پديد آورندگان :
ﻧﻌﻤﺘﯽ ﺷﻤﺲ آﺑﺎد، ﻓريبا داﻧﺸﮕﺎه ﺷﺎﻫﺪ - ﮔﺮوه ﻋﻠﻮم ﺧﺎك , تراﺑﯽ ﮔﻞﺳﻔﯿﺪ، ﺣﺴﯿﻦ داﻧﺸﮕﺎه ﺷﺎﻫﺪ - ﮔﺮوه ﻋﻠﻮم ﺧﺎك , ناجي، اميرمحمد اﻧﺸﮕﺎه ﺷﺎﻫد - ﮔﺮوه اﺻﻼح ﻧﺒﺎﺗﺎت و ﺑﯿﻮﺗﮑﻨﻮﻟﻮژي
كليدواژه :
ﻧﺎﻧﻮ و ﻣﯿﮑﺮو زﺋﻮﻟﯿﺖ آﻟﯽ , رس آلي , ﻫﮕﺰادﺳﯿﻞﺗﺮيﻣﺘﯿﻞآﻣﻮﻧﯿﻢ , ﻇﺮﻓﯿﺖ ﺗﺒﺎدل ﮐﺎﺗﯿﻮﻧﯽ ﺑﯿﺮوﻧﯽ , ﮐﻠﯿﻨﻮﭘﺘﯿﻠﻮﻟﯿت
چكيده فارسي :
ﺳﺎﺑﻘﻪ و ﻫﺪف: آﻧﯿﻮن ﻧﯿﺘﺮات ﺑﻪ ﻋﻠﺖ دارا ﺑﻮدن ﺑﺎر ﻣﻨﻔﯽ ﺗﻤﺎﯾﻠﯽ ﺑﻪ ﺟﺬب روي ذرات ﺧﺎك ﻧﺪارد، ﺑﻨﺎﺑﺮاﯾﻦ از ﻧﯿﻤﺮخ ﺧﺎك ﺧﺎرج و وارد آبﻫﺎي ﺳﻄﺤﯽ و زﯾﺮزﻣﯿﻨﯽ ﻣﯽ ﺷﻮد .رسﻫﺎ در ﺣﺎﻟﺖ ﻃﺒﯿﻌﯽ، اﻏﻠﺐ داراي وﯾﮋﮔﯽ آﻧﯿﻮن ﮔﺮﯾﺰي ﺑﻮده و ﻗﺎدر ﺑﻪ ﺟﺬب ﻣﻮﻟﮑﻮلﻫﺎي ﮐﻢ ﻣﺤﻠﻮل در آب، ﻏﯿﺮﻗﻄﺒﯽ و ﻣﻮﻟﮑﻮلﻫﺎي آﻟﯽ ﻏﯿﺮﯾﻮﻧﯽ ﻧﯿﺴﺘﻨﺪ، اﻣﺎ ﻣﯽﺗﻮان ﺑﺎ اﺻﻼح رسﻫﺎ آنﻫﺎ را ﺑﻪ رس آﻟﯽ ﺗﺒﺪﯾﻞ و ﺑﺮاي ﺟﺬب و ﭘﺎﻻﯾﺶ آﻧﯿﻮنﻫﺎ و ﺗﺮﮐﯿﺒﺎت آﻧﯿﻮﻧﯽ و ﻏﯿﺮآﻧﯿﻮﻧﯽ آﻟﯽ ﻣﻀﺮ در ﻣﺤﯿﻂ آﺑﯽ اﺳﺘﻔﺎده ﮐﺮد .اﯾﻦ ﻣﻄﺎﻟﻌﻪ ﺑﻪ ﻣﻨﻈﻮر ﺑﺮرﺳﯽ راﻧﺪﻣﺎن ﺟﺬب و واﺟﺬب ﻧﯿﺘﺮات ﺗﻮﺳﻂ رس زﺋﻮﻟﯿﺖ - ﮐﻠﯿﻨﻮﭘﺘﯿﻠﻮﻟﯿﺖ اﯾﺮاﻧﯽ(ﺳﻤﻨﺎن) اﺻﻼح شده با سورفكتانت هگزادسيل تري متيل آمنيوم برومايد ( HDTMA-Br) صورت گرفت .
ﻣﻮاد و روش ﻫﺎ: راﻧﺪﻣﺎن ﺟﺬب ﻧﯿﺘﺮات ﺗﻮﺳﻂ زﺋﻮﻟﯿﺖ اﯾﺮاﻧﯽ اصلاح شده با سورفكتانت كاتيوني (HDTMA-Br) تحت ﺳﻪ ﺗﯿﻤﺎر اﻧﺪازه ذره، ﺳﻄﻮح ﺳﻮرﻓﮑﺘﺎﻧﺖ و ﻏﻠﻈﺖ اوﻟﯿﻪ ﻧﯿﺘﺮات ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺖ .ﺟﻬﺖ ﺑﺮرﺳﯽ ﺛﺒﺎت ﻧﯿﺘﺮات ﺟﺬب ﺷﺪه، واﺟﺬب در ﺳﻄﺢ ﺳﻮرﻓﮑﺘﺎﻧﺖ 200درصد ودر دو غلظت 3 و 14 ميلي مولار در زمان هاي مختلف بررسي شد. .آزﻣﺎﯾﺶ ﻫﺎ ﺑﻪ ﺻﻮرت ﻓﺎﮐﺘﻮرﯾﻞ در ﻗﺎﻟﺐ ﻃﺮح ﭘﺎﯾﻪ ﮐﺎﻣﻼً ﺗﺼﺎدﻓﯽ اﻧﺠﺎم ﺷﺪ .ﻧﺎﻧﻮ و ﻣﯿﮑﺮو ذرات زﺋﻮﻟﯿﺖ ﺑﺎ اﺳﺘﻔﺎده از روش ﺳﺎﻧﺘﺮﯾﻔﯿﻮژ ﺟﺪا ﺷﺪﻧﺪ. .ﻇﺮﻓﯿﺖ ﺗﺒﺎدل ﮐﺎﺗﯿﻮﻧﯽ ﺑﯿﺮوﻧﯽ زﺋﻮﻟﯿﺖ ﺑﺎ اﺳﺘﻔﺎده از روش ﺟﺎﯾﮕﺰﯾﻨﯽ ﺳﺪﯾﻢ ﺑﺎ ﯾﻮن ترت- بوتيل آمونيم تعيين شد. مورفولوژي و ساختار كاني زئوليت مورد مطالعه با استفاده از روش هاي AFM,SEM,EDX,XRD مورد بررسي و شناسايي قرار گرفت .
يافته ها : درنانو زئوليت آلي ، راندمان جذب و پالايش نيترات در سطح سورفكتانت 200 درصد CEC بيروني ، در غلظت هاي اوليه 3 ، 6، 14، 20 و 30 ميلي مولار نيترات به ترتيب ، 92 ، 88 ، 77 ، 67 و 56 درصد ، در حالي كه راندمان جذب و پالايش ذرات ميكرو زئوليت در غلظت هاي فوق به ترتيب ، 75 ، 67 ، 50 ، 41 و 33درصد بود. راندمان جذب نيترات توسط ميكروزئوليت آلي در سطح سورفكتانت 100درصد CEC بيروني ، به ترتيب ، 53 ، 46 ، 35 ، 28 و20 درصد بود. درصد واحذب در غلظت 3 ميلي مولار نيترات در نانو زئوليت آلي ، بين 2/6 تا 5/7 درصد و در غلظت 14 ميلي مولار نيترات ، بين 8/9 تا 12/2 درصد و در ميكرو زئوليت 21 نا 33 درصد بود .
ﻧﺘﯿﺠﻪ ﮔﯿﺮي: ﻧﺘﺎﯾﺞ اﯾﻦ ﭘﮋوﻫﺶ ﻧﺸﺎن داد ﮐﻪ ﺗﻔﮑﯿﮏ دﻗﯿﻖ ذرات ﻧﺎﻧﻮ زﺋﻮﻟﯿﺖ ﺑﻪ روش ﺳﺎﻧﺘﺮﯾﻔﯿﻮژ، ﻏﻠﻈﺖ اوﻟﯿﻪ ﻧﯿﺘﺮات و ﺳﻄﺢ ﺳﻮرﻓﮑﺘﺎﻧﺖ در اﻓﺰاﯾﺶ راﻧﺪﻣﺎن ﺟﺬب و ﭘﺎﻻﯾﺶ ﻧﯿﺘﺮات از ﻣﺤﯿﻂ ﻫﺎي آﺑﯽ ﺗﺄﺛﯿﺮ ﺑﺴﯿﺎر زﯾﺎدي دارد .ﻧﺎﻧﻮ زﺋﻮﻟﯿﺖ آﻟﯽ ﻋﻼوه ﺑﺮ دارا ﺑﻮدن راﻧﺪﻣﺎن ﺑﺴﯿﺎر ﺑﺎﻻ در ﺟﺬب و ﺣﺬف ﻧﯿﺘﺮات از ﻣﺤﯿﻂ، ﺛﺒﺎت و ﭘﺎﯾﺪاري ﺧﻮﺑﯽ ﻧﯿﺰ در ﻧﮕﻬﺪاﺷﺖ ﻧﯿﺘﺮات از ﺧﻮد ﻧﺸﺎن دادﻧﺪ
چكيده لاتين :
Background and Objectives: Nitrate anion can be repelled by the negative charges on clay minerals' surface and leached from soil profile to surface and groundwater. Natural clays are not effective adsorbents and entrapment media for anions, low water soluble, nonpolar and non-ionic organic molecules. However, the natural clays may be modified using organic cations (surfactant) to adsorb and trap varieties of nonionic, anionic compounds and enhanced anions retention capacity that are detrimental to our aqueous environments. The objective was to study the adsorption efficiency and desorption of nitrate in aqueous solutions by modified Iranian zeolite-clinoptilolite (Semnan) with hexadecyltrimethylammonium bromide (HDTMA-Br), a cationic surfactant.
Materials and Methods: The micro and nano-zeolite was separated by centrifuge method. The micro and nano-zeolites were first modified by HDTMA-Br. In this study, adsorption efficiency in initial concentrations of nitrate by modified zeolite with surfactant loading of 100 and 200% ECEC was investigated in a completely randomized factorial design. The nitrate release as affected by time at 4 and 14 mM of nitrate in surfactant loading 200% ECEC were also evaluated. The external cation exchange capacity (ECEC) of zeolite was determined by replacing the Na in non-zeolitic exchange sites with tert-butyl ammonium ions. Structure and morphology of zeolite was determined using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and atomic force microscope (AFM).
Results: The results showed that adsorption efficiency of nitrate by nano-organozeolite with surfactant loading of 200% ECEC in 3, 6, 14, 20 and 30 mM nitrate were 92, 88, 77, 67 and 56%, whereas in micro-zeolite were 75, 67, 50, 41 and 33% respectively. Adsorption efficiency of nitrate by micro-organozeolite with surfactant loading of 100% ECEC were 53, 46, 35, 28 and 20% respectively. In nano-organozeolite, nitrate desorption were 2.6 to 5.7% and 8.9 to 12.2% in 3 and 14 mM, respectively, whereas for micro-organozeolite were 21% and 33% in 3 and 14 mM of initial nitrate concentration, respectively.
Conclusion: Results of this research showed that the particular separation of zeolite, initial nitrate concentration and level of surfactant loading had a highly effect on adsorption efficiency and cleaning of nitrate in aqueous solutions. Moreover, nano-organozelite showed high adsorption efficiency of nitrate and good quality to trap and retain of nitrate.
