Preparation and characterization of wet-proofed CuO/Al2O3 catalysts for the oxidation of phenol solutions

Abstract

Two wet-proofed catalysts were prepared by subsequent coating steps with polytetrafluoroethylene fibers over a CuO/cAl 2 O 3 catalyst. They were tested for the oxidation of phenol solutions in a semi-batch reactor. Phenol conversion as well as Chemical Oxygen Demand (COD) was recorded. The hydrophobic coverage reduces the loss of active phase by leaching. Therefore, deactivation was attributed to the deposition of carbonaceous residues on the catalytic surface.

Conventional and wet proofed CuO/Al2O3 catalysts for phenol oxidation: deactivation studies in a trickle bed reactor

“…Base CuO/γAl 2 O 3 catalyst (CNT) were prepared from Cu(NO 3 ) 2 .3H2O (p.a., Merck, Darmstadt, Germany) and γAl 2 O 3 (Alfa Aesar, Ward Hill, MA, USA, 1/8″ pellets, BET surface area 214 m 2 /g) following the molten salt method described elsewhere 7. Part of the sample was coated with PTFE fibers following the impregnation procedure described by Massa et al ,2 for catalyst C3T (three successive impregnation cycles with PTFE). The samples were dried at 120 °C in an oven and calcined at 400 °C for 12 h in air.…”

“…The copper content of the samples was determined by AA and also confirmed by TPR, using an AANALYST 300 Perkin‐Elmer (Waltham, MA, USA) spectrophotometer 2…”

“…A large variety of catalytic systems have been studied for the CWAO of phenolic solutions 1–3. Most of these systems are based on metal oxides that show good activity, but serious stability problems 3–5.…”

“…The second strategy was to cover conventional CuO/Al 2 O 3 with a polytetrafluorethylene (PTFE) layer and test it for the oxidation of phenol solutions in a RCBR 2. The results showed that the hydrophobic coverage could effectively reduce the leaching of the active phase.…”

Growth and microstructural study of CuO covered ZnO nanorods

“…CuO is a transition metal oxide with p-type semiconductivity and a narrow direct band gap of 1.21-1.51 eV [6,7]; additionally, it has high absorbance below 850 nm being suitable for solar energy applications [8]. Furthermore, it is a Mott insulator, a giant magneto resistant and a superconductor material [9] being attractive for electronic devices and nanofluids [10]; industrially, CuO has great interest, as pigment, gas sensor and catalyst [11,12]. Synthesis of CuO nanoparticles has been reported by photodeposition, homogeneous co-precipitation, electrodeposition [13,14], physical/ chemical vapor deposition [15] and wet chemical methods [16][17][18], and also impregnation and thermal decomposition [19].…”