Fe-TiO2/AC and Co-TiO2/AC Composites: Novel Photocatalysts Prepared from Waste Streams for the Efficient Removal and Photocatalytic Degradation of Cibacron Yellow F-4G Dye

Roberto Machado Garcia,Maria Arada Pérez,Robert Carleer,Ying Gu,Jan Yperman,Pieter Samyn,Jeamichel Puente Torres

doi:10.3390/catal11101137

Roberto Machado Garcia, Maria Arada Pérez + Show 5 more

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https://doi.org/10.3390/catal11101137

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Abstract

Fe-TiO2/AC and Co-TiO2/AC composites were prepared from activated carbon (AC) derived from residues of peanut hulls and TiO2 photocatalyst, electrochemically prepared from titanium scrap, and doped with Fe and Co, respectively. The adsorption capacity and photocatalytic activity of the Fe-TiO2/AC and Co-TiO2/AC composites were studied for removing and degrading Cibacron Yellow F-4G (CYF-4G) from wastewater. Doped ACs were characterized by thermogravimetry (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD), a new X-ray absorption technique (XRA), and elemental analysis (EA). Interesting relationships were found between SEM, XRA, and TGA data and the doped amount of catalyst on ACs. Optimal dye adsorption was found at a pH of 2.0. The CYF-4G adsorption kinetics are followed according to the pseudo-second order model. The experimental data revealed that the Langmuir model fits better than the Freundlich and Temkin models. A decrease in adsorption capacity was observed when the catalyst dope percentage increased. A removal and degradation efficiency of the dye close to 100% was achieved around 120 min. A synergistic adsorption and photocatalytic degradation effect of the Fe-TiO2/AC and Co-TiO2/AC composites could be observed when adsorption experiments were conducted under simulated visible radiation.

Highlights

There is an increasing awareness of wastewater pollution caused by growing industrialization in recent years
Industrial wastewater discharged mainly from the paper and textile industries contains a complex mixture of various organic compounds, heavy metals, and azo-dyes that are hard to remove in natural environments due to their high solubility, stability, and low bio-degradability in aqueous media [1,2]
Is associated with the initial evaporation of free moisture. Another minor weight loss at temperatures between 400 and 550 ◦ C is mainly due to the volatile compounds left in the carbonaceous material and a limited degradation amount

Summary

Introduction

There is an increasing awareness of wastewater pollution caused by growing industrialization in recent years. Certain dyes and their decomposition intermediates can be considered as possible contaminants because the azo group (N=N) is converted into aromatic amines that can be carcinogenic for humans [3]. If these wastes are discharged directly to the receiving sources (for example, rivers and creeks) without prior treatment, this could cause serious environmental problems and directly affect human health and aquatic ecological systems [3]. A strong interest has emerged in the application of advanced and more efficient procedures for wastewater remediation, driven by the disadvantages of conventional technologies (i.e., reverse osmosis, ion exchange resins, and adsorption) for the treatment of difficult to remove toxic substances [2,6,7,8]

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