Adsorption 1 Adsorptive capacity Chemisorption 1 Clay structure 1 Design of experiments 1 Differential thermal analysis 1 Drug 1 Effect of acids 1 Fourier transform infrared spectroscopy 1 Functionalized 1 Monolayers 1 Organo-functionalization 1 Palygorskite clays 1 Sodium 1 Sodium diclofenac 1 Thermogravimetric analysis 1 X ray fluorescence 1 X- ray diffractions 1 adsorption 1 design of experiment 1 drug 1 palygorskite clay 1