Abstract The discharging of Rhodamine B (RhB) from wastewater has caused huge environment pollution. Peroxymonosulfate (PMS) oxidation is an effective way to remove it from wastewater. However, finding an environmentally… Click to show full abstract
Abstract The discharging of Rhodamine B (RhB) from wastewater has caused huge environment pollution. Peroxymonosulfate (PMS) oxidation is an effective way to remove it from wastewater. However, finding an environmentally friendly metal to activate PMS is a key step for the oxidation process. In this study, nanorod α-MnO2 loaded palygorskite (α-MnO2/Pal) was fabricated by a simple hydrothermal method. The analysis of field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) confirmed the loading of α-MnO2 on the surface of Pal and characterized the surface of the composite. The surface area of α-MnO2/Pal composite was 159.13 m2/g, which was much higher than that of Pal and α-MnO2. The Pal, α-MnO2, Mn2+, and α-MnO2/Pal were used to activate PMS for RhB degradation. Nearly 100% RhB degradation was obtained in α-MnO2/Pal + PMS system in 180 min and in α-MnO2 + PMS system in 300 min, while only 50% degradation was obtained in Pal + PMS system and 71.4% degradation in Mn2+ + PMS system in 300 min. The degradation fitted the pseudo-first-order reaction kinetics well with rate constant of 0.02041 min−1 for α-MnO2/Pal + PMS system, 0.01192 min−1 for α-MnO2 + PMS system, and 0.00435 min−1 for Mn2+ + PMS system, respectively. The factors affecting RhB degradation were further investigated. The RhB degradation efficiency increased with the increase of α-MnO2/Pal dosages, PMS dosages and temperatures. The degradation was inhibited at pH > 5.5, while was favorable at pH − and 1O2. The possible mechanism was further proposed based on the results. The α-MnO2/Pal composite showed nearly 50% mineralization ratio in the presence of PMS and an excellent reusability. The results from this study revealed that α-MnO2/Pal composite is an effective catalyst to activate PMS for RhB degradation.
               
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