Removal of arsenic by adsorption using pervious concrete partially substituted with fly ash

• Main Authors: Li, Nacey Bianca, Revalde, Rea Sergio, Ching, Daniel Dominic L.
• Format: text
• Language: English
• Published: Animo Repository 2014
• Subjects: Fly ash > Environmental aspects; Water > Purification > Arsenic removal; Acid mine drainage; Chemical Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/10712
• Institution: De La Salle University

This research aims to remove Arsenic, a heavy metal, which is a harmful water pollutant. Pervious concrete is inexpensive and can be easily obtained or made thus making it an economical solution. The method of adsorption was incorporated for the removal of Arsenic. Pervious concrete was used as the medium where 20% of its Portland cement is substituted with fly ash. Several admixtures were considered but fly ash was the most practical since it is abundant in supply and is already used to make concrete. Using fly ash also reduces the risk of it as a hazardous waste. The fly ash acted as an admixture to adsorb the Arsenic because fly ash is known to have a high amount of iron oxide (Fe2O3). Three initial Arsenic concentrations, 1, 1.4, and 3.7 ppm, were tested for the concrete with 20% fly ash-replaced cement (20% FA-RC) and the pure Portland concrete. The flow rates of the 20% FA-RC concrete and pure Portland concrete were 5.43 and 1.56 L/m2-s while the compressive strengths were 2.11 and 1.01 MPa respectively. The initial and final Arsenic concentrations were determined to obtain the percent removal of Arsenic by the pervious concrete with 20% FA-RC concrete and compared with the percent removal of Arsenic of the concrete with no fly ash. The average percent removal of Arsenic by 20% FA-RC was 55%, 17.86%, and 28.38% where the initial concentrations were 1, 1.4, and 3.7ppm respectively. The pure Portland concrete, on the other hand, was able to remove 60%, 28.57%, and 16.22% of Arsenic. The effect of the fly ash content with the Arsenic removed was shown to have no significant effect according to the ANOVA results because the pervious concrete with no fly ash was also able to remove Arsenic. However, when analyzed per initial concentration, the 20% FA-RC pervious concrete would be the most practical and economical since its percentage removal increased when the initial concentration reached 3.7 ppm where as the pure Portland pervious concrete steadily decreased. The significance of the findings is the implication of an alternate and low-cost solution to remove Arsenic from water supplies for marginalized communities.