Synthesis and characterization of catalysts based on mesoporous silica partially hydrophobized for technological applications.
In this work, mesoporous silica mobil composition of matter no. 41 (MCM-41) was synthesized by the sol-gel method. Two different surface modifications were made to transform this material into a very active adsorbent and catalyst support: (i) impregnation of iron nanoparticles and (ii) hydrophobization via chemical vapor deposition (CVD) with ethanol. The materials prepared with different iron contents, i.e., 2.5, 5, and 10 %, after hydrophobization, were characterized by several techniques. CHN analysis and Raman spectroscopy proved that approximately 15 % of carbon is deposited during CVD process mainly as organized carbonaceous structures. The specific surface area was determined by the BET method as up to 1080 m2g-1, which explains the excellent results of the materials in the adsorption of model dyes methylene blue and indigo carmine. Mössbauer spectroscopy, thermogravimetric (TG)/DTG analysis, and transmission electron microscopy (TEM) images showed that the iron supported may be partially reduced during the CVD process to Fe2+species, which are stabilized by the carbon coating. This iron species plays an important role in the oxidation of different contaminants, such as quinoline and methylene blue. The results obtained in the catalytic tests showed to be very promising.
Departamento de Química, ICEx, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG, Brazil, CEP 31270-901.
Amanda R
AR
Martins
Departamento de Química, ICEx, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG, Brazil, CEP 31270-901.
Adriana B
AB
Salviano
Departamento de Química, ICEx, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG, Brazil, CEP 31270-901.
Aline A S
AAS
Oliveira
Centro Federal de Educação Tecnológica de Minas Gerais, Av. Amazonas 5253, Nova Suíça, Belo Horizonte, MG, CEP 30421-169, Brazil.
Raquel V
RV
Mambrini
Departamento de Química, ICEx, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG, Brazil, CEP 31270-901. flaviamoura@ufmg.br.
Flávia C C
FCC
Moura
D057927:Hydrophobic and Hydrophilic Interactions; D007501:Iron / Q000737:chemistry; D053768:Metal Nanoparticles; D036103:Nanotechnology; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
C509968:MCM-41; D012822:Silicon Dioxide; D007501:Iron
Adsorption; CVD; Carbon; Fenton; Heterogeneous catalysis; Hydrophobization; MCM-41; Mesoporous material; Oxidation; Supported iron