SYNTHESIS AND CHARACTERIZATION Fe3O4 NANOPARTICLES FROM IRON SAND FOR HUMIC ACID ADSORPTION

• Main Author: Intan Suri, Fraulein
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/34013
• Institution: Institut Teknologi Bandung

Indonesia is one of countries having massive peatlands. Peatlands contain organic compounds that play an important role in fertilizing soil. However, the content of organic compounds in peat, as a result of decomposition of lignin, carbohydrates and protein, may produce acidic, odor, and brownish water. Consequently, it is difficult for the people living in the areas to obtain utilizable fresh water. One of the main components of the peat water is humic acid. The humic acid complex, combined with the halogen group derived from the process of disinfection using chlorin, can produce carcinogenic trihalometan which is dangerous for human health ranging from neurological disorders to cancer. Ministry of Health through PERMENKES 492 / Menkes / PER / IV / 2010 classifies peat water as raw water which does not meet the qualification of clean water. To make the peat water safe to consume, various water treatment methods have been applied such as ozonation and oxidation, coagulation, ion exchange, biodegradation, flocculation, sedimentation, filtration and adsorption. Adsorption is becoming the most widely used method in water treatment as it is more economical, efficient, and adjustable in the adsorbent usage. A kind of adsorbents which is now being widely used is the nanoparticle Fe3O4. This material has a number of advantages on account of its wide surface and for adsorption incuding its magnetic properties facilitating separation processes, especially in a batch process. This study has successfully synthesized Fe3O4 nanoparticles with local iron ore as its raw materials through co-precipitation process. Iron sand concentrate was diluted with 37% HCl at temperature close to 70°C, stirred for 30 minutes using a magnetic stirrer and then filtered using a filter paper. Next, 25.0 mL NH4OH 25% (v / v) was slowly added to the solution, heated at a temperature close to 70° C and stirred for about 30 minutes using magnetic stirrer. The results of the reaction were then washed and dried. The characterization of Fe3O4 nanoparticles was attained through FTIR spectroscopy, XRD, SEM and TEM processes. FTIR spectra showed the absorption for Fe3O4 at wave number 574 and 446 cm-1 and the spinel structure of Fe-O tetrahedral and octahedral Fe-O. In addition, there also appeared other absorptions at wave number 1600 cm-1, indicating a bending vibration of the hydroxyl group (-OH) and the wave number 3400 cm-1 indicating the stretching vibration of -OH or H2O on the surface of Fe3O4. The characterization of Fe3O4 nanoparticle using XRD diffractogram produced a pattern that corresponds to the standrad diffractogram. The characterization using the TEM showed that Fe3O4 nanoparticles was fully synthesized at the average of 18.26 nm diameter. The optimum conditions of humic acid adsorption using the Fe3O4 nanoparticles adsorbent with a batch method showed the value of the maximum adsorption capacity of 45 mg.L-1at pH 3 with a contact time of 90 minutes and 0.05 gram of adsorbent mass. The isothermic adsorption analysis using Freundlich and Langmuir isothermic adsorption models showed that the adsorption of humic acid using Fe3O4 nanoparticles corresponded to the Langmuir isotherm with a correlation coefficient of 0.988 and the value Langmuir capacity (qm) 45.45 g.mg-1. The study of kinetics adsorption based on pseudo first order and pseudo second order indicated that the adsorption process followed the pseudo second order kinetics with a rate constant from 0.021 to 0.026 in the concentration range 10-30 mg.L-1. The parameter of thermodynamic adsorption showed increasingly negative ?G value with the increasing in temperature, which indicates that the adsorption is more effective at higher temperatures. In addition, the adsorption value of ?H at 149.37 kJ mol-1 revealed that this process was endothermic and chemisorptic.