Bioinspired catecholamine/starch composites as superadsorbent for the environmental remediation

Abstract

Focusing on the encouraging properties of starch-based composite materials, starch‑g‑(acrylic acid‑co‑acrylamide) superabsorbent was synthesized using solution polymerization method, and then the catecholamine functional groups were introduced on to pore surface of the absorbent via oxidative polymerization of dopamine (DA). The adsorbent was optimized in terms of the monomers' mass ratio and synthesis conditions, and characterized by different characterization techniques. The polydopamine (PDA) coating thickness was estimated using transmission electron microscopy (TEM) image and it was found to be 83 nm. The bimodal mesoporous adsorbent with 5914.66% swelling ratio bearing micropores with a specific surface area of 2.8031 m2 g−1 was used for the adsorption of methylene blue (MB) as a model water pollutant dye. The maximum adsorption capacity was obtained 2276 mg g−1 at pH 9 and within 100 min. The adsorbent with unprecedented super high adsorption capacity can be encouraging from different environmental remediation points of view.