Bisphenol A molecularly imprinted material adsorption selectivity study

Introduction

With the acceleration of industrialization, the pollution of bisphenol A(Bisphenol A, BPA) in the environment is becoming more and more serious. Bisphenol A is a chemical widely used in the manufacture of plastics, epoxy resins and coatings, but it has endocrine disrupting effects and poses a potential threat to human health and the ecological environment. Therefore, it is particularly important to develop efficient and selective adsorption materials to remove bisphenol A. Molecular imprinting technology (Molecularly Imprinted Technology, MIT) has become an important means to solve this problem because of its unique advantages in selective adsorption. In this paper, the adsorption selectivity of bisphenol A molecularly imprinted materials will be studied in depth, and the influencing factors and optimization methods will be analyzed.

Molecular Imprinting Technology Principle and Advantages

Molecular imprinting technology is a technology that forms a specific molecular recognition site by fixing a target molecular template in a synthetic material. Bisphenol A molecularly imprinted materials (BPA-MIPs) form a three-dimensional structure with specific recognition ability by combining bisphenol A with functional monomers and crosslinking agents in the polymerization process. This material is highly selective for bisphenol A and can effectively distinguish the target molecule from other compounds of similar structure, such as bisphenol F(BPF) and bisphenol S(BPS).

Compared with traditional adsorption materials, such as activated carbon or silica gel, the advantage of bisphenol A molecularly imprinted materials is their specific recognition ability at the molecular level. This selectivity comes from the precise design of the gap and structure inside the material, which can achieve efficient adsorption with bisphenol A molecules through hydrogen bonding, hydrophobic interaction and other interactions.

Factors Affecting the Adsorption Selectivity of Bisphenol A Molecularly Imprinted Materials

1. Template molecular structure and properties

The structural properties of bisphenol A directly affect the adsorption selectivity of molecularly imprinted materials. Bisphenol A molecule has a rigid benzene ring structure and two hydroxyl functional groups, which determine its interaction with the surrounding environment. In the process of molecular imprinting, the design of the gap and binding site of the material needs to match the shape, size and functional group of the bisphenol A molecule, so as to improve the selectivity.

Studies have shown that bisphenol A molecularly imprinted materials have a certain degree of cross-adsorption to bisphenol compounds with similar structures (such as BPF and BPS). Therefore, it is necessary to optimize the proportion of template molecules and the degree of crosslinking in the preparation process to reduce the adsorption of non-target molecules and improve the selectivity.

2. Functional monomer and crosslinking agent selection

Functional monomers play the role of immobilizing template molecules in molecularly imprinted materials, and their types and proportions directly affect the adsorption properties of the materials. Common functional monomers include methacrylic acid (MAA), acrylic acid (AA), and the like. These monomers form specific binding sites through interaction with bisphenol A molecules.

The introduction of crosslinking agent can improve the mechanical strength and thermal stability of the material, and affect the porosity and adsorption capacity of the material. Commonly used crosslinking agents are ethylene glycol dimethacrylate (EDMA) and divinylbenzene (DVB). Reasonable selection of the ratio of functional monomer and crosslinking agent can optimize the adsorption performance and selectivity of the material.

3. Preparation conditions are optimized

The preparation conditions have an important influence on the adsorption selectivity of bisphenol A molecularly imprinted materials. Polymerization temperature, time, solvent type and other factors will affect the structure and performance of the material. For example, high temperatures may result in excessive crosslinking of the material, reducing porosity and adsorption capacity. Conversely, too low a temperature may affect the efficiency of the polymerization reaction, resulting in a non-uniform material structure.

The amount and distribution of template molecules also affect the adsorption performance of the material. Too many template molecules may cause the porosity of the material to decrease, while too few template molecules cannot form enough binding sites, thereby reducing selectivity.

Bisphenol A molecularly imprinted materials adsorption selectivity research progress

In recent years, researchers have made significant progress in the adsorption selectivity of bisphenol A molecularly imprinted materials. By introducing a variety of functional monomers and crosslinking agents, and optimizing the preparation conditions, the adsorption selectivity of bisphenol A molecularly imprinted materials has been significantly improved. For example, the BPA-MIPs prepared by thermal polymerization and solvent evaporation method has an adsorption capacity of 30-50 mg/g for bisphenol A in simulated water, and the selectivity coefficient (α value) is between 5-10.

The application of new preparation methods such as dynamic full concentration molecular imprinting (DCIM) further improves the adsorption selectivity and stability of the material. These studies show that BPA molecularly imprinted materials have broad application prospects in water treatment and industrial wastewater treatment.

Practical Applications and Challenges

Although bisphenol A molecularly imprinted materials have made significant progress in adsorption selectivity, they still face some challenges in practical applications. The concentration of bisphenol A in environmental water is usually low, which requires the material to have a high adsorption capacity and the ability to be reused many times. The cost and complexity of preparation of the material may limit its large-scale application.

The selective adsorption properties of bisphenol A molecularly imprinted materials may be affected by ionic strength, pH and other factors in aqueous solution. Therefore, it is necessary to further optimize the stability and adaptability of the material in practical applications.

Future research directions

In order to further improve the adsorption selectivity of bisphenol A molecularly imprinted materials, future research can start from the following aspects:

1. Functional modification: by introducing nanomaterials (such as graphene oxide, magnetic nanoparticles) to perform functional modification on molecularly imprinted materials to improve the adsorption capacity and selectivity of the materials.

2. Shape selectivity optimization: By regulating the structure and polymerization conditions of the template molecule, the shape selectivity of the material is optimized to reduce the adsorption of non-target molecules.

3. Dynamic performance research: strengthen the study of dynamic adsorption-desorption process to improve the dynamic selectivity of materials.

4. Practical application verification: The application of bisphenol A molecularly imprinted material in actual water treatment and industrial wastewater treatment was carried out to verify its adsorption selectivity and economy.

Conclusion

Bisphenol A molecularly imprinted material is a kind of material with high adsorption selectivity, which has broad prospects in environmental management and industrial applications. By optimizing the molecular structure of the template, functional monomer, crosslinking agent and preparation conditions, the adsorption selectivity and stability of the material can be further improved. Future research should be devoted to the functional modification and practical application verification of the material, and provide a more effective solution to solve the problem of bisphenol A pollution.