Abstract:
Coagulation is one of the most important steps during the conventional water treatment train . Salts and prehydrolysed salts of aluminum and iron were used as coagulants in water and waste water treatment; These effective materials play a vital role in the removal of a board range of impurities from water including colloidal particles, dissolved organic substances and some heavy metals.
Because of superior efficiency and relatively low cost of these materials compared with traditional coagulant alum, aluminum salts and iron salted of the prehydrolysed iron and aluminum salts with active silica were favorable in addition to the following features: very fast hydrolysis , promote rapid settling rates, extremely efficient in cold water, give low soluble residual aluminum, consume less alkalinity, very little effect on pH, increase stability of coagulant and denser compacted sludge.
The objective of this study is to prepare four new types of poly inorganic co-agulants (PIC); these are poly aluminum chloride silicate ( PAClSi ), poly hydroxy aluminum sulphate silicate ( PHASSi ), poly ferric chloride silicate ( PFeClSi ), and poly ferric aluminum chloride silicate ( PFeAlClSi ) based on silica. The characterization of the materials obtained was carried out by means of by FTIR, NFTIR, XRD, and SEM., in order to select the optimum condition suitable for removal of some pollutants. Under this study the maximum removal of some ground water pollutants as turbidity , colour, Fe, Mn, Pb, As, NO3-1 and F-1 are about 70%,75% 97.5%, 96%, 97%, 97%, 97%, and 99% respectively ; the maximum removal of Pb in industrial waste water reach to 99%; the maximum removal of BOD, COD and TSS in sewage waste water are 92 %, 90 %, 93 % , respectively .