Mesoporous Activated Carbon from Leaf Sheath Date Palm Fibers by Microwave-Assisted Phosphoric Acid Activation for Efficient Dye Adsorption.

Remazol Brilliant Blue R (RBBR) is a common dye used in the industry, and its presence in wastewater and discharge into the environment can create a serious concern for the ecosystem and human health. Activated carbon produced from crop residues has emerged as a promising technique for removing contaminants from wastewater. In this study, leaf sheath date palm fiber-based activated carbon (LSDAC) was synthesized via phosphoric acid, H 3 PO 4 , treatment, followed by a microwave-induced carbonization process. The produced LSDAC was found to have a BET surface area of 604.61 m 2 /g, a Langmuir surface area of 922.05 m 2 /g, a total pore volume of 0.35 cm 3 /g, and an average pore size of 2.75 nm. The highest removal of RBBR was achieved at a solution pH of 3 (92.56 mg/g) and a solution temperature of 50 °C (90.37 mg/g). Adsorption of RBBR onto LSDAC followed the Langmuir isotherm model with a maximum monolayer capacity, Q m , of 243.43 mg/g, whereas in terms of kinetics, this adsorption system was best described by the pseudo-first-order (PFO) model. The calculated thermodynamic parameters Δ H °, Δ S °, Δ G °, and Arrhenius activation energy, E a , were 4.71 kJ/mol, 0.10 kJ/mol·K, -26.25 kJ/mol, and 5.88 kJ/mol, respectively, indicating that the adsorption of RBBR onto LSDAC was endothermic in nature, exhibited increased randomness at the solid-liquid interface, and was spontaneous and controlled by physisorption.