Copper-Binding Properties of Polyethylenimine-Silica Nanocomposite Particles

A novel deep eutectic solvent modified magnetic covalent organic framework for the selective separation and determination of trace copper ion in medicinal plants and environmental samples

BACKGROUND

Pretreatment techniques should be introduced before metal ion determination because there is very low content of heavy metals in Chinese medicinal plants and environmental samples. Magnetic dispersive micro solid phase extraction (MDMSPE) has been widely used for the separation and adsorption of heavy metal pollutants in medicinal plants and environmental samples. However, the majority of MDMSPE adsorbents have certain drawbacks, including low selectivity, poor anti-interference ability, and small adsorption capacity. Therefore, modifying currently available adsorption materials has gained attention in research.

RESULTS

In this study, a novel adsorbent MCOF-DES based on a magnetic covalent organic framework (MCOF) modified by a new deep eutectic solvent (DES) was synthesized for the first time and used as an adsorbent of MDMSPE. The MDMSPE was combined with inductively coupled plasma optical emission spectrometry (ICP-OES) for selective separation, enrichment, and accurate determination of trace copper ion (Cu2+) in medicinal plants and environmental samples. Various characterization results show the successful preparation of new MCOF-DES. Under the optimal conditions, the enrichment factor (EF) of Cu2+ was 30, the limit of detection (LOD) was 0.16 μg L-1, and the limit of quantitation (LOQ) was 0.54 μg L-1. The results for the determination of Cu2+ were highly consistent with those of inductively coupled plasma mass spectrometry (ICP-MS), which verified the accuracy and reliability of the method.

SIGNIFICANCE

The established method based on a new adsorption material MCOF-DES has achieved the selective separation and determination of trace Cu2+ in medicinal and edible homologous medicinal materials (Phyllanthus emblica Linn.) and environmental samples (soil and water), which provides a promising, selective, and sensitive approach for the determination of trace Cu2+ in other real samples.

Linear Polyethyleneimine-Based and Metal Organic Frameworks (DUT-67) Composite Hydrogels as Efficient Sorbents for the Removal of Methyl Orange, Copper Ions, and Penicillin V

This research explores the integration of DUT-67 metal organic frameworks into polyethyleneimine-based hydrogels to assemble a composite system with enough mechanical strength, pore structure and chemical affinity to work as a sorbent for water remediation. By varying the solvent-to-modulator ratio in a water-based synthesis path, the particle size of DUT-67 was successfully modulated from 1 μm to 200 nm. Once DUT-67 particles were integrated into the polymeric hydrogel, the composite hydrogel exhibited enhanced mechanical properties after the incorporation of the MOF filler. XPS, NMR, TGA, FTIR, and FT Raman studies confirmed the presence and interaction of the DUT-67 particles with the polymeric chains within the hydrogel network. Adsorption studies of methyl orange, copper(II) ions, and penicillin V on the composite hydrogel revealed a rapid adsorption kinetics and monolayer adsorption according to the Langmuir's model. The composite hydrogel demonstrated higher adsorption capacities, as compared to the pristine hydrogel, showcasing a synergistic effect, with maximum adsorption capacities of 473 ± 21 mg L-1, 86 ± 6 mg L-1, and 127 ± 4 mg L-1, for methyl orange, copper(II) ions, and penicillin V, respectively. This study highlights the potential of MOF-based composite hydrogels as efficient adsorbents for environmental pollutants and pharmaceuticals.