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 (Cu) from other competing cations. The yellow color of the receptor changed to pink upon adding Cu 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 × 10 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 Cu ions. The results confirmed that 50 mg receptor functionalized DE could adsorb 10 mL of 1 ppm Cu ions from water. Furthermore, a proof-of-concept device that is inexpensive, simple to operate, and continuously removes Cu ions from water has been developed. The efficiency of the device in Cu 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 locations where water contamination is a significant issue.