一种改性微生物吸附剂的制备及其对镉离子的吸附特性

Modified adsorbents have become a research focus because of its excellent capacity to remove heavy metal ions. In this study, a modified adsorbent was prepared by applying different salts in the culture media of Raoultella sp. X13, and the adsorption characteristics of modified adsorbent to Cd²⁺ were studied. The results showed that Cd²⁺ adsorption capacities of Raoultella sp. X13 were improved in the presence of KCl, K₂SO₄, KH₂PO₄, (NH₄)₂SO₄, and NH₄Cl. Interestingly, the maximum adsorption capacity of Raoultella sp. X13 (named R5-1) modified by NH₄Cl for Cd²⁺ could reach 66.40 mg•g^-1, which increased by 47.30% compared with the control owing to the surface structure change of Raoultella sp. X13. different parameters, such as initial pH, contact time, and initial Cd²⁺ concentration, affected the adsorption capacity of Cd²⁺. The Cd²⁺ adsorption behavior by R5-1 was well fitted with Langmuir isotherm model and the pseudo-second-order kinetic model. FTIR analysis results showed that there are multiple functional sites on the surface of R5-l for the binding of Cd²⁺ ions, such as -OH, -CH₂, N-H, -COO, phosphate or sulfate functional groups. Simulation results showed that the biosorbent R5-l could efficiently remove a variety of heavy metal ions from wastewater. Therefore, the modified biosorbent R5-l can be used as a potential material for the remediation of Cd²⁺ pollution. This study provides a method for the preparation of modified biosorbents that are efficient, simple, and environmental-friendly.