Abstract
Geopolymer is an emerging “green” cementitious material which has a potential to valorize waste such as rice hull ash (RHA). Geopolymer is a kind of alkali-activated material which forms from the reaction of alumino-silicates in an alkaline solution. This study uses RHA as the raw material for alkaline activator while metakaolin (MK) serves as a geopolymer precursor to synthesize the so-called geopolymer sphere. Then its capacity as a porous matrix was explored upon incorporation of TiO2 nanomaterial using horizontal vapor phase growth (HVPG) technique to enhance its photocatalytic property. Indication suggests that the synthesized MK-geopolymer spheres activated with RHA-based water glass solution (WGS) were comparable to that of commercial WGS. Furthermore, the geopolymer spheres were successfully coated with TiO2 in the form of nanocrystals. Its photocatalytic activity was evaluated in terms of methylene blue degradation. This material’s potential environmental application for water purification and wastewater treatment will be investigated for future works.
Highlights
The Philippines is an agricultural country whose staple is rice, generating around 19 million metric tons (MMT) of paddy rice in 2017 alone
The water glass solution synthesized from rice hull ash was used solely for producing geopolymer spheres
The raw material used as the alumino-silicate source was metakaolin was sourced from Tarlac, Philippines (SiO2 = 55.06 wt% and Al2O3 = 44.12% wt), which allows it to become a feasible geopolymer raw material
Summary
The Philippines is an agricultural country whose staple is rice, generating around 19 million metric tons (MMT) of paddy rice in 2017 alone. This has increased by around 8% from the previous year [1]. With the existing problem of rice hull generation that far outweighs its utilization, several strategies to make use of this waste have emerged, one of which is in concrete production [3]. Because of its low energy consumption during its processing, researchers have shifted their focus on the use of waste materials or its by-products (pozzolanic materials) as ingredients in concrete production with the objective of having minimal environmental impact and maximal sustainability [5]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
