Rhodamine 6G derivative for the selective copper detection and remediation using nanoporous diatomaceous earth-engineered functional receptor

A rhodamine-derived receptor was synthesized and comprehensively characterized for structural confirmation. The receptor was able to distinguish the copper ions (Cu2}) from other competing cations. The yellow color of the receptor changed to pink upon adding Cu2} ions, however, other competing cations ions were impotent towards any color variation. The UV-visible titration studies revealed the binding stoichiometry of a 1:1 ratio with a detection limit of 9.663 x 10-8 M. Additionally, a novel idea of the work resides in the use of diatom for the practical application, where the receptor has been tethered on nanoporous diatomaceous earth microparticles (P2D) to remove Cu2} ions. The results confirmed that 50 mg receptor functionalized DE could adsorb 10 mL of 1 ppm Cu2} ions from water. Furthermore, a proof-of-concept device that is inexpensive, simple to operate, and continuously removes Cu2} ions from water has been developed. The efficiency of the device in Cu2} ion removal could be realized through the naked eye by observing the color change of P2D particles, which has excellent potential for application in remote loca-tions where water contamination is a significant issue.

Automated summary

A rhodamine-derived receptor that can distinguish copper ions (Cu2+) from other competing cations was synthesized and characterized. The receptor exhibited a color change from yellow to pink upon addition of Cu2+ ions, while other competing cations showed no color variation. The binding stoichiometry of the receptor with Cu2+ ions was found to be 1:1, with a detection limit of 9.663 x 10-8 M. Furthermore, the receptor was tethered on nanoporous diatomaceous earth microparticles (P2D) for practical application in removing Cu2+ ions from water, with promising results.