Immobilization of 5,10,15,20-tetrakis-(2-fluorophenyl)porphyrin into MCM-41 and NaY: Routes toward photodegradation of pesticides

Abstract

NaY zeolite and MCM-41 mesoporous molecular sieve were used as supports for immobilization of 5,10,15,20-tetrakis-(2-fluorophenyl)porphyrin (TFPP) using adsorption and ship-in-the-bottle routes involving the nitrobenzene method. The materials obtained were characterized by thermogravimetry/differential thermal analysis (TG/DTA), nitrogen adsorption, UV–vis absorption, diffuse reflectance (DRS), and luminescence spectroscopy. Although the porphyrin could easily be synthesized inside MCM-41 pores using the ship-in-the-bottle route, no significant porphyrin was formed in the smaller supercages of NaY zeolite, since the reaction stops at the dipyrrolylmethene intermediate (FDPM). Promising preliminary studies were made in the photodegradation of the pesticides, 2,3,5-trimethylphenol (TMP) and mecoprop (MCPP), using as catalyst TFPP encapsulated in mesoporous MCM-41 material. The 2-hydroxy-methyl-hydroquinone and 4-chloro-2-methylphenol were identified as the main degradation products of MCPP. The encapsulated system resulting from the TFPP template synthesis shows significantly enhanced performance when compared with adsorbed porphyrin in both supports.