REGENERATION OF ADSORBEN FROM COAL FLY ASH AND ITS MODIFICATION TO ADSORP INDIGO CARMINE DYE

• Main Author: Khotimah, Mujaroh
• Format: Theses
• Language: Indonesia
• Subjects: Teknik saniter dan perkotaan; teknik perlindungan lingkungan
• Online Access: https://digilib.itb.ac.id/gdl/view/51835
• Institution: Institut Teknologi Bandung

One of significant processing methods in dye removal is adsorption method in tertier treatment unit. This study uses fly ash and its modification which has been used for the previous adsorption process. Fly ash and its modification (FA modified by 3M NaOH, FA Geopolymer, and FA Zeolite LTA) become adsorbent to absorb (sorption) anionic textile dye, Indigo Carmine (IC). Each adsorbent has a maximum capacity until it reaches the saturation phase. Another solution besides the replacement of new and more environmentally friendly adsorbents (reducing the amount of second pollutants) is to apply the adsorbent reuse process after the regeneration process. The purpose of this study was to determine the potential yield of regenerated saturated adsorbents with indicators of post-regeneration adsorbent desorption efficiency, post-regeneration removal percentage and adsorbent capacity, number of adsorption cycles, post-regeneration adsorption kinetics and post-regeneration adsorbent physical changes. The experimental method was carried out using a batch method with desorption and re-adsorption process. The chemical adsorbent regeneration study using the desorption method was carried out to determine which desorption agent was good for regeneration and the best adsorbent which had the potential to be reused for the next adsorption process. The variations that were carried out, the type of desorption agent (acidic and base solutions) along with their concentrations and variations in desorption time. Meanwhile, the parameters were desorption efficiency of IC dye and pH. Then after the regeneration process, the research study conducted was post-regeneration adsorption to determine the efficiency of sorbate removal, adsorption capacity, pH and possible adsorption cycles. The data from the results of the time variation experiment will be processed into adsorption kinetics using two models, namely pseudo first order and pseudo second order. The equilibrium isotherm models used are langmuir, freundlich, and dubinin-reduskevich models. The results showed that the best desorption agent for all adsorbents was 0.75 M HCl with a desorption efficiency of 29.3%. The adsorption ability of IC dyes after regeneration was almost the same as the previous adsorption for FA and there was an increase in the adsorption ability of FA-NaOH, FA Geopolymer and FA Zeolite LTA but the ability of FA to absorb IC material remained the best. The sequence is FA> FA-NaOH> FA Geopolymer> FA Zeolite LTA. The final pH of the adsorption did not change significantly from the initial pH and increased every time the adsorption cycle was increased. The post-regeneration adsorption cycle was still able to be carried out three times, especially for FA adsorbent with an IC dye removal efficiency> 50%. The equilibrium isotherm model in FA followed the langmuir model, while LTA tends to follow the freundlich model. The dubinin-reduskevich model explains that the E value in adsorption using FA adsorbent is 8.4575 kJ / mol, and for LTA adsorbent is 9.1287 kJ / mol. The adsorption kinetics of the IC dye on the four types of adsorbent followed the pseudo second order model. But there was an interaction of electrostatic forces from different charges with sorbate and adsorbent which also explained that the adsorption mechanism takes place physically. So that physical forces, electrostatic forces and forces by chemical processes (ion exchange) did not work independently, in general the three forces that cause adsorption work together or sequentially. The changes in the morphology of the LTA adsorbent became more amorphous from the SEM test results, the reduced number of quartz crystals from the XRD test, the decrease and shift in functional groups from FTIR, and the presence of reduced and increased compounds from the EDS test. In the presence of amorphous and other conditions, it was thought to be preferred by anionic dye sorbates.