فهرست مطالب

Catalysis - Volume:11 Issue: 3, Summer 2021

Iranian Journal of Catalysis
Volume:11 Issue: 3, Summer 2021

  • تاریخ انتشار: 1400/07/20
  • تعداد عناوین: 8
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  • Kasun Seneviratne, Imalka Munaweera *, Sriyani Peiris, Colin Peiris, Nilwala Kottegoda Pages 217-245

    The applications of photocatalytic nanomaterial technology received intense scientific focus with the advent of nanotechnology. Applications based on TiO2 nanoparticles have shown promise of photocatalytic efficiency among many semiconductor metal oxides. Titanium dioxide is utilized in many practical applications such as water and air purification, self-cleaning of surfaces, and energy production. The major drawback with TiO2 based photocatalysts is the wide band gap, which requires UV light to produce the electron-hole pairs. This review article focus on techniques/methods to eliminate band gap which reduces photocatalytic efficiency. Application of semiconductor photocatalytic techniques to degrade organic pollutants and their antimicrobial activity is discussed here using model systems. Synthetic and natural nanohybrids are available today and have varying characteristics as options. Recently developed natural mineral based nanohybrids is the new trend in photocatalytic applications. It appears that the removal efficiency of existed photocatalysts is higher than that of synthetic products. Natural nanohybrids carry the advantages of low costs, avoiding extensive synthesizing conditions in future photocatalytic applications.

    Keywords: Antibacterial activity, Metal doped TiO2, Natural, synthetic based TiO2 nanohybrids, Semiconductor nanomaterial, Visible active photocatalyst
  • Ailin Yousefi, Alireza Nezamzadeh-Ejhieh * Pages 247-259
    Here, SnO2, BiVO4, and CuO nanoparticles (NPs) were hydrothermally synthesized and mixed in an agate mortar mechanically. The coupled ternary SnO2-BiVO4-CuO (SBC) catalyst and the individual NPs were then briefly characterized by powder X-ray diffraction (XRD), scanning electron microscope (SEM), and diffuse reflectance spectroscopy (DRS). Average crystallite size of 25 nm was obtained from the XRD data based on the Scherrer formula. The absorption edge (λAE) values of 1095, 430, 558, and 636 nm, corresponding to the band gap (Eg) values of 1.13, 2.88, 2.22, and 1.95 eV, were respectively obtained for the as-synthesized CuO, SnO2, and BiVO4 NPs and the as-prepared ternary SBC catalyst based on DRS results. The PZP degradation% of 11, 15, 17, and 24% were obtained by the CuO, SnO2, BiVO4 NPs, and SBC catalyst (with the same moles of each component). But, when the moles of BiVO4 in the SBC were two times greater than the others, about 43% of PZP were removed. The k-value of 9.9 × 10-3 min-1 corresponding to the t1/2-value of 70 min was obtained by applying the Hinshelwood plot on the photodegradation results. Photodegradation experiments were carried out in pH 5, CPhP: 3.35 ppm, and catalyst dosage: 0.55 g L-1. Further, when the photodegraded solutions were subject to the COD experiment, the Hinshelwood plots showed a slope of 0.01 min-1 which corresponds to the t1/2-value of 69.3 min.
    Keywords: Photodegradation, SnO2-BiVO4-CuO heterogeneous catalyst, Phenazopyridine
  • Akbar Rostami-Vartooni *, Leila Rostami, Mojtaba Bagherzadeh Pages 261-274
    In this study, Ag and Pd nanoparticles (NPs) were immobilized on natural zeolite and magnetized zeolite (Fe3O4/natural zeolite) by using an aqueous Chrysanthemum morifolium flower extract, as a green and low-cost method. Different techniques such as FTIR, XRD, FESEM, EDS, and VSM were used for the characterization of prepared nanocomposites. The FESEM and TEM images of nanocomposites showed that the quasi-spherical Ag and Pd NPs with mostly 20–50 nm particles size have successfully formed and are well dispersed on the supports surface. The effect of various parameters such as nanocomposite type, initial dye, NaBH4 concentrations, catalyst dose, and pH were studied in the catalytic reduction/decolorization of three organic dyes. In the absence of NaBH4 or catalyst, no color changes were observed even after 90 min. The reduction rates of the selected dyes in the presence of stable catalysts were found to be in an order of Pd/Fe3O4/natural zeolite > Pd/natural zeolite > Ag/Fe3O4/natural zeolite > Ag/natural zeolite > Fe3O4/natural zeolite.
    Keywords: natural zeolite, Heulandite, Fe3O4 nanocomposites, C. morifolium, Catalytic reduction, Decolorization
  • Adeleh Moshtaghi Zonouz, Abdolreza Abri *, Nasrin Babajani, Hemayat Shekaari Pages 275-286
    Novel deep eutectic solvent (DES) using Choline Chloride (ChCl) as the hydrogen bond acceptor and triflouroacetic acid (TFA) as hydrogen bond donor (1.0:1.5 molar ratio) was prepared at room temperature and characterized by FT- IR and 1H NMR spectroscopy. Also, this novel acidic RTDES (room temperature deep eutectic solvent) was successfully used both as a reaction medium and catalyst in Biginelli, Biginelli-like, and Hantzsch reactions. The procedures have the advantages of high yields, short reaction times and easy work-up as well as relatively mild conditions and they do not require additional catalysts and organic solvents. The DES could be easily recycled without considerable loss of activity even after more than three cycles.
    Keywords: Deep eutectic mixture, Choline chloride, Triflouroacetic acid, Biginelli reaction, Hantzsch reaction
  • Fatemeh Hassani, Mahboubeh A. Sharif *, Masoumeh Tabatabaee, Mahboobeh Mahmoodi Pages 287-294
    The Cu(II) complex of 2,6-pyridine dicarboxylic acid (PydcH2, dipiconilic acid) was successfully prepared and readily trapped in the nanocavity of zeolite-X (NaX) through a flexible synthetic method. The characterization of nanocomposite ([Cu(pydcH2)(pydc)]-NaX) was performed by FT-IR, XRD, BET isotherm, SEM, TEM, and elemental analysis, that approved the encapsulating of coordination compound in the channels of NaX, with no change in the zeolite structure and morphology. The catalytic activity of the prepared material was also studied in respect of the oxidation of aniline with hydrogen peroxide as an oxidizing agent. The experiments were performed to optimize aniline oxidation under different extents of catalyst, temperature, and time. Optimized reaction conditions of this catalyst exhibited moderate activity (~92%) of aniline oxidation. This catalyst was stable in the oxidation of aniline as recovered and reused for an additional three runs. The outcomes reflected that the catalyst was reusable with no considerable loss in the catalytic activity.
    Keywords: Zeolite X, nanocomposite, nanoporosity, flexible ligand method, oxidation of aniline, dipicolinic acid
  • Dwi Kurniawati, Jumaeri Jumaeri, Silvester Tursiloadi *, Osi Arutanti, Muhammad Safaat Pages 295-302
    Desilication of natural zeolite by alkali treatment to produce solketal was successfully prepared.  Natural zeolite from Tasikmalaya, West Java, Indonesia, has been used as a catalyst source. The natural zeolite source was mordenite type structure. The experimental condition was varied to study their effect on the catalyst efficiency. Several characterization methods, such as Thermogravimetric Analysis (TGA), Brunauer Emmett Teller (BET), X-ray Diffraction (XRD), Scanning Electron microscopy (SEM), etc., were used to analyze the physicochemical properties of the prepared catalyst. From the temperature-programmed desorption of NH3 (TPD analysis), the acidity of zeolite decreased from 0.597 to 0.444 by increasing NaOH concentration from 0.1 to 0.7 M, respectively.  The result showed that alkali treatment did not change the phase structure of natural zeolite significantly. Here, the ratio of Si/Al decreased by increasing NaOH concentration, resulting in the decrease of acidity value. Interestingly, the efficiency of zeolite catalyst (HZ-01) shows the highest conversion and selectivity at around 98.73% and 74.66%, respectively. This exciting result opens the possibility to develop an economic catalyst with high efficiency from the abundant Indonesian mineral resource.
    Keywords: Desilication, glycerol, natural zeolite, clipnotilolite, mordenite
  • Navid Allahyar *, Cemal Özeroğlu Pages 303-315
    The negative effects of silver, which is one of the heavy metals, on the environment are known. Hence, to remove this dangerous heavy metal from the environment, poly(methacrylic acid), whose adsorption capability has been tested in previous studies, was used. But unfortunately, it performed poorly for silver ions. Therefore, this polymer was modified as poly(sodium methacrylate) using NaOH catalyst and used in the adsorption experiment process to obtain more efficient results. Some important functional groups in the modified copolymer were analyzed by FTIR measurement and the thermal stability of the copolymer by TGA measurement. To better interpret the adsorption process, some isotherms such as Freundlich, Langmuir, and Dubinin-Radushkevich (D-R) isotherms were examined. Using the (D-R) isotherm, the reaction energy was found to be 8.98 kJ/mol, which indicates that the adsorption process is of a chemical ion exchange type. The data from the experimental processes were also evaluated with some kinetic models such as the Elovich, the modified Freundlich, the pseudo-first-order, and the pseudo-second-order kinetic models. Among these models, the pseudo-second-order kinetic models of the adsorption of Ag(I) on poly(sodium methacrylate) showed the best agreement with the experimental data.
    Keywords: Isotherm, Dimethyl aniline, Kinetic equations, Silver ions, Catalyst
  • Naghmeh Darya, Hassan Tajik * Pages 317-329
    In this research, we report a novel and green magnetic nanocatalyst; Fe3O4@SiO2@Vitamin C@Fe2O3 for clean synthesis of 3-amino-1-aryl-1H-benzo[f]chromene-2-carbonitriles with high-yield in water as solvent at room temperature. The nanocatalyst is stable under the synthetic conditions and it can be reused several times without considerable reduction in its catalytic activity. The catalyst structure was characterized by using various analytical techniques; SEM, FT-IR, thermogravimetric analysis (TGA), UV-vis spectroscopy, VSM and EDS. Also, the products were separated and characterized by determining their melting points, IR spectra and compared to those of the authentic samples.  Environmentally friendly, availability, high catalytic activity and ease of separation are the main reasons for using Fe3O4@SiO2@Vitamin C@Fe2O3 as a green catalyst.
    Keywords: green chemistry, Magnetite nanocatalyst [Fe3O4@SiO2@Vitamin C@Fe2O3], Multi-component reactions, 3-amino-1-aryl-1H-benzo[f]chromene-2-carbonitrile