Optimization and mechanistic approach for removal of crystal violet and methylene blue dyes via activated carbon from pyrolyzed-ZnCl2 bamboo waste

• Published in: International Journal of Phytoremediation
• Main Author: Hapiz A.; Jawad A.H.; Wilson L.D.; ALOthman Z.A.; Abdulhameed A.S.; Algburi S.
• Format: Article
• Language: English
• Published: Taylor and Francis Ltd. 2024
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85172384071&doi=10.1080%2f15226514.2023.2256412&partnerID=40&md5=d84fa3629813595fc56c618a4432f021

In this study, bamboo waste (BW) was subjected to pyrolysis-assisted ZnCl2 activation to produce mesoporous activated carbon (BW-AC), which was then evaluated for its ability to remove cationic dyes, specifically methylene blue (MB) and crystal violet (CV), from aqueous environments. The properties of BW-AC were characterized using various techniques, including potentiometric-based point of zero charge (pHpzc), scanning electron microscopy with energy dispersive X-rays (SEM-EDX), X-ray diffraction (XRD), gas adsorption with Brunauer–Emmett–Teller (BET) analysis, infrared (IR) spectroscopy. To optimize the adsorption characteristics (BW-AC dosage, pH, and contact time) of PBW, a Box-Behnken design (BBD) was employed. The BW-AC dose of 0.05 g, solution pH of 10, and time of 8 min are identified as optimal operational conditions for achieving maximum CV (89.8%) and MB (96.3%) adsorption according to the BBD model. The dye removal kinetics for CV and MB are described by the pseudo-second-order model. The dye adsorption isotherms revealed that adsorption of CV and MB onto BW-AC follow the Freundlich model. The maximum dye adsorption capacities (qmax) of BW-AC for CV (530 mg/g) and MB (520 mg/g) are favorable, along with the thermodynamics of the adsorption process, which is characterized as endothermic and spontaneous. The adsorption mechanism of CV and MB dyes by BW-AC was attributed to multiple contributions: hydrogen bonding, electrostatic forces, π-π attraction, and pore filling. The findings of this study highlight the potential of BW-AC as an effective adsorbent in wastewater treatment applications, contributing to the overall goal of mitigating the environmental impact of cationic dyes and ensuring the quality of water resources. © 2023 Taylor & Francis Group, LLC.