Synthesis and adsorption properties of superabsorbent hydrogel and peanut hull composite

• SAH–PNH composite was synthesized by peanut hull cellulose, AA, AM, and AMPS firstly.
• The optimal case of the synthesis reaction was selected from the orthogonal tests.
• The adsorption capability of SAH–PNH for Pb(II) was higher than that of SAH.

The cellulose was extracted from peanut hull by methanoic acid and hydrogen peroxide, then superabsorbent hydrogel composite was synthesized by aqueous solution polymerization, using peanut hull cellulose, acrylic acid (AA), acrylic amide (AM), 2-acrylamide-2-methyl-1-propanesulfonic acid (AMPS) as raw materials, N,N′-methylene bisacrylamide (MBA) as cross-linker, and K2S2O8 as initiator. The structure and morphologies of the superabsorbents were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscope (SEM). The kinetic studies for Pb(II) adsorption onto hydrogel composite showed that the pseudo-second-order adsorption mechanism was predominant. The adsorption isotherm data were found to be well described by Freundlich model.