Adsorption Soluble Cutting Fluid Emulsion by Modified Chitosan with SLES
This study examined the effect of modifying chitosan (MC) with sodium lauryl ether sulfate (SLES) in adsorbing soluble cutting fluid emulsion (SCFE). The adsorbent was prepared by the addition of SLES to chitosan solution followed by sulfuric acid immersion. Batch adsorption was carried out as a function of initial concentration of the soluble cutting fluid emulsion. The point of zero charge of the adsorbent was also measured at pH 1.9. The percent adsorption was calculated and found out to decrease, whereas the adsorption capacity increases as the initial concentration of the adsorbate increases. Experimental results showed that using 2.0 g of the modified chitosan in a 72,227 mg/L soluble cutting fluid emulsion concentration, a 2,518.8 mg/g adsorption capacity was calculated. Models of Langmuir and Freundlich were applied to describe the adsorption isotherm together with coefficient of determination and chi-square error function calculations. The Langmuir isotherm best fitted the experimental data of the modified chitosan. In addition, the significant uptake of the soluble cutting fluid emulsion was demonstrated by the changes in the FTIR spectra and the heat of combustion of the modified chitosan before and after the adsorption process.