Adsorption and extraction performance for phenolic compounds with magnetic-thermal dual-responsive composite material

In this paper, poly(N-isopropylacrylamide) (PNIPAM) composite materials were successfully prepared through free radical polymerization. Utilizing its thermosensitive properties, PNIPAM can control the adsorption and desorption processes by adjusting the temperature. Due to the presence of hydrophobic interactions and hydrogen bonds, this polymer exhibits excellent adsorption performance for bisphenol A and bisphenol B. The adsorption process follows the pseudo-second-order kinetic model and the Freundlich isotherm model, indicating that its adsorption behavior is non-uniform. Under optimized conditions, the maximum adsorption capacities for BPA and BPB are 187.13 mg·g⁻¹ and 271.45 mg·g⁻¹, respectively. In addition, a magnetic solid-phase extraction method was established for extracting four phenolic compounds from water samples. Under the optimal conditions, the limits of detection are in the range of 0.0005 - 0.02 mg·L⁻¹, and the limits of quantification are in the range of 0.00165 - 0.066 mg·L⁻¹, respectively. The applicability of this method was evaluated by analyzing three water samples, and the spiked recovery rates are in the range of 75.81 - 97.54 %. The results show that the magnetic and thermal dual-responsive properties of the synthesized polymer contribute to efficient separation and recovery.