ABSTRACT
A facile eco-friendly approach for acetampirid pesticide removal is presented. The method is based on the use of micro- and mesoporous activated carbon (TPAC) as a natural adsorbent. TPAC was synthesized via chemical treatment of tangerine peels with phosphoric acid. The prepared activated carbon was characterized before and after the adsorption process using Fourier- transform infrared (FTIR), X-ray diffraction (XRD), particle size and surface area. The effects of various parameters on the adsorption of acetampirid including adsorbent dose (0.02-0.2 g), pH 2-8, initial adsorbate concentration (10-100 mg/L), contact time (10-300 min) and temperature (25-50 °C) were studied. Batch adsorption features were evaluated using Langmuir and Freundlich isotherms. The adsorption process followed the Langmuir isotherm model with a maximum adsorption capacity of 35.7 mg/g and an equilibration time within 240 min. The adsorption kinetics of acetamiprid was fitted to the pseudo-second-order kinetics model. From the thermodynamics perspective, the adsorption was found to be exothermic and spontaneous in nature. TPAC was successfully regenerated and reused for three consecutive cycles. The results of the presented study show that TPAC may be used as an effective eco-friendly, low cost and highly efficient adsorbent for the removal of acetamiprid pesticides from aqueous solutions.
Subject(s)
Charcoal/chemistry , Insecticides/isolation & purification , Lignin/chemistry , Neonicotinoids/isolation & purification , Water Pollutants, Chemical/isolation & purification , Water Purification/methods , Adsorption , Agriculture , Green Chemistry Technology , Humans , Hydrogen-Ion Concentration , Kinetics , Lignin/isolation & purification , Porosity , Temperature , Thermodynamics , Waste ProductsABSTRACT
The objective of this study is to perform a safety assessment of chromafenozide residue level on tomato at the Egyptian national level. An open field decline study of chromafenozide on tomato was performed. The theoretical maximum daily intake (TMDI) of chromafenozide was calculated for assessing the chronic dietary exposure indicating that the ADI value of chromafenozide (0.27 mg/kg bw/day) was not exceeded. As a result, the safety assessment of chromafenozide residue levels was attained. A validated method of the QuEChERS approach followed by HPLC-DAD analysis was used to determine the chromafenozide residues. The recoveries ranged from 70 to 88% with relative standard deviations ranging from 2.0 to 9.0%. The limit of quantitation was 0.01 mg/kg. The half-life of chromafenozide on tomatoes was 3.5 days.
Subject(s)
Benzopyrans/analysis , Environmental Monitoring , Hydrazines/analysis , Pesticide Residues/analysis , Solanum lycopersicum/chemistry , Chromatography, High Pressure Liquid/methods , Egypt , Half-LifeABSTRACT
This study presents a method validation for extraction and quantitative analysis of azoxystrobin residues in green beans and peas using HPLC-UV and the results confirmed by GC-MS. The employed method involved initial extraction with acetonitrile after the addition of salts (magnesium sulfate and sodium chloride), followed by a cleanup step by activated neutral carbon. Validation parameters; linearity, matrix effect, LOQ, specificity, trueness and repeatability precision were attained. The spiking levels for the trueness and the precision experiments were (0.1, 0.5, 3 mg/kg). For HPLC-UV analysis, mean recoveries ranged between 83.69% to 91.58% and 81.99% to 107.85% for green beans and peas, respectively. For GC-MS analysis, mean recoveries ranged from 76.29% to 94.56% and 80.77% to 100.91% for green beans and peas, respectively. According to these results, the method has been proven to be efficient for extraction and determination of azoxystrobin residues in green beans and peas.