Recycling some byproducts for fabrication of green cement with good mechanical strength and high efficiency for wastewater treatment

This research aims to produce green cement, as an alternative to traditional cement, with outstanding performance. Five alkali-activated cement pastes were fabricated based on NaOH-activation of slag (GGBFS), bypass (B), and/or silica fume (S). Codes of five pastes are C, C-20B, C-30B, C-10B10S, and C-20B10S, as C is the control paste containing 100% slag. The compressive strength of the fabricated pastes was measured at different curing regimes: Conventional curing for 3 months and autoclave curing at 4 bar/153◦C, 7 bar/178◦C, and 10 bar/198◦C for 4 h. XRD, TGA/DTG, SEM/EDX, and BET/BJH techniques were utilized to clarify the phase development, morphological and texture features of the formed alkali-activated composite pastes. Besides, the removal capacity of some pastes for methylene blue and indigo-carmine dyes from aqueous media was evaluated. The results confirmed that C and C10B10S (80%GGBFS + 10%B + 10%S) pastes have significant mechanical properties and distinctive meso-porosity that can remove both anionic and cationic dyes.