Oil removal from used cutting fluid by continuous adsorption on modified chitin-chitosan

Abstract

The aim of this thesis is to study a removal of cutting fluids by adsorption on chitosan and modified chitosan. 10 adsorbents used in this study are chitosan, blended chitosan/PVA 1:1, benzoyl chitosan, quateraminated chitosan, chitosan-sodium lauryl sulfate, chitosan-hexadecyltrimethy ammonium bromide, chitosan- polyoxyethylene sorbitanmonooleate, blended chitosan/PVA-sodium lauryl sulfate, blended chitosan/PVA-hexadecyltrimethy ammonium bromide and blended chitosan/PVA-polyoxyethylene sorbitanmonooleate. Adsorption capacity of chitosan- sodium lauryl sulfate is the highest at pH 3 with amount of 2516 mg/g. After increasing pH of cutting fluids from pH 7 to 11, it can adsorb the cutting fluids from 747 to 309 mg/g. The adsorption capacity of adsorbents will be better when adding either NaCl or CaCl2. The chitosan-sodium lauryl sulfate can adsorb cutting fluids through hydrophobic interaction. The significant uptake of cutting fluids on all adsorbents is supported by analysis contact angle, SEM, FT-IR, CHN and heating value. Langmuir, Freundlich and BET models were applied to describe the experimental isotherms. The experimental data fitted well with pseudo-second-order kinetic model. The cutting fluids adsorption was found to be controlled by intraparticle diffusion stage. The rate of adsorption cutting fluid increased with increasing temperature. The adsorption of cutting fluids is endothermic reaction. The bed depth/service time model can be used to predict the adsorption performance in a case when there is a change in flow rate.