Chitosan Glutaraldegyde Cryogels for Wastewater Treatment and Extraction of Silver Nanoparticles

Abstract

The discharge of nanoparticles into the environment, such as through industrial plants and municipal wastewater treatment plants, can pose a hazard to aquatic life. This study demonstrates the effective removal of silver nanoparticles (AgNPs) using a chitosan-based cryogel, which has potential applications in agriculture, as well as in water treatment or in industrial plants that discharge into environmentally sensitive water bodies. The adsorbent is economically viable, has high affinity toward metal nanoparticles, is biodegradable and biocompatible, and displays a good removal of nanoparticles. AgNP adsorption was monitored using UV/Vis spectroscopy and TEM analysis. SEM, nitrogen adsorption, TGA, and FTIR analysis were used for cryogel characterization. The BET model of nitrogen adsorption revealed a specific surface area of 7.7 m2/g for chitosan–glutaraldehyde (CHI–GA) cryogels. The elasticity modulus of the CHI–GA cryogel was estimated as 543 ± 54 kPa. The AgNPs were characterized by a negative charge (−38 ± 17 mV) and an average diameter of 64 nm with a polydispersity index of 0.16. The mechanism of AgNP adsorption involved electrostatic interactions between the oppositely charged surfaces of the cryogel and particles. The temperature of the cryogel preparation affected the water permeability and adsorption efficiency. CHI–GA illustrated a capacity of 63 mg/g at a flow rate of 0.8 mL/min under a solution pressure of 500–970 Pa. The increase in pressure of the model plant extract-stabilized AgNP suspension (14 mg/L AgNPs) to 3.42–3.9 kPa led to an increase in the water permeability rate to 10 mL/min and a significant decrease in the efficiency of particle removal. The CHI–GA adsorbent demonstrated up to 96.5% AgNP removal until the breakthrough point due to adsorbent saturation. The CHI–GA cryogel adsorbent (1 g) can be used for efficient filtering of about 4.5 L of contaminated water.

Nanoremediation and Antioxidant Potential of Biogenic Silver Nanoparticles Synthesized Using Leucena’s Leaves, Stem, and Fruits

“…In addition, it is also important to explore how these nanomaterials can be efficiently recovered after the end of a remediation cycle and the possibility to reuse them. Regarding the recovery process, bio-based adsorbents are an interesting solution; a chitosan-based cryogel, for example, could remove up to 96.5% of AgNPs from water samples [86].…”

Antimicrobial Activity of Silver Nanoparticles Stabilized by Liposoluble Extract of Artemisia terrae-albae

“…This analysis aimed to investigate the stability and dimensions of the produced AgNPs. Zetasizer systems employ electrophoretic (ELS) and dynamic light scattering (DLS) techniques, offering insights into particle mobility, charge, and size in dispersive systems, spanning from nanometers to micrometers [28]. The following configuration involved running 5 scans for each sample run, with a total of 3 runs conducted.…”