کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
595832 1454025 2009 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Surfactant binding by humic acids in the presence of divalent metal salts
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی شیمی کلوئیدی و سطحی
پیش نمایش صفحه اول مقاله
Surfactant binding by humic acids in the presence of divalent metal salts
چکیده انگلیسی

The binding of metal ions and surfactant to humic substances plays an important role in the distribution of toxic metal ions and toxic organic contaminants in the environment. We measured the binding of dodecyl- (C12TA+) and decyltrimethylammonium (C10TA+) surfactants to humic acid in the presence of heavy metal salts (Cu(II), Cd(II), Zn(II), Pb(II), and Ca(II)) at pH 8 using a surfactant ion-selective electrode. The binding curves of the surfactant cation were analyzed using the Langmuir equation to determine the binding constant K and capacity m. From the dependence of K on ionic strength, the hydrophobic interaction term is inferred to have Gibbs energy of −28 kJ/mol for the binding of C12TA+ ion to HA, and the dependence of K on the surfactant chain length revealed a 4 kJ/mol difference in Gibbs energy between C12TA+ and C10TA+ ion binding. In the presence of 0.5 mM divalent metal salts, K decreased significantly, partly because of territorial binding and partly because of the irreversible binding of metal ions. Aldrich humic acid had a smaller binding constant and capacity.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Colloids and Surfaces A: Physicochemical and Engineering Aspects - Volume 347, Issues 1–3, 5 September 2009, Pages 45–49
نویسندگان
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