Effects of Al2O3, SiO2 nanoparticles, and g-C3N4 nanosheets on biocement production from agricultural wastes.

ABSTRACT

Environmental issues are brought up concerning the production of Portland cement. As a result, biocement serves as a reliable substitute for Portland cement in green construction projects. This study created a brand-new technique to create high-quality biocement from agricultural wastes. The technique is based on nanomaterials that improve and accelerate the "Microbially Induced Calcite Precipitation (MICP)" process, which improves the quality of the biocement produced. The mixture was further mixed with the addition of 5 mg/l of graphitic carbon nitride nanosheets (g-C3N4 NSs), alumina nanoparticles (Al2O3 NPs), or silica nanoparticles (SiO2 NPs). The cement sand ratio was 13, the ash cement ratio was 19, and water cement ratio was 12. Cubes molds were prepared, and then cast and compacted. Subsequent de-molding, all specimens were cured in nutrient broth-urea (NBU) media until testing at 28 days. The medium was replenished at an interval of 7 days. The results show that the addition of 5 mg/l of g-C3N4 NSs with corncob ash delivered the highest "Compressive Strength" and the highest "Flexural Strength" of biocement mortar cubes of 18 and 7.6 megapascal (MPa), respectively; and an acceptable "Water Absorption" (5.42%) compared to all other treatments. This treatment delivered a "Compressive Strength", "Flexural Strength", and "Water Absorption" reduction of 1.67, 1.26, and 1.21 times the control (standard Portland cement). It was concluded that adding 5 mg/l of g-C3N4 NSs to the cementitious mixture enhances its properties, where the resulting biocement is a promising substitute for conventional Portland cement. Adding nanomaterials to cement reduces its permeability to ions, increasing its strength and durability. The use of these nanomaterials can enhance the performance of concrete infrastructures. The use of nanoparticles is an effective solution to reduce the environmental impact associated with concrete production.