چكيده به لاتين
Abstract
This research work employs naturally magnetic Iranian clinoptilolite zeolite modified by the cetyltrimethylammonium bromide(CTAB) cationic surfactant and ligand diphenylthiocarbazone(DTZ) as adsorbent for the purpose of preconcentration and non-continuously and simultaneously measurement lead(II) and cadmium(II) heavy metals via spectrophotometry of flame atomic adsorption. To do so, design of experiment was used to determine the number and manner of experiments as well as a more accurate calculation of optimal conditions. Accordingly, an average optimal condition with PH=1, adsorption time equal to 3.30 min., desorption time of 4 min. and adsorbent amount of 7.12 mg was obtained. Further, The 100 mL solution containing 20 μg/l of lead and cadmium metal ions and 0.5 mL of elution solvent 1 M nitric acid were obtained by a variable at the time. Under the optimized condition, the concentration ranges of lead and cadmium are in order 2-130 and 5-150 μg/l and the limit of detection (LOD) of this method for lead and cadmium was found 0.93 and 1.08 μg/l, respectively. The relative standard deviation (RSD) for 7 times of repeating at the optimal point was 2.13 and 2.78 for lead and cadmium, respectively. It must be mentioned that in this experiment, adsorption and desorption processes were conducted through a bath under ultrasonic waves.
Key Words: ultrasonic waves, design of experiment, simultaneous preconcentration of lead and cadmium, modified naturally magnetic zeolite, spectrophotometry of flame atomic absorption
