| Summary: | 博士 === 國立交通大學 === 土木工程學系 === 85 === ABSTRACT Cyanide compound is commonly found as a waste water contaminant on s
everal industrial processes such as electroplate, mining, photographic, metall
urgical, synthetic fiber and industrial gas purification and so on. Although c
yanide compound exists in small amount in the nature system, it is tightly con
trolled and highly toxic chemical material. "Industrial cyanide salt" includes
simple free cyanide and metal complex cyanide, the former exists in the form
of CN- and HCN. Free cyanide is highly toxic, the le This proposed research p
roject aims at the study of adsorption behavior of ferricyanide and ferrocyani
de on the aluminum oxide (g-Al2O3) surface as a functions of pH and concentrat
ion with batch experiments. Attempts to describe and predict the adsorption of
ferrocyanide/ferricyanide by aluminum oxide particle will be treated surface
sites as homogeneous groups with intrinsic constant using a triple-layer mode
l or with a single adsorption constant incorporating proton competition effect
using a modified The experiment results indicated, the adsorption percentag
es of ferricyanide and ferrocyanide on g-aluminum oxide decreased with increas
ing pH and initial concentration of ferricyanide and ferrocyanide. The triple-
layer model was used for simulating ferricyanide and ferrocyanide adsorption o
n g-aluminum oxide surface. Then, AlOH2+--Fe(CN)63- and AlOH2+--HFe(CN)63- hav
e been shown with outer-sphere reaction products to be more agreeable with exp
erimental adsorption observation than complexation with other The modified L
angmuir isotherm model developed herein can accurately predict the apparent eq
uilibrium constant at different pH values and temperature for ferrocyanide and
ferricyanide adsorption onto aluminum oxide surface. In the experimental pH r
ange of 5~7.5, adsorption capacity and apparent constants decrease as the temp
erature increases. According to the Gibbs-Helmholtz equation, these apparent c
onstants at various temperature and pH conditions can be applied to determine
enthalpy changes (DHo) for t By batch experiments, under the condition of pH
6.0, 25℃, electrolyte concentration 0.01M, the maximum adsorption capacity of
kaolinite, aluminum oxide and hydrous iron oxide are 3.1*10-8、4.2*10-7、5.0*
10-7 mol/m2 for ferricyanide and 5.8*10-8、6.3*10-7、1.1*10-6 mol/m2 for ferro
cyanide adsorption。This results shown a strong relationship between the value
s of adsorption capacity and the site density of oxide surface. From there
highly valence, the ferrocyanide and ferricyanide ion have strong coagulation
ability in natural water system. In our study, a series of batch test with al
uminum oxide turbid water were performed to evaluate the coagulation effective
ness of anion with different valence. There are dramatic difference in the coa
gulation abilities of simple ions (Cl-、SO42-、Fe(CN)63-、Fe(CN)64-), and othe
r species that interact chemically with the oxide surface (H2PO4-). The eviden
ces infer that the mechanism of
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