Highly brilliant green removal from wastewater by mesoporous adsorbents: Kinetics, thermodynamics and equilibrium isotherm studies

The study focuses on evaluation of three mesoporous adsorbents: unmodified Algerian montmorillonite (Mt), unmodified lemon peel waste (LP) and activated carbon (AC) in elimination of brilliant green (BG) textile dye from wastewater. The three adsorbents were characterized by the elementary analysis, the infrared spectroscopy, X-ray diffraction, N-2-BET analysis and point of zero charge (pHPZC). The operational conditions of BG adsorption as initial dye concentration, contact time, pH of BG solution and temperature were evaluated in batch mode. Results revealed that BG adsorption kinetics onto Mt, LP and AC are best described by the pseudo-second order model. BG adsorption onto adsorbents follows well Langmuir model indicating that the BG molecule's adsorption is uniform; having the same adsorption energy and a monolayer adsorption takes place. The adsorbed amounts of BG onto prepared adsorbents Mt, LP, and AC are of 229, 150, and 826 mg/g respectively. Activated carbon has the higher adsorption capacity, but it is of a very high cost. Compared to the AC, Montmorillonite and lemon peels were very low-cost and very effectiveness adsorbents in the elimination of cationic dyes from wastewater.