Keywords: batch adsorption, Langmuir isotherms, MWFs, metalworking fluids, Cajanus cajan, SCF, spent cutting fluids, emulsified oil, agro-waste, lubricant disposal, coolants, agricultural waste, safe disposal
Adsorption of emulsified oil from spent metalworking fluid using agro-waste of Cajanus cajan
Safe disposal of spent cutting fluids generated by the use of semi-synthetic fluids as coolant in material processing industries is a serious problem. The ultra-filtration method is mostly employed for the processing of spent cutting fluids. This method is costly and difficult to adopt by small and medium sized industries. In this study, efforts have been made to produce adsorbent using agro-waste, i.e. stem of Cajanus cajan in unmodified and modified form for the removal of emulsified oil. Batch adsorption studies demonstrated that chemically modified adsorbent has significant capacity to absorb emulsified oil. The parameters investigated in this study included pH, temperature, contact time, initial oil concentration, adsorbent dosage and particle size. The data obtained was also analysed using Langmuir isotherm model and linear plots conforms its applicability. The dimensionless equilibrium parameter, RL, signified a favourable adsorption of oil. The adsorption process appeared to follow pseudo second-order kinetics.