Diels-Alder clickable furan-thiosemicarbazide cellulose for selective ruthenium (III) imprinting

Developing an efficient adsorbent for Ru³⁺ ions in wastewater is crucial for both environmental protection and resource recovery. This study introduces a novel approach using cellulose-based adsorbents, specifically modified with furan-thiosemicarbazide (FTC), to enhance their selectivity for Ru³⁺ ions. By cross-linking the Ru³⁺/FTC-modified cellulose (FTC-CE) complex with a bis(maleimido)ethane (BME) cross-linker, we created a Ru³⁺ ion-imprinted sorbent (Ru-II-CE) that exhibits a strong affinity and selectivity for Ru³⁺ ions. The synthesis process was thoroughly characterized using NMR and FTIR spectroscopy, while the surface morphology of the sorbent particles was examined with scanning electron microscopy. The Ru-II-CE sorbent demonstrated exceptional selectivity for Ru³⁺ among competing metal cations, achieving optimal adsorption at a pH of 5. Its adsorption capacity was notably high at 215 mg/g, fitting well with the Langmuir isotherm model, and it followed pseudo-second-order kinetics. This study highlights the potential of FTC-CE for targeted Ru³⁺ removal from wastewater, offering a promising solution for heavy metal decontamination.