Carbon quantum dots-containing poly(β-cyclodextrin) for simultaneous removal and detection of metal ions from water

Emilly C Silva; Charlie G Gomes; João Pina; Rui F P Pereira; Dina Murtinho; André R Fajardo; Artur J M Valente

doi:10.1016/j.carbpol.2023.121464

Carbon quantum dots-containing poly(β-cyclodextrin) for simultaneous removal and detection of metal ions from water

Carbohydr Polym. 2024 Jan 1:323:121464. doi: 10.1016/j.carbpol.2023.121464. Epub 2023 Oct 6.

Authors

Emilly C Silva¹, Charlie G Gomes², João Pina³, Rui F P Pereira⁴, Dina Murtinho³, André R Fajardo⁵, Artur J M Valente⁶

Affiliations

¹ Laboratório de Tecnologia e Desenvolvimento de Compósitos e Materiais Poliméricos (LaCoPol), Universidade Federal de Pelotas (UFPel), Campus Capão do Leão, 96010-900, Pelotas-RS, Brazil; Chemistry Center and Chemistry Department, University of Minho, 4710-057 Braga, Portugal.
² Laboratório de Metrologia Química (LabMequi), Universidade Federal de Pelotas (UFPel), Campus Capão do Leão, 96010-900, Pelotas-RS, Brazil.
³ University of Coimbra, CQC-IMS, Department of Chemistry, 3004-535 Coimbra, Portugal.
⁴ Chemistry Center and Chemistry Department, University of Minho, 4710-057 Braga, Portugal.
⁵ Laboratório de Tecnologia e Desenvolvimento de Compósitos e Materiais Poliméricos (LaCoPol), Universidade Federal de Pelotas (UFPel), Campus Capão do Leão, 96010-900, Pelotas-RS, Brazil. Electronic address: andre.fajardo@ufpel.edu.br.
⁶ University of Coimbra, CQC-IMS, Department of Chemistry, 3004-535 Coimbra, Portugal. Electronic address: avalente@ci.uc.pt.

PMID: 37940321
DOI: 10.1016/j.carbpol.2023.121464

Abstract

This study investigates the synthesis and characterization of supramolecular composites composed of poly(β-cyclodextrin-co-citric acid) and carbon quantum dots (QDs). These composites serve a dual purpose as adsorbents and photoluminescent probes for divalent metal ions, including Ni(II), Cu(II), Cd(II), and Pb(II), which can have detrimental effects on the environment. Various characterization techniques were employed to confirm the successful synthesis of the composites and the interaction between cyclodextrins and QDs. By using mathematical tools, optimal conditions for metal adsorption were determined, resulting in the composites exhibiting high adsorption capacities, reaching 220 mg/g, and impressive removal efficiencies exceeding 90 % for Ni(II) and Cu(II). The supramolecular composites also exhibit selective adsorption of metal ions with small ionic radio and can be reused with minimal loss of efficiency. In addition to their adsorption capabilities, these composites display luminescence quenching upon the adsorption of metal ions, which can be utilized for sensing applications. Spectroscopic evaluation reveals Stern-Volmer quenching constants for the accessible fraction of QDs in the range of 3777 to 13,359 M^-1. The high stability of QDs on the composites allows for long-term storage. In summary, this original supramolecular composite shows promise for simultaneously monitoring and treating water and wastewater, making it a valuable tool in environmental applications.

Keywords: Adsorption; Carbon dots; Metal ions; Poly(cyclodextrins); Sensing; Supramolecular composites.