Cationic surfactant-aided surface modification of the activated carbon-based materials for the enhancement of phenol adsorption-capacity determined by ultraviolet-visible spectroscopy

Abstract

The present investigation reports the phenol adsorption contemporaneity of a cationic surfactant CTAB (N-cetyl-N,N,N-trimethyl ammonium bromide)-modified activated coal to identify a befitting absorbent material. The process parameters are optimized and enunciated based on adsolubilization by the modified activated coal. The phenol concentration, surfactant concentration, pH, and temperature were varied from 10 to 50 mg dm⁻³, 0.1 − 1.6 mM, 3 − 7, and 298 − 318 K, respectively. The cation-electron co-relativity between the CTAB and phenol, along with the hydrophobic synergy, is significant to the phenol adsolubilization. The degree of adsorption on the surfactant modified (by 0.8 mM solution) activated coal for phenol is augmented from 22.86 to 34.98 mg g⁻¹ (53.02%) at the pH value 3.0, and 50 mg dm⁻³ phenol solution at 298 K. The spontaneous adsorption process was endothermic, and with the increase of temperature from 298 K to 318 K, the adsorption capacity was increased from 34.98 mg g⁻¹ to 38.98 mg g⁻¹. With the increase of pH, the adsorption capacity was decreased from 34.88 to 17.72 mg g⁻¹. In comparison, it was increased from 8.06 to 34.88 mg g⁻¹ with the increment of phenol concentration from 10 to 50 mg dm⁻³. The adsorption process followed the pseudo-second-order kinetic model and the Freundlich and Dubinine-Radushkevich, isotherm models.

Graphical Abstract

Highlights

• Commercial coal particles were used to synthesize the activated carbons.

• The surfactant, CTAB was used to modify the surface of the activated coal.

• Phenol adsorption kinetics and isotherm were investigated for the surface-modified carbons.

• The adsorption capacity was enhanced from 22.86 to 34.98 mg g⁻¹ (53.02%) by surface-modification.

• Thermodynamic parameters for the adsorption process were estimated.

Keywords:

• Activated carbon
• surface modification
• CTAB
• kinetics
• isotherm

Acknowledgments

The authors are thankful to the Indian Institute of Technology Guwahati for the financial support to perform the study, and Mr. Purusarth Prasannam, Jadavpur University, for his help during the ACs preparation.

Conflict of interest

The authors declare that there is no conflict of interest.