Quality assessment of drinking water with HCPTA

A simple and rapid extraction method for copper lead and cadmium with a new reagent 4-(4-chlorophenyl)-2-phenyl5-thiazoleacetic acid (HCPTA) in n-butyl acetate has been developed. The determination of metal ions was carried out with flame atomic absorption spectrophotometry subsequent to their preconcentration using this extraction method. Physicochemical parameters of extraction method have been optimized with respect to pH, extractant concentration, equilibration time and additional cations and anions. The quantitative extraction was observed at pH 8.2 within 10 minutes. The stoichiometric composition of the extracted complexes was determined to be [M(CPTA)2], where M = metal ion. The extraction constants (log Kex) of copper, lead and cadmium were found to be -10.3 9 ± 0.12, -9.7 ± 0.11 and -10.44 ±0.11 respectively. The developed procedure was applied the determination of these metals in samples of drinking water from Rawalpindi/Islamabad area and the results have been compared with the permissible levels of WHO

Removal of copper ions from aqueous solution using NaOH-treated rice husk

The present study investigates the removal of copper ions (Cu (II)) from aqueous solution using chemically treated rice husk (TRH). The chemical treatment was carried out using NaOH solution and the effect of contact time (tc), adsorbent dosage (Dad), initial Cu (II) concentration ([Cu]i), and temperature (T) on the percentage removals of Cu (II) (%RCu) were investigated. Different analytical techniques (FTIR, SEM, and EDX) were used to confirm the adsorption (ads) of Cu (II) onto the TRH. The ads kinetics was tested against pseudo-first-order (PFO) and pseudo-second-order (PSO) models as well as Langmuir and Freundlich isotherms. Treating RH with NaOH altered the surface and functional groups, and on the surface of RH, the ionic ligands with high electro-attraction to Cu increased and thus improved the removal efficiency. The %RCu decreased by increasing the [Cu]i and increased by increasing the ct, Dad, and T. Up to 97% Cu removal was achieved in ct of 30 min using Dad of 0.3 g [Cu]i of 25 mg L−1 and T = 280 K. The ads of Cu on TRH is endothermic, spontaneous, follows Langmuir isotherms, and exhibited a PSO kinetics. Moreover, the TRH was successfully regenerated and used for further adsorption cycles using 1 M HNO3.Other Information Published in: Emergent Materials License: https://creativecommons.org/licenses/by/4.0See article on publisher's website: http://dx.doi.org/10.1007/s42247-020-00126-w</p

Biological screening, DNA interaction studies, and catalytic activity of organotin(IV) 2-(4-ethylbenzylidene) butanoic acid derivatives: synthesis, spectroscopic characterization, and X-ray structure

<div><p>A series of organotin(IV) carboxylates, [Me₂SnL₂] (<b>1</b>), [Bu₂SnL₂] (<b>2</b>), [Oct₂SnL₂] (<b>3</b>), [Me₃SnL] (<b>4</b>), and [Ph₃SnL] (<b>5</b>), where L = 2-(4-ethylbenzylidene) butanoic acid, have been synthesized and characterized by elemental analysis, FT-IR, and NMR (¹H, ¹³C, and ¹¹⁹Sn). [Me₃SnL] (<b>4</b>) was analyzed by single crystal X-ray analysis which showed polymeric structure with distorted trigonal bipyramidal geometry. The complexes were screened for biological activities including antibacterial, antifungal, and cytotoxic activities. UV–vis absorption studies of <b>HL</b>, <b>1</b> and <b>4</b> with SS-DNA revealed groove binding as well as intercalation, which may be due to the presence of planar phenyl groups that facilitate interaction with DNA. The determined intrinsic binding constants, 6.04 × 10³ M⁻¹ (<b>HL</b>), 9.6 × 10³ M⁻¹ (<b>1</b>), and 1.7 × 10⁴ M⁻¹ (<b>4</b>), showed that <b>HL</b> and <b>1</b> have less binding strength than <b>4</b>. The catalytic activities of di- and tri-organotin(IV) complexes were assessed in transesterification of triglycerides (linseed oil) into fatty acid methyl esters (biodiesel). The tri-organotin(IV) complexes have better catalytic activity than their di-analogs.</p></div