Membranes 2023, 13(7), 625

DOI:10.3390/membranes13070625

Nowadays, membrane technology is an efficient process for separating compounds with minimal structural abrasion; however, the manufacture of membranes still has several drawbacks to being profitable and competitive commercially under an environmentally friendly approach. In this sense, this review focuses on bio-based polymeric membranes as an alternative to solve the environmental concern caused by the use of polymeric materials of fossil origin. The fabrication of bio-based polymeric membranes is explained through a general description of elements such as the selection of bio-based polymers, the preparation methods, the usefulness of additives, the search for green solvents, and the characterization of the membranes. The advantages and disadvantages of bio-based polymeric membranes are discussed, and the application of bio-based membranes to recover organic and inorganic contaminants is also discussed.

Wastes Management  2023, 165 , 59-69

DOI:10.1016/j.wasman.2023.04.017

Carbon fiber is one of the most widely used materials in high demand applications due to its high specific properties, however, its post-recycling properties limit its use to low performance applications. In this research, the carbon fiber recovering is examined using two methods: two-step pyrolysis and microwave-assisted thermolysis. The results indicate that the fibers recovered by pyrolysis show reduced surface and structural damage, maintaining the original mechanical properties of the fiber with losses below 5%. The fibers recovered by microwaves undergo significant surface changes that reduce their tensile strength by up to 60% and changes in their graphitic structure, increasing their degree of crystallinity by Raman index ID/IG from 1.98 to 2.86 and their amorphous degree by ID”/IG ratio from 0.411 to 1.599. Recovering fibers from microwave technique is 70% faster compared to two step pyrolysis, and provides recycled fibers with superior surface activation with the presence of polar functional groups –OH, –CO, and –CH that react with the epoxy matrix. The thermal, morphological, structural and mechanical characterizations of the recovered fibers detailed in this work provide valuable findings to evaluate their direct reuse in new composite materials.

Journal of Chilean Chemical Society  2023, 68 (1) , 5755-5771

DOI:10.4067/S0717-97072023000105755 

In recent decades the increase in the use of plastics has been exponential around the world, reaching a presence in places such as rivers, oceans and lakes, as well as in terrestrial environments such as agricultural soils. Associated with the great use of plastics in all areas of work, plastic particles smaller than 5 mm, called microplastics, have been found in all environmental matrices: aquatic environment, dispersed throughout the water column, terrestrial environment, infiltrating the soil sedimenting, and in the air, being transported by the wind. In each of these matrices, microplastic serves as transport for highly polluting compounds such as heavy metals, polycyclic aromatic hydrocarbons and organochlorine pesticides. In addition to environmental matrices, microplastics have been found in animals and humans in alarming numbers. In this way, this review addresses issues related to the formation and distribution of microplastics throughout the ecosystem and different organisms.