عنوان المقالة:دراسة تبوثية جزيئات التتانيوم النانونية باستخدام المواد الطبيعية Stability studies for titanium dioxide nanoparticles upon adsorption of Suwannee River humic and fulvic acids and natural organic matter

محمد ارحيم عمر ارحيم | Mohamed Erhayem | 9293

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نوع النشر

مجلة علمية

المؤلفون بالعربي

محمد ارحيم وماري سون

المؤلفون بالإنجليزي

M Erhayem, M Sohn

الملخص العربي

In many studies humic acid, fulvic acid, or natural organic matter is used interchangeably to model the effect of naturally derived organic matter on geochemical processes in the environment. In this study, the term NOOM (naturally occurring organic matter) is used to include both humic and fulvic acids aswell as natural organicmatter and compares the effect of NOOMtype on NOOMremoval onto nano-TiO2. In general, regardless of variations in solution chemistry, the order of the percentage of removal of NOOMonto nano-TiO2was humic acid N natural organic matter N fulvic acid. The order of adsorption constant values of NOOMonto nano-TiO2 was also found to be humic acid N natural organic matter N fulvic acid under all conditions studied. The extent of NOOM removal by nano-TiO2 was enhanced in the presence of the divalent ions, magnesium and calcium, at pH 7.8 when compared to the presence of themonovalent ions, sodiumand potassium. Also, lowerNOOMremoval by nano-TiO2 in the presence of sodiumsalts of dihydrogen phosphate, bicarbonate and nitrate relative to chloridewas observed and was likely due to the competition between polyatomic anions and NOOM adsorption onto the surface of nano-TiO2 indicating an anionic effect. Low concentrations of NOOM (10–20 mg L−1) destabilized nano-TiO2 in solution, however, the stability of nano-TiO2 increased as the amount of NOOM adsorbed onto nano-TiO2 increased at higher dissolved NOOM concentrations and significant stabilization was seen at 25 mg L−1 NOOM. Thus, the three fractions of NOOM, humic and fulvic acids and natural organic matter and their concentrations were found to affect nano-TiO2 stability to different degrees although pH dependent trends in cation and anion effects had similar patterns. While the effects of adsorption of these three commonly used types of NOOM onto nanoparticles are similar, there are important differences that can be related to structural differences. © 2013 Elsevier B.V. All rights reserved.

الملخص الانجليزي

In many studies humic acid, fulvic acid, or natural organic matter is used interchangeably to model the effect of naturally derived organic matter on geochemical processes in the environment. In this study, the term NOOM (naturally occurring organic matter) is used to include both humic and fulvic acids aswell as natural organicmatter and compares the effect of NOOMtype on NOOMremoval onto nano-TiO2. In general, regardless of variations in solution chemistry, the order of the percentage of removal of NOOMonto nano-TiO2was humic acid N natural organic matter N fulvic acid. The order of adsorption constant values of NOOMonto nano-TiO2 was also found to be humic acid N natural organic matter N fulvic acid under all conditions studied. The extent of NOOM removal by nano-TiO2 was enhanced in the presence of the divalent ions, magnesium and calcium, at pH 7.8 when compared to the presence of themonovalent ions, sodiumand potassium. Also, lowerNOOMremoval by nano-TiO2 in the presence of sodiumsalts of dihydrogen phosphate, bicarbonate and nitrate relative to chloridewas observed and was likely due to the competition between polyatomic anions and NOOM adsorption onto the surface of nano-TiO2 indicating an anionic effect. Low concentrations of NOOM (10–20 mg L−1) destabilized nano-TiO2 in solution, however, the stability of nano-TiO2 increased as the amount of NOOM adsorbed onto nano-TiO2 increased at higher dissolved NOOM concentrations and significant stabilization was seen at 25 mg L−1 NOOM. Thus, the three fractions of NOOM, humic and fulvic acids and natural organic matter and their concentrations were found to affect nano-TiO2 stability to different degrees although pH dependent trends in cation and anion effects had similar patterns. While the effects of adsorption of these three commonly used types of NOOM onto nanoparticles are similar, there are important differences that can be related to structural differences. © 2013 Elsevier B.V. All rights reserved.

تاريخ النشر

10/09/2014

الناشر

Science of the Total Environment

رقم المجلد

رقم العدد

رابط DOI

http://dx.doi.org/10.1016/j.scitotenv.2013.08.038

الصفحات

249-257

الكلمات المفتاحية

Humic acid Fulvic acid Natural organic matter Titanium dioxide nanoparticles Adsorption constants Sedimentation