Correlations between pore textures of activated carbons and Langmuir constants – case studies on methylene blue and congo red adsorption

Abstract

The discharge of dye-containing wastewater has caused severe problems as dye is harmful and toxic to living things. Activated carbon adsorption is an efficient removal strategy to treat dye wastewater. The removal of dye has continuously improved by various activated carbons derived from organic sources rich in carbon content. This paper aims to highlight the correlations between textural characteristics and Langmuir constants for the commonly used textile dyes. Zinc chloride-activated mangosteen peels with a 1622 m²/g specific surface displays an outstanding methylene blue capacity at 1166 mg/g, while sodium hydroxide-activated popcorn with a 3291 m²/g specific surface renders a 2120 mg/g of congo red capacity. A well-developed surface area with mesopore-rich content often prompts a favorable affinity for high capacity, although surface chemistry also plays a considerable role in adsorption. Although the commentary is not exhaustive, it sheds some insight into the relationships of removal performance for future applications of activated carbon in dye wastewater treatment.

Keywords:

• Activated carbon
• adsorption
• affinity
• correlation
• methylene blue
• congo red

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was fully supported by the Ministry of Education Malaysia through Fundamental Research Grant Scheme [FRGS No. 4F995].