Enhanced removal of Indigo Carmine dye from textile effluent using coal fly ash and Its Modification: Adsorption, kinetics, and mechanisms Mujaroh Khotimah (a*,b), Milna Kurniawati (b), Suprihanto Notodarmojo (b)
a) Environmental Engineering Study Program, Department of Biosystems Engineering, Faculty of Agricultural Technology, Universitas Brawijaya, Malang, Indonesia 65145 *mujarohkhotimah[at]ub.ac.id
b) Department of Environmental Engineering, Institut Teknologi Bandung, Bandung, Indonesia 40132
Abstract
The release of Indigo Carmine into aquatic environments can lead to significant consequences for both aquatic ecosystems and human well-being. There is a growing desire to create environmentally friendly and efficient adsorbents for extracting harmful dyes from textile wastewater. This study proposed to investigate the potency of coal fly ash (FA) and its modification to remove IC dye in an aqueous solution. The modification included: (1) reacting FA with NaOH 3M solution (FA-NaOH), (2) Geopolymer, and (3) converting to zeolite A (FA-LTA). To identify physical and chemical changes during modification used analysis of XRF, XRD, SEM, BET, FTIR, CEC, and pHpzc methods. The effect of pH, adsorbent dose, contact time, and initial concentration of IC were studied in this research. Results showed the ability of IC dye adsorption by fly ash (FA)> FA-NaOH> Geopolymer> FA-LTA. Kinetics model analysis of IC dye adsorption towards all types of adsorbents was fitted well with a pseudo-second-order model, with adsorption rate constant (k2) values for FA, FA-NaOH, Geopolymer, and FA-LTA were 0,01149- 0,02359- 0,07402- and 0,07203 (g/mg. minute), respectively. The adsorption process fitted the Freundlich isotherm model with Freundlich constant value kinetic and 1/n being 0,148 mg/g (L/mg) and 0,7895, respectively.
Keywords: adsorption, indigo carmine, coal fly ash, geopolymer, zeolite A, freundlich model
