Study on Adsorption of Soybean Protein based Composite Gel Spheres for Methylene Blue.

In this paper, soybean protein based composite gel spheres were prepared by double crosslinking technology based on green natural macromolecule soybean protein and sodium alginate as raw materials. The composition and microstructure of soy protein based composite gel spheres were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), Zeta potential analysis, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results showed that the soybean protein based composite gel spheres were porous nanostructures, and the Zeta potential on the surface of the gel spheres decreased with the increase of the pH value of the solution environment. Weakly alkaline environment (pH=8) was conducive to the adsorption of positively charged methylene blue dye molecules. Soybean protein based composite gel spheres have excellent adsorption capacity for methylene blue, and the maximum removal efficiency can reach 91%. The adsorption behavior conforms to the pseudo-second-order kinetic model and the Langmuir isotherm adsorption model. Langmuir model calculated that the maximum adsorption capacity could reach 596 mg/g. The soybean protein based composite gel spheres showed good regeneration and recycling performance. [ABSTRACT FROM AUTHOR]