Large surface area activated carbon from low-rank coal via microwave-assisted KOH activation for methylene blue adsorption

• Published in: Desalination and Water Treatment
• Main Author: Jawad A.H.; Mehdi Z.S.; Ishak M.A.M.; Ismail K.
• Format: Article
• Language: English
• Published: Desalination Publications 2018
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85054397148&doi=10.5004%2fdwt.2018.22226&partnerID=40&md5=a78c8d2c79e71910c493134d87c47491

Merit Kapit (MK) as a low-rank Malaysian coal was utilized as a precursor to develop a large surface area activated carbon (MKAC) via a microwave-induced KOH activation. The characterizations of the raw MK and MKAC were investigated by surface area analysis, scanning electron microscopy, X-ray diffraction, Fourier transform infrared, elemental analysis (CHNS) and point of zero charge (pHPZC) method. The surface area of MKAC was remarkably increased up to 1,100.18 m²/g compared with 332.61 m²/g of MK before activating process. The adsorptive properties of the MKAC with methylene blue (MB) was conducted at different adsorbent dose (0.3–3.6 g/L), solution pH (2–12), initial dye concentrations (25–350 mg/L), contact time (0–240 min) using batch mode operation. The impregnation ratio is 1:2 (MK:KOH), microwave power of 600 W, and radiation time of 15 min resulted in MKAC with a monolayer adsorption capacity of 200 mg/g for MB at 30°C and carbon yield of 63.6%. The kinetic profiles were described by the pseudo-second-order kinetics. Thermodynamic functions indicate a spontaneous and endothermic nature of the adsorption. This study introduces MK as a promising renewable precursor for developing a large surface area activated carbon. © 2018 Desalination Publications. All rights reserved.