Study the effect of copper(II) ions towards photodegradation of metamifop

The rising demand on our staple food, rice, demands the need to protect the crops from weeds by means of using herbicides. Metamifop, a post emergent herbicide belongs to the phenolic hydrocarbon group. It is commonly used in the Asian countries especially in the production of paddy. The persistence of this herbicide in the irrigation water has lead to the issue of water pollution. Hence, photodegradation, which is an Advanced Oxidation Process (AOP) is applied by using UV light to trigger production of effective hydroxyl radicals (•0H) to degrade the targeted pollutant. However, the presence of Cu(II) ions, which is among the commonly found heavy metal pollutant from surface water may effect this process. Therefore, the study on the effect of Cu(II) ions towards the photodegradation of metamifop was conducted. To study this effect, two conditions which are in the absence of Cu(II) ions and in the presence of Cu(II) ions (10 ppm and 15 ppm) towards photodegradation of metamifop (150 ppm and 200 ppm) has been conducted. It was identified that, photodegradation in the absence of Cu(II) ions achieved 23.36 % degradation (150 ppm metamifop) and 20.90 % degradation (200 ppm metamifop). Whereas in the presence of 10 ppm Cu(II) ions, 1.52 % degradation (150 ppm metamifop) and 1.65 % degradation (200 ppm metamifop) was achieved. When the effect of 15 ppm of Cu(II) ions was tested, 0.74 % degradation (150 ppm metamifop) and 0.65 % degradation (200 ppm metamifop) was achieved. As the concentration of Cu(II) ions increases, the lesser is the percentage degradation of metamifop. Hence, through this study the presence of Cu(II) ions has been proven to retard the photodegradation of metamifop.