oxygen supply. However, no significant effect was observed for the degradation of
methylene blue, likely due to the lower initial concentration that lowers the amount
of oxygen required for its degradation.
Even if such a technology is promising, there is still a lack of knowledge to
develop the scale up of the process at the industrial scale.
2.6 Titania and Photocatalysis in Industry
Up to now titania-based systems for the water treatment by photocatalysis remain
mainly at the laboratory stage, and efforts are mainly focused on the preparation of
efficient photocatalysts. Besides the different studies reported in academic publications and cited in this chapter, some patents also exist (Park et al. 2002; Willmer and
Ranjit 2002; Toledo et al. 2014; Balaya et al. 2015). For example, Willmer et al. have
patented the preparation method of doped TiO 2 with lanthanide metal. Materials are
obtained by the acid-catalyzed sol-gel process, and the obtained photocatalysts
exhibit an enhanced efficiency for the photochemical degradation of the organic
substrates such as p-chlorophenoxyacetic acid than the unmodified TiO 2 (Willmer
and Ranjit 2002). To implant such material at the industrial scale, much attention
should be paid on the shaping. As a matter of fact, the main drawback of using titania
is due to the fact that powder form of TiO 2 is considered and that a filtration step is
required. This filtration step is a drawback for the economic viability of
photocatalysis process based on titania. Nevertheless, it should be noted that several
company such as Clearwater Industries, Photox Bradford Ltd., Lynntech Inc., and
Ishihara Sangyo Kaisha Ltd. have products at the development stage for water
purification using semiconductor photocatalyst (Butters and Powell 1996, 2000;
Gonzalez-Martin et al. 1998; Gonzalez-Martin et al. 2000). For example, the
Lynntech Inc. company has patented a method and an apparatus based on the
photocatalytic oxidation method using a porous titanium dioxide membrane for
the mineralization of organic contaminants in water (Gonzalez-Martin et al. 1998).
The photocatalytic reactor operates effectively at ambient temperature and low
pressures. A packed-bed photoreactor using photocatalyst coated particles is also
proposed (Gonzalez-Martin et al. 2000). More recently, Kisalius and Kinsinger have
patented a method for synthesis of doped or undoped titania with controlled size,
phase, morphology, and porosity (Kisalius and Kinsinger 2017). The prepared
photocatalysts are integrated in a device for water treatment. The few examples
reported above concerning water treatment allow to conclude that photodegradation
of dyes by porous titania is a promising technology that will grow in the future and
that it can reach the commercialization stage if we succeed to control the shaping of
the photocatalysts.
76
B. Lebeau et al.
methylene blue, likely due to the lower initial concentration that lowers the amount
of oxygen required for its degradation.
Even if such a technology is promising, there is still a lack of knowledge to
develop the scale up of the process at the industrial scale.
2.6 Titania and Photocatalysis in Industry
Up to now titania-based systems for the water treatment by photocatalysis remain
mainly at the laboratory stage, and efforts are mainly focused on the preparation of
efficient photocatalysts. Besides the different studies reported in academic publications and cited in this chapter, some patents also exist (Park et al. 2002; Willmer and
Ranjit 2002; Toledo et al. 2014; Balaya et al. 2015). For example, Willmer et al. have
patented the preparation method of doped TiO 2 with lanthanide metal. Materials are
obtained by the acid-catalyzed sol-gel process, and the obtained photocatalysts
exhibit an enhanced efficiency for the photochemical degradation of the organic
substrates such as p-chlorophenoxyacetic acid than the unmodified TiO 2 (Willmer
and Ranjit 2002). To implant such material at the industrial scale, much attention
should be paid on the shaping. As a matter of fact, the main drawback of using titania
is due to the fact that powder form of TiO 2 is considered and that a filtration step is
required. This filtration step is a drawback for the economic viability of
photocatalysis process based on titania. Nevertheless, it should be noted that several
company such as Clearwater Industries, Photox Bradford Ltd., Lynntech Inc., and
Ishihara Sangyo Kaisha Ltd. have products at the development stage for water
purification using semiconductor photocatalyst (Butters and Powell 1996, 2000;
Gonzalez-Martin et al. 1998; Gonzalez-Martin et al. 2000). For example, the
Lynntech Inc. company has patented a method and an apparatus based on the
photocatalytic oxidation method using a porous titanium dioxide membrane for
the mineralization of organic contaminants in water (Gonzalez-Martin et al. 1998).
The photocatalytic reactor operates effectively at ambient temperature and low
pressures. A packed-bed photoreactor using photocatalyst coated particles is also
proposed (Gonzalez-Martin et al. 2000). More recently, Kisalius and Kinsinger have
patented a method for synthesis of doped or undoped titania with controlled size,
phase, morphology, and porosity (Kisalius and Kinsinger 2017). The prepared
photocatalysts are integrated in a device for water treatment. The few examples
reported above concerning water treatment allow to conclude that photodegradation
of dyes by porous titania is a promising technology that will grow in the future and
that it can reach the commercialization stage if we succeed to control the shaping of
the photocatalysts.
76
B. Lebeau et al.