The Synthesis of Superabsorbent Hydrogels Containing Naturally Derived Components and Their Use for the Environmental Cleanup of Dye Pollutants

The utilization of naturally derived sustainable components is an increasing trend in polymer and materials science and technology. This paper reports on the synthesis of superabsorbent hydrogels (SAHs) containing acrylic acid (AA), styrene (St, 10 wt.% of AA) and poly(ethylene glycol diacrylate) (PEGDA) using one-pot radical suspension copolymerization. Cassava starch (CS, 1 wt.% of AA) was added to the copolymerization mixture as a natural hydrophilic gel modifier. Cardanol acrylate (CA) was used as a natural alternative to PEGDA, and its effect on SAH properties (gel content, swelling rate, swelling capacity, morphology, thermal stability, rheology and dye absorption) was investigated. The swelling capacity reached its maximum at 63,000% for the gel containing 50% of CA. CA also significantly increased SAH rigidity, as revealed by rheology tests that confirmed the gel-like behavior of all networks as well. The amphiphilic gels showed a remarkable binding capacity for the selected dyes, with 38.7 mg/g for crystal violet, 41.5 mg/g for Acridine Orange, 47.4 mg/g for Methylene Blue and 33.5 mg/g for Auramine Orange, indicating a promising application potential for the environmental cleanup of aqueous waste.