THE EFFECT OF ACTIVATED CARBON PARTICLE SIZE ON TEXTILE DYE METHYLENE BLUE ADSORPTION PROCESS

• Main Author: Masykur Hadi Musthofa, Akhmad
• Format: Theses
• Language: Indonesia
• Subjects: Teknik saniter dan perkotaan; teknik perlindungan lingkungan
• Online Access: https://digilib.itb.ac.id/gdl/view/70843
• Institution: Institut Teknologi Bandung

Textile industry is the largest producer of dye effluents with a percentage of 54% of the total dye effluents produced in the world. Azo dyes are the most widely used dyes in the textile industry, reaching 60-70% of the total dyes produced. An example of an azo dye is methylene blue which is commonly used in dyeing wool, silk, and cotton fabrics. An effective, inexpensive, fast, simple, and non-sludge-producing textile wastewater treatment method is adsorption process with activated carbon. As an effort to increase the efficiency of the adsorption process, several efforts have been made. Reducing the particle size of activated carbon is one of the efforts made to increase the adsorbent capacity in addition to changing the functional groups on the surface of activated carbon. Therefore, in this study, variations in the size of activated carbon were carried out into granular, powder, and superfine powder to determine its effect on the overall methylene blue adsorption process. The analysis carried out in this study included the physical/chemical characterization, isotherms, kinetics, and thermodynamics of the adsorption process. Physical characterization analysis was carried out using particle distribution test, SEM, and BET while chemical characterization was carried out using FTIR and point of zero charge tests. In the isotherm, kinetics, and thermodynamics tests, 1 gram of activated carbon (granular, powder, or superfine powder) is contacted with 500 mL of methylene blue artificial wastewater with various concentrations at various contact times based on preliminary tests. Specifically for the thermodynamic test, the temperature was varied to 35,45, and 55oC. From the test results it is known that changes in particle size cause changes in the physical and chemical characterization of activated carbon. There was an increase in surface area and pore volume of activated carbon in smaller particle sizes. This increase contributed to changes in the adsorption capacity of each activated carbon based on preliminary tests. The adsorption capacity of methylene blue by granular activated carbon ranged from 4.34 – 16.66 mg/g, while the adsorption capacity of activated carbon powder and superfine powder ranged from 34.67 – 60.96mg/g and 112.57 – 122.21. Isotherm analysis showed that the adsorption process on all activated carbon follows a high affinity isotherm based on the Giles isotherm classification with a monolayer adsorption mechanism. Further isotherm analysis using the Langmuir isotherm model showed an increase in maximum adsorption capacity and Langmuir coefficient at smaller particle sizes. Kinetic analysis also showed that there is no difference in the kinetic model that applies to each activated carbon because all activated carbon follows the pseudo first order model. However, there was an increase in the rate of adsorption kinetics as indicated by an increase in the value of the kinetic coefficient on activated carbon with smaller particle sizes. Meanwhile, in thermodynamic analysis it is known that the adsorption process takes place more spontaneously and better at smaller particle sizes and at higher temperatures, thus indicating that the adsorption process is endothermic. Based on the analysis of the standard enthalpy change values, it is known that there were differences in the dominant adsorption mechanism for each activated carbon. In granular activated carbon and superfine powder, the predominant adsorption mechanism were electrostatic interaction, while in powder activated carbon, the dominant adsorption mechanism was van der Waals forces. This adsorption mechanism was supported by the FTIR test results on methylene blue contained wastewater before and after the adsorption process and activated carbon after the adsorption process. Based on the FTIR test, the adsorption mechanism can be caused by several mechanisms including ?-? interactions between aromatic functional groups on the adsorbent surface and methylene blue aromatic bonds such as (C=C-C), electrostatic interactions between negatively charged functional groups on the adsorbent surface and methylene blue molecules which positively charged, and the formation of hydrogen bonds between nitrogen elements (N) and oxygen-containing functional groups such as hydroxyl (OH-) on the surface of activated carbon.