Environmental application of MgMn-layered double oxide for simultaneous efficient removal of tetracycline and Cd pollution: Performance and mechanism

The MgMn-layered double oxide (MgMn-LDO), which was fabricated by calcining MgMn-layered double hydroxide (MgMn-LDH), was used to remove tetracycline (TC) and cadmium (Cd) pollution. In MgMn-LDO activated peroxymonosulfate (PMS) system, 97.1% of TC was degraded within 20 min. The high oxidizing site...

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Published in:Journal of environmental management Vol. 246; pp. 164 - 173
Main Authors: Chen, Meiqing, Wu, Pingxiao, Huang, Zhiyan, Liu, Junqin, Li, Yihao, Zhu, Nengwu, Dang, Zhi, Bi, Yinzhi
Format: Journal Article
Language:English
Published: England Elsevier Ltd 15-09-2019
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Summary:The MgMn-layered double oxide (MgMn-LDO), which was fabricated by calcining MgMn-layered double hydroxide (MgMn-LDH), was used to remove tetracycline (TC) and cadmium (Cd) pollution. In MgMn-LDO activated peroxymonosulfate (PMS) system, 97.1% of TC was degraded within 20 min. The high oxidizing sites exposed on MgMn-LDO surface played a main role on activating PMS to generate OH, SO4−, O2− and 1O2 (the key species) for TC degradation. MgMn-LDO could keep excellent degradation performance in a wide range of pH (from 4 to 10). The degradation degree of TC in distilled water is basically the same as that in Pearl River water, and even above 80% of TC could be degraded in human urine. The good reusability and high structure stability of MgMn-LDO were further verified. Meanwhile, Cd immobilization on MgMn-LDO reached equilibrium within 10 min, and its maximum fixed quantity was 8.234 mmol g−1 (922.208 mg g−1). The outstanding Cd fixed ability resulted from the formation of CdCO3 and Cd (OH)2. In combined system, the existence of TC promoted the immobilization of Cd on MgMn-LDO. Low concentration of Cd (0.0125 mM) had synergism effect on TC degradation, while high concentration of Cd (0.025 and 0.05 mM) had inhibiting action. Finally, a column filled with MgMn-LDO was designed for repairing TC and Cd pollution hierarchically. This study provided an effective strategy to clean up the organic-heavy metal combined pollution. [Display omitted] •Large BET with higher oxidizing sites of MgMn-LDO contributed to efficient TC degradation.•MgMn-LDO had a wide pH working, practical applicability and high stability.•The mechanism of excellent Cd immobilization attributed to form of CdCO3 and Cd (OH)2.•Low concentration of Cd had a synergism effect on TC degradation.•Layered repair by column filled with MgMn-LDO toke advantage of the synergism action.
ISSN:0301-4797
1095-8630
DOI:10.1016/j.jenvman.2019.06.002