Volume 237, Issue 1-2

Designating an organic inhibitor with a specific chemical structure that actively participates in steel protection by increasing adsorption on the steel surface. Based on that, we synthesized three zwitterionic surfactants based on azomethine with different hydrophobic chain lengths labeled ZWSO, ZWSD, and ZWSH. The presence of azomethine group, electrons, and heteroatoms in the zwitterionic surfactant’s amphipathic structure helped to improve C-steel protection. Their inhibitory activity toward steel corrosion was investigated utilizing electrochemical impedance spectroscopy (EIS), gravimetrical, and potentiodynamic polarization techniques. Importantly, the surfactant tail influenced corrosion inhibition performance; as surfactant tail length increased, so did inhibition efficiency due to increased adsorption affinity. The inhibition efficiencies of ZWSO, ZWSD, and ZWSH are 87.15, 89.82, and 91.36%, respectively. Tafel data clarified that ZWSO, ZWSD, and ZWSH inhibitors behave as mixed-type inhibitors following the modified Langmuir isotherm. The inhibitors can adsorb physiochemically on the steel surface with ∆ G ads ranges from −38.48 to −44.6 kJ mol −1 . The SEM confirms that the morphology of C-steel becomes smoother because of inhibitor adsorption. The DFT and MCs output data supported the experimental performance of the tested ZWSO, ZWSD, and ZWSH inhibitors and especially their dependence on surfactant tail length.

Potentiodynamic and cyclic voltammetric studies were carried out on nickel in borate buffered saline (pH = 8.49). The anodic excursion spans of nickel in borate buffer solution do not involve active/passive transition. The passive film starts to break down in the presence of Cl-ions, which causes pitting damage. The data reveal that the increasing Cl − concentration and solution temperature shifts the E pit to the active direction while the increasing in scan rate shifts the E pit to the positive direction. The pitting potential ( E pit ) shifted in a positive direction when increasing concentrations of Wo 4 −2 and MoO 4 −2 anions were added to a borate buffer solution containing Cl − ions, showing that the additional anions had an inhibitory influence on the pitting corrosion. While the NO 3 − anion is ineffectual as an inhibitor and rather speeds up pitting corrosion, the NO 2 − anion has a slight inhibitory impact on pitting corrosion.

In this study, the interactions in aqueous binary and ternary systems containing polyethylene glycol (6000) and erythromycin at different temperatures were investigated to utilize this information in the aqueous two-phase method for different purposes, including separation and purification. Through experimental methods, density, sound velocity, and viscosity at 293.15, 303.15, and 313.15 K were measured in aqueous solutions, including erythromycin and polyethylene glycol. From the experimental density data, apparent molar volume ( ϕ V ), limiting apparent molar volume ( ϕ V 0 ) and transfer molar volume ( ∆ t r ϕ V 0 ) ${{\increment}}_{\mathrm{t}\mathrm{r}}{\phi }_{\mathrm{V}}^{0})$ have been calculated. Also, the experimental sound velocity data determined apparent molar isentropic compressibility ( ϕ k ), limiting apparent molar isentropic compressibility ( ϕ k 0 ) and transfer isentropic compressibility ( ∆ tr ϕ k 0 ) ${{\increment}}_{\mathrm{tr}}{\phi }_{\mathrm{k}}^{0})$ values of polyethylene glycol (6000) from water to erythromycin solutions. Furthermore, experimental viscosity data and the Jones–Dole equation determined viscosity β ′ -coefficient and transfer viscosity β ′ -coefficient ( ∆ t r β ′ ) ${{\increment}}_{\mathrm{t}\mathrm{r}}{\beta }^{\prime })$ values. The obtained results investigated the polymer effect as kosmotropic or chaotropic on erythromycin drug and the interaction between polyethylene glycol and erythromycin (solute-solute interactions). The results show that the interaction between drug and polymer is more desirable in the high-concentration polymer. Finally, results indicate that polyethylene glycol (6000) has played a kosmotropic role in aqueous solutions of erythromycin.

Sol-gel auto combustion method was adopted to fabricate magnesium ferrite (MgFe 2 O 4 ) nanoparticles. The structural and morphological properties was studied by XRD, FTIR, and SEM analysis. The average particle sizes of MgFe 2 O 4 was in the range of 35–55 nm. The octahedral & Tetrahedral bond lengths, R AE (tetrahedral edge length), R BE (shared octahedral edge length) and R BEU (individual octahedral edge length), cationic radii (tetra and octa-sites) were also determined. The magnetic strength also showed direct reliance on bond angle and indirect to bond length. Hoping length L a and L b and bond angles are also measured. The frequency dependent conductivity and dielectric properties of MgFe 2 O 4 were investigated by Impedance analyzer. The photocatalytic activity (PCA) is appraised against MB (methylene blue) dye and MgFe 2 O 4 calcined at 800 °C showed promising degradation (78%) under visible light irradiation. The findings revealed that MgFe 2 O 4 is can harvest the solar light, which could be employed for the remediation of wastewater contains textile dyes.

This study reports the aggregation behavior of polylactic acid (PLA) with ionic surfactants e.g. sodium dodecyl sulphate (SDS) and hexadecyltrimethylammonium bromide (CTAB) at different temperatures. Surface tension and conductivity techniques were used to investigate these physicochemical properties. Surface tension measurements were carried out to find out critical micelle concentration (CMC), free energy change of micellization (Δ G m ), free energy change of adsorption (Δ G ads ) and surface excess concentration (Γ). Conductivity measurements were used to determine CMC, degree of ionization ( α ) and degree of counter ion binding ( β ). The values of α and β obtained for SDS were (0.389 and 0.611 respectively), while for CTAB the values of α and β were (0.239 and 0.761 respectively). This type of electrostatic interactions is very important which can be applied in various industrial applications (e.g. pharmaceutical, industrial foaming, oil recovery etc.).

Instead of water reversed micelles can also be formed with polar organic solvents possessed with high dielectric constant and very low solubility in oil phase. Nonaqueous reverse micelles or microemulsions represent an interesting microreactors for various reactions, especially for reactions, where reagents can react with water. Study of localization places of molecular probes in organic polar pockets of reverse micelles is topical. The solvatochromic behavior of optical probes ortho-nitroaniline (o-NA) and methyl orange (MO) was studied in nonaqueous reverse micelles on the basis of surfactants sodium bis (2-ethylhexyl) sulfosuccinate (AOT) and polyoxyethylene (4) lauryl ether (C 12 E 4 ) and polar organic solvents (acetonitrile, dimethylformamide, glacial acetic acid, etc.) insoluble in oil phase hexane. The strength of binding of o-NA and MO to AOT and C 12 E 4 reversed micelles was assesssed via binding constant ( K b ) and association degree ( α ) respectively. Donor, acceptor, or dipole-dipole interactions ability of the solvent to the head groups of surfactant was taken into account in order to explain results obtained with UV–visible spectroscopic method. The binding constants of o-NA with reverse AOT micelles in the presence of various solvents in the pockets of reversed micelles increase in the following row water < glacial acetic acid < acetonitrile < dimethylformamide < dimethyl sulfoxide, but this sequence is reversed when o-NA binds to C 12 E 4 reverse micelles. The high value of the proton donor or acidity parameter in the water molecule ( x d  = 0.37) determines the weak binding of o-NA to the head AOT groups ( K b  = 20.8) in case of aqueous reverse micelles. The high value of the dipole parameter in the dimethylformamide molecule ( x n  = 0.40) promotes its strong interaction with nonionic polyoxyethylene groups of C 12 E 4 , which results in low value of binding constant ( K b  = 26.5) in case of optical probe o-NA and low value of association degree ( α  = 0.60) using MO as absorption probe. The results of this article will contribute to the improvement of the concept of interfacial processes, viz.: (i) some issues of supramolecular chemistry, (ii) revealing the contribution of parameters of donor, acceptor or dipole-dipole interaction in a polar organic solvent at the surfactant/nonpolar organic solvent interface, and (iii) features of the dissolution of optical probes in non-aqueous reverse micelles.

In this article, we reported the micron sized particles of poly (methacrylic acid) (p [MAA]) microgel and explored their applications as anionic adsorbents. The micron sized particles of poly (methacrylic acid) microgel were prepared by a simple inverse suspension polymerization method. The adsorptive elimination of adsorbates of cationic nature including malachite green (MG) and methylene blue (MB) from the aqueous medium was studied systematically. The adsorption tests were carried out using various initial concentrations of dyes and with different amounts of adsorbents. The adsorption equilibrium was established in 60 min. The adsorption capacity of the p (MAA) microgel was found as high as 351 mg/g for MG and 65 mg/g for MB. The maximum removal percentage for MG and MB was recorded as 88 and 68%, respectively. The adsorption data was computed with adsorption isotherm models including Langmuir, Freundlich, and Temkin. The Langmuir model was observed to be more applicable for the adsorption of MG while the adsorption of MB was best matched with Temkin model. The adsorption data was also treated with pseudo first order and pseudo second order kinetic models along with intraparticle diffusion and Elovich models. The pseudo second order kinetic model was most suitable with adsorption of both the MG and MB.

A facile and green approach to extract silica from the coal fly-ash waste is extremely critical for environmental sustainability and economically suitable. In this study, we have used acid-alkali coupled approach to improvised the proficiency of the extraction process. The sodium hydroxide (NaOH) soaking results the formation of the sodium silicate (Na 2 SiO 3 ) solution then pure silica was obtained by heating at high temperature; this coupled route-way results better yield of silica (SiO 2 ) which is ∼ 40 g. The efficiency of pure silica is not enough to remove toxic effluents from the aqueous media. A highly versatile approach of composite formation was adopted to fabricate silica-clay composite using kaolinite-clay and extracted silica. Both materials, extracted silica and its silica-clay composite were analyzed using scanning electron microscopy (SEM), energy dispersive X-ray (EDX) method, X-ray diffraction technique (XRD) and Fourier transform infra-red spectroscopy (FTIR). The silica-clay composite showed plate-tubular like morphology with enormous binding sites available for the sorption pollutants like organic dyes. It has shown excellent sorption of methylene blue (MB) efficiency of 131.5 mg/g, while silica furnished the sorption of 70.5 mg/g. Results revealed that the synthesized material could probably have better potential for dye removal from industrial effluents.

2D carbides and nitrides-based nanomaterials because of their unusual physical and chemical properties and a vast range of energy-storage applications have attracted tremendous attention. However, 2D carbides and nitrides-based nanomaterials and their corresponding composites have many intrinsic constraints in terms of energy-storage applications. The nano-engineering of these 2D materials is widely investigated, to improve their performance for practical application. In this Review article, the current progress and research on 2D carbides and nitrides-based nanostructures are presented and debated, concentrating on their methods of preparation, and energy conservation applications for example Lithium-ion-battery, supercapacitors, and Sodium-ion-battery. In conclusion, the problems, and recommendations essential to be discussed for the progress of these 2D nanomaterials for energy-storage applications based on carbides and nitrides are displayed.

Azo dyes are extremely toxic and pose significant environmental and health risks. Consequently, mineralization and conversion to simple compounds are required to avoid their hazardous effects. A variety of enzymes from the bacterial system are thought to be involved in the degradation and metabolism of azo dyes. Bioremediation, a cost effective and eco-friendly biotechnology, involving bacteria is powered by bacterial enzymes. As mentioned, several enzymes from the bacterial system serve as molecular weapons in the degradation of these dyes. Among these enzymes, azoreductase, oxidoreductase, and laccase are of great interest for the degradation and decolorization of azo dyes. Combination of the oxidative and reductive enzymes is used for the removal of azo dyes from water. The aim of this review article is to provide information on the importance of bacterial enzymes. The review also discusses the genetically modified microorganisms in the biodegradation of azo dyes in polluted water.