Adsorptive removal of Ag/Au quantum dots onto covalent organic frameworks@magnetic zeolite@arabic gum hydrogel and their catalytic microwave-Fenton oxidative degradation of Rifampicin antibiotic

Recent progress in nanotechnology via incorporation of small particle size as quantum dots (QDs) (1- 10 nm) in many industrial activities and commercial products has led to significant undesired environmental impacts. Therefore, QDs removal from wastewater represents an interesting research topic with a lot of challenges for scientists and engineers nowadays. In this work, the coagulative removal of metal quantum dots as silver and gold from industrial water samples is explored. A novel biosorbent was assembled via binding of covalent organic frameworks (COFs) with magnetic zeolite and Arabic gum hydrogel (COFs@MagZ@AGH) as a promising removal material for Ag-QDs and Au-QDs. This was fully characterized by EDX, SEM, TEM, FT-IR, XPS, XRD and surface area and applied in coagulative removal of Au-QDs and Ag-QDs in presence of several experimental factors as pH, presence of other electrolytes, stirring time, initial QDs concentration, coagulant dosage, and temperature in order to optimize the removal processes. At optimum conditions, COFs@MagZ@AGH was able to recover 99.19% and 87.57% of Ag-QDs and Au-QDs QDs, respectively via chemical adsorption mechanism with perfect fitting to pseudo-second order model. Reuse of the recovered Ag/Au-QDs@COFs@MagZ@AGH as efficient catalysts in catalytic degradation of Rifampicin antibiotic (Rf) from water was additionally investigated andoptimized via microwave-Fenton catalysts with excellent oxidative degradation efficiency (100%). Reusability and applicability of the biosorbent (COFs@MagZ@AGH) and catalysts (Ag/AuQDs@COFs@MagZ@AGH) in real industrial water samples were also explored and successfully accomplished. (c) 2022 Elsevier Inc. All rights reserved.

Automated summary

Recent progress in nanotechnology has led to the incorporation of small particle size quantum dots (QDs) in industrial activities and products, resulting in undesired environmental impacts. This study focuses on the removal of metal quantum dots, such as silver and gold, from industrial water samples using a coagulative method. A novel biosorbent, COFs@MagZ@AGH, was developed and showed promising results for the removal of Ag-QDs and Au-QDs. The biosorbent was characterized and optimized under various experimental factors to achieve high removal efficiency. The recovered Ag/Au-QDs@COFs@MagZ@AGH were also explored as efficient catalysts for the degradation of an antibiotic in water, showing excellent oxidative degradation efficiency. The reusability and applicability of the biosorbent and catalysts in real industrial water samples were successfully demonstrated.