Effervescent tablets for carbon-based nanofluids production

Abstract

This research investigates the fabrication of nanofluids from effervescent tablets for potential thermal applications. Effervescent tablet-based nanofluids of multi-walled carbon nanotubes (MWCNTs) were produced by mixing then consolidating effervescing agents with surfactant and MWCNTs. The effervescent reactions were first simulated to determine the production of CO2 gas at 25 °C using different concentrations of effervescing agents, sodium dodecyl sulfate (SDS) surfactant, and MWCNTs. Next, the powders were mixed then compressed into tablets. These tablets were later immersed in water to produce the tablet-based nanofluids. The resulting nanofluids were analysed for dissolution duration, dispersion physical stability, and thermal conductivity. Moreover, the characteristics of the effervescent tablet-based nanofluids were compared with those of similar MWCNTs dispersions produced using the conventional two-step approach. Also, a cost analysis was conducted to determine the feasibility of both conventional and effervescent tablets suspension production approaches. The results have shown that increasing the amount of effervescing agents improves the dispersion stability of the suspension due to the increase in generated CO2 bubbles from the tablets, but also increases the duration for producing the nanofluid. Furthermore, it was found that using ball milling to mix the tablet’s powders content can introduce residuals that would strongly affect the nanofluids formation mechanism. In comparison with conventionally produced dispersions, the effervescent tablet-based nanofluids showed enhanced physical stability, effective thermal conductivity, and economic feasibility.