Aromatic compounds photodegradation catalyzed by ZnS and CdS nanoparticles

Abstract

A B S T R AC TThe photodegradation of aromatic compounds such as nitrobenzene (NB), phenol, 2-nitrophenol (2-NP), 3-nitrophenol (3-NP), 4-nitrophenol (4-NP), 4-chlorophenol (4-CP), 2,4-dichlorophenol (2,4-DCP) and 2,4,6-trichlorophenol (2,4,6-TCP) are catalyzed by nanoparticles of zinc and cadmium sulfi des. The photocatalytic degradation is studied in aqueous samples. The results show the highest degradation in pH of 11. The optimum dosages of catalysts obtained 0.3 and 0.5 g l −1 in degradation of NB and other aromatic compounds, respectively. The degradation kinetic of pollutants follows pseudo-fi rst-order kinetic. The CdS semiconductor with band-gap 2.42 eV in comparison to ZnS with band-gap 3.54 eV indicates a higher photoactivity. The studies show the degradation rate of aromatic compounds in this order: NB > phenol, 2-NP > 4-NP > 3-NP > phenol and 2,4,6-TCP > 2,4-DCP > 4-CP > phenol. A reduction 90% in COD value and increasing 91% in TOC removal are obtained after photo-degradation of a sample contains all of aromatic compounds at duration time of 24 h.

Recent advances in non-metal modification of graphitic carbon nitride for photocatalysis: a historic review

“…135,136 The photodegradation of organic pollutants in water was also investigated. 137,138 Bulk MoS 2 is not a good photocatalyst, while nanoscaled MoS 2 can exhibit excellent photocatalytic activity. 139 Other metal sulfides, such as WS 2 , 140 NiS, 141 CuS, 142 In 2 S 3 , 142 Ag 2 S, 143 and some complex sulfides, such as A 2 (I)-Zn-A(IV)-S 4 (A(I) = Cu and Ag; A(IV) = Sn and Ge), 144 CuInS 2 , 145 and Zn 1−x Cd x S, 146 have demonstrated their photocatalytic activities in a variety of photocatalytic reactions.…”

Low-temperature Synthesis of a-Fe2O3/MWCNTs as Photocatalyst for Degradation of Organic Pollutants

“…5. At basic value, the repulsion force between catalyst and phenolate ions play the main role in decrease the efficiency while, in acidic medium the catalyst has a positive charge and it's become a favorite for an adsorption of ions on the surface 20,21 . on the other side, the ferric ions in oxide were reduced to ferrous ions in acidic medium and adsorbed on (001) surface of a-Fe 2 O 3 and this cause the Fenton system.…”