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169 results on '"Ren, Hejun"'

40. The impact of Pseudomonas monteilii PN1 on enhancing the alfalfa phytoextraction and responses of rhizosphere soil bacterial communities in cadmium-contaminated soil

Author

Yang Ru, Jianjun Hao, Hongyu Wang, Wang Yan, Ren Hejun, and Mengqi Sun

Subjects
Rhizosphere, Cadmium, biology, Inoculation, Pseudomonas monteilii, Chemistry, Process Chemistry and Technology, fungi, food and beverages, chemistry.chemical_element, biology.organism_classification, Pollution, Soil contamination, Phytoremediation, Horticulture, Catalase, biology.protein, Chemical Engineering (miscellaneous), Waste Management and Disposal, Bacteria
Abstract

Cadmium (Cd) is a hazardous contaminant when dispersed into soil. It is toxic to plants and further decreases the efficiency of phytoremediation. To improve plant tolerance to Cd, applying plant-associated bacteria is an effective way. This work aimed to determine the effect of a plant growth promoting bacterium Pseudomonas monteilii strain PN1 on alfalfa (Medicago sativa L.) growth, Cd phytoextraction, and bacterial communities in rhizosphere. A pot trail was performed with alfalfa planted in soil containing Cd at various concentrations and drenched with PN1 suspension. Plants and soil were sampled for biochemical and microbial analyses. Results showed that alfalfa growth was negatively correlated with Cd concentration. However, PN1 inoculation enhanced the growth of alfalfa, and augmented the capacity of Cd phytoextraction. Phytohormone (indole-3-acetic acid) production and antioxidant enzymatic activities (guaiacol peroxidase, superoxide dismutase, and catalase), and 1-aminocyclopropane-1-carboxylic acid deaminase activities of alfalfa were enhanced, which indicated PN1 might mitigate Cd stress. There was a negative impact of Cd on the rhizosphere bacterial communities. However, PN1 can restore the bacterial community in Cd contaminated soil to a certain level. Relative abundance of beneficial bacteria in soil increased and their interactions were strengthened in the presence of PN1 under Cd stress, which was indicated by increased alfalfa growth. All the activities on alfalfa and bacteria in soil facilitated the adaptability of plant-bacteria systems to Cd stress. Thus, the association of alfalfa with PN1 can be a potential biological system for in-situ remediating Cd-contaminated soil.

Published
2021

44. Magnetic mesoporous FeCo2O4–Fe3O4 microrods as novel peroxymonosulfate activators for effective metronidazole degradation.

Author

Ren, Hejun, Li, Chenguang, Han, Zhonghui, Li, Tingting, Jin, Xiong, and Zhou, Rui

Subjects
ORGANIC water pollutants, CHLOROPHENOLS, HETEROGENEOUS catalysis, HYDROXYL group, CHEMICAL industry, ORGANIC compounds, ANTIBIOTIC residues
Abstract

BACKGROUND Metronidazole (MNZ) is a highly typical representative antibiotic widely occurring in wastewaters. Its release poses potential threats to the environment and human health. Advanced oxidation processes based on heterogeneous catalysis are promising technologies for organic matter removal. In this study, a new type of magnetic mesoporous FeCo2O4–Fe3O4 microrods was prepared and evaluated as catalyst to activate peroxymonosulfate (PMS) for metronidazole (MNZ) degradation. RESULTS: The effects of catalyst dosage, PMS concentration, and pH on MNZ degradation were investigated. A 96.8% removal of MNZ (100 mg L−1) was attained in the FeCo2O4–Fe3O4/PMS under the optimum conditions of 4 mM PMS, 0.4 g L−1 FeCo2O4–Fe3O4 loading, pH 7 and 60 min reaction time. The hydroxyl radicals (•OH) and sulfate radicals (SO4•−) were identified as the primary reactive species attributed to MNZ removal. The plausible mechanism of the catalytic degradation was proposed and assumed to be related to the Co/Fe species that exerted the synergistic effect during reactions. FeCo2O4–Fe3O4 showed excellent reusability and stability, which was testified by the successive degradation experiments. More importantly, FeCo2O4–Fe3O4 exhibited general applicability in eliminating various antibiotics, including ciprofloxacin, 2,4‐dichlorophenol, ofloxacin, and tetracycline. The efficiencies of which were 78.8%, 77.1%, 81.3%, and 60.7%, respectively, under identical reaction conditions as MNZ. CONCLUSION: This study proved that mesoporous FeCo2O4–Fe3O4 microrods are efficient PMS activators and provided a novel strategy for developing FeCo2O4–based catalysts for the removal of organic pollutants from water. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Published
2020
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50. Enhanced 2,4-DCP removal by electro-Fenton process using PEDOT modified graphite felt cathode: Promoting H2O2generation and Fe3+/Fe2+cycle

Author

Liu, Fangyuan, Ren, Hejun, and Lin, Yingzi

Abstract

To simultaneously promote the generation of H2O2and the cycling of Fe3+/Fe2+, and improve the electrical Fenton performance, we propose a strategy of preparing PEDOT/GF cathode for efficient generation of H2O2and reduction of Fe3+in electro-Fenton (EF) process without additional reducing agent. The accumulated concentration of H2O2on the PEDOT/GF-100 cathode reached 67.2mgL–1in 1h, with a current efficiency of 70.6%, which is much higher than that of the raw GF. Moreover, the H2O2concentration by PEDOT/GF-100 could reach 49.3-67.2mgL-1in a wide pH range (3–9). With 2,4-DCP as main target pollutant, the EF process of PEDOT/GF-100 cathode accelerated the degradation of 2,4-DCP. In addition to the improvement of H2O2production, the reduction rate of Fe3+in the EF process of PEDOT/GF-100 cathode system was also increased compared to the raw GF, while the total iron remained stable. The quenching experiment confirmed the dominant role of • OH in the degradation of 2,4-DCP. The PEDOT/GF-100 cathode can synergistically promote the electrosynthesis of H2O2and iron interconversion, thereby accelerating the production of •OH. The utilization of PEDOT/GF cathode can simultaneously solve the problems of low Fe3+/Fe2+cycling efficiency and low H2O2production in the EF process, promoting its application in practical wastewater treatment.

Published
2024
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