Chitosan–Graphene Oxide Composite Membranes for Solid-Phase Extraction of Pesticides

Abstract

Solid-phase extraction (SPE) coupled to LC/MS/MS analysis is a valid approach for the determination of organic micropollutants (OMPs) in liquid samples. To remove the greatest number of OMPs from environmental matrices, the development of innovative sorbent materials is crucial. Recently, much attention has been paid to inorganic nanosystems such as graphite-derived materials. Graphene oxide has been employed in water-purification processes, including the removal of several micropollutants such as dyes, flame retardants, or pharmaceutical products. Polysaccharides have also been widely used as convenient media for the dispersion of sorbent materials, thanks to their unique properties such as biodegradability, biocompatibility, nontoxicity, and low cost. In this work, chitosan–graphene oxide (CS_GO) composite membranes containing different amounts of GO were prepared and used as sorbents for the SPE of pesticides. To improve their dimensional stability in aqueous medium, the CS_GO membranes were surface crosslinked with glutaraldehyde. The composite systems were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, swelling degree, contact angle, and mechanical measurements. As the GO content increased, a decrease in surface homogeneity, an improvement of mechanical properties, and a reduction of thermal stability of the CS-based membranes were observed. The increased dimensional stability in water, together with the presence of high GO amounts, made the prepared composite membranes more efficacious than the ones based just on CS in isolating and preconcentrating different hydrophilic/hydrophobic pollutants.

Molecularly Imprinted Polymers Based on Chitosan for 2,4-Dichlorophenoxyacetic Acid Removal

“…Its benefits derive from being biodegradable, non-toxic, biocompatible, and bioactive [ 11 , 12 ]. These properties, combined with the advantage of having many functional groups on its backbone (-OH and NH2), have made CS particularly interesting for many applications such as tissue engineering [ 6 , 7 , 8 , 13 , 14 , 15 ], bioremediation [ 16 , 17 , 18 ], agriculture [ 19 ], cosmetics [ 20 ] and as sorbent materials [ 21 , 22 , 23 ] for a wide range of contaminants. CS possesses a suitable reactivity to be modified by chemical or physical processes with the aim of widening its use.…”

Carbon nanomaterial-based membranes in solid-phase extraction

“…The solution casting technique was applied to prepare GO/CS composite membranes with different percentages of GO (from 1 to 20% w/w) [47]. Such a technique is a process in which a polymer phase is dissolved in a solvent and mixed with a nanosized material prior to casting on a flat surface (for example a Petri dish).…”

Nanomaterials with Excellent Adsorption Characteristics for Sample Pretreatment: A Review

“…In 2021, Silvestro and co-workers [ 70 ] adjusted the hydrophilicity of chitosan-based membranes by introducing different amounts of GO in order to obtain multifunctional materials used as adsorbents in SPE. The results showed that the introduction of GO indeed reduced the hydrophilicity of the composite membrane and increased the adsorption capacity of hydrophobic pollutants.…”