and applicable design (Tanveer and Tezcanli Guyer 2013). However, even the
perfected design involved with some process limitations include (i) more effective
performance for oxidative process like dyes with low concentration, (ii) sensitivity to
mutability in solar intensity, (iii) complete contact of catalyst and effluent and then
asking for separation of catalyst and treated effluent, and (iv) far from of headed
commercialization. Resolving the last case along with commercial livability needs a
facile, cost-effective, sustainable, and safety operation. To achieve the respected
goals and minimize the pertinent limitations, it seems employing of proper
UV-visible light photocatalysts is promised.
9.5 Conclusions
One can state that the best technique and material for pesticide removing can be
chosen according to all involved parameters such as pH, temperature, quantity of
contaminated environments, kind of matrix, and solubility of pesticides. The applied
physicochemical process of pesticides remediation is permanently based on the
forms of usage energy to degradation of the related pollutants, along with photolysis,
ultrasound, and the other alternative methods. For purpose of pesticides remediation,
metal oxide photocatalysts like TiO 2 using Fenton reactions joined to light, electric
current, and ultrasound can highly extend the destruction of pesticides especially in
aqueous phase. However, the current study was furnishedthe fundamental issues of
the photocatalytic process. The most important ones contents are appropriate mechanism, thermodynamics, kinetics and recombination of reaction, suggested mechanism of an active photocatalyst, and the impact of effective factors on photocatalytic
performance. Typical heterogeneous photocatalysis progresses by generation of
electron–hole pairs commenced through band gap agitation of particle of a semiconductor. Adsorption of a photon with required potential equal or greater than band
gap as the initial necessity of photocatalytic reactions resulted in electron transition
from valence band to conduction band. Desired thermodynamically catalytic process
can be evaluated based on intrinsic, apparent, and official quantum yield and
efficiency of conversion. Conclusive measurement of total carbon content of the
contaminants in terms of TOC or COD can be used to quantity determination of the
photoreaction rate in a pseudo-L–H model. Since visible light active photocatalysts
have small band gap energy, arresting of charge recombination is needful. The main
mechanisms of effectual excitation and charge pair separation have been noted and
discussed with clear examples. The governed parameters influencing on
photocatalytic activity have been studied at length, completed with accounted results
in literature. The parameters are (i) intrinsic photocatalyst type related to contents
and band structure, (ii) irradiation energy effect on the number of generated
electron–hole pairs, (iii) kind and character of pollutants having different functional
groups, (iv) scattering and blockage of adventure light that can restrict the amount of
loaded catalyst into the system, (v) pH of media and substrate, and (vi) value and
property of dopant in composited catalystÀsubstrate influenced on surface
308
M. Chahkandi and M. Zargazi
perfected design involved with some process limitations include (i) more effective
performance for oxidative process like dyes with low concentration, (ii) sensitivity to
mutability in solar intensity, (iii) complete contact of catalyst and effluent and then
asking for separation of catalyst and treated effluent, and (iv) far from of headed
commercialization. Resolving the last case along with commercial livability needs a
facile, cost-effective, sustainable, and safety operation. To achieve the respected
goals and minimize the pertinent limitations, it seems employing of proper
UV-visible light photocatalysts is promised.
9.5 Conclusions
One can state that the best technique and material for pesticide removing can be
chosen according to all involved parameters such as pH, temperature, quantity of
contaminated environments, kind of matrix, and solubility of pesticides. The applied
physicochemical process of pesticides remediation is permanently based on the
forms of usage energy to degradation of the related pollutants, along with photolysis,
ultrasound, and the other alternative methods. For purpose of pesticides remediation,
metal oxide photocatalysts like TiO 2 using Fenton reactions joined to light, electric
current, and ultrasound can highly extend the destruction of pesticides especially in
aqueous phase. However, the current study was furnishedthe fundamental issues of
the photocatalytic process. The most important ones contents are appropriate mechanism, thermodynamics, kinetics and recombination of reaction, suggested mechanism of an active photocatalyst, and the impact of effective factors on photocatalytic
performance. Typical heterogeneous photocatalysis progresses by generation of
electron–hole pairs commenced through band gap agitation of particle of a semiconductor. Adsorption of a photon with required potential equal or greater than band
gap as the initial necessity of photocatalytic reactions resulted in electron transition
from valence band to conduction band. Desired thermodynamically catalytic process
can be evaluated based on intrinsic, apparent, and official quantum yield and
efficiency of conversion. Conclusive measurement of total carbon content of the
contaminants in terms of TOC or COD can be used to quantity determination of the
photoreaction rate in a pseudo-L–H model. Since visible light active photocatalysts
have small band gap energy, arresting of charge recombination is needful. The main
mechanisms of effectual excitation and charge pair separation have been noted and
discussed with clear examples. The governed parameters influencing on
photocatalytic activity have been studied at length, completed with accounted results
in literature. The parameters are (i) intrinsic photocatalyst type related to contents
and band structure, (ii) irradiation energy effect on the number of generated
electron–hole pairs, (iii) kind and character of pollutants having different functional
groups, (iv) scattering and blockage of adventure light that can restrict the amount of
loaded catalyst into the system, (v) pH of media and substrate, and (vi) value and
property of dopant in composited catalystÀsubstrate influenced on surface
308
M. Chahkandi and M. Zargazi