Synthesis, Characterization of Nanosized ZnCr2O4 and Its Photocatalytic Performance in the Degradation of Humic Acid from Drinking Water

Abstract

Zinc chromite (ZnCr 2 O 4 ) has been synthesized by the thermolysis of a new Zn(II)-Cr(III) oxalate coordination compound, namely [Cr 2 Zn(C 2 O 4 ) 4 (OH 2 ) 6 ]·4H 2 O. The coordination compound has been characterized by chemical analysis, infrared spectroscopy (IR), and thermal analysis. The zinc chromite obtained after a heating treatment of the coordination compound at 450 • C for 1 h has been investigated by XRD, FE-SEM, TEM/HR-TEM coupled with selected area electron diffraction (SAED) measurements. The photocatalytic performance of nanosized zinc chromite was assessed for the degradation and mineralization of humic acid (HA) from a drinking water source, envisaging the development of the advanced oxidation process for drinking water treatment technology. A mineralization efficiency of 60% was achieved after 180 min of 50 mg L −1 HA photocatalysis using zinc chromite under UV irradiation, in comparison with 7% efficiency reached by photolysis.

Synthesis Gas Conversion to Lower Olefins over ZnCr‐SAPO‐34 Catalysts: Role of ZnO−ZnCr2O4 Interface

“…Dumitru and coworkers believed that the formation of ZnCr 2 O 4 with a spinel crystal form is effortless and stable by reacting both Zn and Cr. [25] With the increase of Zn/Cr molar ratio, these characteristic diffraction peaks ascribed to ZnO phase (JCPDS card no. 36-1451) become increasingly obvious, indicating that ZnO phase underwent a gradual change process from absence to presence, while the diffraction peaks of ZnCr 2 O 4 spinel are perpetual in all calcined catalysts.…”

Nanomaterials for Environmental Purification and Energy Conversion

“…It should be pointed that also other semiconductors have been used successfully for environmental applications, such as ZnO [36], graphitic carbon nitride (g-C3N4) [37], WO 3 [10], BiVO 4 [38], and SrTiO 3 [39], and some of them exhibited higher activity than that of titania even under UV irradiation [40][41][42]. Accordingly, the photocatalytic activity of other semiconductors has also been discussed in this special issue, such as ZnCr 2 O 4 [23], TiOF 2 (modified with NaOH) [20], SnO 2 (fluorine-doped SnO 2 (FTO), surface modified with Cu NPs) [25], and rectorite/Fe 3 O 4 /ZnO [22]. Wang et al prepared rectorite/Fe 3 O 4 /ZnO composities with photocatalytic and magnetic properties enabling efficient photocatalyst separation after reaction [22].…”

“…The high stability during recycling (24-h irradiation) should be considered as high advantage of this material. The nanosized ZnCr 2 O 4 was synthesized by Dumitru et al by thermolysis of a new Zn(II)-Cr(III) oxalate coordination compound [23]. The photocatalyst was much more efficient for humic acid degradation than simple photolysis (7%), reaching 60% degradation after 3 h of UV irradiation.…”

Nanomaterials for Environmental Purification and Energy Conversion

“…It should be pointed that also other semiconductors have been used successfully for environmental applications, such as ZnO [36], graphitic carbon nitride (g-C3N4) [37], WO 3 [10], BiVO 4 [38], and SrTiO 3 [39], and some of them exhibited higher activity than that of titania even under UV irradiation [40][41][42]. Accordingly, the photocatalytic activity of other semiconductors has also been discussed in this special issue, such as ZnCr 2 O 4 [23], TiOF 2 (modified with NaOH) [20], SnO 2 (fluorine-doped SnO 2 (FTO), surface modified with Cu NPs) [25], and rectorite/Fe 3 [23]. The photocatalyst was much more efficient for humic acid degradation than simple photolysis (7%), reaching 60% degradation after 3 h of UV irradiation.…”

“…Accordingly, the Special Issue "Nanomaterials for Environmental Purification and Energy Conversion" is a collection of 17 papers, including 16 research papers and one review. Eleven papers present heterogeneous photocatalysis for efficient degradation of organic pollutants (phenol [17,18], 2-propanol [19], dyes [20][21][22], humic acid [23]), inactivation of microorganisms (Escherichia coli, Staphylococcus epidermidis [24], Bacillus subtilis, and Clostridium sp. [18]), H 2 evolution [25], and CO 2 reduction [26,27].…”