ADSORPTION ISOTHERMS OF CALCIUM ÍONS (Ca+2) FROM HARD WATER IN CELLULOSIC MATERIALS

Abstract

Water used in industrial processes requires a special treatment to achieve a high level of quality. In this context, the aim of this study was to investigate the use of cellulosic materials for water softening, such as microcrystalline cellulose (101 µm and 500 µm) and bleached Eucalyptus Kraft pulp. Firstly, the kinetic study was made in order to optimize operation parameters and then the adsorption processes were conducted, at three different levels of pH and different concentrations of calcium. The results showed that the pseudo-second order kinetic model had the best correlation coefficient and the Freundlich isotherm model was more appropriate to fit the experimental data, with the highest adsorption capacity observed at pH 7,0 for all the tested materials. At this pH, the microcrystalline cellulose adsorbed more than the bleached Eucalyptus Kraft pulp. Thus, it could be concluded that the proposed objectives were achieved.

Keywords

• Água dura
• Isotermas de adsorção
• Celulose microcristalina
• Polpa Kraft de Eucalyptus branqueada
• Ions cálcio (Ca+2).