Environmental Engineering Reference
In-Depth Information
38.6 Summary
Environmental nanotechnology will bring signiicant transformation in the ield of envi-
ronmental monitoring and treatment. Preparation and application of nanomaterials, nano-
adsorbents, and sensors bring more and more attractive topics and breakthroughs in this
area. The development of nano-IPFs is obviously one of the important contributions in the
sequential potential changes.
The physicochemical properties and speciation distribution of coagulants are among the
deciding factors in the coagulation process. IPFs developed from the traditional salts can be
regarded as the second generation of coagulants. The third generation based on the nano-
species is then discussed concerning aspects of possibility, stability, coagulation behavior,
and mechanism, and the general production methods. However, on the basis of the rapid
development of the hydrolysis chemistry of Al(III) and nanospecies, several knotty problems
remain to be answered: What are the optimum coagulation species and coagulation mecha-
nisms involved? How to design molecularly the optimum coagulation species? How to make
the third-generation coagulants meet the change of water quality? How to develop the water
treatment process it for the needs of application of new coagulants, the reactors, the micro-
interface process, and the process control? All these need further deep investigation and
discussion. A large volume of research previously paid much attention on nano-Al 13 species
being considered as one of the optimum coagulation species owing to its special physico-
chemical properties and stability. However, with more recognition on the Al 6 , Al 8 , KEGGIN-
non-KEGGIN Al 13 , Al 30 , and Al 13 aggregates, answers to what is the optimum species and
how to maintain its optimum performance will be reached in the near future.
Acknowledgments
The authors want to thank the students involved in this research, namely S.F. Wang,
Q.  Gao, G.H. Li, C.Q. Ye, L. Huang, W. Sun, X.H. Wu, Y.J. Chen, Y. Xu, C.H. Feng, M.Q.
Yan, and Z. Bi. This research was supported by a 973 Nano-drinking water project under
2011CB933700; the NSF of China under 51221892, 51025830, 51078348, and 20477054; and
also the 863 program under 2002AA001290.
References
Bi, Z., Chen, Y.J., Wang, S.F., Wang, D.S. (2014) Hydrolyzed Al(III)-clusters. II: Speciation transforma-
tion and stability of Al 13 aggregates, Colloids Surf. A , 440, 59-62.
Bertsch, P.M. (1996) The Environmental Chemistry of Aluminum , CRC Press: NY; Chapter 4.
Bottero, J.Y., Axelos, M., Tchoubar, D., Cases, J.M., Fripiat, J.J., Fiessinger, F. (1987) Mechanism of
formation of aluminum trihydroxide from Keggin Al 13 polymers, JCIS , 117, 47.
Hu, C.Z., Liu, H.J., Qu, J.H., Wang, D.S., Ru, J. (2006) Coagulation behavior of aluminum salts in
eutrophic water: Signiicance of Al 13 species and pH control, ES&T , 40(1), 325-331.
Huang, L., Tang, H.X., Wang, D.S., Wang, S.F., Deng, Z.J. (2006a) Al(III) speciation distribution and
transformation in high concentration PACl solutions, J. Environ. Sci. , 18(5), 872-879.
 
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