Solid Phase Extraction of Hazardous metals from Aqua System by Nanoparticle Modified Agrowaste Composite Adsorbents
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Date
2014-03-15
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Elsevier
Abstract
This study reports for the first time the adsorption of Cd(II) and Hg(II) ions from simulated wastewaters onto Nauclea diderrichii agrowaste (NDS) modified with mesoporous SiO2 (MND) and mesoporous SiO2 + graphene oxide (GND). Modification of NDS with mesoporous SiO2 and graphene oxide improved its adsorption capacity for Cd(II) and Hg(II) in aqueous solution with surface area increasing from 5.4 m2/g (in NDS) to 209 m2/g (in MND) and 267 m2/g (in GND) respectively. The modification of NDS also improved its rate of uptake of both metal ions with uptake rate of Hg(II) being more than that of Cd(II). Kinetic data
obtained gave better fit to the pseudo-second order kinetic model than to pseudo-first order, Elovich, modified pseudo-first order, ion exchange or Weber–Morris intraparticle diffusion kinetic models. Data obtained from the Weber–Morris intraparticle diffusion model suggests that pore diffusion mechanism may have played a significant role in the adsorption process. Thermodynamic data showed negative and positive values for ΔG⸰ and ΔH⸰ respectively for the adsorption systems, which supports the fact that the adsorption of both Cd(II) and Hg(II) by MND and GND adsorbents was feasible, spontaneous and endothermic in nature.
Description
The authors acknowledge the support of The World Academy of
Sciences-for the advancement of science in developing countries
(TWAS), Italy and the Chinese Academy of Sciences (CAS), China for
providing Fellowship (FR Number: 3240240234) to Martins O.
Omorogie at the Laboratory for Nanodevices of the National Center
for Nanoscience and Technology, Beijing, China where this
research was done. This work was also supported in part by the
National Basic Research Program of China (973 Program No.
2011CB933401) and the National Natural Science Foundation of
China (21005023). Prof. Jian R. Gong gratefully acknowledges the
support of the K.C. Wong Education Foundation, Hong Kong.
Keywords
Nanoparticles, Agrowaste, Surface Area, Kinetics, Adsorption, Thermodynamics
Citation
58