Alginate/organo-selenium composite hydrogel beads: Dye adsorption and bacterial deactivation

Post-COVID-19, the risk and spread of germs, coupled with wastewater contamination, have become critical concerns. Wastewater contains waterborne bacteria and various contaminants like dye molecules, threatening water safety. Traditional adsorption methods address pollutant removal or pathogen inactivation separately, but a dual-action solution is increasingly essential. This study presents alginate/selenium composite hydrogel beads with the potential to simultaneously remove dyes and deactivating bacteria. Fabricated by dropping suspension droplets into a calcium ion bath, these beads were tested for dye adsorption and antibacterial efficacy. Beads with 50 wt% organo‑selenium demonstrated the highest methylene blue (MB) adsorption capacity and nearly 100 % deactivation efficiency against Pseudomonas aeruginosa, while those with 20 wt% showed no significant improvement. Mechanistic studies reveal that organo‑selenium induces stacking effects and reduces surface charges, enhancing MB adsorption and antibacterial performance. The alginate/organo‑selenium composite hydrogel beads offer a potential effective and sustainable solution for tackling the complex issue of wastewater pollutants.