# Recent Strategies for Environmental Remediation of Organochlorine Pesticides
## 5 Photocatalysts for Pesticides Degradation
### g-C\({}_{3}\)N\({}_{4}\)-Based Photocatalysts for Pesticide Degradation  
Since most existing semiconductors used in heterogeneous photocatalysis only absorb in the UV region. The search for a good semiconductor photocatalysts that will utilize visible light, which is approximately forty percent of the solar spectrum, led to the emergence of graphitic carbon nitride(g-C\({}_{3}\)N\({}_{4}\)) [102]. It is a polymeric materials and with a band gap energy of approximately 2.7 eV [103]. As a result of high condensation grade and its structure, it exhibits photochemical, chemical and thermal stability [104]. In addition, its synthesis is simple since it can be prepared from nitrogen-rich precursors such as melamine, thiourea and urea. Interestingly, chemical doping can be used to modify its band structure [102; 104]. This important photocatalyst (g-C\({}_{3}\)N\({}_{4}\)) has been utilized to destroy an emerging organochlorine pesticide (imidazoloprid). The urea derived graphitic carbon nitride was able to degrade almost 90% of the pesticide within 5 h, in the presence of visible light. Further studies revealed that change in precursor type affects the photocatalytic efficiency of graphitic carbon nitride. The degradation route for imidacoprid degradation using graphitic carbon nitride was proposed (Figure 8) [71]. Another interesting study was carried out by [PERSON] [9], where Z-scheme silver-doped g-C\({}_{3}\)N\({}_{4}\)/Bi\({}_{2}\)O\({}_{3}\) nanocomposite was prepared through a hydrothermal process for degrading imidacoprid. The nanocomposite was used to completely mineralize the organochlorine pesticides within 10 h under visible light irradiation. This degradation followed pseudo-first order kinetics and the photocatalyst was stable even after 10 recycle times. A nanocomposite of bismuth oxide and graphitic carbon nitride was synthesized, but without doping by [PERSON] et al. [105]. The nanocomposite was successfully used to degrade 4-chlorophenol under the visible light irradiation. This organochlorine compounds has also been degraded by mesoporous graphitic carbon nitride in a study by [PERSON] et al. [106]. [PERSON] et al. [107; 108] degraded pesticides by using graphitic carbon nitride and also by using its nanocomposite with chitosan. This photocatalyst was able to degrade 85% of the toxic pesticide. Four different graphitic carbon nitride-based nanocomposites have been fabricated [109]. The nanocomposites were phosphorus-dopedgraphitic carbon nitride with graphene oxide, phosphorus-doped graphitic carbon nitride with fullerene, phosphorus-doped graphitic carbon nitride with carbon nanotube and phosphorus-doped graphitic carbon nitride with graphene. Each of these was used to degrade four different pesticides including organochlorine pesticides. They were all found to be good photocatalysts for removing pesticides. These nanocomposites were also used for inactivating _Pseudomonas aureus_, _Staphylococcus aureus_, _Pseudomonas fluorescens_, _Bacillus subtilis_ and _Escherichia coli_ bacteria. [PERSON] et al. [110] used graphitic carbon nitride nanovessel to remove pesticides from juice. More than 80% of the pesticides were removed from soil and food samples by using graphitic carbon nitride nanosheet [111]. Graphitic carbon nitride that was doped with carbon was fabricated by [PERSON] et al. [112] This photocatalyst was found to be very potent in degrading persistence organic pollutant from both wastewater and natural water better than when pure graphitic carbon nitride was used for the same purpose. Fluazaindolizine was degraded in aqueous solution with the use of nanosheet of graphitic carbon nitride under visible light irradiation [113]. An improvement in the half-life to 2.7 h was recorded when 5 mg of the catalyst was used. A nanocomposite composed of peroxymonosulfate, graphitic carbon nitride and activated carbon was prepared and used to degrade pesticide (atrazine). A higher efficiency was obtained compared to when the nanocomposite without peroxymonosulfate was used as photocatalyst [114].