Chelating (pyrazolylmethyl)pyridine ligands: Coordination chemistry and binding properties with zinc(II) and cadmium(II) cations

Perspectives and prospects of chelation extraction of heavy metals from wastewater: A review

Heavy metals' contamination of water resources is a global environmental issue due to their detrimental effects on human health. To safeguard humans and the environment, toxic heavy metals must be removed from contaminated water because they cannot be broken down. Diverse technologies are employed to reduce the levels of heavy metals in wastewater. However, these technologies suffer from being either costly or ineffective, particularly when the effluent has extremely low residual amounts. This review outlines the main accomplishments and promising future directions for solvent extraction as one of the potential methods of extracting heavy metals from water, utilizing literature reports. In addition to reviewing some of the commercial chelating reagents now in use, this article also discusses some of the obnoxious effects on human health that are associated with exposure to heavy metals.

Liquid-liquid extraction of copper(II), zinc(II), cadmium(II), and lead(II) from aqueous solution and sewage effluent using phenoxy-amino ligands

The phenoxy-amino ligands 2-(((2-(diethylamino)ethyl)amino)methyl)phenol (L1) and 2-(((2-mercaptoethyl)amino)methyl)-phenol (L2) were studied as model chelating agents for liquid-liquid extraction of copper(II), zinc(II), cadmium(II), and lead(II) cations from water using dichloromethane-water biphasic system. The relative affinities of these chelating ligands for copper(II), zinc(II), cadmium(II), and lead(II) by liquid-liquid extraction were found to be in the order copper(II)> zinc(II) > cadmium(II) > lead(II). The ligands L1 and L2 showed binding efficiencies ranging from 78%-97% for copper(II), 75%-91% for zinc(II), 76%-92% for cadmium(II), and 59%-67% for lead(II). The extraction protocol was successfully applied to sewage effluent.

Protective Effect of L-Theanine on Cadmium-Induced Apoptosis in PC12 Cells by Inhibiting the Mitochondria-Mediated Pathway

L-Theanine is an amino acid derivative from green tea. The present work was aimed at the effect of L-theanine on neuron-like rat pheochromocytoma (PC12) cells stimulated with cadmium chloride. Treatment with L-theanine before cadmium exposure increased cell viability; the experiments of Annexin V/PI staining indicated that L-theanine inhibited cadmium-induced cell apoptosis. Meanwhile, L-theanine decreased ROS production and protected from cadmium-induced disruption of mitochondrial transmembrane potential. Compared with cadmium-treated cells, L-theanine could also decrease the ratio of Bax/Bcl-2, as well as the level of cleaved caspase-9, caspase-3 and poly(ADP-ribose) polymerase. Furthermore, L-theanine depresses cadmium-induced up regulation of phosphorylations of PI3K/Akt, MAPK ERK1/2, and JNK signaling. These data suggest that L-theanine pretreatment reduces severity of cadmium toxicity probably via antioxidant action. Therefore, it may be concluded that L-theanine could be exploited for prevention of cadmium-induced diseases.