pH-controlled synthesis of sustainable lauric acid/SiO2 phase change material for scalable thermal energy storage

Abstract

Lauric acid (LA) has been recommended as economic, eco-friendly, and commercially viable materials to be used as phase change materials (PCMs). Nevertheless, there is lack of optimized parameters to produce microencapsulated PCMs with good performance. In this study, different amounts of LA have been chosen as core materials while tetraethyl orthosilicate (TEOS) as the precursor solution to form silicon dioxide (SiO2) shell. The pH of precursor solution was kept at 2.5 for all composition of microencapsulated LA. The synthesized microencapsulated LA/SiO2 has been characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-Ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), and Transmission electron microscopy (TEM). The SEM and TEM confirm the microencapsulation of LA with SiO2. Thermogravimetric analysis (TGA) revealed better thermal stability of microencapsulated LA/SiO2 compared to pure LA. PCM with 50% LA i.e. LAPC-6 exhibited the highest encapsulation efficiency (96.50%) and encapsulation ratio (96.15%) through Differential scanning calorimetry (DSC) as well as good thermal reliability even after 30th cycle of heating and cooling process.

Investigating the high‐shear mixed catalytic esterification of lauric acid with methanol using central composite design

“…LA advantageously exhibits a characteristic X‐ray powder pattern thus allowing to determine its degree of purity by applying the XRD technique. A single LA phase was detected when comparing the corresponding XRD pattern displayed in Figure 1 to the JCPDS card 38‐1976 confirming that LA is in a very pure form, which is in good agreement with other reports 36,37 …”

“…A single LA phase was detected when comparing the corresponding XRD pattern displayed in Figure 1 to the JCPDS card 38-1976 confirming that LA is in a very pure form, which is in good agreement with other reports. 36,37 The FTIR spectra of LA and ML are shown in Figure 2. ML was obtained at the following reaction conditions: temperature = 60 C, methanol:LA ratio = 13, catalyst mass = 4 wt.%, mixing speed = 500 rpm and time = 12 min.…”

Large-scale synthesis of 2D-silica (SiOx) nanosheets using graphene oxide (GO) as a template material

“…The Si–C peak was only observed in the APTES-coated GO, being a characteristic peak for the aminosilane. 28–31 In comparison the TEOS-coated GO showed three peaks at 102.9, 104.2, and 105.7 eV, which where attributed to Si–OH, SiO 2 , and Si–O–Si, respectively. 29,32,33 After heat treatment, no new bonds where observed for the TEOS-coated GO, instead a shift in intensity occurred as SiO 2 increased markedly in comparison to Si–OH and Si–O–Si, from the conversion of Si–OH and Si–O–Si bonds into SiO 2 .…”

Encapsulation methods for phase change materials – A critical review

“…Ishak et al [215] optimized parameters for production of lauric acid (LA)/silicon dioxide microcapsules. The pH is controlled at 2.5.…”