CO2 capturing evaluation of single-step silica nanofluid through rheological investigation for nanofluid use in carbon utilization applications

• Published in: Journal of molecular liquids 2020-04, Vol.304, p.112765, Article 112765
• Main Authors: Chaturvedi, Krishna Raghav, Narukulla, Ramesh, Sharma, Tushar
• Format: Article
• Language: English
• Subjects: CO2 capturing; Nanofluid; Polymer; Rheology; Temperature; Viscoelasticity
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2020.112765

Single-step silica nanofluids offer better stability and size-control due to less nanoparticle (NP) agglomeration. Uniform distribution and desired size of NP make nanofluid a rheologically modified fluid to be suitable for carbon utilization applications. Thus, in this work, single-step (sol-gel) technique is used to prepare silica nanofluids of different particle sizes (34–142 nm) in base of polyacrylamide (PAM, 1000 ppm). These nanofluids was tested for CO2 capturing applications using rheological measurements (shear and dynamic) as a function of different conditions [particle concentration = 0.1, 0.5, and 1 wt% and temperature = 303, 323, and 353 K]. Increasing particle size was found to affect rheological properties insignificantly while increasing particle concentration led to increment in viscosity and viscoelastic moduli (elastic: G′ and viscous: G″), good for nanofluid usage in oilfield practices where improved viscosity is required for higher oil recovery. The inclusion of CO2 made nanofluid lighter and thus, viscosity and moduli values slightly reduced for CO2 laden nanofluids. The effect of high temperature (353 K) on capturing potential of nanofluids was found marginal as viscosity and viscoelastic properties and their flow trends remained almost similar at each test temperature, which indicates CO2 capturing into the networks of NP and PAM was intact and even temperature could not deform it. However, a slight reduction in viscosity and moduli of nanofluids was attributed to temperature effect on PAM rheology. Thus, the synthesized nanofluids behaved almost thermally stable and showed marginal effects of flow conditions (shear rate, amplitude, and frequency) on rheological properties and CO2 capturing potential of silica nanofluids, which is of key importance for various applications where conditions differ on a large scale. Rheologically stable single-step silica nanofluid for carbon capturing applications. [Display omitted] •Size controlled single-step silica nanofluid was synthesized.•Novel rheology modification of simple polymer (PAM) methods.•Thermally stable CO2 capturing with improved viscoelastic properties is obtained.•Nanofluid exhibited enhanced CO2 capturing at high temperature.