The molecularly imprinted polymer (MIP) based on methacrylic acid functionalized β-cyclodextrin (MAA-β-CD) monomer was synthesized for the purpose of selective recognition of benzylparaben (BzP). The MAA-β-CD monomer was produced by bridging a methacrylic acid (MAA) and β-cyclodextrin (β-CD) using toluene-2,4-diisocyanate (TDI) by reacting the -OH group of MAA and one of the primary -OH groups of β-CD. This monomer comprised of triple interactions that included an inclusion complex, π-π interaction, and hydrogen bonding. To demonstrate β-CD performance in MIPs, two MIPs were prepared; molecularly imprinted polymer-methacrylic acid functionalized β-cyclodextrin, MIP(MAA-β-CD), and molecularly imprinted polymer-methacrylic acid, MIP(MAA); both prepared by a reversible addition fragmentation chain transfer polymerization (RAFT) in the bulk polymerization process. Both MIPs were characterized using the Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), and Brunauer-Emmett-Teller (BET). The presence of β-CD not only influenced the morphological structure, it also affected the specific surface area, average pore diameter, and total pore volume of the MIP. The rebinding of the imprinting effect was evaluated in binding experiments, which proved that the β-CD contributed significantly to the enhancement of the recognition affinity and selective adsorption of the MIP.
The usage of phenols in the marketplace has been increasing tremendously, which has raised concerns about their toxicity and potential effect as emerging pollutants. Phenol's structure has closely bonded phenyl and hydroxy groups, thereby making its functional characteristics closely similar to that of alcohol. As a result, phenol is used as a base compound for commercial home-based products. Hence, a simple and efficient procedure is required to determine the low concentration of phenols in environmental water samples. In this research, a method of combining magnetic nanoparticles (MNPs) with surfactant Sylgard 309 was developed to overcome the drawbacks in the classical extraction methods. In addition, this developed method improved the performance of extraction when MNPs and the surfactant Sylgard 309 were used separately, as reported in the previous research. This MNP-Sylgard 309 was synthesised by the coprecipitation method and attracts phenolic compounds in environmental water samples. Response surface methodology was used to study the parameters and responses in order to obtain an optimised condition using MNP-Sylgard 309. The parameters included the effect of pH, extraction time, and concentration of the analyte. Meanwhile, the responses measured were the peak area of the chromatogram and the percentage recovery. From this study, the results of the optimum conditions for extraction using MNP-Sylgard 309 were pH 7, extraction time of 20 min, and analyte concentration of 10.0 μg mL-1. Under the optimized conditions, MNP-Sylgard 309 showed a low limit of detection of 0.665 μg mL-1 and the limit of quantification was about 2.219 μg mL-1. MNP-Sylgard 309 was successfully applied on environmental water samples such as lake and river water. High recovery (76.23%-110.23%) was obtained.
This work reports the synthesis and characterization of a hybrid molecularly imprinted polymer (MIP) membrane for removal of methylene blue (MB) in an aqueous environment. MB-MIP powders were hybridized into a polymer membrane (cellulose acetate (CA) and polysulfone (PSf)) after it was ground and sieved (using 90 µm sieve). MB-MIP membranes were prepared using a phase inversion process. The MB-MIP membranes were characterized using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM). Parameters investigated for the removal of MB by using membrane MB-MIP include pH, effect of time, concentration of MB, and selectivity studies. Maximum sorption of MB by PSf-MB-MIP membranes and CA-MB-MIP membranes occurred at pH 10 and pH 12, respectively. The kinetic study showed that the sorption of MB by MB-MIP membranes (PSf-MB-MIP and CA-MB-MIP) followed a pseudo-second-order-model and the MB sorption isotherm can be described by a Freundlich isotherm model.
In this study, a unique magnetic molecularly imprinted polymer (MMIP) adsorbent towards bisphenol A (BPA) as a template molecule was developed by bulk polymerization using β-cyclodextrin (β-CD) as a co-monomer with methacrylic acid (MAA) to form MMIP MAA-βCD as a new adsorbent. β-CD was hybridized with MAA to obtain water-compactible imprinting sites for the effective removal of BPA from aqueous samples. Benzoyl peroxide and trimethylolpropane trimethacrylate were used as the initiator and cross-linker, respectively. The adsorbents were characterized by Fourier transform infrared spectroscopy, scanning electronic microscopy, transmission electron microscopy, vibrating sample magnetometer, Brunauer-Emmett-Teller and X-ray diffraction. 1H nuclear magnetic resonance spectroscopy was used to characterize the MAA-βCD and BPA-MAA-βCD complex. Several parameters influencing the adsorption efficiency of BPA such as adsorbent dosage, pH of sample solution, contact time, initial concentrations and temperature as well as selectivity and reusability study have been evaluated. MMIP MAA-βCD showed significantly higher removal efficiency and selective binding capacity towards BPA compared to MMIP MAA owing to its unique morphology with the presence of β-CD. The kinetics data can be well described by the pseudo second-order kinetic and Freundlich isotherm and Halsey models best fitted the isotherm data. The thermodynamic studies indicated that the adsorption reaction was a spontaneous and exothermic process. Therefore, MMIP based on the hybrid monomer of MAA-βCD shows good potential of a new monomer in molecularly imprinted polymer preparation and can be used as an effective adsorbent for the removal of BPA from aqueous solutions.