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A rapid, simple, reliable, sensitive, and selective extractive spectrophotometric method was developed for the determination of silver(I) using 1-(2′,4′-dinitro aminophenyl)-4,4,6-trimethyl-1,4-dihydro pyrimidine-2-thiol, [2′,4′-dinitro APTPT] as a chromogenic reagent. The procedure is based on the synergistic extraction of silver(I) with 2′,4′-dinitro APTPT in presence of 0.5 mol L–1 pyridine. 2′,4′-Dinitro APTPT reacts with silver(I) to form an orange–red ternary complex (λmax 440 nm) in the presence of 0.5 mol L–1 pyridine having a molar ratio 1:1:1 (M:L:Py) in the pH range 2.7–4.3. The Beer’s law is obeyed in the concentration range of 1–11 μg mL–1 silver(I). The molar absorptivities and Sandell’s sensitivities of the complex in the chloroform are 1.131 × 104 L·mol–1·cm–1 and 0.010 μg cm–2 in the presence of pyridine, while they are 4.962 × 104 L·mol–1·cm–1 and 0.021 μg cm–2 in the absence of pyridine, respectively. A reproducibility of the method was checked by finding the relative standard deviation (RSD) (n = 5), which was 0.12%. The method is free from interferences due to the large number of cations and anions and has been successfully applied for the determination of silver in synthetic mixtures, ayurvedic samples, silver nano materials, photographic washing wastes (hypo solution), and waste effluent from silver refineries. It is also used for sequential separation of silver(I), copper(II), and gold(III) from their mixture. The accuracy was assessed using atomic absorption spectrometry (AAS), which tested the validity of the method.

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NiO nanosheets were deposited on the surface of a stainless steel substrate by using a facile, environmentally friendly, reflux deposition approach for supercapacitor (SC) applications. X-ray diffraction patterns and field emission scanning electron microscopy images revealed the formation of a face centred cubic crystal structure with a uniform, compact, smoothly ordered nanosheet like structure. This study focuses on the electrochemical supercapacitive properties of NiO nanosheets with respect to cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy techniques in a 1-(2 ,3-dihydroxypropyl)-3-methylimidazolium hydroxide [DHPMIM][OH] ionic liquid (IL) as an electrolyte. The electrochemical study revealed that NiO (0.3 M) showed a high-specific capacitance of 205.5 F g −1 and an excellent cycling stability (80% specific capacitance retention after 5000 cycles) in the [DHPMIM][OH] IL electrolyte. Thus, the result showed that NiO nanosheets act as an active electrode material hold for SCs.

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Continuous oil–water separation is not only an important topic for scientific research but also for practical applications to clean oil from industrial oily wastewater and oil‐spill pollution. In this work, polyurethane sponges are coated by ZnO using dip coating technique. ZnO‐coated sponges are modified by stearic acid to achieve superhydrophobicity. The ZnO‐coated sponges exhibit water contact angle ≈165° and oil contact angle ≈0°. The prepared superhydrophobic sponge is sustained in oil–water separation and in separation of oil–hot water mixture. Also the wetting properties of the sponge are stable in mechanical test like cutting and twisting. Stearic acid modified ZnO‐coated sponge holds good promise for oil‐spill cleanup as well as oil/water separation from harsh environments.