Magnetic CoFe₂O₄ nanoparticles supported on graphene oxide (CoFe₂O₄/GO) with high catalytic activity for peroxymonosulfate activation and degradation of rhodamine B

Abstract

Herein, we report the preparation of magnetic CoFe 2 O 4 nanoparticles and CoFe 2 O 4 /graphene oxide (GO) hybrids and evaluate their catalytic activity as heterogeneous peroxymonosulfate (PMS) activators for the decomposition of rhodamine B. The surface morphologies and structures of both CoFe 2 O 4 nanoparticles and CoFe 2 O 4 /GO hybrids were investigated by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and nitrogen adsorption-desorption isotherms. The magnetic properties of the samples were assessed using a SQUID magnetometer at 298 K. Catalytic oxidation experiments demonstrated that CoFe 2 O 4 /GO hybrids exhibited much better catalytic activity than CoFe 2 O 4 nanoparticles or CoFe 2 O 4 /reduced graphene oxide (rGO) hybrids, suggesting that GO plays an important role in CoFe 2 O 4 /GO hybrids in the decomposition of rhodamine B. The influence of various reaction conditions such as temperature, concentration of PMS, pH and decomposition time of rhodamine B over the CoFe 2 O 4 /GO catalyst were investigated and optimized. The rhodamine B degradation process was found to fit a pseudo-first order kinetics model. The catalyst could be easily separated from the reaction mixture by applying an external magnet. In particular, the as-prepared CoFe 2 O 4 /GO hybrid exhibited good reusability and stability in successive degradation experiments in PMS solution.

A colorimetric and ratiometric fluorescent sensor for sequentially detecting Cu2+ and arginine based on a coumarin–rhodamine B derivative and its application for bioimaging

“…As illustrated in Fig. 4D(a), the two peaks located at 1721 and 1610 cm À1 could correspond to the antisymmetric and symmetric stretching vibrations of C]O (the rhodamine B unit), 48 and the strong band at 1520 cm À1 could be assigned to C]C stretching of benzenoid units. 49 For the 1-Cu 2+ complex, because of the disappearance of the C]O group (1721 cm À1 ) absorption band, the absorption peak at 1610 cm À1 shied to 1590 cm À1 , indicating that the C]O functional group bonded with Cu 2+ and the spirolactam structure in rhodamine B changed from off to on.…”

Catalytic activation of peroxymonosulfate with manganese cobaltite nanoparticles for the degradation of organic dyes

“…The term g Dt indicates the degradation efficiency of MB obtained aer Dt min of treatment. The investigated experimental parameters were catalyst dose (10,20,30,40, and 60 mg L À1 ), Oxone concentration (100, 300, 500, 700, 1000, and 1500 mg L À1 ), MB concentration (5,10,15,20,30, and 40 mg L À1 ), temperature (25,35,45, and 55 C), initial solution pH (3.5, 4.5, 5.5, 7.0, 8.0, 9.0, 10.0, 11.0, and 12.5), type of dye (RhB, MO, OG, and MB), reaction sequence, coexisting anions (Cl À , HCO 3 À , CO 3 2À , NO 3 À ), type of oxidant (PS, PMS, and H 2 O 2 ). In the experiment to investigate the inuence of temperature, the radical-generating reactions were stopped by quickly adding 0.2 mL of Na 2 SO 3 0.1 M and the catalyst NPs were removed by centrifugation.…”

“…Therefore, the development of efficient heterogeneous catalysts for PMS activation becomes a priority in many studies. So far, Co(II)-based heterogeneous catalysts such as CoFe 2 O 4 , 9,10 Recently, Co(III)-based spinels with general formula MCo 2 O x (M is transition metals) have been paid great attention due to their excellent electrochemical properties. 13,14 For PMS activation, these compounds exhibit several key advantages such as high catalytic activity and low Co leachability in acidic environment (CuCo 2 O 4 (ref.…”

A nickel nanoparticle engineered CoFe2O4@GO–Kryptofix 22 composite: a green and retrievable catalytic system for the synthesis of 1,4-benzodiazepines in water

“…CoFe 2 O 4 nanoparticles decorated on graphene oxide to obtain CoFe 2 O 4 @GO composite, will achieve further stabilization of these nanoparticles, and also prevents formation of aggregates in solution. [16][17][18][19] On the other hand, Kryptox 22 (K 22) as a specic class of aza-crown ether have been known for their high affinity and selectivity to bind transition metals (Fig. 1).…”