TY - JOUR
T1 - Inhomogeneous complexation of trace metals in water with organic nano-complexants
AU - Dolgin, Bella
AU - Bulatov, Valery
AU - Hadar-Abuhatzira, Hodayah
AU - Japarov, Julia
AU - Schechter, Israel
N1 - Funding Information:
This project has been supported by the Israel Council for High Education – the Planning & Budgeting Committee, by the Grand Water Research Institute and by the James Frank program in laser matter interaction. V.B. thanks the Ministry of Immigrant Absorption for financial support (KAMEA Program).
PY - 2011/12
Y1 - 2011/12
N2 - The complexation of heavy metals, such as Cd2+ and Ni 2+, with organic complexants such as 1-(2-pyridylazo)-2-naphthol (PAN) and 1-(2-thiazolylazo)-2-naphthol (TAN) in water has been investigated. Under such conditions, both the reagents and the products form nano-particulates. These materials are important because their spectrum changes upon exposure to heavy metals and they may be used for design of new optical detectors. The kinetic schemes so far suggested for these complexation reactions are not valid for such experimental conditions, since they assume homogeneous behavior. We provide evidences to the inhomogeneous nature of these reactions. The complexation has been studied using TEM imaging, zeta-potentiometry, time-dependent particulate size analysis and time-dependent spectroscopy. Many of the experimental results are explained in terms of the nature of the nano-particulates of these two complexants. Several processes were identified, including crystal growing of the complexant, its reaction with metal ions in solution and on the surface area, chemical erosion of complexant crystallites and their decomposition, re-crystallization of the formed complexes and long term aggregation of both the complexant and the resulted complex. It was found that the needle-like nano-structures on the surface of the TAN particulates governs its reaction and particulate behavior. The known optimal complexation conditions, such as pH, and delay time are now understood in terms of the zeta-potential minima of the suspensions and in terms of the kinetic parameters. Also the interferences of some ions in the Ni-TAN complexation are now quantified and the kinetic data indicate the best delay time when the interfering effects are minimal.
AB - The complexation of heavy metals, such as Cd2+ and Ni 2+, with organic complexants such as 1-(2-pyridylazo)-2-naphthol (PAN) and 1-(2-thiazolylazo)-2-naphthol (TAN) in water has been investigated. Under such conditions, both the reagents and the products form nano-particulates. These materials are important because their spectrum changes upon exposure to heavy metals and they may be used for design of new optical detectors. The kinetic schemes so far suggested for these complexation reactions are not valid for such experimental conditions, since they assume homogeneous behavior. We provide evidences to the inhomogeneous nature of these reactions. The complexation has been studied using TEM imaging, zeta-potentiometry, time-dependent particulate size analysis and time-dependent spectroscopy. Many of the experimental results are explained in terms of the nature of the nano-particulates of these two complexants. Several processes were identified, including crystal growing of the complexant, its reaction with metal ions in solution and on the surface area, chemical erosion of complexant crystallites and their decomposition, re-crystallization of the formed complexes and long term aggregation of both the complexant and the resulted complex. It was found that the needle-like nano-structures on the surface of the TAN particulates governs its reaction and particulate behavior. The known optimal complexation conditions, such as pH, and delay time are now understood in terms of the zeta-potential minima of the suspensions and in terms of the kinetic parameters. Also the interferences of some ions in the Ni-TAN complexation are now quantified and the kinetic data indicate the best delay time when the interfering effects are minimal.
KW - Complexation
KW - Heavy metals
KW - Nanoparticles
KW - Spectral detection
KW - Water
UR - http://www.scopus.com/inward/record.url?scp=81555195207&partnerID=8YFLogxK
U2 - 10.1016/j.optmat.2011.05.022
DO - 10.1016/j.optmat.2011.05.022
M3 - 文章
AN - SCOPUS:81555195207
SN - 0925-3467
VL - 34
SP - 391
EP - 398
JO - Optical Materials
JF - Optical Materials
IS - 2
ER -