| Abstrakt: |
Laundry waste contain high concentration of phosphate can be recovered and converted into struvite crystals (MgNH4PO4.6H2O) that widely used as fertilizer. Formation of struvite crystals required supersaturation of solution that contain forming ions: Mn2+, NH4+, and PO43-. Moreover, external parameter also highly effected crystallization and quality of resulting struvite crystals, e.g. pH, reaction time, temperature, stirring speed and addition of catalyst. Supersaturation and optimum reaction condition are important aspects of nucleation and growth of struvite crystals. However, it has been reported that present of Mg2+ ions and phosphate at standard incubation conditions: temperature of 37°C, partial CO2 pressure p(CO2) = 5.0% and pH close to 7.5, precipitation formation of bobierrite crystal (Mg3(PO4)2·8H2O) also considered possible. In this study we try to establish optimum fabrication condition of struvite crystals with high crystallinity and low impurity content. Reaction temperature and stirring speed vary from 25 and 30°C and 100 to 250 rpm, respectively, on the other hand solution volume, reaction ration, pH and reaction time are similar. X-ray diffraction (XRD) were implemented to confirm formation of struvite crystal as well as impurity. Our study shown that optimum reaction temperature and stirring speed are between 25-30°C and 100 rpm, respectively, confirmed by the absent of impurity and high crystallinity of struvite. [ABSTRACT FROM AUTHOR] |
