Remediation of Cd (II) ions in aqueous and soil phases using novel porous cellulose/chitosan composite spheres loaded with zero-valent iron nanoparticles

Novel porous cellulose/chitosan composite spheres loaded with nanoscale zero-valent iron (nZVI/PCSs) were fabricated for the removal of Cd (II) from aqueous solution and the remediation of Cd species in contaminated soil. The green-based nZVI/PCSs exhibited the improved dispersion and antioxidability of nZVI compared to the pristine one. The results from SEM/EDS suggested that the Fe (0) took part in the adsorption of the Cd (II) ions; whereas XPS analysis revealed that Fe (0) and amino groups in nZVI/PCSs played crucial roles in Cd (II) removal via the effects of precipitation or chelation. The results of the experiments in aqueous solution and model fitting showed that the adsorption of Cd (II) induced by nZVI/PCSs was better described by Langmuir isotherm and the maximum adsorption capacity reached up to 110.3 mg/g. The soil remediation tests demonstrated that nZVI/PCSs could significantly enhance cadmium immobilization, enabling the conversion of most exchangeable Cd species to Fe Mn oxides and organic matters in contaminated soil after the remediation. Overall, nZVI/PCSs have great potential as an excellent adsorbent with cost-effectiveness in Cd (II) removal from the aqueous solution and the remediation of Cd species in contaminated soil phases. The nZVI/PCSs composite spheres could be used in Cd (II) removal in water as well as Cd (II) immobilization in soil. • Porous cellulose/chitosan composite spheres loaded with nZVI were prepared. • The adsorption mechanisms were well elucidated based on the fitting of models. • The nZVI/PCSs exhibited high adsorption capacity towards Cd (II) ions from water. • The nZVI/PCSs could significantly enhance Cd immobilization in contaminated soil.