Hybridization of superparamagnetic Fe3O4 nanoparticles with MWCNTs and effect of surface modification on electromagnetic heating process efficiency: A microfluidics enhanced oil recovery study

[Display omitted] •Effect of surface modification on MWCNT-Fe3O4 nanohybrid performance in EM-heating.•Characterizing synthesized nanohybrids and checking their stability over time.•Finding the ultimate oil recovery factor using microwave radiation in a micromodel.•Coating nanohybrids with PEG 6000 reduces their microwave absorption ability.•Citric acid is the best agent to have high microwave absorption and oil recovery. This study investigated the effect of different surface modifications on the microwave absorption performance of new synthesized MWCNT-Fe3O4 nanohybrid. MWCNT-Fe3O4 nanohybrids were synthesized via a co-precipitation method. For the dispersion of these nanomaterials into the water (as the injected fluid), the surfaces of them were modified. For this purpose, three different materials included 3-AminoPropylTriEthoxySilane (APTES), citric acid (CA), and polyethylene glycol (PEG 6000) were used as the surface modification agents. The nanoparticles were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray crystallography (XRD), vibrating sample magnetometer (VSM), and field emission scanning electron microscopy (FESEM). Stability of the coated nanomaterials in distilled water studied by zeta potential analysis and qualitative deposition of particles over time. Microwave absorption of coated nanomaterials investigated by determining the temperature rises of solution (oil and water) containing nanoparticles. The results showed that modification of nanohybrid particles by citric acid had a significant impact on the no sediment condition of them in distilled water in comparison with APTES and PEG 6000. All of the coated nanoparticles were superparamagnetic and citric acid, APTES and PEG had minimum effects on the magnetic properties of uncoated nanoparticles, respectively. Also, by adding only 0.1 wt% of MWCNT-Fe3O4 nanohybrid modified with citric acid, the solution temperature rises significantly. Therefore, after 180 s of microwave radiation, the water-based solution temperature would increase about 11° C more than the deionized water. Finally, it was found that, by using 400 W microwave radiation, the microfluidic oil recovery increased 24.9%, 30.3%, and 43.9% in comparison with water, Fe3O4 @ CA, and Fe3O4-MWCNT @ CA injection without microwave radiation, respectively.