Restoration of critical dielectric properties of waste/aged transformer oil using biodegradable biopolymer-activated clay composite for power and distribution transformers

The defiling characteristics of petroleum-based mineral oil (MO) release toxic pollutants and have carcinogenic effects on life on earth. Discontinuing MO applications in transformers has instigated alarms to dispose of waste transformer oils (wTOs) from in-service/off-service; lack of treatment may predispose a life on earth to put at risk. Oil degradation was studied for waste transformer oils (wTOs) collected from various substations. The contemporary analysis uses magnetic treatment followed by a biopolymer-clay microcomposite, chitosan-activated bentonite composite (C-ABC), as an effective environment-friendly adsorbent. In addition to being biocompatible, the C-ABC composite’s exceptional adsorption ability—boosted active sites and high surface area—restores the dielectric characteristics of wTOs to the maximum extent possible for brand-new transformer oil (fTO). The reclamation strength of the proposed method using the C-ABC microcomposite was compared with the conventional adsorption materials. The interaction between negatively charged chitosan and positively charged activated bentonite shows significant improvement in the dielectric properties of wTOs. The CIE chromaticity coordinates study confirms the removal of polar and non-polar compounds. The dielectric properties and CIE were found to be improved after careful investigation procedures. Energy-dispersive X-ray (EDX) spectroscopy studies were used to examine the elemental analysis of C-ABC before and after mechanochemical synthesis, and scanning electron microscopy (SEM) was used to examine the topography of C-ABC. The investigated oils were also subjected to Fourier transform infrared (FTIR) analysis. The statistical studies show that at 50% survival, the treated oils show a dielectric breakdown voltage of 45 kV for wTO3, 42.5 for wTO2, 41.5 for wTO1, and 40 for wTO4. The mathematical models for the investigated oils and their response surface show interactive effects between the process and response variables. Moreover, SWOT analysis shows the various influential factors of the proposed technique with respect to future scope. Hence, this proposed method is environment-friendly, affordable, easily available, cost-effective, and efficient for the remediation of wTOs. Graphical abstract