Waste lubricant oil treatment by adsorption process using modified activated carbon

Abstract

Waste lubricating oil (WLO) is a spent waste that is no longer fit for purpose owing due to contamination and degradation. Recycling WLO can turn waste into a valuable and reducing environment impact. This study mainly focused on determines the performance of adsorbents activated carbon (AC) in recovering WLO through adsorption process. The adsorbent AC was modified by nitric acid (HNO₃) to increase its adsorption capacity.  First treatment of WLO was done by mixed it with glacial acetic acid and followed by adsorption treatment using modified AC (MAC). The treated WLO was analyses at different dosage at 2g, 4g and 6g at temperatures 40^oC, 50^oC and 60^oC with contact time 30 min, 1 hour and 1 hour 30 min, respectively.  The treated lubricant oil underwent comprehensive physical and chemical characterization water content, density and viscosity. The highest water content for treated lubricant oil observed is 4.83%.  It was found out that sample C1 using MAC has better density value with 0.799 g/m and viscosity 88 mPa.s. The characterization of the recovered oil before and after treatment was analyzed by using Fourier Transform Infrared Spectroscopy (FTIR) and Ultraviolet-Visible (UV-Vis) spectrophotometry. The functional group obtained from the treated lubricant oil exhibits the presence of aliphatic hydrocarbons, methylene and ester which the value is within the range from the virgin oil.  In UV-Vis analysis, the lowest concentration absorbance values were observed in sample C1 (0.291) and sample C2 (0.328) at wavelength 400nm indicates decomposition of these absorbing species through breakdown of the oil components. To conclude, this study gives insightful method in treating lubricant oil through absorption process by using MAC and unmodified AC.

Keywords:  waste lubricant oil; adsorption ; modified activated carbon; nitric acid