Valorization of Tunisian Pottery Clay onto Basic Dyes Adsorption

Abstract

This study examined the adsorption behavior of two cationic dyes used in textile industries (CI<br />Basic Red 46 and CI Basic Blue 3) on Tunisian clay used in pottery. The ability of pottery clay to remove the<br />basic dyes from aqueous solution was compared to that of the commercial powdered activated carbon (PAC)<br />and raw clay. Physicochemical characteristics of these adsorbents were performed by Boehm dosage, pHPZC<br />and CEC determination, particle size distribution and spectroscopic analysis (FTIR and UV-Vis). The pHPZC<br />of the pottery clay was about 9.86 and the CEC was about 15.6 meq/g. The empirical kinetic data fitted very<br />well the pseudo second order model for the adsorbent studied. The isotherm data fitted rightly to the Langmuir<br />isotherm model. The maximum adsorption capacities of the raw clay, pottery clay and PAC onto CI Basic Red<br />46 (CI Basic Blue 3) were respectively2806 mmol/g(785 mmol/g), 2114mmol/g (116.2mmol/g) and 2123mmol/<br />g (343.9 mmol/g). These results showed the large adsorption capacities of the studied samples onto the basic<br />dyes. Based on thermodynamic study, the adsorption of the cationic dye on raw clay, pottery clay and PAC<br />appears to be physical adsorption process. The effect of the ionic strength study showed that the presence of<br />electrolyte had an important effect on the basic dyes removal.