Adsorptive removal of 2,4-dinitrophenol using active carbon: kinetic and equilibrium modeling at solid–liquid interface

Abstract

Adsorption is found to be a feasible technique for the removal of even trace amounts 2,4-dinitrophenol (2,4-DNP) from aqueous phase using active carbon from rubber wood. Prior to adsorption studies, surface and physical properties of active carbon were determined using X-RD, FT-IR, and particle size analyzer. Batch adsorption experiments were carried out to optimize various conditions, such as solution pH, contact time, initial solute concentration, and adsorbent dose, for the effective removal of 2,4-DNP from aqueous phase. The favorable pH range for the adsorption process was found to be 2.0–5.0. The maximum adsorption of 99.9% (24.98 mg/g), 98.2% (49.10 mg/g) and 96.9% (96.89 mg/g) of 2,4-DNP onto active carbon was observed at pH 4.0 for different initial concentrations of 50, 100, and 200 mg/L, respectively. Kinetics and isotherm studies showed that the adsorptive removal process follows pseudo-second-order kinetics and Langmuir isotherm, respectively.

Keywords:

• Adsorption
• Active carbon
• Wastewater treatment
• Kinetic parameters
• Phenol

Acknowledgments

The authors are thankful to the Director of NCESS, Dr N.P. Kurian for providing the laboratory and knowledge resource facilities. We also thank the national program COMAPS (Coastal Ocean Monitoring and Prediction System) funded by MoES (Ministry of Earth Sciences), Government of India for extending their working facilities. The work was initiated as part of the PG Studentship Program of NCESS and is greatly acknowledged. The facilities provided by the X-ray Diffraction Laboratory and Particle Size Analyser Lab of NCESS are also greatly acknowledged. The authors also thank the Department of Chemistry, University College, Palayam, Trivandrum for providing the FT-IR spectra.