Free-sustaining three-dimensional S235 steel-based porous electrocatalyst for highly efficient and durable oxygen evolution

A novel oxygen evolution reaction (OER) catalyst (3D S235-P steel) based on steel S235 substrate has been successfully prepared via a facile one-step surface modification. The standard Carbon Manganese steel was phosphorizated superficially leading to the formation of a unique 3D interconnected nanoporous surface with high specific area which facilitates the electrocatalytically initiated oxygen evolution reaction. The prepared 3D S235-P steel exhibits enhanced electrocatalytic OER activities in alkaline regime confirmed by a low overpotential (η=326 mV at j=10 mA cm-2) and a small Tafel slope of 68.7 mV dec-1. Moreover, the catalyst was found to be stable under long-term usage conditions functioning as oxygen evolving electrode at pH 13 as evidenced by the sufficient charge to oxygen conversion rate (Faradaic efficiency: 82.11% and 88.34% at 10 mA cm-2 and 5 mA cm-2, respectively). In addition, it turned out that the chosen surface modification renders steel S235 into an OER electrocatalyst sufficiently and stable to work in neutral pH condition. Our investigation revealed that the high catalytic activities are likely to stem from the generated Fe/(Mn) hydroxide/oxo-hydroxides generated during the OER process. The phosphorization treatment is therefore not only an efficient way to optimize the electrocatalytic performance of standard Carbon-Manganese steel, but also enables for the development of low cost and abundant steels in the field of energy conversion

A Review on Pharmaceutical Waste Pollution in Water: Extent, Management and Removal Strategies

Pharmaceutical waste and presence of hazardous pollutants in them is a growing concern due to their fate, origin, higher rate of utilization and varying nature of active ingredients resulting in water contamination. However, there is few research on the graving nature of the problem. Cascading impacts on human and ecosystems can be expected from contaminated groundwater and other aquatic channels. While, various technologies used and studied for the removal/reduction/sedimentation of pharmaceutical pollutants. At the initial stages, level of toxicity should check with respect to flora, fauna, environment, and human health. Furthermore, the production of by-products from pharmaceutical pollutants should also be checked and regulated. These by-products can be much more toxic, than the original contaminants and can exert significant toxic effects. It was concluded that there should be ongoing efforts to reduce the cost associated with pharmaceutical waste and their pollutants removal processes to ensure sustainability in the environment and human being

Structure Elucidation and Toxicity Analysis of the Byproducts Formed after Biodegradation of Aflatoxins B1 and B2 Using Extracts of Mentha arvensis

The aqueous extracts of leaves and shoots of Mentha arvensis were checked for their potential to biodegrade aflatoxin B1 and B2 (AFB1; 100 µg/L and AFB2; 50 µg/L) through in vitro assays. Overall, the results showed that leaf extract degrades aflatoxins more efficiently than the shoot extract. First, the pH, temperature and incubation time were optimized for maximum degradation by observing this activity at different temperatures between 25 and 60 °C, pH between 2 and 10 and incubation time from 3 to 72 h. In general, an increase in all these parameters significantly increased the percentage of biodegradation. In vitro trials on mature maize stock were performed under optimized conditions, i.e., pH 8, temperature 30 °C and an incubation period of 72 h. The leaf extract resulted in 75% and 80% biodegradation of AFB1 and AFB2, respectively. Whereas the shoot extract degraded both toxins up to 40–48%. The structural elucidation of degraded toxin products by LCMS/MS analysis showed seven degraded products of AFB1 and three of AFB2. MS/MS spectra showed that most of the products were formed by the loss of the methoxy group from the side chain of the benzene ring, the removal of the double bond in the terminal furan ring and the modification of the lactone group, indicating less toxicity compared to the parent compounds. The degraded products showed low toxicity against brine shrimps, confirming that M. arvensis leaf extract has significant potential to biodegrade aflatoxins

Semicrystalline Block Copolymers in Rigid Confining Nanopores

We have investigated PLLA crystallization in lamellae-forming PS-<i>b</i>-PLLA confined to straight cylindrical nanopores under weak confinement (nanopore diameter <i>D</i>/equilibrium PS-<i>b</i>-PLLA period <i>L</i>₀ ≥ 4.8). Molten PS-<i>b</i>-PLLA predominantly forms concentric lamellae along the nanopores, but intertwined helices occur even for <i>D</i>/<i>L</i>₀ ≈ 7.3. Quenching PS-<i>b</i>-PLLA melts below <i>T</i>_G(PS) results in PLLA cold crystallization strictly confined by the vitrified PS domains. Above <i>T</i>_G(PS), PLLA crystallization is templated by the PS-<i>b</i>-PLLA melt domain structure in the nanopore centers, while adsorption on the nanopore walls stabilizes the outermost cylindrical PS-<i>b</i>-PLLA shell. In between, the nanoscopic PS-<i>b</i>-PLLA melt domain structure apparently ripens to reduce frustrations transmitted from the outermost immobilized PS-<i>b</i>-PLLA layer. The onset of PLLA crystallization catalyzes the ripening while transient ripening states are arrested by advancing PLLA crystallization. Certain helical structure motifs persist PLLA crystallization even if PS is soft. The direction of fastest PLLA crystal growth is preferentially aligned with the nanopore axes to the same degree as for PLLA homopolymer, independent of whether PS is vitreous or soft