Reduction and Immobilization of Potassium Permanganate on Iron Oxide Catalyst by Fluidized-Bed Crystallization Technology

Guang-Xia Li,Yao-Hui Huaug,Yu-Jen Shih,Teng-Chien Chen,Hui Zhang

doi:10.3390/app2010166

Guang-Xia Li, Yao-Hui Huaug + Show 3 more

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https://doi.org/10.3390/app2010166

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Abstract

A manganese immobilization technology in a fluidized-bed reactor (FBR) was developed by using a waste iron oxide (i.e., BT-3) as catalyst which is a by-product from the fluidized-bed Fenton reaction (FBR-Fenton). It was found that BT-3 could easily reduce potassium permanganate (KMnO4) to MnO2. Furthermore, MnO2 could accumulate on the surface of BT-3 catalyst to form a new Fe-Mn oxide. Laboratory experiments were carried out to investigate the KMnO4-reduction mechanism, including the effect of KMnO4 concentration, BT-3 dosage, and operational solution pH. The results showed that the pH solution was a significant factor in the reduction of KMnO4. At the optimum level, pHf 6, KMnO4 was virtually reduced in 10 min. A pseudo-first order reaction was employed to describe the reduction rate of KMnO4.

Highlights

Numerous researches have focused on adsorptive arsenic removal, in which iron oxide was considered to be an appropriate adsorbent due to its high affinity [1,2,3,4,5,6,7]
According to the diffraction files of the Joint Committee on Powder Diffraction Standards (JCPDS), the main diffraction peaks of BT-3 adsorbent at 2θ = 21.5°, 36.7°and 53.3° adsorbent was identified as the α-FeOOH phase
Contrary to the reduction of KMnO4 with homogeneous catalytic oxidation, as shown in Equation (3), this study aimed to investigate the reduction of KMnO4 with heterogeneous catalysis by iron oxide, which is seldom discussed in the literature

Summary

Introduction

Numerous researches have focused on adsorptive arsenic removal, in which iron oxide was considered to be an appropriate adsorbent due to its high affinity [1,2,3,4,5,6,7]. A novel binary oxide concept in which the Mn-O catalyzed the As(III) pre-oxidation to As(V) and the Fe-O functioned as adsorbent, was proposed [11,12]. Based on the perspective of Mn-Fe binary oxide for arsenic removal, this study applied a millimeter scale iron oxide (BT-3) as support and aims at the synthesis of manganese oxides on its surface through the redox of potassium permanganate + in a fluidized bed reactor (FBR). The FBR technology could immobilize potassium permanganate onto BT-3, which was a waste iron oxide from real fluidized bed-Fenton (FBR-Fenton) instruments and was mainly composed of poorly crystallized goethite [14]

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