Study on alcoholysis recovery and performance of luminous materials in waste luminous fibers

Abstract

To alleviate the wastage of resources and environmental pollution caused by waste luminous polyester fibers, glycolysis was found rapidly to degrade luminescent polyester fibers and assist in recovering luminescent materials from the fibers. However, the luminescent performance of recycled luminescent materials is poor. To improve the performance of recovered luminescent materials, this study employs the recovery rate of luminescent materials, initial brightness, and recovery rate of Bis (2-hydroxyethyl) terephthalate as performance indexes. The present study aims at optimizing the alcoholysis process by influencing factors such as the amount of catalyst, amount of ethylene glycol added, and reaction temperature to improve the luminous performance, and explores the mechanism of alcoholysis reaction in the recovery process of luminescent materials. The results showed that, when the catalyst content is 0.1 g, the mass ratio of polyethylene terephthalate:ethylene glycol is 1:10, the reaction temperature is 170°C for 4 hours, the Bis (2-hydroxyethyl) terephthalate conversion rate reaches 61.92%, the recovery rate of luminescent materials reaches 92.53%, and the initial brightness is as high as 5.607 cd/m2.

Highly transparent Ce3+,Cr3+ co-doped GYAGG single crystals with enhanced persistent luminescence

“…Indeed, upon Gd 3+ addition in GYAGG, the crystal field around Ce 3+ is stronger and the 5 d 1 stabilizes whereas 5 d 2 destabilizes, hence the corresponding bands in the GYAGG crystals are shifted to lower and higher energies in the spectra, respectively favouring their excitation by blue light at 450 nm. According to previous literature, the three other 5 d [3][4][5] bands should appear at about 263, 227 and 207 nm respectively [26]. The first one was proved to be defect-related since it is present in undoped YAG.…”

“…A quick search on published articles and patents on Google scholar of these two terms in 2022 shows 12,000 entries. This is due to their very broad range of applications that extend from core uses as indoor lighting [1], sensing [2,3], watch components [4], textiles [5,6], dosimetry [7], anti-counterfeiting [8,9], bioimaging [10][11][12] and therapy [13][14][15][16] to emerging applications combating the greenhouse effect such as road marking and lighting of outdoor cycling paths [17], stimulation of photosynthesis and regulation of photomorphogenesis in plants [18], feeding of solar cells [19][20][21] or even applications related to human wellbeing such as facilitating sleep. The persistent luminescence in solid-state inorganic phosphors is related to the trapping of charge carriers in defect electronic states and their delayed release upon time or temperature [1,22,23].…”