerals in SS and VTS. The existence of PG pro-motes the formation of AFt, and the formation of AFt further promotes the fracture of [AlO4]5− and [SiO4]4− along the bridge oxygen in VTS and SS.

High-Temperature Rotating Disk Electrode Study of Platinum Bimetallic Catalysts in Phosphoric Acid

Understanding the H3PO4 effect on the catalyst’s activity under a relevant condition is important for high-temperature polymer electrolyte membrane fuel cell (HT-PEMFC) catalyst research. Here, we report a high-temperature rotating disk electrode (HT-RDE) study of oxygen reduction reaction (ORR) in H3PO4. With the regular electrochemical protocol, we found that H3PO4 reduction could occur during cyclic voltammetry study and form a reductive species─phosphorus acid (H3PO3). To obtain reliable ORR measurement, we optimized the protocol to avoid the H3PO3 generation. The ORR activity of carbon-supported PtM (M = Fe, Co, Ni, Ru, Pd, and Ir) bimetallic alloy catalysts measured with this HT-RDE method showed higher ORR activity than Pt. To understand the alloying effect, we combine experiments in diluted solutions to distinguish the alloying effect on Pt–O binding and Pt–H3PO4 binding. The results indicate that H3PO4 mainly reduces available sites for ORR, with little effect on neighboring site’s Pt–O binding via Pt–H3PO4 interaction, which is also supported by the density functional theory calculation of the Pt–O binding energy with/without H2PO4. Further study in a phosphoric acid-doped quaternary ammonium-biphosphate ion pair coordinated polyphenylene (PA-QAPOH) membrane electrode assembly (MEA) shows that the active alloy catalyst has better performance in both the HT-RDE and MEA. Also, the MEA gives higher ORR activity than the HT-RDE because of the higher pressure and less phosphoric acid content of the MEA. Yet, the gap between the HT-RDE and MEA is significantly smaller than that between the room temperature (RT)-RDE and MEA, suggesting the importance of temperature and H3PO4 concentration in understanding ORR in HT-PEMFCs.

Efficiency of chemically modified activated carbon derived from banana peel for removal of Pb2+ and Zn2+ from aqueous Solution

Natural and anthropogenic activities generally result to large production of heavy metals. These heavy metals produced are indiscriminately discharged into rivers and other water bodies. Wastewater treatment of industrial effluents become very necessary due to toxic effect of heavy metal pollutants and its indirect effect pose to human health. Banana peel, an agricultural waste biomass can be used to produce bio-sorbent for adsorption of heavy metals from industrial wastewater. This study focused on the production of chemically modified activated carbon using various concentrations of phosphoric acid for removal of lead and zinc metals from aqueous solution. Activated carbon was produced from waste banana peel through thermal pretreatment at temperature of 450℃ preceding chemical modification with different concentrations of phosphoric acid of 0.5 M, 1.0 M and 1.5 M. The three different concentrations of the phosphoric acids represent sample X, Y and Z respectively. To study the adsorption efficiency of chemically modified activated carbon using different concentrations of phosphoric acid, batch experiments were conducted on chemically modified samples to assess the adsorption of lead (II) and zinc metals from aqueous solution. The three adsorbents were interacted with varying parameters such as effect of initial concentration of lead and zinc metal of concentration of 10 mg/L and 2 mg/L respectively. Based on batch experiments conducted, results indicated that adsorbent dose, pH, initial concentration as well as contact time are important factors influencing lead (II) and Zinc metals adsorption from aqueous solutions. Percentage adsorption of lead (II) and zinc metals was above 80 % for all three chemically modified adsorbents investigated. The adsorption capacities of the adsorbents under study showed high adsorption capacity for both zinc and lead metals. This implies that sample X, Y and Z are good adsorbents for adsorption of both zinc and lead metals in an aqueous solution.

Properties Optimization of Soft Magnetic Composites Based on the Amorphous Powders with Double Layer Inorganic Coating by Phosphating and Sodium Silicate Treatment

Core-shell structured amorphous FeSiBCr@phosphate/silica powders were prepared by phosphating and sodium silicate treatment. The soft magnetic composites (SMCs) were fabricated based on these powders. The effects of phosphoric acid (H3PO4) concentration and annealing temperature on their properties were investigated. During the phosphating process, the powder coated with a low concentration of H3PO4-ethanol solution leads to uneven phosphate coating, while the peeling of phosphate coating occurs for the high H3PO4 concentration. Using 0.5 wt.% phosphoric solution, a uniform and dense insulation layer can be formed on the surface of the powder, resulting in increased resistivity and the reduced eddy current loss of the amorphous soft magnetic composites (ASMCs). This insulation layer can increase the roughness of the powder surface, which is beneficial to the subsequent coating of sodium silicate. By optimizing sodium silicate treatment, a complete and uniform SiO2 layer can be formed on the phosphated powders well, leading to double layer core-shell structure and excellent soft magnetic properties. The magnetic properties of amorphous SMCs can be further improved by post annealing due to the effectively released residual stress. The enhanced permeability and greatly reduced core loss can be achieved by annealing at 773 K, but the deterioration of magnetic properties occurs as the annealing temperature over 798 K, mainly due to the increase of α-Fe(Si) and Fe3B phases, which hinder the domain wall displacement and magnetic moment rotation. The excellent soft magnetic properties with permeability μe = 35 and core loss Ps = 368 kW/m3 at 50 mT/200 kHz have been obtained when the SMCs prepared with the powders coated by 0.5 wt.% H3PO4 and 2 wt.% sodium silicate were annealed at 773 K.

Strength, microstructure, CO2 emission and economic analyses of low concentration phosphoric acid-activated fly ash geopolymer

Phosphoric acid (PA)-activated geopolymer is a potential construction material with superior mechanical performance and high temperature resistance. However, the synthesis of phosphoric acid-activated fly ash (FA) geopolymer (PAFG) usually requires high concentrations of PA. In this study, the mechanical properties and microstructure of PAFG samples prepared with varying low PA concentrations (LPA, 1–4 M), liquid/FA ratios (0.3–0.45), and curing temperatures (25, 60, 90 °C), as well as their effects on the environment and economy, were investigated. The compressive strengths of PAFG with activation of LPA were generally low. The PAFG prepared with a L/F = 0.35 and 4 M PA solution curing at 60 °C for 6 days obtained the highest compressive strength of 13.23 MPa. The formation of geopolymer gels of Si-O-Al-O-P, Al-O-P, or Si-O-P were the primary reaction products and strength gain for PAFG samples. The increase in PA concentration and L/F ratio accelerated the FA dealumination reaction and the polymerization reaction by increasing the H+ and P-O concentrations of solution. In comparison to low concentration NaOH-activated fly ash geopolymer and cement pastes, the CO2 emission intensity and energy consumption intensity of PAFG curing at 25 °C were reduced by 70.9% and 35.6%, and 90.6% and 90.6%, respectively. Albeit the cost increased by 87.4% and 30.7%, respectively. Therefore, it is essential to develop inexpensive chemical processes for the preparation of PA solutions.

Trade-off of abiotic stress response in floating macrophytes as affected by nanoplastic enrichment

Nanoparticles have been found in large-scale environmental media in recent years, causing toxic effects in various organisms and even humans through food chain transmission. The ecotoxicological impact of microplastics on specific organisms is currently receiving much attention. However, relatively little research to date has examined the mechanisms through which nanoplastic residue may exert an interference effect on floating macrophytes in constructed wetlands. In our study, the aquatic plant Eichhornia crassipes was subjected to 100 nm polystyrene nanoplastics at concentrations of 0.1, 1 and 10 mg L-1 after 28 days of exposure. E. crassipes can decrease the concentration of nanoplastics in water by 61.42∼90.81% through phytostabilization. The abiotic stress of nanoplastics on the phenotypic plasticity (morphological and photosynthetic properties and antioxidant systems as well as molecular metabolism) of E. crassipes was assessed. The presence of nanoplastics reduced the biomass (10.66%∼22.05%), and the functional organ (petiole) diameters of E. crassipes decreased by 7.38%. The photosynthetic efficiency was determined, showing that the photosynthetic systems of E. crassipes are very sensitive to stress by nanoplastics at a concentration of 10 mg L-1. Oxidative stress and imbalance of antioxidant systems in functional organs are associated with multiple pressure modes from nanoplastic concentrations. The catalase contents of roots increased by 151.19% in the 10 mg L-1 treatment groups compared with the control group. Moreover, 10 mg L-1 concentrations of the nanoplastic pollutant interfere with purine and lysine metabolism in the root system. The hypoxanthine content was reduced by 6.58∼8.32% under exposure to different concentrations of nanoplastics. In the pentose phosphate pathway, the phosphoric acid content was decreased by 32.70% at 10 mg L-1 PS-NPs. In the pentose phosphate pathway, the phosphoric acid content was decreased by 32.70% at 10 mg L-1 PS-NPs. Nanoplastics disturb the efficiency of water purification by floating macrophytes, which reduces the chemical oxygen demand (COD) removal efficiency (from 73% to 31.33%) due to various abiotic stresses. This study provided important information for further clarifying the impact of nanoplastics on the stress response of floating macrophytes.