A Facile Salt‐Assisted Dewatering for Carboxymethyl Cellulose‐Based Hydrogels

ABSTRACT Natural polymer‐based hydrogels are gaining attention as an environmentally friendly alternative to petroleum‐based superabsorbent polymers. The hydrogel fabrication process involves washing and drying hydrated gels. However, due to their high hydrophilicity, hydrogels absorb significant amounts of water during washing and take a considerable time to dry, resulting in high energy costs. Therefore, we propose a method for dewatering acrylic acid/carboxymethyl cellulose (CMC)‐based hydrogels using sodium chloride (NaCl) solution. Washing water‐swollen hydrogels with a 7% NaCl aqueous solution removes 97% of the water. Simple pre‐dewatering with NaCl effectively minimizes the amount of ethanol required for ethanol washing. This work presents a novel approach for dewatering CMC‐based hydrogels and proposes potential applications for eco‐friendly absorbent materials.