Amino-containing polymer-coated magnetite nanoparticles as nano-adsorbents for bisphenol A: Synthesis, kinetic and thermodynamic study

Magnetite nanoparticles coated with poly(dimethyl aminoethyl methacrylate) (PDMAEMA@MNPs) and their quarternized form (PQDMAEMA@MNPs) were successfully synthesized and used as nano-adsorbents for bisphenol A (BPA). The particles were spherical with the average particle size between 10 nm and 20 nm in diameter with a moderate degree of nanoclustering (ca.150 to 200 particles/cluster). In terms of adsorption properties, the PDMAEMA@MNPs exhibited a higher BPA adsorption capacity (1.05 mg center dot g(-1) MNP at pH 9) than the quaternized form (0.50 mg center dot g(-1) MNP at pH 9). Equilibrium isotherm, kinetic, and thermodynamic characteristics of BPA adsorption on the PDMAEMA@MNPs were investigated. It was found that the BPA adsorption on the MNPs reached an equilibrium within 5 min and the maximum adsorption capacity (q(e)) was 9.88 mg center dot g(-1). The adsorption isotherm study results indicated that the BPA adsorption process on PDMAEMA@MNPs exhibited the best fit with the Freundlich model, and the adsorption kinetics followed the pseudo-second order model with the R-2 value of 1.00. The thermodynamic data exhibited a negative enthalpy change (Delta H degrees = -2585.571 J center dot mol(-1)), indicating exothermic BPA adsorption, and a negative Gibbs free energy (Delta G degrees), implying a spontaneous BPA adsorption process.

Automated summary

Poly(dimethyl aminoethyl methacrylate) coated magnetite nanoparticles were successfully synthesized and used for bisphenol A (BPA) adsorption. The PDMAEMA@MNPs demonstrated higher BPA adsorption capacity compared to the quaternized form. Equilibrium, kinetic, and thermodynamic characteristics of BPA adsorption on PDMAEMA@MNPs were investigated, revealing that the adsorption process reached equilibrium quickly and followed Freundlich and pseudo-second order models. Thermodynamic analysis indicated an exothermic and spontaneous adsorption process.