Adsorption effectiveness and properties of an enriched activated carbon from residual biomass materials for non-polar benzene in gaseous environment

Abstract

During the last century, benzene (C6H6) has been a highly studied substance, with some acute and chronic exposures leading directly to hematologic effects detected in humans. This work reports on preparing and examining biomass-derived activated carbons (HPACs) featuring high benzene adsorptive capacity. The fundamental goal of this paper is to propose a green approach for generating HPACs from Heracleum platytaenium Boiss. (Cow parsnip) as woody biomass using a low-cost approach. The characterization showed that chemical activation elicits more enhanced mesoporous structure, a higher degree of graphitization, and bulk porous structure with higher specific surface area and pore volume. To minimize the use of chemicals in the manufacture of high-performance HPACs, an essential pre-pyrolysis step was implemented prior to the chemical activation of biomass by NaOH. The samples were carbonized at different temperatures (500-900 degrees C) and named as HPAC500, HPAC600, HPAC700, HPAC800, and HPAC900. Considering micropore volume and total surface area, HPAC600 was superior, and maximum benzene adsorption capacities were: HPAC600 (127 mg/g) > HPAC700 (117 mg/g) > HPAC800 (101 mg/g) > HPAC500 (80 mg/g) > HPAC900 (59 mg/g) at selected conditions. Freundlich, Langmuir, and pseudo-first-order (PFO) and pseudo-second-order (PSO) models were used to mathematically describe HPAC600-vapor benzene sorption on HPAC600. The kinetic findings fitted PFO with optimal values of R-2 = 0.999, and the isotherm model adsorption fitted Freundlich model (R-2 = 1.000). The finding revealed that H. platytaenium is a useful material for producing adsorbents, and successful testing outcomes demonstrate that H. platytaenium products serve as a suitable benzene absorbent.