Synthesis and characterization of the molecularly imprinted composite as a novel adsorbent and its competition with non-imprinting composite for removal of dye

Abstract

ue to its high visibility, high resistance, and toxic effects, colored substances in the textile and other dyeing industries waste-water cause great damage to biological organisms and ecology. Therefore, current research efforts to develop high selectivity, specificity, and efficient water treatment technologies are very intense, and molecularly imprinting methods (MIM) constitute a category of functional materials to meet these criteria. Polymethylmethacrylate-chitosan molecularly imprinted composite (PMMAC-MIC) and non-imprinted composite (PMMAC-NIC) were successfully prepared by MIM. Dye adsorption performance of MIC and NIC composites was investigated by comparison. The obtained adsorbents were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and zeta potential techniques. The kinetics of adsorption followed a pseudo-first-order model while the Langmuir adsorption isotherm provided the best fit. The maximum adsorption capacity of dye was found as 93.78 mg/g for PMMAC-MIC and 17.70 mg/g for PMMAC-NIC at 298 K temperature, the initial dye concentration was 100 mg/L. Thermodynamic parameters indicated that the removal of dye from PMMAC-MIC was endothermic and spontaneous. Besides, the regeneration of composite was recycled four times.