Crystal Growth Rate Research Articles

The Effects of Electric Fields on Protein Phase Behavior and Protein Crystallization Kinetics.

We experimentally studied the effects of an externally applied electric field on protein crystallization and liquid-liquid phase separation (LLPS) and its crystallization kinetics. For a surprisingly weak alternating current (AC) electric field, crystallization was found to occur in a wider region of the phase diagram, while nucleation induction times were reduced, and crystal growth rates were enhanced. LLPS on the contrary was suppressed, which diminishes the tendency for a two-step crystallization scenario. The effect of the electric field is ascribed to a change in the protein-protein interaction potential.

Nanoengineering Multilength-Scale Porous Hierarchy in Mesoporous Metal-Organic Framework Single Crystals.

Developing a reliable method for constructing mesoporous metal-organic frameworks (MOFs) with single-crystalline forms remains a challenging task despite numerous efforts. This study presents a solvent-mediated assembly method for fabricating zeolitic imidazolate framework (ZIF) single-crystal nanoparticles with a well-defined micro-mesoporous structure using polystyrene-block-poly(ethylene oxide) diblock copolymer micelles as a soft-template. The precise control of particle sizes, ranging from 85 to 1200 nm, is achieved by regulating nucleation and crystal growth rates while maintaining consistent pore diameters in mesoporous nanoparticles and a rhombohedral dodecahedron morphology. Furthermore, this study presents a robust platform for nanoarchitecturing to prepare hierarchically porous materials (e.g., core-shell and hollow structures), including microporous ZIF@mesoporous ZIF, hollow mesoporous ZIF, and mesoporous ZIF@mesoporous ZIF. Such a multimodal pore design, ranging from microporous to microporous/mesoporous and further micro-/meso-/macroporous, provides significant evidence for the future possibility of the structural design of MOFs.

Electrodeposition of Crystalline Si Using a Liquid Ga Electrode in Molten KF–KCl–K2SiF6

In this study, the electrodeposition of silicon (Si) using a liquid gallium (Ga) electrode in molten KF–KCl was further investigated. Electrochemical measurements and electrolysis were conducted at 923 K in a KF–KCl–K2SiF6 melt. Cyclic voltammograms at liquid Ga electrodes revealed that the reduction current at 0.6–0.9 V vs K+/K was due to the formation of Si–Ga liquid alloys. Si was deposited via potentiostatic electrolysis at 0.80 V using liquid Ga held in a crucible as an electrode. The Si grains were primarily located at the boundary of the Ga and the crucible, indicating that they were deposited from the Si–Ga liquid alloy. X-ray diffraction confirmed the crystallinity of the deposited Si, with a maximum grain size of approximately 6 mm. Potentiostatic electrolysis at varying charges showed that the Si grain size increased with increased charge, confirming the growth of crystalline Si. The Si grains obtained using the liquid Ga electrode were larger than those obtained using a liquid Zn electrode. Finally, the differences in Si crystal growth rates between the Ga and Zn electrodes were discussed.

The Valence-Dependent Activity of Colloidal Molecules as Ice Recrystallization Inhibitors.

Inspired by advances in cryopreservation techniques, which are essential for modern biomedical applications, there is a special interest in the ice recrystallization inhibition (IRI) of the antifreeze protein (AFPs) mimics. There are in-depth studies on synthetic materials mimicking AFPs, from simple molecular structure levels to complex self-assemblies. Herein, we report the valence-dependent IRI activity of colloidal organic molecules (CMs). The CMs were prepared through polymerization-induced particle-assembly (PIPA) of the ABC-type triblock terpolymer of poly(acryloxyethyl trimethylammonium chloride)-b-poly(benzyl acrylate)-b-poly(diacetone acrylamide) (PATAC-b-PBzA-b-PDAAM) at high monomer conversions. Stabilized by the cationic block of PATAC, the strong intermolecular H-bonding and incompatibility of the PDAAM block with PBzA contributed to the in situ formation of Janus particles (AX1) beyond the initial spherical seed particles (AX0), as well as the high valency clusters of linear AX2 and trigonal AX3. Their distribution was controlled mainly by the polymerization degrees (DPs) of PATAC and PDAAM blocks. IRI activity results of the CMs suggest that the higher fraction of AX1 results in the better IRI activity. Increasing the fraction of AX1 from 27% to 65% led to a decrease of the mean grain size from 39.8% to 10.9% and a depressed growth rate of ice crystals by 58%. Moreover, by replacing the PDAAM block with the temperature-responsive one of poly(N-isopropylacrylamide) (PNIPAM), temperature-adjustable IRI activity was observed, which is well related to the reversible transition of AX0 to AX1, providing a new idea for the molecular design of amphiphilic polymer nanoparticle-based IRI activity materials.

Three-Dimensional Modeling of Polygonal Ridges in Salt Playas.

In this work, we investigate the formation of the curious polygonal salt ridges that tessellate salt playas worldwide using suitable three-dimensional modeling and simulation of the dynamical processes that are responsible for their formation. We employ the principles of fracture mechanics under cyclic wetting and drying, fluid and mass transport in fracture channels, and processes of crystallization and self-organization to finally replicate the almost Voronoidal pattern of salt ridge mosaics observed in playas. The model is generic and applicable to playas having different salt compositions, as the effect of the salt diffusion coefficient and critical salinity for crystallization are factored in. The final pattern of polygonal salt ridges obtained by simulation visually resembles the geometry of the salt ridges reported in the literature. A single equation describing the time of first crystallization of salt in terms of evaporation suction pressure P, diffusion coefficient D of salt, and relative salinity Δc with respect to critical salinity at saturation, has been proposed. The saturation of crystal growth rate is shown to be a dynamic equilibrium between advection and diffusion processes. We show that the stable polygonal geometry of the salt playas is an effort toward the total minimization of system energy.

Influence of silica on the crystallization of sodium hydroaluminate

To extract aluminium from highly concentrated aluminate solutions of alumina-containing raw materials, decomposition is performed through the crystallization of sodium hydroaluminate. This paper presents the results of a study on the stability of aluminate solutions. To calculate the probable yield of Al2O3 in the solid phase, it is necessary to determine the crystallization rate of sodium hydroaluminate according to the composition of the initial solutions and the conditions of the process. The influences of SiO2 content on the decomposition of aluminate solutions with Na2Ok concentrations of 540 g/dm3 and 590 g/dm3 with and without inoculum were studied. In addition, the influence of silica on the appearance of precipitating crystals of sodium hydroaluminate was considered. A sharp increase in the stability of the aluminate solutions at rest in the presence of silica was observed. Different crystallization conditions for sodium hydroaluminate have been investigated. Silica slows the crystallization process of sodium hydroaluminate, affecting both the nucleation and crystal growth rates. The effect of SiO₂ on the rate of decomposition is similar to the reduction in the degree of supersaturation.

Advancing crystal growth prediction: An adaptive kMC model spanning multiple regimes

Traditional batch crystallization processes encounter challenges like batch-to-batch variability, and difficulty in scale-up and achieving desired crystal size and morphology. These challenges stem from various growth mechanisms within crystallizers, influenced by operating conditions that dictate the dynamic surface structure of crystals. To overcome this, we developed a novel microscopic kinetic Monte Carlo model, which uses a specialized adsorption rate that adapts to different growth regimes by considering surface thermodynamic effects for different growth mechanisms. Specifically, the adaptive adsorption rate redefines the driving force of crystallization by considering the attachment energies of different adsorption sites (e.g., kink, adatom, and edge) and supersaturation. This approach enables seamless transitions across growth regimes. We use the lysozyme crystal system as a case study, demonstrating the model's superior predictive power in regime-to-regime transitions. Overall, the developed work provides a valuable new approach to understanding crystal morphology and predicting crystal growth rates in different growth regimes.

The effect of various crystalline forms of HFC 134a hydrate on the growth rate and desalination efficiency

Experimental studies on the synthesis of HFC 134a hydrate in the liquid HFC 134a – water system were performed. Despite today's lack of research on the use of HFC 134a hydrate for desalination of seawater and separation of harmful impurities by HFC 134a hydrate synthesis, this method has prospects for development: HFC 134a hydrate is synthesized at relatively high temperature and low pressure; it is poorly soluble in water, which simplifies gas hydrate separation from water–salt solution; it has high volumetric storage density and relatively high thermal conductivity. In spite of its low solubility in water, HFC hydrate exhibits relatively high growth rates. The growth of various crystalline forms and the peculiarities of their occurrence in pure water, aqueous salt solution, as well as with the addition of surfactant are considered. The use of SDS increases the HFC hydrate growth rate. For the first time, it was shown that the intensive growth of HFC 134a hydrate in the form of needles throughout the entire volume of the liquid allows increasing the efficiency of desalination. It is important to consider the desalination process comprehensively, taking into account the crystal forms, crystal growth rate, crystal defects, as well as taking into account the degree of salt removal. Simultaneously with the bubble growth, a thin gas hydrate film is shown to grow on the bubble surface. A detailed consideration of the stages of such hydrate growth is provided to explain the high-speed synthesis of porous HFC hydrate due to boiling of liquid HFC and vaporization.

Phosphorus recovery via struvite crystallization in batch and fluidized-bed reactors: Roles of microplastics and dissolved organic matter

Struvite crystallization, a promising technology for nutrient recovery from wastewater, is facing considerable challenges due to the presence of emerging contaminants such as microplastics (MPs) ubiquitously found in wastewater. Here, we investigate the roles of MPs and humic acid (HA) in struvite crystallization in batch and fluidized-bed reactors (FBRs) using synthetic and real wastewater with a Mg:N:P molar ratio of 1:3:(1–1.3) at an initial pH of 11. Batch reactor (BR) experiment results show that MPs expedited the nucleation and growth rates of struvite (e.g., the rate of crystal growth in the presence of 30 mg L−1 of polyethylene terephthalate (PET) was 1.43 times higher than that in the blank system), while HA hindered the formation of struvite. X-ray diffraction and the Rietveld refinement analysis revealed that the presence of MPs and HA can result in significant changes in phase compositions of the reclaimed precipitates, with over 80 % purity of struvite found in the precipitates from suspensions in the presence of 30 mg L−1 of MPs. Further characterizations demonstrated that MPs act as seeds of struvite nucleation, spurring the formation of well-defined struvite, while HA favors the formation of newberyite rather than struvite in both reactors. These findings highlight the need for a more comprehensive understanding of the interactions between emerging contaminants and struvite crystallization processes to optimize nutrient recovery strategies for mitigating their adverse impact on the quality and yield of struvite-based fertilizers. Environmental ImplicationThe presence of microplastics in wastewater poses a significant challenge to struvite crystallization for nutrient recovery, as it accelerates nucleation and growth rates of struvite crystals. This can lead to changes in the phase compositions of the reclaimed precipitates, with implications for the quality and yield of struvite-based fertilizers. Additionally, the presence of humic acid hinders the formation of struvite, favoring the formation of other minerals like newberyite. Understanding the interactions between emerging contaminants and struvite crystallization processes is crucial for optimizing nutrient recovery strategies and mitigating the environmental impact of these contaminants on water quality and struvite-based fertilizers.

Insight into the Manipulation Mechanism of Polymorphic Transformation by Polymers: A Case of Cimetidine.

Employing polymer additives is an effective strategy to realize the manipulation of polymorphic transformation. However, the manipulation mechanism is still not clear, which limit the precise selection of polymeric excipients and the development of pharmaceutical formulations. The solubility of cimetidine (CIM) in acetonitrile/water mixtures were measured. And the polymorphic transformation from CIM form A to form B with the addition of different polymers was monitored by Raman spectroscopy. Furthermore, the manipulation effect of polymers was determined based on the results of experiments and molecular simulations. The solubility of form A is consistently higher than that of form B, which indicate that form B is the thermodynamically stable form within the examined temperature range. The presence of polyvinylpyrrolidone (PVP) of a shorter chain length could have a stronger inhibitory effect on the phase transformation process of metastable form, whereas polyethylene glycol (PEG) had almost no impact. The nucleation kinetics experiments and molecular dynamic simulation results showed that only PVP molecules could significantly decrease the nucleation rate of CIM, due to the ability of reducing solute molecular diffusion and solute-solute molecular interaction. A combination of crystal growth rate measurements and calculations of the interaction energies between PVP and the crystal faces of CIM indicate that smaller molecular weight PVP can suppress crystal growth more effectively. PVP K16-18 has more impact on the stabilization of CIM form A and inhibition of the phase transformation process. The manipulation mechanism of polymer additives in the polymorphic transformation of CIM was proposed.

Removal of magnesium and aluminum from wet phosphoric acid by ralstonite precipitation: Thermodynamic and performance analysis, mechanistic studies and precipitate characterization

The purification of wet-process phosphoric acid has always posed a challenge for both academic and industrial researchers. In order to address this issue, a treatment unit was developed to mitigate magnesium and aluminum impurities from industrial semi-aqueous wet process phosphoric acid (SWPPA) (39.4 wt% P2O5) through ralstonite precipitation using Na+/F− as the precipitator (F− provided by HF). Thermodynamic analysis, DFT calculation and separation experiments results were used to investigate the impact of sodium sources properties on impurities removal rates and H3PO4 yield. Additionally, the effects of reaction temperature, reaction time, precipitating agent dosage, and aging time on precipitation efficiency were also examined. The results show that the ability of sodium source to ionize Na+ and react with H3PO4 and HF plays a crucial role in determining the impurity removal performance of magnesium and aluminum. The precipitants NaCl and Na2CO3 exhibit the highest removal rates for magnesium and aluminum, which is attributed to the easy ionization of Na+ ions. In comparison to Na2CO3, the higher H3PO4 yield with NaCl as precipitator can be achieved due to its lower nucleation rate and higher crystal growth rate in the phosphoric acid system. NaCl and HF as precipitants effectively reduces the concentrations of magnesium and aluminum in the untreated SWPPA solution from 23.47 g MgO/kg P2O5 to 3.29 g MgO/kg P2O5, 48.98 g Al2O3/kg P2O5 to 15.54 g Al2O3/kg P2O5. The removal rates for magnesium and aluminum are found to be 85.98% and 68.27%, respectively, with minimal residue of Na+/F−.

The dual action of N2 on morphology regulation and mass-transfer acceleration of CO2 hydrate film

The morphology characteristics of CH4, CO2 and CO2+N2 hydrate film forming on the suspending gas bubbles are studied using microscopic visual method at supercooling conditions from 1.0 to 3.0 K. The hydrate film vertical growth rate and thickness along the planar gas-water interface are measured to study the hydrate formation kinetics and mass transfer process. Adding N2 in the gas mixture plays the same role as lowering the supercooling conditions, both retarding the crystal nucleation and growth rates, which results in larger single crystal size and rough hydrate morphology. N2 in the gas mixture helps to delay the secondary nucleation on the hydrate film, which is beneficial to maintain the pore-throat structure and enhance the mass transfer. The vertical growth rate of hydrate film mainly depends on the supercooling conditions and gas compositions but has weak dependence with the experimental temperature and pressure. Under the same gas composition condition, the final film thickness shows a linear relationship with the supercooling conditions. The mass transfer coefficient of CH4 molecules in hydrates ranges from 4.54 to 7.54×10–8 mol·cm–2·s–1·MPa–1. The maximum mass transfer coefficient for CO2+N2 hydrate occurs at the composition of 60% CO2+40% N2, which is 3.98×10–8 mol·cm–2·s–1·MPa–1.

Diffusion proxies reveal the dynamic process in supercooled and glassy lithium diborate

Understanding the effective diffusion coefficient (D) is crucial for describing atomic transport during crystal nucleation in supercooled liquids and glasses. However, pinpointing the key structural units driving crystallization in intricate, multicomponent glass-formers remains a challenge. This study presents a novel analysis of lithium diborate (Li₂O·2 B₂O₃ - LB₂) crystallization in supercooled and glassy states by using available viscosity and crystallization data for samples of the same batch. An original key feature is that the nucleation rates were measured using a single-stage rather than the traditional double-stage heat treatment. We compared three proxies for D: Dη obtained from viscosity, DU derived from crystal growth rates, and Dτ estimated from nucleation time-lags. Our analysis revealed that at deep supercoolings, below the glass transition temperature, DU and Dτ yield similar steady-state nucleation rate estimates, which significantly exceed those predicted by using Dη (the most frequently used diffusion proxy). This result suggests that the atomic jumps governing crystal nucleation may be comparable to those in crystal growth, but distinct from those associated with cooperative rearrangements controlling viscous flow. Additionally, the estimated kinetic spinodal temperature (Tks) is above the Kauzmann temperature Tk, implying that crystal nucleation precedes relaxation to the supercooled liquid state, circumventing the entropy paradox and corroborating recent MD simulations for other substances. These findings are valuable for refining theoretical models of crystal nucleation and highlight the complexities of the glassy state.

The Controlled Preparation of a Carrier-Free Nanoparticulate Formulation Composed of Curcumin and Piperine Using High-Gravity Technology.

Carrier-free nanoparticulate formulations are an advantageous platform for the oral administration of insoluble drugs with the expectation of improving their bioavailability. However, the key limitation of exploiting carrier-free nanoparticulate formulations is the controlled preparation of drug nanoparticles on the basis of rational prescription design. In the following study, we used curcumin (Cur) and piperine (Pip) as model water-insoluble drugs and developed a new method for the controlled preparation of carrier-free drug nanoparticles via multidrug co-assembly in a high-gravity environment. Encouraged by the controlled regulation of the nucleation and crystal growth rate of high-gravity technology accomplished by a rotating packed bed, co-amorphous Cur-Pip co-assembled multidrug nanoparticles with a uniform particle size of 130 nm were successfully prepared, exhibiting significantly enhanced dissolution performance and in vitro cytotoxicity. Moreover, the hydrogen bonding interactions between Cur and Pip in nanoparticles provide them with excellent re-dispersibility and storage stability. Moreover, the oral bioavailability of Cur was dramatically enhanced as a result of the smaller particle size of the co-assembled nanoparticles and the effective metabolic inhibitory effect of Pip. The present study provides a controlled approach to preparing a carrier-free nanoparticulate formulation through a multidrug co-assembly process in the high-gravity field to improve the oral bioavailability of insoluble drugs.

Morphology and Microstructural Optimization of Zeolite Crystals Utilizing Polymer Growth Modifiers for Enhanced Catalytic Application

Rationally controlling the morphology and microstructure of the zeolite crystals could play a significant role in optimizing their physicochemical properties and catalytic performances for application in various zeolite-based heterogeneous catalysis processes. Among different controlling strategies, the utilization of zeolite growth modifiers (ZGMs), which are molecules capable of altering the anisotropic rates of crystal growth, is becoming a promising approach to modulate the morphology and microstructural characteristics of zeolite crystals. In this mini-review, we attempt to provide an organized overview of the recent progress in the usage of several easily available polymer-based growth modifiers in the synthesis of some commonly used microporous zeolites and to reveal their roles in controlling the morphology and various physicochemical properties of zeolite crystals during hydrothermal synthesis processes. This review is expected to provide some guidance for deeply understanding the modulation mechanisms of polymer-based zeolite growth modifiers and for appropriately utilizing such a modulation strategy to achieve precise control of the morphology and microstructure of zeolite crystals that display optimal performance in the target catalytic reactions.

Self‐Regulated Growth of Large‐Grain Sb2S3 Thin Films for High‐Efficiency Solar Cells

AbstractAntimony sulfide (Sb2S3) has attracted extensive attention due to its excellent photoelectric characteristics, including a high absorption coefficient (α > 104 cm−1) and a suitable bandgap (≈1.7 eV). However, due to its Q1D (quasi‐1D) structure, numerous deep‐level defects are identified in the Sb2S3 film, limiting the device's performance, and necessitating more efforts to overcome this situation. In this context, an ethanol solvent‐assisted chemical bath deposition (S‐CBD) strategy, a novel high‐quality thin film manufacturing technique is presented that modifies the supersaturation of the precursor solution by varying the boiling point and solvent polarity. This approach enables the effective regulation of the correlation between the crystal nucleation and growth rates, resulting in Sb2S3 films with large grains (≈4.25 µm, 37.5% ethanol), excellent crystallinity, well‐oriented structures (TC(211)/TC(020) = 2.39), low defect density, and prolonged carrier lifetimes (τAve ≈ 12.1 ns). Consequently, the final Sb2S3‐based solar device (FTO/CdS/Sb2S3/Spiro‐OMeTAD/Au) shows significant improvements in both FF (61.63%) and JSC (17.61 mA cm−2), yielding an excellent power conversion efficiency (PCE) of 7.84%. This research gives particular insights into the growth mechanism of high‐quality Sb2S3 thin films by CBD method as well as a potential route for enhancing Sb2S3 solar cell performance.

Real-time control of microcrystal formation with inline process microscopy

The control of microcrystal formation during crystallization is necessary to ensure good separation of crystals and molasses without adding excessive wash water. This paper presents an automatic inline process microscope measurement of sugar crystals and how its results are utilized in a real-time process control. The system captures high-precision transilluminated images of sugar crystals flowing through a 10-mm wide gap in the evaporating crystallizer. It automatically analyses the sugar crystals in size range from 10 µm to 4 mm visible in images. System reports the number of detected microcrystals (10–30 µm) and crystals (>30 µm), mean aperture of crystals (MA), co-efficient of variation in size (CV), crystal growth rate and volume fractions of the specified crystal size classes in real time. The performance of the control and monitoring approach is highlighted with the results of example strikes.

Enhanced boron removal via seed-induced crystal growth of barium perborate in sequential fluidized-bed crystallization

Chemical oxo-precipitation (COP) is an enhanced precipitation method for boron removal with the conversion of boric acid to perborate anions. When using barium-based precipitant, the boron can be effectively precipitated as barium perborates (BaPBs). The phase transformation of BaPBs from amorphous (A-BaPB, Ba(B(OH)3OOH)2) to crystalline (C–BaPB, BaB2(OO)2(OH)4) form is crucial for effective boron removal. However, scaling up this phase transformation of BaPBs is hindered by poor diffusion. This study aims to promote the growth of C–BaPB through seed-induced crystal growth, eliminating the need for phase transformation. By examining the relationship between crystal growth rate and supersaturation, surface spiral growth was identified as the rate-limiting step of the growth of micron-sized seeds near pHpzc. To enable continuous crystal growth, granular seeds of C–BaPB were prepared and employed as the medium for fluidized-bed crystallization (FBC). The system reached steady state 3 hydraulic retention times, achieving 90% boron removal. The effect of surface loading, ionic strength, and dosages on steady-state crystal growth rate was studied, revealing a shift of the rate-limiting step in FBC to diffusion. Lastly, the system that constituted of two FBCs in-series for sequential crystallization of A-BaPB and C–BaPB was demonstrated. The integrated system provided 97.8% of boron removal from synthetic wastewater containing 500 mg-B/L, with 92.3% of boron crystallized on the granular seeds of BaPBs.

Manipulating the Crystallization of Perovskite via Metal‐Free DABCO‐NH4Cl3 Addition for High Efficiency Solar Cells

AbstractThe performance of perovskite cells closely relies on the quality of films, leading to a special focus on crystallization manipulation and defect control. In this study, a novel approach using 1D metal‐free perovskites, specifically DABCO‐NH4Cl3, is proposed to facilitate the crystallization process of 3D FAPbI3 perovskites, while simultaneously addressing surface defects. Analysis of crystallization kinetics reveals that the introduction of 1D metal‐free perovskites provides numerous nucleation sites, effectively slowing down crystal growth rates and resulting in the formation of uniform, large‐grain perovskite films. Furthermore, the organic groups present in 1D perovskites play a crucial role in passivating defects within the perovskite structure. The synergistic impact of these factors enables the perovskite to achieve an efficiency of 24.72% while demonstrating exceptional stability. This research offers a promising approach for controlling perovskite crystallization, leading to the development of high‐efficiency and stable perovskite materials.

In situ construction of Ag/Bi2O3/Bi5O7I heterojunction with Bi-MOF for enhance the photocatalytic efficiency of bisphenol A by facet-coupling and s-scheme structure

In this study, Ag/Bi2O3/Bi5O7I with s-scheme heterostructures were successfully synthesized in situ by nano-silver modification of CUA-17 and halogenated hydrolysis.The growth rate of Bi2O3 crystals was effectively controlled by adjusting the doping amount of Ag, resulting in the formation of a facet-coupling heterojunctions. Through the investigation of the microstructure and compositional of catalysts, it has been confirmed that an intimate facet coupling between the Bi2O3 (120) facet and the Bi5O7I (312) facet, which provides robust support for charge transfer. Under visible light irradiation, the AgBOI.3 heterojunction photocatalyst exhibited an outstanding degradation rate of 98.2% for Bisphenol A (BPA) with excellent stability. Further characterization using optical, electrochemical, impedance spectroscopy, and electron spin resonance techniques revealed significantly enhanced efficiency in photogenerated charge separation and transfer, and confirming the s-scheme structure of the photocatalyst. Density functional theory calculations was employed to elucidate the mechanism of BPA degradation and the degradation pathway of BPA was investigated by LC-MS. Finally, the toxicity of the degradation intermediates was evaluated using T.E.S.T software.