Adsorption of Cu(II) and Methylene Blue by Succinylated Starch Nanocrystals

Starch nanocrystals (SNCs) have a small particle size and large surface area compared with traditional modified starch. In this study, SNCs were chemically modified by succinic anhydride in aqueous alkaline condition. With the ratio of succinic anhydride/SNCs (0.1-0.5) increasing, the degree of substitution of succinylated SNCs increases from 0.0481 to 0.1009, and the zeta potential becomes more negative. The SNCs and succinylated SNCs were characterized by Fourier transform infrared (FTIR), Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD). The adsorption of Cu(II) and methylene blue (MB) by SNCs and succinylated SNCs in aqueous solutions is also studied. The results show that succinylated SNCs have great adsorption capacity for Cu(II) and MB. The pseudo-second-order kinetics is correspond both with the adsorption of Cu(II) or MB and are also found to be well fitted by Freundlich isotherms model, which shows that adsorption of Cu(II) or MB on succinylated SNCs is mainly multilayer adsorption.