Appraisal of the adsorption potential of novel modified gellan gum nanocomposite for the confiscation of methylene blue and malachite green.

In the present investigation a novel, environmentally affable and economical, modified gellan gum nanocomposite (MAA-g-GG/Ppy/MMT) was fabricated via free-radical polymerization for the liquid-phase mitigation of Methylene blue (MB) and Malachite green (MG) dyes. The innovation of this work is substantiated by the intentional combination of diverse materials, the strategic incorporation of polypyrrole for enhanced adsorption, and the thoughtful addition of MMT as a nanofiller to address mechanical strength and improve adsorption capacity. The physico-chemical facets of MAA-g-GG/Ppy/MMT and its interaction with the dye molecules were elucidated using FT-IR, SEM-EDX, BET, TEM, and XRD techniques. The optimum conditions for the sorption of MB and MG were deemed to be dosage (1.2 g/L for both dyes), contact time (50 min for both dyes), initial MG/MB concentration (MB = 40 mg/L & MG = 30 mg/L), and pH (MB = 10 & MG = 7). The Freundlich isotherm was identified as the most suitable model, as evidenced by the highest R2 value (∼0.999), indicating multilayer adsorption. The pseudo second-order model appraised the kinetic data. Thermodynamic findings revealed the adsorption process to be spontaneous, viable and exothermic which was ascertained by negative ∆H⸰ values (-22.8 kJ/mol for MB and -18.3 kJ/mol for MG). The substantial Langmuir adsorption capacity (Qm: MG =185.185; MB = 344.827) can be ascribed to the reason for strong interactions between MAA-g-GG/Ppy/MMT and dyes. The high reliability of MAA-g-GG/Ppy/MMT was determined by the regeneration studies that worked up to four cycles for both dyes. The real water (distilled water, tap water, and river water) samples spiked with MG/MB demonstrated a substantial uptake of dyes (>85 %) and the marginal influence of ionic strength on the adsorptive potential of MAA-g-GG/Ppy/MMT validated its efficacy for the decontamination of real effluents. The forces of attraction between the dyes and MAA-g-GG/Ppy/MMT included van der Waals, electrostatic forces of attraction, and π-π interaction. This green, economical, and viable MAA-g-GG/Ppy/MMT will prove to be an efficient adsorbent for the decontamination process of sequestration of dyes to achieve a sustainable environment.

Analyzing synthesis routes for BaCuPO4: implications for hydrogen evolution and supercapattery performance.

In recent years, energy storage and conversion tools have evolved significantly in response to rising energy demands. Owing to their large surface area, superior electric and chemical stabilities, and thermal conductivities, barium copper phosphate (BaCuPO4) materials are promising electrode materials for electrochemical energy storage systems. In this study, the synthesis of nanostructures (NSs) using hydrothermal and chemical precipitation methods and exploring the electrochemical characteristics of BaCuPO4 in asymmetric supercapacitors provides a comparative investigation. Systematic characterization shows that nanomaterials prepared by applying the hydrothermal method have a more crystalline and large surface area than chemical precipitation. In the three cell arrangements, the hydrothermally prepared BaCuPO4 NSs delivered a high specific capacity (764.4 C g-1) compared to the chemical precipitation route (660 C g-1). Additionally, the supercapattery associated with the two electrode assemblages delivers an optimum specific capacity of 77 C g-1. The energy and power density of BaCuPO4//AC NSs were 52.13 W h kg-1 and 950 W kg-1, respectively. A durability test was also performed with BaCuPO4//AC NSs for 5000 consecutive cycles. Further, the coulombic efficiency and capacity retention of BaCuPO4//AC after 5000 cycles were 81% and 92%, respectively. Bimetallic phosphate is comparatively suggested for future perspectives towards HER to overcome the performance of single metal phosphate materials. This is the first approach, we are aware of, for investigating the electrochemical behavior of BaCuPO4, and our results suggest that it may be useful as an electrode material in electrochemical systems requiring high energy and rate capabilities.

Synergistic redox enhancement: silver phosphate augmentation for optimizing magnesium copper phosphate in efficient energy storage devices and oxygen evolution reaction.

The implementation of battery-like electrode materials with complicated hollow structures, large surface areas, and excellent redox properties is an attractive strategy to improve the performance of hybrid supercapacitors. The efficiency of a supercapattery is determined by its energy density, rate capabilities, and electrode reliability. In this study, a magnesium copper phosphate nanocomposite (MgCuPO4) was synthesized using a hydrothermal technique, and silver phosphate (Ag3PO4) was decorated on its surface using a sonochemical technique. Morphological analyses demonstrated that Ag3PO4 was closely bound to the surface of amorphous MgCuPO4. The MgCuPO4 nanocomposite electrode showed a 1138 C g-1 capacity at 2 A g-1 with considerably improved capacity retention of 59% at 3.2 A g-1. The increased capacity retention was due to the fast movement of electrons and the presence of an excess of active sites for the diffusion of ions from the porous Ag3PO4 surface. The MgCuPO4-Ag3PO4//AC supercapattery showed 49.4 W h kg-1 energy density at 550 W kg-1 power density and outstanding capacity retention (92% after 5000 cycles). The experimental findings for the oxygen evolution reaction reveal that the initial increase in potential required for MgCuPO4-Ag3PO4 is 142 mV, indicating a clear Tafel slope of 49 mV dec-1.

Effect of cobalt addition on the corrosion behavior of near equiatomic NiTi shape memory alloy in normal saline solution: electrochemical and XPS studies.

The electrochemical and corrosion (uniform and localized) behavior of a binary Ni52Ti48 shape memory alloy (SMA) and two ternary Ni52Ti48-x Co x (x = 1.5 and 4.0 wt%) SMAs were studied. Measurements were conducted in 0.9% NaCl solution at 37 °C employing various electrochemical methods. These include: linear polarization resistance (LPR), linear sweep voltammetry (LSV), chronoamperometry and dynamic electrochemical impedance spectroscopy (DEIS). Such measurements were complemented with scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analysis. Results revealed that the addition of alloyed Co to NiTi significantly reduced the uniform corrosion rate of the studied SMA and greatly enhanced its pitting corrosion resistance. XPS measurements evidenced high stability of the passive layer and limited adsorption of chloride ions. Additionally, it was found that the passive layer remained primarily composed of titanium oxides. Microstructure changes accompanying the addition of Co were also used to account for its role in improving the corrosion resistance of these materials.