REMOVAL OF INDIGO CARMINE DYE BY ADSORPTION METHOD USING COAL FLY ASH AND ITS MODIFICATION

• Main Author: Kurniawati, Milna
• Format: Theses
• Language: Indonesia
• Subjects: Teknik saniter dan perkotaan; teknik perlindungan lingkungan
• Online Access: https://digilib.itb.ac.id/gdl/view/46747
• Institution: Institut Teknologi Bandung

The scarcity of fresh water has warranted an increasing demand for wastewater reuse in the textile industry. Textile dye which still exists after conventional treatment has limited this purpose, especially in West Java Province, Indonesia. Some of textile dyes are carcinogenic and mutagenic to living organisms. Indigo Carmine (IC) or Acid Blue 74 is a well-known textile dye, especially for denim or blue-colored fiber. Despite its wide usage, Indigo Carmine is irritant to the digestive system, thus causing nausea, vomiting, and diarrhea. This indigoid class dye is also irritant to the respiratory system, indicated by coughing and hard to breathe. Textile dye removal by adsorption method has become economically feasible technology. In recent years, experiments related to adsorption are more focused on finding alternative adsorbents to activated carbon, which are inexpensive and environmentally friendly. Coal fly ash, which categorized as hazardous waste in Indonesia, is considered to be potential adsorbent for heavy metals, textile dye and organic pollutants removal in wastewater due to its similar properties with activated carbon. The adsorption capacity of coal fly ash is strongly affected by its origin and after-combustion treatment. Physical and chemical modification of coal fly ash can increase its adsorption capacity. This research aimed to investigate the potency of coal fly ash (CFA) and its modification to remove IC dye in aqueous solution. The modification included: (1) by reacting CFA with NaOH 3M solution (FA-NaOH), (2) by converting to geopolymer (Geopolymer), and (3) by converting to zeolite A (FA-LTA). In order to identify physical and chemical changes during modification, each adsorbents analyzed using XRF, SEM, BET, XRD, FTIR, CEC and pHpzc method. Effect of pH, adsorbent dose, contact time and initial concentration of IC was studied in this research. The optimum condition from these variables used to treat the original wastewater effluent from textile industry. These experimental results were studied further by three kinetics models (pseudo-first-order, pseudo-second-order, and intraparticle diffusion), and three isotherm models (Langmuir, Freundlich, and Dubinin-Radushkevich). Results shown the ability of IC dye adsorption by fly ash (FA)> FA-NaOH> Geopolymer> FA-LTA for all experiments conducted. This is probably related to the number of crystalline phases consist in the adsorbents and low cation exchange capacity (CEC) property of fly ash, thus able to attract anionic dye to its structure. Kinetics model analysis of IC dye adsorption towards all type of adsorbents is fitted well with pseudo second order model, with adsorption rate constant (k2) value for FA, FA-NaOH, Geopolymer and FA-LTA are 0,01149; 0,02359; 0,07402; and 0,07203 (g/mg.minute), respectively. Meanwhile, isotherm model analysis towards FA, FA-NaOH, and Geopolymeric adsorbent are fitted well with Langmuir isotherm model, with maximum adsorption capacity value (qm) are 2,856; 1,753; and 1,381, respectively. Adsorption towards FA-LTA are following Freundlich isotherm model, with Freundlich’s constant value Kf and 1/n are 0,148 mg/g (L/mg)1/n and 0,7895, respectively.