Scholarly Literature

Electrocatalytic Oxygen Reduction Reaction Using a Water-Stable Ni-Based Coordination Polymer with Two-Dimensional Honeycomb Architecture

2026-04-15T09:49:53Z

Electrocatalytic Oxygen Reduction Reaction Using a Water-Stable Ni-Based Coordination Polymer with Two-Dimensional Honeycomb Architecture Sarkar, S.; Nayak, B.; Purohit, S. V.; Singha, D. K.; Dash, B.; Laha, S.; Jena, B. K.; Mahata, P. A new Ni(III)-based metal-organic coordination polymer (MOCP) of formula [Ni(4,4 '-IPDPA)1.5(H2O)3]& centerdot;6H2O (4,4 '-IPDPA = 4,4 '-isopropylidenediphenoxyacetate), 1, has been synthesized at ambient temperature using the slow layer diffusion method. The framework of compound 1 was obtained through single-crystal X-ray diffraction (SCXRD). It was comprehensively analyzed by various methods, including powder X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), ultraviolet-visible (UV-vis) spectroscopy, luminescence spectroscopy, Brunauer-Emmett-Teller (BET) analysis, and X-ray photoelectron spectroscopy (XPS). Compound 1 shows promising electrocatalytic activity for the oxygen reduction reaction (ORR) in alkaline conditions. With a nearly four-electron reduction mechanism and a half-wave potential of 0.72 V versus a reversible hydrogen electrode (RHE), compound 1 exhibits remarkable ORR performance. The compound 1 most intriguingly showed good long-term stability. In addition to the presence of accessible pores within the framework, the emergence of the reduced Ni(II) moiety from Ni(III) during cathodic polarization is believed to be responsible for the high level of activity. Compound 1 also demonstrated exceptional resistance toward methanol poisoning during the ORR activity. Moreover, the density functional theory (DFT) analysis suggests that the as-prepared Ni3+-ion-based MOCP follows the four-electron-guided ORR pathway with the formation of *O intermediate as the potential-determining step (PDS).

Enhanced selectivity in Scheelite-Calcite flotation using oleic and palmitic acid mixed collectors: experimental and molecular dynamics insights

2026-04-15T09:17:09Z

Enhanced selectivity in Scheelite-Calcite flotation using oleic and palmitic acid mixed collectors: experimental and molecular dynamics insights Das, S.K.; Swain, P.; Angadi, S. I.; Rath, S. S. The flotation separation of scheelite from calcite remains a significant challenge in mineral processing due to their similar surface characteristics. The present study proposes a novel approach using a 1:1 mixture of oleic acid and palmitic acid as a mixed collector to achieve effective separation. The mixed collector system enriched the WO3 content from 0.19% in the feed to 2.2% in the float fraction, with an overall recovery of approximately 81.2% in a single flotation stage. In comparison, calcite recovery was as low as 26.8%, supporting the scheelite selectivity of the mixed collector system. Additionally, the flotation mechanism, involving the interaction between collector species and mineral surfaces, was investigated using Fourier transform infrared spectroscopy, UV-vis diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy. The results revealed that adsorption under the mixed collector system facilitated the formation of a greater number of Ca-carboxylate complexes on the scheelite surface than on calcite, indicating preferential adsorption on scheelite. Moreover, the molecular dynamics simulation results suggested that the mixed collector system exhibited the maximum water-displacing ability and the highest accumulation of collector molecules on the scheelite (1 1 2) surface, compared to both collectors used individually.

Assessment of heavy metal enrichment, ecological risk with in-situ phyco-remediation approach: A regional study from Odisha's coastal creeks, India

2026-04-09T05:48:37Z

Assessment of heavy metal enrichment, ecological risk with in-situ phyco-remediation approach: A regional study from Odisha's coastal creeks, India Mishra, D.; Patra, S.; Kumar, M.; Kumar, S. D.; Sathish, R.; Dhal, N.K. Increasingly, coastal creeks are vulnerable to heavy metal (HM) pollution, while their ecological risks and remediation potential remain poorly understood. This work investigated HM pollution, ecological risks, and bioaccumulation potential of indigenous marine macroalgae (seaweed), Chaetomorpha linum, in two contrasting creeks, Jatadhar Muhan Creek (JMC) and Haripur Creek (HC), along Odisha's coast, India. Accumulation potential was assessed using geochemical indices, including enrichment factor (EF), contamination factor (CF), geo-accumulation index (Igeo), pollution load index (PLI), ecological risk factor (E-r(i)), and potential ecological risk index (PERI), while CCME and NOAA sediment quality guidelines were employed to evaluate ecological risks. Most studied elements showed low to moderate levels of pollution, with significant enrichments and high ecological risks mainly caused by Cd and Pb. The dominant element, Cd, ranged from moderate to extreme pollution (2.35 <= Igeo <= 6.62) with very high enrichments (EF up to 1311.3) at HC. Although PLI values (<1) indicated low pollution, elevated EF and Cdeg values indicated anthropogenic stress. Field observations documented naturally abundant seaweed and bioaccumulation metrics (BAF, MAI) to determine the uptake efficiency of bioavailable metals under ambient conditions. The presence of C. linum with high metal uptake capacity suggests its potential as a passive, nature-based solution. These region-specific findings support integrating ecological risk assessment (ERA) with biological indicators for sustainable management of tropical coastal creeks.

Role of critical parameters on the rheology and pipeline transportation of concentrated non-Newtonian iron ore slurry

2026-04-07T05:21:38Z

Role of critical parameters on the rheology and pipeline transportation of concentrated non-Newtonian iron ore slurry Prasad, V; Dubey, A. Achieving optimal flow characteristics while handling a complex slurry system in the pipeline needs greater attention. This study aims to demonstrate the role of iron ore concentration and size distribution on slurry rheology and their subsequent effect on slurry pipeline transportation. The concentrated iron ore slurries are sheared in the shear rate range between 0.1 - 500 s-1, where the experimental data is well-represented by the Bingham-plastic model. The model parameters are employed to calculate pressure drop and energy consumption. A thorough investigation through rheomicroscopy analysis reinforces the validity of the rheological hypothesis. The rheological analysis reveals the yieldpseudoplastic flow behaviour of iron ore slurries irrespective of particle concentrations and coarse particle addition. The slurry containing iron ore fines contributes to an increase in viscosity, mitigated by introducing coarse particles. Rheomicroscopy suggests that the viscosity reduction is attributed to the obstruction of floc formation and disintegration of the slurry structure. The pressure drop and energy consumption escalate with increasing slurry velocity regardless of pipe diameters. However, these entities decrease by including coarse iron ore particles in slurries. This work advocates optimizing rheology to reduce pipeline transportation costs while handling bulk iron ore with minimum environmental repercussions.