Engineering efficient carrageenan materials for simultaneously removing herbicide, eight anionic/cationic dyes and...

Developing highly efficient biomass-based adsorbents capable of simultaneously removing various water contaminants is highly desired amidst the growing depletion of fossil resources. Herein, a versatile κ-carrageenan/polyethyleneimine/glycerol triglycidyl ether (KC/PEI/GTE) biomass adsorbent was engineered and succeeded in removing herbicide, eight anionic/cationic dyes and metal ion from solutions. Systematic investigations examined the effects of adsorption conditions on the carrageenan adsorbent's performance towards these contaminants from five perspectives. Additionally, the impacts of four cationic chloride salts and four anionic sodium salts in solutions on contaminant adsorption and adsorbent recyclability were evaluated. Attractingly, the KC/PEI/GTE demonstrates exceptional adsorption performance, recycling capability and application potential, notably outperforming most reported adsorbents (adsorption capacities (removal efficiencies) of sodium 2,4-dichlorophenoxyacetate (2,4-D), acid blue-25 (AB25), methyl orange (MO) and methylene blue (MB) are 365 mg g^-1 (91 %), 2357 mg g^-1 (91 %), 743 mg g^-1 (93 %) and 91 mg g^-1 (90 %), respectively). A thermodynamic, four kinetic and four isothermal models, SEM, FT-IR and XPS analyses revealed that hydrogen bonding and electrostatic interactions are the primary driving forces for contaminants removals. Benefiting from its outstanding advantages, the adsorbent developed in this study shows a great potential for applications in wastewater purification.