Search

Currently, due to the decreasing availability of sulfide ores, laterite ores are attracting much attention as nickel reserves. Laterite ore with nickel content of 1.35% can not be processed in Indonesia, therefore it is necessary to do processing in order to increase the laterite ore grade. One of nickel laterite processing is leaching in sulfuric acid solution. To produce a product with high levels of the metal nickel-metal impurities that come dissolved, particularly iron must be removed first from the results of the leaching solution. After separating the iron, nickel is deposited so that an intermediate product is produced in the form of Mixed Hydroxide Precipitate. The experiment was started by leaching using 1 M H2SO4 solvent, leaching time 6 hours, S/L 10 g/100 ml, stirring speed 400 rpm, variations in the addition of hydrogen peroxide 3, 5, 7, and 9 ml, and variations in temperature 30, 50, 70, and 90°C. The leached solution was then separated from the iron in 2 stages, namely the first stage with the addition of 25 wt.%/wt.% CaCO3 at a temperature of 90°C, a time of 2 hours, and a pH of 4.25. Then the second stage was with the addition of CaCO3 12.5 w/w with a temperature of 70°C, time of 1 hour, and pH 7. After that, nickel was deposited using MgO 20% wt.%/wt.% at a temperature of 50°C, 1 hour, and pH 9. The results showed that the highest extraction percent was achieved in 1 M H2SO4 conditions, leaching time of 6 hours, S/L 10 g/100 ml, stirring speed of 400 rpm, the addition of 9 ml of hydrogen peroxide and a temperature of 90°C is equal to 94.47%. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass from agricultural byproducts is an abundant resource with value-added components that could be enhanced through separation. Cellulose, the primary and value-added component in the lignocellulosic biomass, has played a wide range of applications, particularly for biodegradable materials and fuel purposes. Corncob, one of those agricultural byproducts, contains from 30 to 41.7% cellulose has a great prospect to utilize with an enormous amount available in Indonesia. However, due to the recalcitrant structures of natural lignocellulosic biomass, corncob also has a considerable amount of lignin and hemicellulose, hindering cellulose fiber accessibility. Therefore, an effective treatment is needed to remove impurities while increasing cellulose fiber purity. In this study, cellulose fiber from corncob has been enhanced by combining physical and chemical treatments. The classical sodium hydroxide treatment followed by hydrogen peroxide treatment under microwave assistive was performed for corncobs processing with some variations. After these sequential steps, the results showed that the cellulose fiber in treated corncob potentially rose to 83.10%, while hemicellulose and lignin content declined to 4.38% and 3.70%, respectively. The scanning electron microscopy (SEM), Fourier transform infra-red (FTIR), and x-ray diffraction (XRD) analysis are further analyses employed as verification of these results. [ABSTRACT FROM AUTHOR]

The level consumption of Polyethylene Terephthalate (PET) as a packaging of colored beverage bottles occupies the fourth largest in the world. In Indonesia, PET consumption increased reaches 7% per year so that it can cause environmental impacts. This study aims to process the recycling PET waste by obtaining a simple potential process to remove the color from PET waste. The decolorized PET waste will be an alternative carbon source for Carbon Nanotube (CNT) synthesis. The colors of PET waste are blue and green bottles. The selected color removal agent is hydrogen peroxide (H2O2) because it is inexpensive reagent and has lower toxicity to environment. The colored PET waste and H2O2 will be heated in the oil bath system at temperature 110°C and pressure 1 atm. The result showed that color removal time for blue PET waste faster than the green PET waste, 72 and 115 minutes per 15 grams PET waste. The quality of color removal of blue PET waste is better than the green PET waste because it has a reflectance value closer to colorless PET waste, namely 80%. The CNT synthesis process from decolorized blue PET waste produce 8.58% yields. The average diameter of CNT crystals from its process is obtained at 37 nm. This shows that PET waste plastic which has been discolored can be used as a carbon source in CNT synthesis. [ABSTRACT FROM AUTHOR]