Mesoporous activated carbon from grass waste <i>via</i> H<sub>3</sub>PO<sub>4</sub>-activation for methylene blue dye removal: modelling, optimisation, and mechanism study
Ali H. Jawad, Nurul Nadiah Mohd Firdaus Hum, Ahmed Saud Abdulhameed, Mohd Azlan Mohd Ishak
Abstract
The grass (G) biomass waste in this work was used as an alternative source for producing high-quality mesoporous activated carbon (AC) via H3PO4 activation.The developed G-based activated carbon by phosphoric (H3PO4) acid activation (GAC-PA) was characterised via various analytical techniques. The surface area property represents a high surface area (756.3 m2/g) and mesoporous structure (mean pore diameter of 11.3 nm) of GAC-PA. The adsorptive property of GAC-PA towards the methylene blue (MB) dye uptake was optimised via a response surface methodology with Box–Behnken design (RSM-BBD). The equilibrium adsorption fitted well with the Langmuir and Temkin isotherm models, and the qm value for the MB dye was 241.3 mg/g at 45°C. The MB dye adsorption mechanism on the GAC-PA surface indicates various dye–adsorbent interactions, such as electrostatic, π–π, and H-bonding. This study demonstrates the applicability of G waste as a promising candidate for developing desirable AC materials with high surface area and mesoporosity for cationic dye adsorption.