Removal of Methylene Blue from Aqueous Solution by Adsorption Onto Modified Attapulgite Clay

The clay minerals have already been extensively investigated to remove various organic pollutants and metal ions, and how to improve their adsorption capacity is critical to practical application. In the paper, raw attapulgite clay was modified by hydrochloric acid to improve its adsorption capacity for dye. The adsorption properties of methylene blue (MB) from aqueous solutions onto modified attapulgite clay were further evaluated. The adsorption capacity of adsorbent increased with the decrease of the absorbent dosage and the increase of the initial concentration and temperature. The equilibrium data are well consistent with Langmuir isotherm model. The maximum adsorption capacity is 217.4 and 271.7 mg . g(-1) at 298 K and 318 K, respectively. The Kinetic experiments show that the adsorption follows the pseudo-second-order kinetic model well. Considering its high adsorption capacity and low cost, the modified attapulgite clay could be used as an effective and economic adsorbent for dye removal.