Controllable synthesis of FeMn bimetallic ferrocene-based metal–organic frameworks to boost the catalytic efficiency for removal of organic pollutants

Abstract

A series of FeMn bimetallic ferrocene-based metal-organic frameworks (FeMn-Fc-MOFs) with various molar ratios of Fe and Mn (1:9, 2:8, 4:6, 6:4) were successfully synthesized using a simple hydrothermal synthesis method and employed as an e cient activator on persulfate (PS) activation for water decontamination. Characterizations demonstrated that Fe and Mn were smoothly introduced into ferrocene-based MOFs and various molar ratios of Fe:Mn had some in uence on crystallinity and surface structure of FeMn-Fc-MOFs. Within 120 min, Fe 4 Mn 6 -Fc-MOFs demonstrated the best catalytic activity among the different molar ratios, and acid orange 7(AO7) degradation rate was up to 92.0%. In addition, electrochemical experiments revealed that Fe 4 Mn 6 -Fc-MOFs possessed superior electron transfer capability than other FeMn-Fc-MOFs, leading to better catalytic performance. Moreover, quenching tests and electron paramagnetic resonance (EPR) detection indicated that hydroxyl radicals and sulfate radicals were both responsible for AO7 decomposition. Notably, the redox cycle of Fe(II)/Fe(III) and Mn(II)/Mn(IV) was discovered in the Fe 4 Mn 6 -Fc-MOFs/PS system, which was considered as the limiting process for the cleavage of the O-O bond in PS to generate active radicals. Ultimately, the Fe 4 Mn 6 -Fc-MOFs exhibits an excellent universality and good cycling stability for 5 continuous runs. This paper broadens the application of ferrocene-based MOFs on heterogeneous PS activation in environmental catalysis. HighlightsFeMn-Fc-MOFs catalysts with various molar ratios were synthesized by hydrothermal method.The Fe 4 Mn 6 -Fc-MOFs exhibited the best catalytic performance due to it's excellent electrochemical properties. SO 4•− and • OH were the main radicals in catalytic degradation of acid orange 7.The synergistic effect of Fe and Mn accelerates the redox reaction.

The use of bimetallic metal–organic frameworks as restoration materials for pollutants removal from water environment

“…Compared with the corresponding monometallic MOFs, the adsorption capacity of FeNi 1/60 -BDC for MB and MO was increased by a factor of 5.3 and 2.6, respectively, which was favourable for the subsequent degradation. Qu et al synthesized a series of MOFs with different Fe-Mn molar ratios (1 : 9, 2 : 8, 4 : 6 and 6 : 4) of FeMn-Fc-MOFs catalysts and selected Fe 4 Mn 6 -Fc-MOFs catalysts for the removal of Acid Orange 7 (AO7) in persulfate (PS) system [27]. Under optimal conditions, this material exhibited the removal of 92.0% for AO7 after 120 min.…”

“…Pollutants are particles that cause environmental damage by getting into the environment naturally or through humankind [52]. Many studies have shown that BMOFs as efficient reducing agents or catalysts can remove pollutants such as ions [35][36][37][38][53][54][55][56], dyes [20][21][22][23][24][25][26][27], PPCPs [28][29][30][31][32][33][34], phenolic compounds [57,58] and microorganisms [59]. Table 1…”

“…Pollutants are particles that cause environmental damage by getting into the environment naturally or through humankind [ 52 ]. Many studies have shown that BMOFs as efficient reducing agents or catalysts can remove pollutants such as ions [ 35 – 38 , 53 – 56 ], dyes [ 20 – 27 ], PPCPs [ 28 – 34 ], phenolic compounds [ 57 , 58 ] and microorganisms [ 59 ]. Table 1 summarizes the removal of different kinds of pollutants by some of the currently reported BMOFs.…”

“…BMOFs have been used to remove various organic pollutants (e.g. dyes) [20][21][22][23][24][25][26][27], pharmaceuticals or personal care products (PPCPs) [28][29][30][31][32][33][34] and inorganic pollutants (e.g. heavy metal ions) [17,[35][36][37][38][39] by adsorption or photocatalysis.…”

Tailored Porous Ferrocene-Based Metal–Organic Frameworks as High-Performance Proton Conductors

“…On the other hand, ferrocene has sparked widespread concern owing to its innovative double-sandwich structure and unique physical and chemical properties. − For instance, several compounds containing ferrocene groups demonstrate high REDOX characteristics due to the reversible REDOX process of ferrocene groups, − which can be exploited to modulate their photochemical properties and achieve REDOX switching effect. − In the field of crystal engineering, for a long time, people have been eager to introduce ferrocene groups into the MOFs to explore their applications in the fields of gas separation, adsorption, catalysis, medicine, − and so on. Nevertheless, proton conduction studies on ferrocene-based MOFs are rare in the literature.…”