Environmental Engineering Reference
In-Depth Information
showed removal capacities of 30.1 ± 2.5 (Zn 2+ ), 14.9± 1.5 (Cd 2+) and 35.6 ±
1.3 mg/g (Pb 2+) . h e TiO 2 l owers were markedly formed upon GO as the
hydrothermal treatment time at 100
C increased from 6 h to 12 h.
Yu a n et al. [85] prepared novel multifunctional microsphere with a large
pore size mesoporous silica shell (10.3 nm) and a magnetic core (Fe 3 O 4 )
which has been successfully synthesized via a facile two-step sol-gel
method. Microspheres were fabricated using cetyltrimethy lammonium
bromide (CTAB) as pore-forming agents, tetraethyl orthosilicate (TEOS).
Compared with small pore size mesoporous silica magnetic microspheres
(2-4 nm), the large pore size one can grat 447 mg/g amino groups in order
to adsorb more heavy metal ions (Pb 2+ : 880.6 mg/g, Cu 2+ : 628.3 mg/g, Cd 2+ :
492.4 mg/g) . h e results suggest that the large pore size multifunctional
microspheres are potentially useful materials which are highly ef ective for
adsorbing and removing dif erent heavy metal ions in aqueous solution.
°
9.4 Conclusion
Nowadays, NMOs are widely investigated as highly ei cient adsorbents for
heavy metal separation from wastewater. h ey exhibit various advantages
such as fast kinetics, high capacity, and preferable sorption toward heavy met-
als in aqueous phase. Nevertheless, to further promote the practical applica-
tion of NMOs in removal of heavy metal pollution, some technical issues
still exist which need to be resolved. For example, when applied in aqueous
solution, NMOs tend to aggregate into large-size particles and their capacity
loss seems inevitable. h e low-cost and ei cient separation of heavy metals
from wastewater still remains an attractive but challenging task. Fortunately,
NMOs-based composite adsorbents seem to be an ef ective approach to
respond to all the above technical problems. However, various issues need to
be solved concerning the development of more facile processes to obtain the
composite adsorbents, the answer to the interplay between the hosts and the
supported NMOs, the long-term performance of the composite adsorbents,
as well as their i eld application in heavy metal contaminated water treatment.
References
1. M. Jamil, M.S. Zia, and M. Qasim, Journal of Chemical Society of Pakistan,
Vol. 32, p. 370, 2010.
2. S. Khan, Q. Cao, Y.M. Zheng, Y.Z. Huang, and Y.G. Zhu, Environmental
Pollution Vol. 152, p. 686, 2008.
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