عنوان مقاله [English]
نویسندگان [English]چکیده [English]
In this paper, the removal of heavy metals, arsenic and lead by modified nano-bentonite (coated with chitosan and carboxymethyl chitosan) has been studied. First, the efficiency of heavy metals removal , arsenic and lead were compared under the conditions fixed by nano-bentonite and modified nano-bentonite. Following, Effective parameters such as pH, dosage of the nano-adsorbent, contact time and initial concentration of lead and arsenic were studied. To determine the optimal parameters and to achieve the highest level of removal, experimental design method was used. Based on the results obtained, nano-bentonite chitosan was found to be more effective for the removal of Pb and As. Also results shows that pH is an effective parameter on the lead removal and also pH and adsorbent dosage are effective on the arsenic removal. Under the optimal conditions: pH=6, contact time of 30 min, the initial concentration of 1000 ppb and dose of adsorbent= 1.2 g/l for lead, pH=4, contact time of 30 min, the initial concentration of 1000 ppb and dose of adsorbent= 1.8 g/l for arsenic, 92.50% and 94.63% of lead and arsenic removal was achieved respectively by chitosan Nano-bentonite.