Thesis Archive
Performance of pervious geopolymer based from bagasse and coal fly ash blends in copper ion removal
CATAPANG, Jacen Mariel S.
CHANG, Charles Steven N.
COLLO, Kenneth A.
Abstract:
Acid mine drainage is a waste effluent that contains heavy metals which can be treated using adsorption through permeable reactive barriers. An emerging potential adsorbent called geopolymer is based from fly ash, a waste product from combusting organic matter for energy. The research is conducted to evaluate the performance of a pervious geopolymer concrete that is based from bagasse and coal fly ash blends in treating aqueous copper solution. The dry raw materials were sieved and were characterized. The alkali solution was prepared with NaOH and Na2SiO3 solutions. The aluminosilicate precursors were designed with 0%, 25%, and 50% by volume of bagasse fly ash. All samples were fabricated using PVC molds and were cured for 28 days. The fabricated pervious geopolymer concretes were characterized using SEM-EDX. Performance tests show that both BFA and CFA are rich in silica. Moreover, the samples show that unreacted coal fly ash particles are present on the surface of the dense geopolymer while unreacted alkali compounds are seen on the surfaces of the geopolymers with BFA. Also, microcracks are observed to increase as the amount of BFA incorporated is increased. This result can relate to the compressive strength values which significantly decrease with increasing BFA and microcracks. The compressive strength obtained from all the samples ranges from 1.2–1.6 MPa. Furthermore, the permeability and porosity of the samples are in the ranges of 2.09–2.20 cm/s and 37.9–39.1%, respectively, and are minimally affected by BFA. Finally, the removal efficiency of the pervious geopolymer concrete is determined using AAS and shows no apparent trend with respect to the BFA/CFA ratio. The samples can remove 67–87% of copper through both adsorption and precipitation. Hence, using bagasse fly ash alongside coal fly ash has no effect on the removal efficiency of pervious geopolymer concrete. Overall, pervious geopolymer concrete from bagasse fly ash and coal fly ash blends is a potential permeable reactive barrier because of significant results in its compressive strength, permeability,porosity, and heavy metal removal efficiency.
Adviser:
PROMENTILLA, Michael Angelo B.
ORBECIDO, Aileen H.