TY - JOUR
T1 - Silica nanopowders/alginate composite for adsorption of lead (II) ions in aqueous solutions
AU - Soltani, R. Darvishi Cheshmeh
AU - Khorramabadi, G. Shams
AU - Khataee, A. R.
AU - Jorfi, S.
PY - 2014/5
Y1 - 2014/5
N2 - The aim of the present work was to study the Pb(II) ions adsorption by entrapped silica nanopowders within calcium alginate to determine the isotherm, kinetic and thermodynamic of the adsorption process. According to the results, an optimal initial pH of 5.0 was found for the Pb(II) adsorption. The adsorbed Pb(II) ions reached to 36.51mg/g as the contact time increased to 180min at an initial Pb(II) concentration of 50mg/L. However, a contact time of 90min was selected as equilibrium time because of no significant increase in Pb(II) adsorption after this time. The results of isotherm and kinetic studies showed the Langmuir isotherm and pseudo-second order kinetic model were the best fitted models (R2>0.999). The maximum adsorption capacity for Pb(II) adsorption onto entrapped silica nanopowders was estimated to be 83.33mg/g. According to the Dubinin-Radushkevich (D-R) isotherm model, Pb(II) adsorption onto the composite follows a chemical mechanism (E=10kJ/mol). Negative δG° and δH° values indicated spontaneous and exothermic nature of the Pb(II) adsorption onto entrapped silica nanopowders, respectively. In addition, the results of continuous flow mode study exhibited that increasing empty-bed contact time (EBCT) from 5 to 20min resulted in increasing the specific throughput (St) from 8.42 to 11.22mL/g, respectively.
AB - The aim of the present work was to study the Pb(II) ions adsorption by entrapped silica nanopowders within calcium alginate to determine the isotherm, kinetic and thermodynamic of the adsorption process. According to the results, an optimal initial pH of 5.0 was found for the Pb(II) adsorption. The adsorbed Pb(II) ions reached to 36.51mg/g as the contact time increased to 180min at an initial Pb(II) concentration of 50mg/L. However, a contact time of 90min was selected as equilibrium time because of no significant increase in Pb(II) adsorption after this time. The results of isotherm and kinetic studies showed the Langmuir isotherm and pseudo-second order kinetic model were the best fitted models (R2>0.999). The maximum adsorption capacity for Pb(II) adsorption onto entrapped silica nanopowders was estimated to be 83.33mg/g. According to the Dubinin-Radushkevich (D-R) isotherm model, Pb(II) adsorption onto the composite follows a chemical mechanism (E=10kJ/mol). Negative δG° and δH° values indicated spontaneous and exothermic nature of the Pb(II) adsorption onto entrapped silica nanopowders, respectively. In addition, the results of continuous flow mode study exhibited that increasing empty-bed contact time (EBCT) from 5 to 20min resulted in increasing the specific throughput (St) from 8.42 to 11.22mL/g, respectively.
KW - Adsorption
KW - Alginate
KW - Heavy metals
KW - Silica nanopowders
KW - Specific throughput
UR - http://www.scopus.com/inward/record.url?scp=84895929698&partnerID=8YFLogxK
U2 - 10.1016/j.jtice.2013.09.014
DO - 10.1016/j.jtice.2013.09.014
M3 - Article
AN - SCOPUS:84895929698
SN - 1876-1070
VL - 45
SP - 973
EP - 980
JO - Journal of the Taiwan Institute of Chemical Engineers
JF - Journal of the Taiwan Institute of Chemical Engineers
IS - 3
ER -