Work

Insight into the adsorption mechanism of cationic dye onto biosorbents derived from agricultural wastes

Year: 2017

Type: article

Abstract: This study investigated the phenomenon and mechanism of adsorption of methylene green 5 (MG5) on three pristine biosorbents: golden shower pod (GS), coconut shell (CC), and orange peel (OP). The results showed that the biosorbents possessed low specific surface areas, but abundant functional groups. Adsorption was strongly affected by the solution’s pH and ionic strength. As revealed in the kinetic study, equilibrium was rapidly established, requiring low activation energies; a removal rate of 30%–87% was achieved within 1 min. The maximum Langmuir adsorption capacities at 30°C exhibited the following order: GS (106 mg/g) > OP (92 mg/g) > CC (59 mg/g). Thermodynamic experiments suggested that the adsorption occurred spontaneously (−ΔG°) and exothermically (−ΔH°). The primary adsorption mechanisms involved electrostatic attraction, hydrogen bonding formations, and n-π interaction. Thermogravimetric analysis (TGA) revealed that three biopolymer components (i.e., hemicellulose, cellulose, and lignin) played controlling roles in the adsorption process. Thus, these three agricultural residues can be considered potential low-cost adsorbents for efficient dye adsorption applications.

Source: Chemical Engineering Communications

DOI: 10.1080/00986445.2017.1336090

Authors: Hai Nguyen Tran, Sheng-Jie You, Tien Vinh Nguyen, Huan-Ping Chao

Institutions: Chung Yuan Christian University, University of Technology Sydney

Language: English

Topic: Adsorption and biosorption for pollutant removal

Subfield: Water Science and Technology

Field: Environmental Science

Domain: Physical Sciences

SDGs: Responsible consumption and production, Clean water and sanitation

Open Access status: green

Funder: Chung Yuan Christian University