کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10377441 | 880729 | 2005 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Lead biosorption study with Rhizopus arrhizus using a metal-based titration technique
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موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
شیمی کلوئیدی و سطحی
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چکیده انگلیسی
Acid-base and metal-based potentiometric titration methods were used to analyze sorption mechanisms of lead by Rhizopus arrhizus fungal biomass. Biosorption was not considered globally but as the result of successive sorption reactions on various binding sites with different selectivities. Precipitation occurred rapidly when lead concentration increased. Lead was sorbed essentially by carboxylic groups and by phosphates and sulfonates (less abundant) of the organic matter. The lead affinity to carboxylic, sulfonate and phosphate binding sites depended on the association coefficient with proton or counter-ion and on the spatial distribution of the surface sites promoting the formation of mono- or bi-dentate complexes. Chemical bonds and binding sites were confirmed using microscopic and spectroscopic techniques (IR, MET-EDAX). It appeared that although the total organic acidity was reached, number of ionized and free carboxylic groups were not involved in lead sorption reactions. In spite of lead speciation in the solution, surface micro-precipitation was observed and the two processes, surface adsorption and micro-precipitation, are sequential and possibly overlapping. At low concentrations (<10â6M) adsorption is the dominant phenomenon and beyond (>10â5M) surface clusters appeared before the predicted solution precipitation phenomenon.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Colloid and Interface Science - Volume 292, Issue 2, 15 December 2005, Pages 537-543
Journal: Journal of Colloid and Interface Science - Volume 292, Issue 2, 15 December 2005, Pages 537-543
نویسندگان
Ghinwa Naja, Christian Mustin, Jacques Berthelin, Bohumil Volesky,