ABSTRACT
Organophosphate (OP) insecticide, such as diazinon is found in the environments like water which is still approved for agricultural uses. When diazinon residues enter the human body, it functions as an acetylcholinesterase (AChE) inhibitor. This research aims to measure of chlorpyrifos (CPF), diazinon, and malathion residues in fruit such as apple, orange, and tomato after optimizing extraction conditions. Pesticide residues are measured by gas chromatography (GC) technique. Effective variables on pesticide residues are studied including pesticides kind, sampling station, and fruit kind. Results show that average concentration CPF, diazinon, and malathion residues in orange water are 7.05 ± 0.01 mg L-1, 6.66 ± 0.03 mg L-1, and 12.38 ± 0.02 µgL-1, respectively. The average concentration CPF, diazinon, and malathion residues in apple water are 0.74 ± 0.02 mgL-1, 0.70 ± 0.01 mgL-1, and 1.10 ± 0.01 µgL-1, respectively. The average concentration CPF, diazinon, and malathion residues in tomato water are 0.60 ± 0.02 mgL-1, 0.57 ± 0.02 mgL-1, and 0.89 ± 0.01 µgL-1, respectively. The highest CPF concentration is observed in the orange fruit from station 20. Due to an appropriate storage condition and presenting organic fruits in the supermarket, the least mean concentration of pesticides is obtained in studied fruits from station 2. The manner of washing, peeling, and storage period before consuming fruits lead to decreasing studied pesticides concentration about 15-35, 40-50, and 50-60%, respectively. Increasing the fruit shelf-life led to decreasing studied pesticides concentration. Between pesticide concentration and variables: pesticides kind, sampling station, fruit kind, are not seen meaningful statistic relationship (P > 0.05). This study showed that pesticide residues in fruits can be decreased by washing, refrigerating, peeling procedures and increase in public surveillance.
ABSTRACT
Ketoconazole is an imidazole fungicide which is commonly used as pharmaceutical and healthcare products. Residual amount of this compound can cause adverse ecological health problems. The present study investigated ketoconazole photocatalytic degradation using Ag3PO4/graphene oxide (GO). Ag3PO4/GO and Ag3PO4 as visible light-driven photocatalysts was synthesized using the in situ growth method. Degradation of ketoconazole at the concentration of 1-20 mg/L in aqueous solutions was optimized in the presence of Ag3PO4/GO nanocomposite with the dosage of 0.5-2 g/L, contact time of 15-20 min, and pH of 5-9 using response surface methodology. A second-order model was selected as the best fitted model with R2 value and lack of fit as 0.935 and 0.06, respectively. Under the optimized conditions, the Ag3PO4/GO catalyst achieved a photocatalytic efficiency of 96.53% after 93.34 min. The photocatalytic activity, reaction kinetics, and stability were also investigated. The results indicated that the Ag3PO4/GO nanocomposite exhibited higher photocatalytic activity for ketoconazole degradation, which was 2.4 times that of pure Ag3PO4. Finally, a direct Z-scheme mechanism was found to be responsible for enhanced photocatalytic activity in the Ag3PO4/GO nanocomposite. The high photocatalytic activity, acceptable reusability, and good aqueous stability make the Ag3PO4/GO nanocomposite a promising nanophotocatalyst for photocatalytic degradation of azoles contaminants.
