Development of industrially viable geopolymers from treated petroleum fly ash

Abstract

This paper investigates the development of stable geopolymers using petroleum fly ash with high compressive strength and water absorption to promote cleaner production, sustainability, and recycling of waste. The paper provided detailed characterizations of the petroleum fly ash, which involved the determination of the particle size diameter, density, surface area, pore-volume, mineralogical identification of recording X-ray diffraction pattern, X-ray fluorescence, Fourier transform infrared, thermogravimetric analysis, and scanning electron microscope. Moreover, metals leachability from the petroleum fly ash using different extracting agents, namely H2SO4, H3PO4, (NH4)2SO4, NH4NO3, and NH4O2CCO2H was also considered. Five geopolymers were prepared using different amounts of petroleum fly ash to assess the influence of petroleum fly ash on the final performance of the prepared geopolymers. The results revealed that the petroleum fly ash was carbonaceous in nature and rich in vanadium oxide and nickel oxide with low in SiO2 and Al2O3. Furthermore, it was found that petroleum fly ash has a low calcium level. The maximum extraction values were 15.6% for V and 55.6% for Ni using H2SO4. All the prepared geopolymers displayed high compressive strength for longer curing times, and the water absorption properties of all geopolymers were improved by incorporating more petroleum fly ash. Increasing the petroleum fly ash from 0 vol% to 61 vol% increased the water absorption value from 6.6 to 13.3 wt% for the samples collected after 28 days of curing. It was concluded that the petroleum fly ash did tend to form successful stable geopolymers with high compressive strength and water absorption.