Carlos Espinoza-González

While polymer-based plastics play a vital role in key sectors such as packaging, construction and transportation, their material value is typically lost after a single use

Micro- and nanoplastics (MPs and NPs) remain a fragmented challenge across prevention, removal, and circular recovery strategies. At the second meeting of the COST Action PRIORITY – Plastics monitoRIng detectiOn RemedIaTion recoverY Working Group 5 (WG5, focused on Remediation, Recovery, and Sustainable Alternatives), bringing together over 550 researchers from 53 countries, participants consolidated advances and defined shared priorities. Reported progress spans: (i) removal — membrane trains, bubble barriers, and graphene-based aerogels enabling water flow with selective adsorption of sub-100 µm polymer particles; (ii) bio-routes — plastisphere-derived microbial consortia and an engineered whole-cell catalyst co-displaying polyethylene terephthalate (PET)-degrading enzymes PETase and MHETase for PET depolymerization to terephthalic acid (TPA) and ethylene glycol (EG); (iii) recovery and upcycling — image-guided quality control to reduce expandable polystyrene (EPS) production waste and a mild, aerobic photochemical protocol converting polystyrene to benzoic acid; and (iv) sustainable alternatives — closed-loop poly(lactic acid) (PLA) systems based on room-temperature ring-opening polymerization and catalytic alcoholysis to alkyl lactates, and bio-derived encapsulants (polysaccharides and candelilla-wax nanoparticles) for slow-release agro-inputs that avoid plastic residues. Cross-cutting needs include reference materials, performance metrics (capture thresholds, yields, life-cycle assessment), and alignment with standardization and regulatory pathways. The meeting advocates prevention at the source as the primary strategy, complemented by controllable recovery and evidence-based remediation. The roadmap outlined connects laboratory validation to field deployment and policy uptake, enabling robust, harmonized, and scalable solutions against plastic pollution.

In modern agriculture, fertilizers are commonly used to increase crop yields; however, their negligent use can lead to environmental pollution and the waste of essential nutrients such as inorganic phosphate (Pi). Encapsulated fertilizers are a feasible alternative that could prevent these issues, as they can protect Pi from leaching and extend the interval between applications. In this study, we developed and tested innovative fertilizers (IFs) manufactured with KH₂PO₄, encapsulated with chitosan modified via high-frequency ultrasound treatment. The characterization of these fertilizers consisted of Fourier-transform infrared spectroscopy analysis and scanning transmission electron microscopy to determine their sizes and forms. In addition, we evaluated the phosphate release profile using electrical conductivity. The IFs were spheroidal microcapsules with an average diameter of 0.5–2 μM and showed slow-release behavior. Their efficacy was assessed via in vivo and in vitro assays, using Arabidopsis thaliana as a study model. As expected, the IFs promoted the growth of seedlings. One of the IFs showed enhanced growth promotion, contrasting with the control. This phenotype was likely promoted by this fertilizer due to the synergistic effect of Pi and the modified chitosan used as an encapsulant matrix. Our results highlight the potential of these formulations, which have unique properties and could be used on a large scale.

A novel, green route for pre-exfoliation of graphite based on a biodegradable polymer and high-power ultrasound is presented. Candelilla wax (CW), derived from the leaves of the candelilla plant, has been used for the first time as a natural non aqueous medium to induce the pre-exfoliation of expanded graphite (EG) under ultrasonic irradiation in an economical way. The proposed method uses also D-limonene as a natural organic solvent for reducing viscosity and increasing the affinity between the polar groups of EG and candelilla wax, thus improving the intercalation/exfoliation of EG. The quality of dispersion of the nanofiller in the natural wax matrix has been evaluated using multiple techniques. The addition of EG to wax and use of ultrasonic treatment leads to a reduced crystallinity, probably due to restrictions of the molecular movements, improved thermal stability of wax, and to an increased shear thinning exponent, which are all indicative of a high degree of EG dispersion. The ultrasonic dynamic mechanical results suggest a reduction in the cluster size and a better filler dispersion in the wax matrix promoted by polar or chemical reactions between the CW fractions and the graphite stacks, which was observed by XPS analysis. The results were compared to those obtained with paraffin, a synthetic wax, and confirmed the dispersion improvement obtained by using natural wax as a pre-exfoliating medium.