KAOLIN GEOPOLYMERIZATION STUDY AS A MATERIAL TO CONTROL POTASSIUM ELEMENT RELEASES IN WATER

• Main Author: Kader, Jesse
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/43826
• Institution: Institut Teknologi Bandung

In the last fifty years, the number of human population in Indonesia has doubled and it is estimated that in 2050, the number of Indonesia’s population will reach 321 million. This is a challenge for the agricultural industry to provide adequate food and nutrition. One way is to improve agricultural efficiency by optimizing the use of fertilizers. However, excessive and uncontrolled use of fertilizers will adversely affect the environment and health. This is caused by the high solubility of fertilizers so that fertilizer elements absorbed by soil improperly. One way to fix this problem is controlling the release of elements in fertilizer by using geopolymer materials. In this research, a mixture of kaolin, K2HPO4.3H2O and waterglass (Na2SiO3) is used to form geopolymer. Kaolin being used was obtained from Karangnunggal, West Java. Solubility tests have been carried out at atmospheric pressure and room temperature to study the effect of geopolymer composition, geopolymerization temperature and briquetting pressure on the potassium dissolution percentage. The effect of geopolymer composition was studied at various ratio of kaolin mass (gram) and waterglass 2,5M volume (ml) 4,0:1, 4,5:1 and 5,0:1. The effect of geopolymerization temperature was studied at various temperature of 110, 120, 130 and 140°C. Meanwhile the effect of forming pressure was studied at various pressure of hand pressed, 20, 30 and 40 kg/cm2. The geopolymer structure was determined by analysis of SEM and FTIR while the percentages of dissolved potassium as a function of time at various conditions were determined by analysis of AAS. The result of AAS analysis shows that the formation of geopolymer with composition of 4,0:1 produces geopolymers with the lowest percent potassium release. The formation of geopolymers at variation of geopolymerization temperature of 140°C produces geopolymers with the lowest percent of potassium release. The formation of geopolymers with variation in forming pressure of 40 kg/cm2 produces geopolymers with the lowest percent of potassium release. At 4:1 composition variation, geopolymerization temperature of 140°C and forming pressure of 40 kg/cm2, the resulting geopolymer releases the lowest potassium at 52,98%