Preparation of TiO2-ZSM-5 zeolite for photodegradation of EDTA

https://doi.org/10.1016/j.molcata.2005.05.023Get rights and content

Abstract

Doping of TiO2 into ZSM-5 zeolite has been achieved by impregnation and solid–solid interaction methods. The produced samples were characterized using X-ray diffraction (XRD), ultraviolet and visible spectroscopy (UV–vis), the Fourier transform infrared (FT-IR) and surface area measurement. The results show that the incorporation of titanium into framework of ZSM-5 using impregnation method is higher than that of solid–solid interaction method. The photocatalytic tests were carried out for degradation of EDTA. The results indicate that photodegradation of EDTA by impregnation method is much better than that of solid–solid interaction method. The EDTA removal efficiency is 99.9% at 3 × 10−3 M EDTA concentration using impregnation method whereas 75% at 3 × 10−5 M EDTA concentration using solid–solid method.

Graphical abstract

Doping of TiO2 into ZSM-5 zeolite has been achieved by impregnation and solid–solid interaction methods. The incorporation of titanium into framework of ZSM-5 using impregnation method is higher than that of solid–solid interaction method. The photodegradation of EDTA by impregnation method is much better than that of solid–solid interaction method.

Section snippets

1-Introduction

Titanium atoms incorporated into the zeolite framework serve as catalytic sites, and thus the content of framework titanium in a zeolite has presented higher activity in performing some catalytic reactions [1], [2], [3], [4]. TiO2 in anatase phase is the best photocatalyst reported so far, poor adsorption and low surface area properties lead to great limitations in exploiting the photocatalyst to the best of its photoefficiency. Supporting TiO2 is commonly reported to be less photoactive due to

Synthesis of Ti/ZSM-5 by impregnation method

The prepared Na-ZSM-5 [27] were stirred in ethanolic solution of TiCl4 to give TiO2 loaded with 2, 4, 6.5 and 8.4 wt%. The samples were dehydrated in an oven for 6 h at 110 °C and calcined eventually at 550 °C for 6 h. The obtained samples were referred as M1, M2, M3 and M4, respectively.

Synthesis of Ti/ZSM-5 by solid–solid interaction method

ZSM-5 was degassed at 300 °C for 3 h to remove physisorbed water molecules prior to being mechanically mixed with TiO2 anatase (Merck) at room temperature in a glove box filled with nitrogen (99% purity), and the

XRD

Fig. 1 presents the XRD patterns of different wt% of titanium from 2 to 8.4% loaded on ZSM-5 by impregnation method, in comparison with that of ZSM-5 synthesized in previous work [27]. The results show that increased of lines at 2-theta = “7.92, 8.76 and 23.07” are related to the presence of titanium silicate [29] which appeared for all samples, but the lines, which indicate the presence of titanium dioxide anatase“ at 2-theta = 25.32, 37.41 and 48.04” [30] appeared with samples M2, M3 and M4. Also

Effect of wt% of Ti loaded on ZSM-5

A series of experiments has been carried out to study effect of wt% of Ti loaded on ZSM-5 by impregnation and solid–solid interaction methods on EDTA removal efficiency under the following conditions: 0.4 g/l M or S/EDTA solution ratio; 5 × 10−3 M Conc. of EDTA; 1 h reaction time and pH 3. The findings are summarized in Table 3. The results indicate that increasing wt% of Ti loaded on ZSM-5 from 2 to 8.4 wt%, leads to decreasing EDTA removal efficiency in the impregnation and solid–solid interaction

Conclusions

Syntheses of Ti/ZSM-5 by impregnation and solid–solid interaction methods have been achieved. The lattice parameters and unit cell of S1 revealed small an enhancement when compared with that of M1 sample, due to the presence of TiO2 anatase phase, which block pores of ZSM-5. Unit cell volume of the M2, M3 and M4 samples revealed large an enhancement when compared with these of S2, S3 and S4 samples, respectively. Incorporation of titanium into ZSM-5 framework is decreased in the following

References (33)

  • R. Millini et al.

    J. Catal.

    (1992)
  • A. Thangaraj et al.

    J. Catal.

    (1991)
  • G. Deo et al.

    Zeolites

    (1993)
  • E. Astorino et al.

    J. Catal.

    (1995)
  • N. Takeda et al.

    J. Catal.

    (1998)
  • T. Ibusuki et al.

    J. Mol. Catal.

    (1994)
  • M.M. Mohamed et al.

    Colloid Surfaces A

    (2002)
  • A.A. Ismail et al.

    J. Photochem. Photobio: A Chem.

    (2004)
  • B. Sulikowski et al.

    Appl. Catal. A: Gen.

    (1992)
  • C.B. Dartt et al.

    Microporous Mater.

    (1994)
  • S. Zhang et al.

    J. Mol. Catal. A: Chem.

    (1996)
  • S. Zhang et al.

    J. Mol. Catal. A: Chem.

    (1998)
  • F.S. Zhang et al.

    Mater. Chem. Phys.

    (1999)
  • X. Wang et al.

    Catal. Today

    (1999)
  • M. Liu et al.

    Catal. Today

    (2004)
  • M. Noorjahan et al.

    Appl. Catal. B

    (2004)
  • Cited by (81)

    • On the impact evaluation of various chemical treatments of support on the photocatalytic properties and hydrogen evolution of sonochemically synthesized TiO<inf>2</inf>/Clinoptilolite

      2018, International Journal of Hydrogen Energy
      Citation Excerpt :

      For the composite samples, an increment in the absorption edge corresponding to TiO2 which had a wavelength at about 400 nm was observed. This result confirms the titanium-dioxide crystals formed on the Clinoptilolite surface, which is the same as the results reported in literatures [16,20,52]. As can be seen, all the treated Clinoptilolite supported TiO2 photocatalysts exhibited similar absorption spectra and appropriate spectroscopic properties for photocatalytic hydrogen production, corresponded to preserving the Clinoptilolite crystal structure after chemical treatments.

    • Designing of experiments for evaluating the interactions of influencing factors on the photocatalytic activity of NiS and SnS<inf>2</inf>: Focus on coupling, supporting and nanoparticles

      2017, Journal of Colloid and Interface Science
      Citation Excerpt :

      One important disadvantage of the heterogeneous photocatalysis is e/h recombination which strongly decreases the photocatalytic activity. This problem can be effectively removed by coupling and supporting of semiconductors onto suitable supports such as zeolites [7–10]. Coupling of semiconductors creates new hetero-structure system in which photogenerated electrons migrate from more negative conduction band (CB) of a semiconductor to the more positive CB of the other.

    • TiO<inf>2</inf>-TON zeolite synthesis using an ionic liquid as a structure-directing agent

      2015, Microporous and Mesoporous Materials
      Citation Excerpt :

      The most challenging step in the synthesis of these materials is the synthesis of a microporous solid with a specific structure and a specific catalytic application [2]. In heterogeneous photocatalysis, for example, several studies have focused on developing zeolites with TiO2 supported as the active species for the reaction [3–5]. There has been considerable academic and industrial interest in this class of materials.

    View all citing articles on Scopus
    View full text