A Simple Pre-concentration Method for the Determination of Nickel(II) in Urine Samples Using UV-Vis Spectrophotometry and Flame Atomic Absorption Spectrometry Techniques

The cloud point technique was effectively utilized for extraction and pre-concentration of nickel(II) in urine samples before measurement by UV-Vis spectrophotometer and AAS techniques. The metal response to a para-aminophenol (PAP) reagent in a non-ionic surfactant Triton X-114 medium was to form the Ni-PAP complex. The adopted concentration for PAP, concentration of Triton X-114, pH effect and water bath temperature, incubation time, salt effect, and interference effects were all optimized. The calibration curve was linear over the range of (0.0625–1.25) mg L–1 with a correlation coefficient r2 of 0.9682 for the UV-Vis spectrophotometer at a λmax of 629 nm. The limit of detection was 0.005 mg/L. The relative standard deviation for six replicates was 1.07%. This method was applied successfully to determine copper (II) concentrations in 44 urine samples of occupational worker samples as determined by UV-Vis spectrophotometry and FAAS techniques

Voltammetric determination of Hg²⁺, Zn²⁺, and Pb²⁺ ions using a PEDOT/NTA-modified electrode

[Image: see text] A novel electrochemical sensor for determining trace levels of Hg(2+), Pb(2+), and Zn(2+) ions in water using square wave voltammetry (SWV) is reported. The sensor is based on a platinum electrode (Pt) modified by poly(3,4-ethylenedioxythiophene) and N(α),N(α)-bis-(carboxymethyl)-l-lysine hydrate (NTA lysine) PEDOT/NTA. The modified electrode surface (PEDOT/NTA) was prepared via the introduction of the lysine-NTA group to a PEDOT/N-hydroxyphthalimide NHP electrode. The (PEDOT/NTA) was characterized via cyclic voltammetry (CV), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). The effects of scan rates on the electrochemical properties of the polymer electrode were also investigated. The electrochemical results were used to estimate the coverage of the electrode polymer surface and its electrostability in background electrolyte solutions. Several analytical parameters, such as polymer film thickness, metal deposition time, and pH of the electrolyte, were examined. Linear responses to Hg(2+), Pb(2+), and Zn(2+) ions in the concentration range of 5–100 μg L(–1) were obtained. The limits of detection (LODs) for the determination of Hg(2+), Pb(2+), and Zn(2+) ions were 1.73, 2.33, and 1.99 μg L(–1), respectively. These promising results revealed that modified PEDOT/NTA films might well represent an important addition to existing electrochemical sensor technologies

Gamma-phase Zn-Ni Alloy Deposition by Pulse-electroplating from a Modified Deep Eutectic Solution

This article describes the electroplating of Znsingle bondNi alloy from a modified deep eutectic solvent (DES), a mixture of choline chloride (ChCl) and ethylene glycol (EG) commonly known by its commercial name Ethaline. In this study the Ethaline was modified with propylene carbonate (PC) to decrease the solution viscosity. Boric acid was also used as an additive to improve surface finish and adhesion. The modifications were shown to increase the reduction rate of metal ions through improved mass transport and also to improve the quality of finish (morphology and interfacial adhesion) of the coating. We demonstrate that it is possible to produce dense, thick and adherent coatings of a γ-phase Znsingle bondNi alloy with 81–85% Zn on mild steel substrates using either potentiostatic deposition or controlled current pulse-plating techniques. Mild steel is a typical substrate for a sacrificial anti-corrosion coating used in many applications where the alloy serves to protect the steel from corrosion in harsh environments

A comparative study of the formation, and ion and solvent transport of polyaniline in protic liquid-based deep eutectic solvents and aqueous solutions using EQCM

Electroactive polymers such as polyaniline, polypyrrole and poly(3,4-ethylenedioxythiophene) have many potential applications, but the nature of the electrolyte can be adversely affected on mass transport processes – of electronic charge, electroneutrality counter-ions (“charge-balancing”), reactant species, and mobility of polymer segments. In this study, polyaniline (PANI) films have been prepared in deep eutectic solvent (Oxaline, a eutectic mixture of oxalic acid and choline chloride) and acidic aqueous media using cyclic voltammetry associated with the electrochemical quartz crystal microbalance (EQCM). PANI was found to grow in both liquids although the rate of growth was slower in Oxaline than aqueous acid due to the higher viscosity of the former. The results showed that PANI electrodes made in aqueous solutions grow by an autocatalytic mechanism, unlike those in deep eutectic solvents (DESs). The stability and durability of some films was examined in DESs and aqueous solutions at 25 °C and 50 °C. The results showed the mobile species are different when cycled in the DES compared to aqueous media. For films grown in different media but cycled in aqueous acid, the anion (HSO4−) was found to dominate the mobile species. However, the mass behaviour of PANI electrodes (deposited from aqueous/Oxaline-DES) in DESs (Ethaline) at 50 °C was most strongly associated with cation (Ch+) egress (i.e., mass decrease) during the oxidation reaction and cation (Ch+) ingress (i.e., mass increase) during the reduction reaction. In addition, the results showed that temperature plays an important role in increasing the rate of diffusion and the stability of mass change in viscous ionic liquids.</p

Comparison activity of pure and chromium-doped nickel oxide nanoparticles for the selective removal of dyes from water

The current study involves a synthesis of a composite of nickel oxide nanoparticles (NiONPs) with a chromium dopant to yield (Cr/NiONPs). Synthesis of nickel oxide was performed by the co-precipitation method. The synthesis of the composite was conducted by the impregnation method. FTIR, EDX, SEM, and XRD were used to characterize the synthesized materials. The synthesised materials’ point zero charges (PZC) were performed using the potentiometric titration method. The obtained results show that the PZC for neat nickel oxide was around 5, and it was around 8 for Cr/NiONPs. The adsorption action of the prepared materials was examined by applying them to remove Reactive Red 2 (RR2) and Crystal Violate (CV) dyes from solutions. The outcomes demonstrated that Cr/NiONPs were stronger in the removal of dyes than NiONPs. Cr/NiONPs achieved 99.9% removal of dyes after 1 h. Adsorption isotherms involving Freundlich and Langmuir adsorption isotherms were also conducted, and the outcomes indicated that the most accurate representation of the adsorption data was offered by Langmuir adsorption isotherms. Additionally, it was discovered that the adsorption characteristics of the NiONPs and Cr/NiONPs correspond well with the pseudo-second-order kinetic model. Each of the NiONPs and Cr/NiONPs was reused five times, and the results display that the effectiveness of the removal of RR2 dye slightly declined with the increase in reuse cycles; it lost only 5% of its original efficiency after the 5 cycles. Generally, Cr/NiONPs showed better reusability than NiONPs under the same conditions.Validerad;2024;Nivå 2;2024-03-07 (hanlid);Funder: University of Babylon, Iraq;Full text license: CC BY</p