Cytotoxicity and performance of Pectin/ Ferric vanadate oxide/ Cetyltrimethylammonium Bromide foaming nano-system for drilling sustainable geothermal wells

Abstract

The geothermal energy industry is exploring environmental friendly alternatives for the current foaming systems used in geothermal well drilling. In this study, Pectin/ Ferric vanadate/ Cetyltrimethylammonium Bromide nanocomposites (P-FV-C) were fabricated through two stages. The structure analysis and thermal stability of the nanomaterials in both stages were confirmed by Fourier Transfer Infra-Red (FT-IR), Dynamic Light Scattering (DLS), Scanning Electron Microscope (SEM), and Differential Scanning Calorimetry (DSC).The main objective is to decrease the cytotoxicity of CTAB without losing its foaming properties by incorporating the pectin heterogeneous vanadate oxide nanocomposite (P-FV) into the CTAB foaming system structure. The best results, in terms of foaming properties and cell viability, were exhibited for P-FV-C5 when the weight ratio of P-FV to CTAB was 1:1. The cytotoxicity results revealed that the cell viability increased from 4.47 to 79.58% for 1 µg/ml of pure CTAB and P-FV-C5 respectively. The temperature and period of aging didn't obviously affect the foaming properties (foam volume and drainage half time) for the P-FV-C nanocomposites unlike the pure CTAB, of which foaming properties were drastically decreased. For CTAB (1.0 wt.%), the foam volume decreased from 700 to 300 ml and the drainage half time decreased from 30 to 16 min when the temperature increased from 150 to 200 °C after dynamic aging for 16 h. At the same previous conditions and concentration, P-FV-C5 showed stable foaming properties (foam volume = 700 ml and drainage half time= 45 min). The foam volume was decreased from 761 to 695 ml and drainage half time was stable by increasing the aging period from 8 to 24 h at 200 °C for P-FV-C5 (1.0 wt.%) while the foam volume decreased from 789 to 253 ml and the drainage half time decreased from 30 to 14 min for pure CTAB at the same conditions and concentration. Also, the drainage half time was decreased from 40 to 15 min by increasing the calcium chloride content from 1 to 5 wt.% while it was stable for P-FV-C5 nanocomposite. These results were explained based on the surface and rheological properties of the nanocomposites. The above findings indicate that the P-FV-C5 nanocomposite could attain environmental and operational success while drilling high temperature and salinity geothermal wells.