Geopolymeric filter based on metakaolin and rice husk ash for removal of chromium ions

Abstract

The objective of this research was to determine the influence of the percentage of rice husk ash (CCA) and the concentration of the alkaline activator on the removal of chromium ions from geopolymer filters based on metakaolin (MK), due to the high toxicity generated by the chromium on health and the environment. The geopolymer was prepared by mixing activated rice husk ash at different percentages (0% , 10%, 20%, 30%) with kaolin at different molarities of sodium hydroxide (10M, 12M, 14M); subsequently, spheres of 4 mm in diameter were formed; was placed in the oven at a temperature of 110°C for 24 hours after 1 day of cooling, the same samples were placed in the oven at a temperature of 900°C for a time of half an hour to achieve sintering of the geopolymer. The results obtained through the adsorption process indicate that the highest percentage of chromium (VI) removal is achieved when the geopolymer is made up of metakaolin with 30% rice husk ash with an alkaline activator concentration (NaOH) of 14M with a time of 3 hours, being 54.42% the percentage of remo va l of chromium VI ions. This study concludes that the higher the percentage of CCA and the higher the molarity of the alkaline activator (NaOH), the higher the percentage of removal of chromium ions.

Improving Sag Resistance in Geopolymer Coatings Using Diatomite Filler: Effects on Rheological Properties and Early Hydration

“…Due to the numerous internal pores in geopolymer coatings, diatomite can act as a fine aggregate filler [48]. Initially, due to its higher water absorption, an increase in diatomite concentration results in higher adsorption of free water, thereby slowing down the progress of geopolymer hydration reactions [84].…”

“…Diatomite is a resource-abundant and economically viable natural mineral. With its unique microporous structure, large specific surface area, and high reactivity, it can effectively enhance the freezing resistance [43], thermal stability [44,45], adsorption capacity [46][47][48][49], and mechanical strength [44,[50][51][52] of geopolymer materials. It is therefore regarded as an effective additive for improving the durability of geopolymer materials.…”

Geopolymer Made from Kaolin, Diatomite, and Rice Husk Ash for Ceiling Thermal Insulation

“…The use of solid wastes or industrial by-products as precursor materials results in reduced CO 2 production, reduced energy usage, and lower costs [14,15]. Geopolymer technology is expected to continue gaining popularity due to its practical and economical solutions in various applications [16,17]. Its exceptional adhesive behavior, mechanical strength, high chemical and thermal stability, and long-term robustness are all remarkable [18,19].…”