5 research outputs found
Chlorophyll extraction from suji leaf (Pleomele angustifolia Roxb.) with ZnCl2 stabilizer
No full text
Cenospheres characterization from Indonesian coal-fired power plant fly ash and their potential utilization
No full textThis study presents the cenospheres formation based on the characteristic of the fly ash and the coal as well as
the potential production of cenospheres from fly ash from six coal-fired power plants in Indonesia. For cenospheres characterization, SEM-EDS, petrography analysis, and particle analyzer distribution were applied
through all samples. Coal and fly ash chemical composition were analyzed using proximate analysis and ICP-MS.
Based on the characterization of cenospheres and fly ash chemical components, we correlate the concentration of
SiO2, Al2O3, SiO2/Al2O3, Fe2O3, Fe2O3+TiO2, CaO, MgO in the fly ash with cenospheres yield and diameter. The
cenospheres yield in six Indonesian coal-fired power plant fly ash is in the range of 0.04–0.16% and inline with
the ash content in the initial coal. Moreover, it was found that the cenospheres yield and diameter are in positive
correlation with the concentration of SiO2 and Al2O3 in the fly ash, but they are in vice versa correlation with
other chemicals. Ternary diagram of the cenospheres was made to their potential application and found that
most of the cenospheres are in the ferrocalsialic
Circular Economy of Coal Fly Ash and Silica Geothermal for Green Geopolymer: Characteristic and Kinetic Study
No full textThe study of geopolymers has become an interesting concern for many scientists, especially in the infrastructure sector, due to having inherently environmentally friendly properties and fewer energy requirements in production processes. Geopolymer attracts many scientists to develop practical synthesis methods, useful in industrial-scale applications as supplementary material for concrete. This study investigates the geopolymerization of fly ash and geothermal silica-based dry activator. The dry activator was synthesized between NaOH and silica geothermal sludge through the calcination process. Then, the geopolymer mortar was produced by mixing the fly ash and dry activator with a 4:1 (wt./wt.) ratio. After mixing homogeneously and forming a paste, the casted paste moved on to the drying process, with temperature variations of 30, 60, and 90 °C and curing times of 1, 3, 5, 7, 14, 21, 28 days. The compressive strength test was carried out at each curing time to determine the geopolymer’s strength evolution and simulate the reaction’s kinetics. In addition, ATR-FTIR spectroscopy was also used to observe aluminosilicate bonds’ formation. The higher the temperature, the higher the compressive strength value, reaching 22.7 MPa at 90 °C. A Third-order model was found to have the highest R2 value of 0.92, with the collision frequency and activation energy values of 1.1171 day−1 and 3.8336 kJ/mol, respectively. The utilization of coal fly ash and silica geothermal sludge as a dry activator is, indeed, an approach to realize the circular economy in electrical power generations
