Removal of Cr (III) from aqueous solutions by carbon lignin-based composite

Carbon spheres were synthesized by hydrothermal method and combined with aminated sodium lignosulfonate to form carbon-lignin based adsorbent. The content of carbon spheres, triethylenetetramine and sodium lignosulfonate was optimized by orthogonal experiment to obtain the adsorbent with the highest adsorption capacity. The materials were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and Raman spectroscopy. The diameter of carbon spheres synthesized by hydrothermal method is about 1 mu m-2 mu m, and the composite of sodium lignosulfonate turns into layered structure. The adsorption rate of 0.8 g L-1 adsorbent to 100 mg L-1 Cr(III) can reach 99% under neutral conditions. The adsorption kinetics and adsorption isotherms show that the pseudo second order kinetics and Langmuir model are most suitable for the adsorption experiment. The regeneration of carbon-lignin based adsorbent shows that it can be reused in the adsorption process.