*2.3.1 X-ray diffraction analysis*

Synthesised TiO2 and M/TiO2 photocatalyst were subjected to powder X-ray diffraction to confirm the crystalline size and the presence of the metal ion. The powder X-ray diffractograms were recorded using a X-ray diffractometer (PANalytical X'Pert Pro) with Cu Kα source having wavelength of 1.54 Å operating at 20 mA and 50 kV. The samples were scanned from 0.5–80° (2*θ*) for the confirmation of phase and presence of metal particles. The diameter of the metal particles was calculated from the (111) reflection of metal atom using Debye Scherrer equation,

$$\mathbf{d} = \mathbf{K}\lambda / \mathfrak{g} \text{ } \mathbf{Cost} \,\mathfrak{g}\tag{1}$$

**79**

values.

*Detoxification of Carcinogenic Dyes by Noble Metal (Ag, Au, Pt) Impregnated Titania…*

reduction of noble metal ions on TiO2 particles and extent of decolourisation were studied using this technique. Further, the band gap energies (Eg) of the synthesised

Eg = h c/λ (2)

The photocatalytic reactor was made up of quartz having dimensions 30 × 3 cm (height × diameter) provided with water circulation arrangement to maintain the

The irradiation was carried out using low pressure mercury arc lamp (wave length 254 nm) as UV source and tungsten lamp (365 nm) as visible light source built into a lamp housing with polished anodised aluminium reflectors placed 6.5 cm away from

M for both RY-17 and RB-5) of the dye

where h, Planck's constant; c, velocity of light (m/s); λ, wavelength (nm).

M for TAZ and 10<sup>−</sup><sup>5</sup>

temperature. The top portion of the reactor has ports for sampling.

the lamps. The entire reactor system was cooled using an inbuilt fan set up.

250 mL of the desired dye sample was taken in a photocatalytic reactor. Calculated amount of TiO2 (P-25 Degussa) or synthesised TiO2 or M/TiO2 was added to the photocatalytic reactor and the reaction mixture was magnetically stirred before and during illumination. After specific time interval of irradiation, suitable aliquots of the sample was withdrawn and analysed to find out the extent of

The extent of photocatalytic decolourisation of dyes was studied by UV-visible

*C*<sup>0</sup> − *C*

*<sup>C</sup>* <sup>×</sup> <sup>100</sup> (3)

spectrophotometer (Hitachi U-2000) from the decrease in the respective λmax

The colour intensity of the dyes was measured in terms of absorbance.

where C0, initial concentration of the dye; C, concentration of dye at time 't'.

The photocatalytic degradation of dyes was evaluated in terms of total organic carbon (TOC). The total organic carbon of the pollutant was determined by using a

Decolourisation was determined by using the calibration curve.

Decolourisation (%)=\_\_\_\_\_

*DOI: http://dx.doi.org/10.5772/intechopen.80467*

**2.4 Photodecolourisation studies**

Stock solutions (10<sup>−</sup><sup>4</sup>

*2.4.3 Photocatalytic reaction*

decolourisation and degradation.

**2.5 Photodegradation studies**

TOC analyser (Shimadzu TOC V series).

*2.4.4 UV-vis analysis of the decolourised products*

*2.4.2 Batch photocatalytic reactor*

*2.4.1 Preparation of synthetic dye samples*

samples were prepared for the present study.

catalysts were calculated according to the equation

where d, diameter of the metal particle; K, constant; λ, wavelength of the X-ray (1.54 Å); β, full width at half maximum; θ, angle of diffraction.
