This study investigated methyl orange (MO) dye adsorption using three biochars produced from agro-waste and invasive plants; the latter consisted of wattle bark (BA), mimosa (BM), and coffee husks (BC). BC had the lowest specific surface area (2.62 m2/g) compared to BA (393.15 m2/g) and BM (285.53 m2/g). The adsorption efficiency of MO was stable at pH 2–7 (95%–96%), whilst it had reduced stability at pH 7–12. Between 0 and 30 min, MO adsorption efficiency was >82%, and at 120 min, representative adsorption equilibrium had occurred. The maximum adsorption capacity of the biochars was 12.3 mg/g. The underlying adsorption mechanisms of the three biochars were governed by electrostatic adsorption and pore diffusion. There was an abundance of active sites for adsorption in BA and BM, while chemical adsorption appeared to be more vital for BC, as it contained more functional groups on its surface. The highest MO adsorption efficiency occurred with BM. BC was not recommended for MO removal, as it was observed to stain the water when a dose exceeding 5.0 g/L was utilized.
|Publication status||Published - 2021 Nov|
Bibliographical noteFunding Information:
This research was funded in part by the Vietnam National Foundation for Science and Technology Development (NAFOSTED) under grant number 105.99–2019.25 and the National Research Foundation (NRF) of Korea (Grant No. 2020R1A2C1101849 ).
© 2021 Elsevier Ltd
All Science Journal Classification (ASJC) codes
- Environmental Engineering
- Environmental Chemistry
- Public Health, Environmental and Occupational Health
- Health, Toxicology and Mutagenesis