Experimental Investigation on the Removal of p-Toluic Acid from Aqueous Solution using Functionalized Polymeric Sorbent

Abstract

Polystyrene-divinylbenzene copolymer (PsDVB) was covalently functionalized with monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA) by a simple method. The functionalized sorbents were characterized in terms of functionality and morphology, and used for the removal of p-toluic acid (p-TA) from aqueous solution. It was found that DEA-PsDVB has higher adsorption capacity than MEA- and TEA-PsDVB due to more accessible nitro and hydroxyl groups on its surface. Further investigation on the adsorptive properties of DEA-PsDVB indicated that the maximum uptake of p-TA occurred at the optimum pH of 5.3. The kinetics data was successfully represented by the pseudo-first-order model, and the behavior of the adsorption isotherms followed the Freundlich model well. Thermodynamic studies showed that the adsorption of p-TA onto DEA-PsDVB was an endothermic and spontaneous process along with the positive change in entropy. The regeneration of DEA-PsDVB was performed with 0.1 M NaOH solution, and results showed that 99% of the initial capacity was conserved after eight successive adsorption/regeneration cycles.

Keywords:

• Adsorption
• Ion exchange
• Kinetics
• Polymers
• Thermodynamics
• Wastewater treatment

Supplemental Material

Supplemental data for this article can be accessed on the publisher's website at http://dx.doi.org/10.1080/00986445.2016.1154850.

Acknowledgment

The authors wish to express their deepest gratitude to Mr. Mostafa Sepahsalari for his support and encouragement.

Additional information

Funding

This work benefited from the financial support of Khorasan Razavi Regional Water Organization (KOE-92006).