Coconut power: a sustainable approach for the removal of Cr6+ ions using a new coconut-based polyurethane foam/activated carbon composite in a fixed-bed column

Tomas Ralph B Tomon; Renz John R Estrada; Rubie Mae D Fernandez; Rey Y Capangpangan; Alona A Lubguban; Gerard G Dumancas; Arnold C Alguno; Roberto M Malaluan; Hernando P Bacosa; Arnold A Lubguban

doi:10.1039/d3ra02266h

Coconut power: a sustainable approach for the removal of Cr⁶⁺ ions using a new coconut-based polyurethane foam/activated carbon composite in a fixed-bed column

RSC Adv. 2023 Jul 12;13(30):20941-20950. doi: 10.1039/d3ra02266h. eCollection 2023 Jul 7.

Authors

Tomas Ralph B Tomon^{1

2}, Renz John R Estrada¹, Rubie Mae D Fernandez^{1

2}, Rey Y Capangpangan³, Alona A Lubguban⁴, Gerard G Dumancas⁵, Arnold C Alguno^{1

6}, Roberto M Malaluan^{1

7}, Hernando P Bacosa^{1

2}, Arnold A Lubguban^{1

7}

Affiliations

¹ Center for Sustainable Polymers, Mindanao State University - Iligan Institute of Technology 9200 Iligan City Philippines arnold.lubguban@g.msuiit.edu.ph.
² Graduate Program of Environmental Science, Department of Biological Sciences, Mindanao State University - Iligan Institute of Technology 9200 Iligan City Philippines.
³ Department of Physical Sciences and Mathematics, Mindanao State University at Naawan 9023 Naawan Philippines.
⁴ Department of Mathematics, Statistics, and Computer Studies, University of the Philippines, Rural High School Paciano Rizal Bay, 4033 Laguna Philippines.
⁵ Department of Chemistry, The University of Scranton Scranton PA 18510 USA.
⁶ Department of Physics, Mindanao State University - Iligan Institute of Technology 9200 Iligan City Philippines.
⁷ Department of Chemical Engineering and Technology, Mindanao State University - Iligan Institute of Technology 9200 Iligan City Philippines.

Abstract

To attain efficient removal of hexavalent chromium (Cr⁶⁺) from aqueous solutions, a novel polyurethane foam-activated carbon (PUAC) adsorbent composite was developed. The composite material was synthesized by the binding of coconut shell-based activated carbon (AC) onto a coconut oil-based polyurethane matrix. To thoroughly characterize the physicochemical properties of the newly developed material, various analytical techniques including FTIR spectroscopy, SEM, XRD, BET, and TGA analyses were conducted. The removal efficiency of the PUAC composite in removing Cr⁶⁺ ions from aqueous solutions was evaluated through column experiments with the highest adsorption capacity of 28.41 mg g^-1 while taking into account variables such as bed height, flow rate, initial Cr⁶⁺ ion concentration, and pH. Experimental data were fitted using Thomas, Yoon-Nelson, and Adams-Bohart models to predict the column profiles and the results demonstrate high breakthrough and exhaustion time dependence on these variables. Among the obtained R² values of the models, a better fit was observed using the Thomas and Yoon-Nelson models, indicating their ability to effectively predict the adsorption of Cr⁶⁺ ions in a fixed bed column. Significantly, the exhausted adsorbent can be conveniently regenerated without any noteworthy loss of adsorption capability. Based on these findings, it can be concluded that this new PUAC composite material holds significant promise as a potent sorbent for wastewater treatment backed by its excellent performance, cost-effectiveness, biodegradability, and outstanding reusability.