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Sorption Kinetics of Cd( II ) Species on Humic Acid‐ B ased Sorbent
Author(s) -
Santosa Sri Juari
Publication year - 2014
Publication title -
clean – soil, air, water
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 66
eISSN - 1863-0669
pISSN - 1863-0650
DOI - 10.1002/clen.201200684
Subject(s) - sorbent , sorption , chemistry , chitin , reaction rate constant , humic acid , nuclear chemistry , kinetics , chromatography , chitosan , adsorption , organic chemistry , physics , fertilizer , quantum mechanics
A new sorption kinetic model has been developed and applied to quantify the sorption rate constant ( k s ) of cadmium(II) (Cd(II)) and humic acid–complexed Cd(II) (dissolved HA–Cd(II)) sorbed on solid humic acid (HA) sorbent. In a medium containing both Cd(II) and dissolved HA–Cd(II) at a relatively comparable initial concentration, the k s value of Cd(II) was half of that of dissolved HA–Cd(II). This lower k s value for Cd(II) may be attributed to the presence of competition between the solid HA sorbent and the dissolved HA fraction in attracting Cd(II). Under these conditions, the developed sorption kinetic model provided better correlation to the experimental data than the pseudo‐first order kinetic known as Lagergren model. The developed model, in comparison to the Lagergren and Ho pseudo‐second order sorption models, was also used to treat the data of Cd(II) sorption on a sorbent of HA and chitin (HA–chitin) hybrid at a wide range of ratios of the initial moles of Cd(II) to the weight of the HA–chitin sorbent from 8.90 to 154.12 × 10 −6 mol/g. At this ratio range, the developed model satisfactorily gave constant values of k s , but the Lagergren and Ho models yielded inconstant β (the pseudo‐first order sorption rate constant) and k (the pseudo‐second order sorption rate constant), respectively. While the correlation of the developed model to the experimental data at that ratio range was satisfactory, the correlation of the Lagergren model to the experimental data decreased as the ratio decreased and that of the Ho model improved.