کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4482334 1316855 2010 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Application of the Nernst–Planck approach to lead ion exchange in Ca-loaded Pelvetia canaliculata
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
Application of the Nernst–Planck approach to lead ion exchange in Ca-loaded Pelvetia canaliculata
چکیده انگلیسی

Ca-loaded Pelvetia canaliculata biomass was used to remove Pb2+ in aqueous solution from batch and continuous systems. The physicochemical characterization of algae Pelvetia particles by potentiometric titration and FTIR analysis has shown a gel structure with two major binding groups – carboxylic (2.8 mmol g−1) and hydroxyl (0.8 mmol g−1), with an affinity constant distribution for hydrogen ions well described by a Quasi-Gaussian distribution. Equilibrium adsorption (pH 3 and 5) and desorption (eluents: HNO3 and CaCl2) experiments were performed, showing that the biosorption mechanism was attributed to ion exchange among calcium, lead and hydrogen ions with stoichiometry 1:1 (Ca:Pb) and 1:2 (Ca:H and Pb:H). The uptake capacity of lead ions decreased with pH, suggesting that there is a competition between H+ and Pb2+ for the same binding sites. A mass action law for the ternary mixture was able to predict the equilibrium data, with the selectivity constants αCaH = 9 ± 1 and αCaPb = 44 ± 5, revealing a higher affinity of the biomass towards lead ions. Adsorption (initial solution pH 4.5 and 2.5) and desorption (0.3 M HNO3) kinetics were performed in batch and continuous systems. A mass transfer model using the Nernst–Planck approximation for the ionic flux of each counter-ion was used for the prediction of the ions profiles in batch systems and packed bed columns. The intraparticle effective diffusion constants were determined as 3.73 × 10−7 cm2 s−1 for H+, 7.56 × 10−8 cm2 s−1 for Pb2+ and 6.37 × 10−8 cm2 s−1 for Ca2+.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Water Research - Volume 44, Issue 13, July 2010, Pages 3946–3958
نویسندگان
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