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Abstract Nafion has been dominating the proton exchange membrane (PEM) market because of its adequacy for the proton exchange operation. However, because of its high cost, low performance at low relative humidity, and finally environmental unfriendliness, researchers have been developing and working on Nafion alternatives. In this review, we assess how biopolymers present an opportunity as an eco‐friendly material able to replace the conventional Nafion membrane in proton exchange membrane fuel cells (PEMFC). Chitosan and cellulose were the most studied in literature owing to their abundance in nature, low cost, and high affinity for water, which are sought‐after properties for PEM. In addition to that, their ease of modification through their hydroxyl or amine groups represents an opportunity to further enhance their characteristics and thus meet the criteria of diverse applications. The use of biopolymers as an adequate PEM is facing many challenges. Having a practical proton conductivity and securing the physicochemical stability of the biopolymers in fuel cell operating conditions are two of the most important challenges to overcome. Promising strategies to simultaneously address these challenges such as crosslinking, making interpenetrated networks, and making blends and composites are reported.

Sulphuric acid (H2SO4) is widely used in various industrial processes, including fertilizer production. However, its highly corrosive nature poses a significant challenge to the materials used for transport and storage, particularly metals and alloys. This review provides an overview of corrosion types in iron and nickel-based alloys, commonly employed for handling sulphuric acid. The paper discusses alloy selection based on their corrosion behavior in different H2SO4 concentrations, temperatures, and harsh conditions such as erosion-corrosion and presence of contaminants. Additionally, it highlights the use of inhibitors and polymeric coatings for corrosion protection. Finally, the paper outlines future research directions for corrosion protection of alloys in sulphuric acid environments.

This study aims at understanding the effect of different heat treatments on the evolution of the microstructure of several Cr–W–V–Mo steels having different compositions and how this latter affects their abrasion resistance. The investigation also gives insights on the formation and effect of core-shell carbides on the abrasion resistance. The commercial highly alloyed stainless steel HCx® and six newly designed Cr–W–V–Mo steels were subjected to three heat treatments: austenitizing at 900 °C and 1100 °C and subsequent quenching, and an ageing treatment at 700 °C. The microstructural analysis demonstrated the formation of Laves phase when austenitizing at 900 °C; this phase is depleting the matrix from carbide forming elements without any improvement in the wear behavior of the alloys. However, increasing the austenitization temperature to 1100 °C favored the development of core-shell carbides that contribute to increase the abrasion resistance of the alloys. The ageing treatment promoted the precipitation of secondary carbides uniformly distributed along the matrix, and they were found to have a beneficial effect on maintaining the good abrasion resistance even after subjecting the steels to a high ageing temperature (700 °C) for long duration (10 h).

This work presents a mathematical tool to estimate the cost of fabricating pumps by traditional casting. The drivers that most affect the cost of the process are identified in each step of the procedure, i.e., material, labour, energy, tools and general expenses associated with any industrial activity. The mathematical expressions used for the calculation of the different cost drivers are presented and used to estimate the cost of fabricating the different parts composing a radial pump in a small Moroccan foundry. Therefore, the input data of the equations carefully consider the economic factors of this country. However, the developed tool is versatile and can be adapted to describe the casting process in other countries with different economies just by changing the input data accordingly. It is observed that the influence of the drivers in the final cost of the pump is very dependent on the number of pumps to be produced. In any case, the cost estimation tool presented in this work will allow for the optimization of the yield of the casting process rendering the involved company more reliable. The tool provides an idea of the implications of changing production factors, allowing the foundry to give accurate and fast responses without compromising its profits.

Numerous adsorbent materials are developed and are able to face specific types of pollution, but none of them can manage the whole pollution. The purpose of this work is to develop a novel hybrid adsorbent, based on chitosan (CS) biopolymer, clay minerals and activated carbon (AC), having complementary adsorption properties and achieving a wide-spectrum water decontamination in a single treatment. Hybrid CS beads, containing dispersed clay and AC, were prepared from dispersions of solid adsorbents in a CS solution and its further coagulation in a basic medium. The porosity and the homogeneity of the hybrid beads were characterized by N2 adsorption at 77 K and Cryo-Scanning Electron Microscopy respectively. The interaction between CS and clay was characterized using X-ray diffraction. Water content and the amount of each adsorbent in the hydrogel beads were determined by thermogravimetric analysis. Such a composite material was still porous and presented a wide adsorption spectrum. As shown by their adsorption kinetics, hydrophobic anionic clofibric acid (CBA) and cationic metoprolol (MTP) were well adsorbed on AC containing beads (21 and 26 mg/g), respectively. Clays containing beads showed interesting adsorption properties towards cationic Zn2+ and MTP. The obtained composite beads were able to adsorb all the pollutant types: Zinc cations, and hydrophobic-charged organic molecules, such as pharmaceutical derivatives (clofibric acid and MTP).

Cross-linking of styrene grafted and sulfonated fuel cell membranes is essential to obtain well-performing and durable membranes. In this study, the properties and fuel cell performance of radiation grafted membranes based on poly(ethylene-alt-hexafluoropropylene) (ETFE) (25 μm) with different extent of cross-linking, using divinylbenzene (DVB) as a cornonorner to styrene, were investigated. The water uptake and proton conductivity decrease as a function of increasing the extent of cross- linking. Also, the membranes become more brittle. Fuel cell performance is limited by the high ohmic resistance of the membrane at high degrees of cross-linking, whereas at low degrees of cross-linking the membrane-electrode interface is of poor quality. Optimum performance is obtained at an extent of cross-linking corresponding to a styrene:DVB monomer ratio (v/v) of 95:5 in the grafting solution. [ABSTRACT FROM AUTHOR]