Starch Nanocrystals Grafted with Epichlorohydrin Dimethylamine for Methyl Blue Dye Removal

Abstract In this paper, modified starch nanocrystals (SNCs) are prepared successfully by grafting the epichlorohydrin‐dimethylamine copolymer (PA) onto oxidized starch nanocrystals (OSNCs). The material is used as an adsorbent to deal with the methyl blue (MB) dye. The OSNCs‐PA is characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, and Scanning electron microscopy. The zeta potential of OSNCs‐5.0%PA is +46.6 mV, which has a good adsorption performance for MB. In the adsorption process, the effects of adsorption time, pH, and initial MB concentration on the adsorption capacity are studied with the different OSNCs‐PA, and the adsorption kinetics and adsorption isothermal curves are also fitted. The results show that the maximum adsorption capacity of OSNCs‐0.5%PA, OSNCs‐3.0%PA, OSNCs‐5.0%PA on MB could reach 142.86, 166.67, and 169.49 mg g −1 , respectively. The adsorption of OSNCs‐PA for MB conform to the second‐order kinetics and the Langmuir adsorption isotherm.