Facile synthesis and effective adsorption of magnetic alginate biogel composite for lanthanum ions from water

A novel eco-friendly magnetic alginate biogel composite (Ca-SA@Fe ₃ O ₄ ) was synthesized through droplet polymerization and characterized using multiple techniques. Furthermore, the impact of factors, such as dosage, pH, contact time, temperature and the presence of co-existing ions on the efficiency of the removal for La(III) ions by the composite were systematically investigated. The evaluation and exploration were conducted on the adsorption performance, reusability, and interaction mechanism of the magnetic composite towards La(III) ions. The results show that the magnetic composite gel beats have a particle scale of approximately 1.3 mm, a peculiar folded structure with numerous surface pores and sensitive magnetive responsiveness. La(III)-ion removal from water by Ca-SA@Fe ₃ O ₄ reached 90.2% at pH 7.0, contact time of 20 h and 298 K. The La(III) adsorption behaviour was in accordance with the Langmuir model, and the maximum adsorption capacity was up to 91.0 mg/g. The spontaneous adsorption process exhibited kinetics that were in accordance with the Pseudo-second-order model, suggesting a favorable agreement. Complexation and electrostatic adsorption between the composite and La(III) ions facilitate the strong adsorption of La(III) ions. The commonly coexisting ions and ionic strength hardly interfered with the La(III) adsorption, apart from a minor influence of Ca ²⁺ ions. The biogel composite following adsorption of La(III) ions can be completely recovered and reused at least four times. Ca-SA@Fe ₃ O ₄ composite would be a cost-effective macroparticle biosorbent.