Synthesis and characterization of green-functionalized graphene nanofluids as an enhanced working fluid in heat transfer applications

Abstract

Energy crisis is one of the major concerns that requires significant attention around the world. An access to reliable, sustainable, and affordable energy will not be attractive if the safety of human and environmental is neglected. Hence, the advancement of energy harvesting method is expected not to be just efficient, but also clean, safe, and environmental-friendly. In this research work, synthesis, and characterization of a green-based functionalized graphene nanofluids is presented. Clove extract was prepared and functionalized on the graphene nanoplatelets (GNP) using apple cider vinegar, followed by dispersion in distilled water to produce clove with apple cider vinegar functionalized graphene (clove+ACV GNP) nanofluids at 0.1 wt.% concentration. Characterization of the clove+ACV GNP nanofluids was carried out using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) to examine the successfulness of the synthesis and functionalization, while the thermal conductivity was determined using KD2 Pro Thermal Properties Analyzer. The covalent bonds shown in the FTIR spectrum, and the morphological structure from the SEM images have indicated that the synthesis and functionalization of clove+ACV GNP have been successfully carried out. As for the thermal conductivity, 0.1 wt.% of clove+ACV GNP nanofluids have shown up to 24.4% enhancement when compared with distilled water, 3.9% enhancement when compared to clove-functionalized GNP at the same concentration, and up to 6.8% when compared with conventional GNP nanofluids. These findings have given a preliminary insight that this safe, non-toxic- clove+ACV functionalized graphene nanofluids is a promising alternative to the conventional, toxic- nanofluids as an enhanced and effective working fluid in heat transfer applications.