Examinando por Autor "Grieken, Rafael Van"

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Enhancing the recyclability of ELV plastic bumpers: Characterization of molecular, morphological, rheological, mechanical properties and ageing degradation
(Elsevier, 2024-12) Juan, Rafael; Expósito, M. Teresa; Paredes, Beatriz; Lechuga, Daniel; Martínez, Cristina; Cardil, Andres; Aguilera-Villegas, Lola; Ramos, Javier; Domínguez, Carlos; Vega, Juan F.; Grieken, Rafael Van; García-Muñoz, Rafael A.
While the automotive industry has traditionally prioritized metal recycling, the increasing use of plastics in vehicles underlines the need for sustainable management of these materials. Recycling rates of plastics from end-of-life vehicles (ELVs) in Europe are low, but recent EU legislation requires 25 % of the plastics in new vehicles to be recycled, forcing innovative designs and strategies to enhance the recovery and quality of recycled resins. This study focuses on post-consumer bumpers, a significant recoverable component of ELVs, by assessing their molecular, morphological, rheological, and mechanical properties to investigate their homogeneity and quality from various sources to assess their suitability for recycling. Since the aging of these materials, caused by thermo-oxidative and thermo-mechanical degradation processes, can compromise the quality of recycled bumpers, we propose a blend of recycled PP from different bumper cars with virgin resin, representing a realistic scenario where the post-consumer ELV bumpers are collected. Interestingly, this blend, which can replace up to 50 % of the virgin resin without additional compatibilizers or additives, mitigates the degradation effects. Furthermore, the study evaluates the degradation resistance of these blends through multiple extrusion cycles and accelerated weathering tests in a temperature-controlled UV chamber to ascertain the number of cycles the material can tolerate without significant quality degradation, and to determine its suitability for long-term applications. Our results not only support the feasibility of using recycled PP for automotive components but also contribute to meeting the EU's recycling targets. This research highlights the potential for significant advances in the circularity of automotive plastics, providing a sustainable pathway for integrating recycled materials into new vehicle production
Influence of the TiO2 crystalline phase on the performance of UVA/brookite/persulfate and UVA/anatase/persulfate systems for the degradation of isothiazolinones in aqueous matrices
(Elsevier, 2024-08) Gómez-Rodríguez, P.; Grieken, Rafael Van; López-Muñoz, M.J.
The activation of persulfate (PS) under UVA irradiation by two TiO2 polymorphs (brookite and anatase) and titanate photocatalysts was evaluated for the simultaneous removal of the biocides methylisothiazolinone (MIT) and chloromethylisothiazolinone (CMIT), in ultrapure water and real sewage treatment plant water (SW). Titania and titanate samples were synthesized by a hydrothermal method and characterized by XRD, SEM, N2 adsorption-desorption isotherms and UV-Vis DR. The reactions were performed in individual (brookite, anatase, titanate and PS) and hybrid (titania/PS and titanate/PS) systems and compared to those with TiO2-P25 as reference. In ultrapure water, the combined brookite/PS system showed a higher performance for MIT and CMIT abatement and a stronger synergistic effect between titania and PS than found in anatase/PS and titanate/PS systems, indicating the higher effectiveness of the brookite phase for PS activation under UVA. The use of SW water revealed the strong inhibitory effect of matrix constituents in the individual brookite, anatase and PS systems, which exhibited a low performance. However, the kinetics of MIT/CMIT in SW were greatly enhanced in the hybrid TiO2/PS systems, especially with brookite, leading to an efficient degradation of both pollutants and the decrease of total organic carbon (TOC). The addition of chemical scavengers showed a similar reactivity of HO• towards both isothiazolinones whereas a preferential attack of to MIT was observed, demonstrating the selective nature of .