Removal of malachite green from aqueous solution using an ionic liquid-based nanoporous organosilica-supported propylamine: Kinetic and thermodynamic studies

Color compounds are one of the most critical pollutants for natural ecosystems in the environment. The purpose of this research is to investigate the removal of malachite green (MG) dye from aqueous solutions using ionic liquid-based nanoporous organosilica-supported propylamine (ILNO-NH 2 ) adsorbent. Adsorbent characteristics were investigated using different analyses such as diffuse reflectance infrared Fourier transform, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and powder X-ray diffraction. The effect of various parameters such as pH, contact time, amount of adsorbent, concentration, and temperature was investigated and optimal values for each were obtained. Langmuir, Freundlich, and Tempkin isotherms were employed to describe the MG adsorption equilibrium. According to the obtained data, the maximum adsorption capacity of ILNO-NH 2 was 344.80 mg/g. Moreover, thermodynamic parameters suggested that adsorptions were endothermic and spontaneous (ΔH 0 = 42.50 kJ/mol and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:mi>Δ</mml:mi> <mml:msubsup> <mml:mtext>G</mml:mtext> <mml:mrow> <mml:mtext>avg</mml:mtext> </mml:mrow> <mml:mn>0</mml:mn> </mml:msubsup> </mml:mrow> </mml:math> = −6.87 kJ/mol).