Cobalt‐doped biogenic manganese oxides for enhanced tetracycline degradation by activation of peroxymonosulfate

Abstract

BACKGROUND: Tetracycline (TC) residues in water and soil have received wide attention due to their adverse effects on human health and ecosystem. Layer-structured biogenic manganese oxides (BMOs) could be obtained from fungi Pleosporales sp. Y-5 culture. Cobalt doping into BMOs (Co-BMOs) was conducted by a facile impregnation-calcination method to eliminate TC residues through activation of peroxymonosulfate (PMS). RESULTS: TheTC in aqueous solution could be nearly completely removed in about 10 minutes under the optimal condition ([TC] = 50 mg L −1 , [catalyst] = 0.2 g L −1 , [PMS] = 0.4 g L −1 , 25 ∘ C). The electron paramagnetic resonance (EPR) identified the coexistence of SO 4 − • and OH• during PMS activation. The Co-BMOs catalyst remained great catalytic activity after five runs. Possible mechanism of PMS activation and TC degradation pathway were proposed. Preliminary biological toxicity test using green algae Chlorella vulgaris (FACHB-8) as ecological indicator confirmed that TC degradation solution was less toxic than the original solution. CONCLUSION: This study demonstrated high catalytic activity and stability of Co-BMOs for degradation of TC by PMS activation. The Co-BMOs/PMS system is helpful in new efforts for TC degradation without generation of more toxic intermediates. Industry 0.4 g L −1 PMS followed by adjustment of pH to 7.0. Then the Chlorella vulgaris was treated with 50 mL fresh TC solution and degraded solution, respectively. Cultures were incubated on an orbital shaker (180 rpm, 30 ∘ C) for 120 hours. The concentration J Chem Technol Biotechnol 2019; 94: 752-760

Rational Design of a Coupled Confronting Z‐Scheme System Toward Photocatalytic Refractory Pollutant Degradation and Water Splitting Reaction

“…As shown in Figure a, the absorbance of TC in aqueous solution comprised of two major peaks at 275 and 357 nm. As time passes, gradual reduction in absorbance of peak 275 indicates the formation of acyl amino and hydroxyl groups . The 360 nm peak originates from rings B and D present in tetracycline and its disappearance is attributed to the fragmentation of phenolic group in ring B into CO 2 , H 2 O, and NH 4 + …”

Iron pyrophosphate doped carbon nanocomposite for tetracycline degradation by activation of peroxymonosulfate

“…The coexistence of multiple reactive species can take full advantage of the oxidative capacity of PMS, producing major intermediates with significantly lower biotoxicity. 59–61 This work involves both radical and non-radical pathways and the results of the quenching experiments confirm that the non-free radical pathway is more dominant. It is more effective for TC removal and less toxic for the intermediates produced during degradation.…”

Pd Nanoparticles Decorated on ZnO/Fe3O4 Cores and Doped with Mn2+ and Mn3+ for Catalytic C–C Coupling, Nitroaromatics Reduction, and the Oxidation of Alcohols and Hydrocarbons

“…However, the comparative analysis of high-resolution Mn 2p spectra of fresh and reused Mn 3+ -Pd@ l -dopa-ZnO/Fe 3 O 4 showed interesting results (Figure A). The Mn 2p region of the fresh catalyst [Figure A­(a)] was resolved into two peaks namely Mn 2p 3/2 and Mn 2p 1/2 at binding energies of 642.2 and 654.2 eV, respectively, which could be rationally assigned to an oxidation state of +3. − The peak observed at 655.8 eV corresponds to the Zn L 2 MM Auger peak . Mn 2p spectra of reused Mn 3+ -Pd@ l -dopa-ZnO/Fe 3 O 4 [Figure A­(b)] revealed the presence of two additional peaks at 640.9 and 652.8 eV, corresponding to 2p 3/2 and 2p 1/2 peaks of Mn 2+ , as compared to that of the fresh catalyst where no such peaks have been observed. − , Furthermore, the satellite peak at 645.8 eV is a characteristic feature of Mn 2+ ions. , This confirms the transformation of some of the Mn 3+ ions of Mn 3+ -Pd@ l -dopa-ZnO/Fe 3 O 4 into Mn 2+ ions during C–C coupling.…”

“…55 Mn 2p spectra of reused Mn 3+ -Pd@L-dopa-ZnO/Fe 3 O 4 [Figure 5A(b)] revealed the presence of two additional peaks at 640.9 and 652.8 eV, corresponding to 2p 3/2 and 2p 1/2 peaks of Mn 2+ , as compared to that of the fresh catalyst where no such peaks have been observed. [51][52][53][54]56 Furthermore, the satellite peak at 645.8 eV is a characteristic feature of Mn 2+ ions. 51,56 This confirms the transformation of some of the Mn 3+ ions of Mn 3+ -Pd@L-dopa-ZnO/Fe 3 O 4 into Mn 2+ ions during C−C coupling.…”