Eco-friendly anti-corrosion performance of chitosan modified with fused heterocyclic compound on mild steel in acidic medium.

This study aims to explore the prevention of chitosan modified with a fused heterocyclic compound as a sustainable corrosion inhibitor for mild steel in 1 M HCl. Electrochemical instruments, including potentiodynamic polarization techniques, and electrochemical impedance spectroscopy (EIS), were employed to evaluate the corrosion protection performance. The outcomes showed that the chitosan modified with a fused heterocyclic compound has outstanding inhibition performance, with an inhibition effectiveness of 98.25 % at 100 ppm. The anti-corrosion features of modified chitosan were ascribed to the presence of hetero atoms in modified chitosan composite which leads to the creation of a protective layer, The modified chitosan composite behaved as mixed-typed inhibitors, as shown by the PDP results. The modified chitosan composite adsorbs on mild steel in the investigated corrosive media via chemisorption interactions, and its adsorption followed the Langmuir adsorption model. Furthermore, increasing the temperature from 303 to 333 K enhanced the corrosion rate, most likely due to the desorption of the inhibitor agent from the steel surface.

Facile synthesis of MOF-derived N doped ZnO/C nanoparticles and its adsorption activity toward dye removal.

Metal-organic framework (MOF)-derived materials have gained an increasing interest and showed potential adsorption features in numerous applications. Significant attempts have been performed to boost the structure, functionality, surface area and porosity in addition to adsorption performance of MOF-derived carbon nanoparticles. Here, nitrogen-doped ZnO/carbon nanoparticles were synthesized by directly pyrolysis of Zn based metal organic framework (ZIF-8) in a nitrogen atmosphere at two different temperatures (600 and 800 °C), followed by chemical impregnation with ZnCl2 solution with ratio (10:1) wt/wt, and thermal activation at 500 °C for 1 h. SEM, TEM, XPS, nitrogen adsorption-desorption method, and TGA characterization techniques were employed to investigate the morphology and structure characteristics. Then, thorough analysis of N doped ZnO/C-(600 and 800), adsorption capacity to remove Remazol brilliant blue reactive (RBBR) dye from aqueous phase was conducted. At room temperature, the porous N doped ZnO/C with high surface area attained a maximum adsorption capacity about 49.3 mg/g and demonstrated a strong adsorption capacity toward RBBR dye. The insights of kinetic, thermodynamic and adsorption isotherm studies of the as-demonstrated samples open up more discussion for MOFs-derived carbon adsorbents for wastewater treatment.

Insight into TEMPO-oxidized cellulose-based composites as electrochemical sensors for dopamine assessment.

The diagnosis and treatment of many neurological and psychiatric problems depend on establishing simple, inexpensive, and comfortable electrochemical sensors for dopamine (DA) detection. Herein, 2,2,6,6 tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibers (TOC) were successfully loaded with silver nanoparticles (AgNPs) and/or graphite (Gr) and crosslinked by tannic acid, producing composites. This study describes a suitable casting procedure for the composite synthesis of TOC/AgNPs and/or Gr for the electrochemical detection of dopamine. Electrochemical impedance spectra (EIS), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were employed to characterize the TOC/AgNPs/Gr composites. In addition, the direct electrochemistry of electrodes treated with the prepared composites was examined using cyclic voltammetry. The TOC/AgNPs/Gr composite-modified electrode improved electrochemical performance towards detecting dopamine compared to TOC/Gr-modified electrodes. Upon employing amperometric measurement, our electrochemical instrument has a wide linear range (0.005-250 µM), a low limit of detection (0.0005 µM) at S/N = 3, and a high sensitivity (0.963 µA µM-1 cm-2). Additionally, it was demonstrated that DA detection seemed to have outstanding anti-interference characteristics. The proposed electrochemical sensors meet the clinical criteria regarding reproducibility, selectivity, stability, and recovery. The straightforward electrochemical method utilized in this paper may provide a potential framework for creating dopamine quantification biosensors.

Polyanionic electrically conductive superabsorbent hydrogel based on sodium alginate-g-poly (AM-co-ECA-co-AMPS): Broadband dielectric spectroscopy investigations.

In this study, the dielectric behavior of polyanionic electrically conductive superabsorbent hydrogel based on sodium alginate-g-poly(AM-co-ECA-co-AMPS) was investigated by broadband dielectric spectroscopy (BDS). The dielectric spectra obtained from -70 to 70 °C showed a superposition of three distinctive processes, electrode polarization, charge carrier's transport, and a molecular relaxation process. These dynamic processes were further analyzed along with the effect of both temperature and reduced graphene oxide (rGO) content. The development of a clear electrochemical double layer (ECDL) at the electrode/hydrogel interface strongly supports its possible application in supercapacitors' forms of energy storage. TGA, DSC, rheology, and electrochemical properties were studied. Furthermore, when the composite hydrogel with rGO content of 2.5 % was assembled into a symmetric supercapacitor, it displayed a specific capacitance of 756 F.g-1 at 1 A.g-1 and 704 F.g-1 after 5000 cycles with high capacitance retention of 93.2 %. The superior conductivity and porous structure of the rGO composite hydrogel are credited with the hydrogel's excellent electrochemical capabilities.

Green and sustainable chitosan-gum Arabic nanocomposites as efficient anticorrosive coatings for mild steel in saline media.

The application of green and sustainable anticorrosive coatings is becoming of upsurge interest for the protection of metallic materials in aggressive environments. Herein, a stable crystalline chitosan/gum Arabic composite (CGAC) nanopowder was successfully synthesized and characterized by various methods. The CGAC nanopowder with different doses (25, 50, 100, and 200 ppm) was used to coat mild steel samples and examined its anticorrosion ability in 3.5 wt.% NaCl solution using gravimetric, electrochemical measurements, and surface characterization techniques. All methods yielded consistent results revealing that nanocomposite coatings can impart good anticorrosive properties to the steel substrate. The obtained protection efficiency was enhanced with increasing CGAC dose in the applied surface layer achieving 96.6% for the 200 ppm-coating. SEM and AFM surface morphologies of uncoated and coated samples after the inundation in the saline solution showed that CGAC coating can block the active corrosive sites on the steel surface, and prevent the aggressive Cl- ions from attacking the metallic substrate. The water droplet contact angle gave further support as it increased from 50.7° for the pristine uncoated surface to 101.2° for the coated one. The current research demonstrates a promising natural and reliable nanocomposite coating for protecting mild steel structures in the marine environment.

High performance hydrogel electrodes based on sodium alginate-g-poly(AM-c o-ECA-co-AMPS for supercapacitor application.

Electrochemical conductive hydrogels are being extensively explored in the fabrication of portable batteries and high-performance supercapacitors. Herein, the rational design of a new polyanionic electrically conductive hydrogels based on sodium alginate-g-poly(AM-co-ECA-co-AMPS) are described. rGO was incorporated into the hydrogel during the polymerization process generating rGO@ sodium alginate-g-poly(AM-co-ECA-co-AMPS) composite hydrogels to study the impact of rGO on the performance of the hydrogels. FT-IR, XRD, and SEM-EDX characterized the chemical composition, crystalline, and morphological structure of the new synthesized hydrogels. The electrochemical performance of as-synthesized hydrogels was investigated by cyclic voltammetry, galvanostatic, charge-discharge rate, and electrochemical impedance spectroscopy. The supercapacitor performance for ECH2.5 composite hydrogel showed a capacitance of 753 F. g-1 at 1 A. g-1 with good rate capability and cycling stability up to 5000 cycles. Thus, ECH2.5 hydrogel is a good candidate as electrode material in supercapacitor applications.

Green and facile synthesis of nickel oxide-porous carbon composite as improved electrochemical electrodes for supercapacitor application from banana peel waste.

Lithium-ion batteries and supercapacitors are examples of energy storage technologies that have a lot of promise in a variety of applications. Herein, NiO-porous carbon composites were prepared by a green and cost-effective facile synthesis route from banana peel waste materials. The surface morphology and chemical composition of the NiO-porous carbon composite were investigated using a scanning electron microscope (SEM) and energy dispersive x-ray analysis (EDX). The prepared samples were also described through Fourier transform infrared (FTIR) spectroscopy, x-ray powder diffraction (XRD), thermal gravimetric analysis (TGA), and surface area measurements. The electrochemical behavior of prepared materials was studied by cyclic voltammetry (CV), galvanostatic charge-discharge, and electrochemical impedance (EIS) to test their applicable suitability as supercapacitor electrode. PC-NiO (3) composite exhibits a remarkable specific capacitance of 811 F/g at a current density of 1 A/g. The specific capacitance of PC-NiO (3) is 5.3 times more than that of PC material at 1.0 A/g. Furthermore, the PC-NiO (3) composite material still exhibits a specific capacitance of 780 F/g at 5.0 A/g, high rate capability of 84.55% retention at a high current density of 10.0 A/g and superior cycle stability at 1000 cycles. Based on its high specific capacitance, the NiO-porous carbon nanocomposite is one of the most promising electrode materials for supercapacitors, according to the above results.

Environmentally benign corrosion inhibitors based on cellulose niacin nano-composite for corrosion of copper in sodium chloride solutions.

There is a high demand for high performance, effective and eco-friendly corrosion inhibitors for industrial applications. Therefore, novel benign high performance corrosion inhibitors based on biopolymer were synthesized in-situ using different cellulosic materials and niacin. Characterization of the cellulose nano-composite was carried out by Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), dynamic light scattering (DLS), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The anticorrosive performance of cellulose composites for copper in 3.5% NaCl solutions were evaluated using polarization and electrochemical impedance spectroscopy (EIS) techniques. Surface morphology of uninhibited and inhibited composites was studied using SEM and EDX. Potentiodynamic polarization measurements confirmed that cellulose based inhibitors act as a mixed type inhibitor. The inhibition efficiency of ethyl cellulose-niacin composite (NEC) was 94.7% outperforms those of microcrystalline cellulose-niacin composite (NMCC) and carboxymethyl cellulose-niacin composite (NCMC) which were 33.2 and 83.4%, respectively, as green corrosion inhibitors for Copper in 3.5% NaCl solutions. The data extracted from EIS were fitted through an equivalent circuit to model the corrosion inhibition.