Conversion of Biowaste Asian Hard Clam (Meretrix lusoria) Shells into White-Emitting Phosphors for Use in Neutral White LEDs

Abstract

The increasing volume and complexity of waste associated with the modern economy poses a serious risk to ecosystems and human health. However, the remanufacturing and recycling of waste into usable products can lead to substantial resource savings. In the present study, clam shell waste was first transformed into pure and well-crystallized single-phase white light-emitting phosphor Ca9Gd(PO4)7:Eu2+,Mn2+ materials. The phosphor Ca9Gd(PO4)7:Eu2+,Mn2+ materials were synthesized by the solid-state reaction method and the carbothermic reduction process, and then characterized and analyzed by means of X-ray diffraction (XRD) and photoluminescence (PL) measurements. The structural and luminescent properties of the phosphors were investigated as well. The PL and quantum efficiency measurements showed that the luminescence properties of clam shell-based phosphors were comparable to that of the chemically derived phosphors. Moreover, white light-emitting diodes were fabricated through the integration of 380 nm chips and single-phase white light-emitting phosphors (Ca0.979Eu0.006Mn0.015)9Gd(PO4)7 into a single package of a white light emitting diode (WLED) emitting a neutral white light of 5298 K with color coordinates of (0.337, 0.344).

Antibacterial Properties of Biobased Polyester Composites Achieved through Modification with a Thermally Treated Waste Scallop Shell

“…Comparing the XRD patterns of the original WWSSP and the TWWSSP prepared at 500 °C (Figure b) indicates that there are two new peaks at about 17.9° (1) and 34.2° (2), respectively. This result is consistent with partial decomposition of CaCO 3 into Ca­(OH) 2 during the thermal treatment of WWSSP at 500 °C . Compared with Figure c, seven new peaks are apparent at 28.6° (3), 32.1° (4), 34.5° (5), 37.2° (6), 47.3° (7), 50.7° (8), and 53.8° (9) in the XRD pattern of the TWWSSP formed at 1000 °C (Figure c).…”

“…This result is consistent with partial decomposition of CaCO 3 into Ca(OH) 2 during the thermal treatment of WWSSP at 500 °C. 32 Compared with Figure 1c, seven new peaks are apparent at 28.6°(3), 32.1°( 4), 34.5°(5), 37.2°(6), 47.3°(7), 50.7°(8), and 53.8°(9) in the XRD pattern of the TWWSSP formed at 1000 °C (Figure 1c). These results indicate that increasing the calcination temperature to 1000 °C led to complete transformation of WWSSP from CaCO 3 to CaO and Ca(OH) 2 33,34 with simultaneous CO 2 release.…”

The effect of clam shell powder on kinetics of water absorption of jute epoxy composite

“…The highest intensity peaks of clamshell are found at 2θ = 26.16°. XRD patterns of the clam shells patterns are matches with the aragonite form (JCPDS 41–1475) (Chang et al , 2016). Hence, it is concluded that the aragonite, polymorphous structure of CaCO 3 is present in the clam shell powder.…”