This research used codeine as the template molecule to create a bulk molecularly imprinted polymer (MIP), with the Fenton reagent serving as the initiator. Ethylene glycol dimethacrylate (EGDMA) was used as the crosslinking agent, and methacrylic acid (MAA) functioned as the monomer. Adsorption procedure obtained by UV-Visible spectrophotometer. Various techniques were employed to characterize the polymers produced, including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), differential thermal analysis (DTA), and thermogravimetric analysis (TGA). The FT-IR data showed clear distinctions between the MIP and the non-imprinted polymer (NIP), validating the successful creation of specific recognition sites. The loss or alteration of characteristic peaks after template removal provided further evidence of binding-cavity formation. Based on SEM observations, the MIP exhibited a rougher, more porous surface than the NIP, which promotes greater adsorption. The thermal analysis indicated that the MIP had higher decomposition temperatures, reflecting enhanced thermal stability and a more robust cross-linked structure. Batch adsorption experiments revealed a maximum adsorption capacity of 111.98 mg g⁻¹, with adsorption behavior well described by the Langmuir isotherm (R² > 0.95) and pseudo-second-order kinetics (R² ≈ 0.99), indicating a strong affinity and significant adsorption capacity. The imprinting factor of 1.83 demonstrated that the presence of codeine-specific binding sites in the MIP nearly doubled the adsorption capacity compared to the NIP, thereby confirming the effectiveness of the molecular imprinting process. Thermodynamic analysis indicated spontaneous and exothermic adsorption with ΔH° = –24.674 kJ mol⁻¹ and ΔG° ranging from –11.04 to –8.88 kJ mol⁻¹.
Sache et al. (Sun,) studied this question.