**3. Conclusion**

**Pesticides Photocatalysts Light source Main findings References**

ZnO, TiO2 Solar DT75, referred to the normalised

Fe- and N-doped TiO2 UV Lowering of the band gap of

slurry Solar Results showed that the overall

slurry UV More than 90% of fungicide was

slurry and Fe2+ Solar Photo-Fenton treatment was found

slurry and Fe2+ Solar Total disappearance of the parent

beads Solar After 420 min illumination by

KBrO3

slurry UV Addition of Fe3+, Cu2+, H2

N-doped and P25 TiO2 UV/solar N-doped TiO2

, SnO2 Solar Half-life <3 min for ZnO, TiO<sup>2</sup>

and TiO2

light

degradation

tandem with Na2

S2 O8

illumination time (t30W), was lower than 40 and 550 min (t30W = 2 and 40 min) for both fungicides using ZnO

 showed higher photocatalytic activity under solar radiation compared to UV and visible

, respectively

titanium dioxide by doping is not always favourable for increasing photocatalytic efficiency of

model fitted the experimental data of herbicides mineralisation in the solar CPC reactor satisfactorily for both

> O2 , K2 S2 O8 or

and more

enhances the photodegradation

cloudy and sunny days

degraded after 75 min

to be shorter than TiO2

Solar The photocatalyst Degussa P25

pesticides tested

degraded into PO4

appropriate for these compounds

was found to be more efficient as compared with other photocatalysts

compounds and nearly complete mineralisation were attained with all

mineralise dimethoate, but the addition of oxidants improved the efficiency of the processes

sunlight, 0.65 × 10−4 mol dm−3 of four organophosphorus pesticides can be completely photocatalytically

3−.

was used for treating pesticide-polluted waters in the

in

[116]

[117]

[118]

[119]

[120]

[121]

[122]

[123]

[124]

[125]

[126]

[127]

Fenamiphos ZnO, TiO2

164 Application of Titanium Dioxide

Cyprodinil, fludioxonil

Methyl parathion, dichlorvos

MCPA, clopyralid, mecoprop

2,4-D, Diuron, ametryne

Carbendazim TiO2

Glyphosate TiO2

Alachlor, atrazine, chlorfenvinphos, diuron, isoproturon, pentachlorophenol

Cymoxanil, methomyl, oxamyl, dimethoate, pyrimethanil, telone

Dichlorvos, monocrotophos, parathion, phorate

period 2005–2016.

TiO2

TiO2

TiO2

TiO2 ·SiO2

**Table 2.** A brief summary of recent research studies in which TiO2

slurries in tandem with electron acceptors

Dimethoate ZnO, TiO2 UV Both catalysts were unable to

Triclopyr, dantinozid Different types of TiO<sup>2</sup>

, WO3

Currently, population growth, technology development, inadequate agricultural practices and land use have created unprecedented water pollution problems. Agricultural wastewater is characterised by high organic matter content and traces of organic pollutants, mainly pesticides. In addition, effluents from the agro-food and other industries have a potentially environmental risk that requires appropriate and comprehensive treatment. The most often used methods for the treatment of the industrial wastewaters, including membrane filtration, chemical coagulation/flocculation, ion exchange, precipitation, adsorption, biological degradation and ozonation, are not efficient enough and have important limitations to remove bio-recalcitrant compounds as many pesticides. In recent years, advanced oxidation processes (AOPs) have been proposed as a most promising way for degradation of various pollutants. Among them, heterogeneous photocatalysis technology is an interesting route among AOPs, which can be conveniently used for the complete degradation of different hazardous compounds including pesticides. Results show that sunlight photoalteration processes are well now to play an important role in the degradation of pesticides and other contaminants in water. These technologies allow pesticides to be removed by mineralisation. Photocatalytic oxidation by semiconductor oxides is an area of environmental interest for the treatment of polluted water, particularly relevant for Mediterranean agricultural areas, where solar irradiation is highly available (more than 2800 h of sunshine per year on average) making this process quite attractive. Due to its specific characteristics, titanium dioxide (TiO<sup>2</sup> ) has been demonstrated to be an excellent catalyst, and its behaviour is very well documented for the photodegradation of pesticide residues in water. Recently, many authors have also developed combined AOP and biological systems to implement in wastewater treatment plants. In addition to the experimental and modelling work, the aspect most lacking of this combination systems for the treatment of bio-recalcitrant specific industrial wastewater is the performance of complete economic studies, which could present this innovative technology as a cost-competitive one.
