Preparation of an inorganic composite flocculant and its effect on dye wastewater treatment
- SUN Shuqing, SUN Fengkai, LIANG Shuang, XU Xiaoli
JOURNAL OF SHANDONG UNIVERSITY (ENGINEERING SCIENCE). 2018, 48(2):
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With FeCl3·6H2O, ZnSO4·7H2O, MgCl2·6H2O and Na2SiO3·9H2O as main materials, the flocculant poly-silicate ferric zinc magnesium was prepared. The optimal molar ratio of iron, zinc, magnesium and silicon and the impact of initial pH and flocculant dosage on the decolorization rate and sludge volume were investigated through the decolorization experiment of Congo red wastewater. The results showed that the optimal molar ratio of Fe, Zn, Mg and Si was 1∶4∶1∶2. The decolorization rate was higher than 90% during the range of pH 9.0~13.0. Especially at pH=10.0 and 11.0, the decolorization rate reached 99%. Under a certain pH condition, the decolorization performance of the flocculant on the Congo red solution increased and then decreased with the addition of dosage. Sludge volume increased with the increase of pH and flocculant dosage. Especially when pH changed from 11.0 to 12.0, the sludge volume increased nearly 3 times. Compared with the traditional magnesium salt flocculant, poly-silicate ferric zinc magnesium had the advantages of wider pH application range and smaller sludge volume when treating dye wastewater.