Adsorption of Hexavalent Chromium and Divalent Lead Ions on the Nitrogen-Enriched Chitosan-Based Activated Carbon.

Fatma Hussain Emamy,Jerzy P Lukaszewicz,Ali Bumajdad

doi:10.3390/nano11081907

Fatma Hussain Emamy, Jerzy P Lukaszewicz + Show 1 more

Open Access

https://doi.org/10.3390/nano11081907

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Journal: Nanomaterials	Publication Date: Jul 24, 2021
Citations: 15	License type: CC BY 4.0

Affiliation: Kuwait University, Nicolaus Copernicus University

Abstract

Optimizing the physicochemical properties of the chitosan-based activated carbon (Ch-ACs) can greatly enhance its performance toward heavy metal removal from contaminated water. Herein, Ch was converted into a high surface area (1556 m2/g) and porous (0.69 cm3/g) ACs with large content of nitrogen (~16 wt%) using K2CO3 activator and urea as nitrogen-enrichment agents. The prepared Ch-ACs were tested for the removal of Cr(VI) and Pb(II) at different pH, initial metal ions concentration, time, activated carbon dosage, and temperature. For Cr(VI), the best removal was at pH = 2, while for Pb(II) the best pH for its removal was in the range of 4–6. At 25 °C, the Temkin model gives the best fit for the adsorption of Cr(VI), while the Langmuir model was found to be better for Pb(II) ions. The kinetics of adsorption of both heavy metal ions were found to be well-fitted by a pseudo-second-order model. The findings show that the efficiency and the green properties (availability, recyclability, and cost effectiveness) of the developed adsorbent made it a good candidate for wastewaters treatment. As preliminary work, the prepared sorbent was also tested regarding the removal of heavy metals and other contaminations from real wastewater and the obtained results were found to be promising.

Highlights

Activated carbon (AC) is a universally used adsorbent for different applications, including industrial wastewater treatment
The pore structure, surface area and porosity of the studied chitosan-based activated carbons (Ch-ACs) were characterized by N2 sorptiometry
AC prepared by pre- and post-treatment methods

Summary

Introduction

Activated carbon (AC) is a universally used adsorbent for different applications, including industrial wastewater treatment. Such applications of AC are related to its high porosity (large surface area) with a broad range of pore size, thermal stability, flexibility, presence of several functional group at its surface, and its uncomplicated way of operation toward toxic pollutants. The two main steps in the preparation of AC are carbonization and activation. Another step which can help is N enrichment ( called N-doping in the literature) to modify the surface composition of the AC. Using a different source of nitrogen for surface modification will provide the ACs with additional physiochemical properties, which is beneficial in many applications [7]

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