A study on the role of surface functional groups of metakaolin in the removal of methylene blue: Characterization, kinetics, modeling and RSM optimization.

In this study, thermally activated kaolinite clay is explored as a suitable material for dye removal applications, which gave rise to highly reactive silica species in a broad range of aluminosilicate clusters. Multinuclear NMR studies described it as a short-range network in which Al sites in IV, V, and VI are coordinated, and Si is present mainly as Si(Q4(1Al)). Critical parameters for methylene blue (MB) were determined by the Placket Burman Design (PBD) as initial dye concentration, contact time, adsorbent dosage, pH and size.