One-step synthesis of Mn-doped MIL-53(Fe) for synergistically enhanced generation of sulfate radicals towards tetracycline degradation
JOURNAL OF COLLOID AND INTERFACE SCIENCE
Authors: Yu, Jun; Cao, Jiao; Yang, Zhaohui; Xiong, Weiping; Xu, Zhengyong; Song, Peipei; Jia, Meiying; Sun, Saiwu; Zhang, Yanru; Zhu, Juan
Abstract
Herein, Mn-doped MIL-53(Fe) were fabricated via one-pot solvothermal method and used for peroxymonosulfate (PMS) activation towards tetracycline (TC) degradation from aqueous solution. The characterizations of SEM, FTIR and XRD were utilized to reveal the morphology and structure of the materials. The results showed that Mn-MIL-53(Fe)-0.3 displayed the optimal catalytic performance, the removal efficiency of TC could reach 93.2%. Moreover, the catalytic activity of Mn-MIL-53(Fe) towards TC under different initial pH values, co-existing anions (Cl, CO32- and SO42-) and humic acid (HA) were investigated. The results of thermodynamic experiment suggested that the catalytic process was endothermic. In addition, integrated with capture experiments results and the characterization results of electron paramagnetic resonance (EPR), which revealed that SO4- and HO- were the reactive radicals involving in the reaction. More importantly, the possible activation mechanism was discussed in detail based on the X-ray photoelectron spectroscopy results. The active species were generated by the active sites of Fe(II) and Mn (II) on Mn-MIL-53(Fe) effectively activated PMS. Furthermore, the degradation intermediates and possible degradation pathway were investigated by LC-MS. Finally, the catalyst also showed good performance in actual wastewater and demonstrated good recyclability. The Mn-MIL-53(Fe)/PMS system exhibited a promising application prospect for antibiotic-containing waste water treatment. (C) 2020 Elsevier Inc. All rights reserved.
Microbial Dynamics and Nutrient Mineralization in Soil Amended with Cacao Pod and Water Hyacinth Composts: Implication for Nitrogen Fixed by Soybean
COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS
Authors: Atere, Cornelius Talade; Osunde, Michael Omofowa; Olayinka, Akin
Abstract
Composting organic wastes can be relatively cheap and environmentally-friendly sources of mineralizable nutrients for legumes. We amended 5 kg topsoil (0-15 cm) samples of an Ultisol (Lixisol) with 0, 2.5 and 5 t ha(-1) each of cacao pod (CC) and water hyacinth (WC) composts with and without starter fertilizer (F) (25 kg N ha(-1) as urea and 26 kg P ha(-1) as single super phosphate). The amended soil samples were used for 16-week laboratory incubation experiment and two-consecutive 8-week plantings of soybean (Glycine max. L. Merril) in the screenhouse. Measurements were carried out on some indices of microbial activity, namely, microbial respiration, N and P mineralization as well as on nodulation and N-2 fixed by soybean. The microbial respiration, and N and P mineralization increased with application rates of the composts, but generally declined with incubation duration. Applications of 5 t ha(-1) each of CC and WC with or without F increased (p < .05) the microbial respiration (24-93%), N mineralized (21-35%), and P mineralized (32-180%) during the incubation period. The highest of these increments was, however, obtained with WC. Increases of 1162 and 981% (CC2F and WC2F) and 28% (CC2F) were also recorded in nodulation and the amount of N-2-fixed, respectively. It was concluded that 5 t ha(-1) water hyacinth or cacao pod composts with starter fertilizer is capable of enhancing soybean N-2 fixation by serving as mineralizable nutrient sources prior to the onset of nodulation and N-2 fixation.