Adsorption of hexavalent chromium by polyacrylonitrile-based porous carbon from aqueous solution.

Bin Feng,Wenzhong Shen,Liyi Shi,Shijie Qu

doi:10.1098/rsos.171662

Bin Feng, Wenzhong Shen + Show 2 more

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https://doi.org/10.1098/rsos.171662

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Abstract

Owing to the unique microporous structure and high specific surface area, porous carbon could act as a good carrier for functional materials. In this paper, polyacrylonitrile (PAN)-based porous carbon materials (PPC-0.6-600, PPC-0.8-600, PPC-0.6-800 and PPC-0.8-800) were prepared by heating KOH at 600°C and 800oC for the removal of Cr(VI) from aqueous solution. The adsorbent was characterized by the techniques of Fourier transform infrared spectroscopy (FT-IR), elementary analysis, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and N2 adsorption techniques. The results showed that the adsorption capacity increased with decreasing pH value of the initial solution. The adsorption capacity of Cr(VI) on PPC-0.8-800 was much greater than that on other materials, and maximum adsorption capacity were calculated to be 374.90 mg g−1. Moreover, PPC-0.8-800 had superior recyclability for the removal of Cr(VI) from wastewater, about 82% of its initial adsorption capacity was retained even after five cycles. The result of kinetic simulation showed that the adsorption of Cr(VI) on the PAN-based porous carbon could be described by pseudo-second-order kinetics. The adsorption process was the ionic interaction between protonated amine groups of PPC and HCrO4- ions.

Highlights

In recent years, pollution of surface and underground water resources with toxic Cr(VI) has become a major environmental problem attracting much more attention to develop and2018 The Authors
The nitrogen content decreases with the increase of carbonization temperature or ratio of KOH to PAN-based porous carbon (PPC), and PPC-0.6-600 had the highest nitrogen content
It can be seen that PPC-0.6-800 maintains a certain fibrous morphology, which is similar to PAN fibres

Summary

Introduction

Pollution of surface and underground water resources with toxic Cr(VI) has become a major environmental problem attracting much more attention to develop and2018 The Authors. Various conventional treatment methods such as membrane separation [6], electrocoagulation [7], ion-exchange [8], chemical precipitation [9], activated sludge [10] and adsorption/filtration [11,12] have been used to remove Cr(VI). Among these methods, adsorption has the advantage of low-cost, easy operation and high efficiency. These materials have all kinds of disadvantages such as high cost, low mechanical efficiency and poor removal efficiency, which limit their application

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