Preparation Of Inorganic Flocculant-Polymeric Aluminum Ferric Silicate-Chloride (PAFCSi) And Treatment Of Papermaking Wastewater

Nowadays, many methods belonging to chemistry and biology, ionic complex reaction, chemical oxidation process and electrodialysis process are employed in the wastewater treatment, but the most widely used and less-cost method is the way of flocculating sedimentation. Obviously, the coagulation effect is largely affected by which coagulant we use and how effective it is. Consequently, it is important to study and manufacture high-effect, low-toxicity and low-cost coagulant in the field of environmental engineering.Using pickling liquid waste water of hydrochloric acid, iron scurf and aluminiferous mine as the raw materials, a new kind of inorganic polymer coagulant -polymeric aluminum ferric silicate-chloride(PAFCSi) was prepared. The transformation of polysilicic, Al(III) and Fe(IH), the electrical character, the structure and stability of PAFCSi were examined completely and deeply by means of various experimental methods and instrumental analysis techniques, including micro-electrophoretic mobility detector, IR spectrum, scanning electron microscope, electron microscope and TG-DTG analysis et al.. And the flocculating mechanism was also studied. The results show that PAFCSi is a new polymer formed by the interactions of polysilicic, Al(III) and Fe(III). Compared with PAC, PAFCSi is characterized by having less positive charge, lower residual aluminum content, and better stability in a certain temperature range. In the experiment, the flocculating properties of PAFCSi were tested in deinking effluent, pulp washing wastewater and bleaching effluent. The results show that the flocculating effectiveness of PAFCSi is better than PAC, PFS and AS. Under the optimum conditions, CODcr of deinking effluent can be reduced from 756.2mg/L to 139.9mg/L, removal of CODcr is 81.5%; the efficiency of PAFCSi plus PAM is better, CODcr of pulp washing wastewater can be reduced to less than 350.0mg/L, 82.9%of CODcr is removed, chroma and SS are 90PCU and 32.6mg/L, respectively; when PAFCSi is applied to treat bleaching effluent, which has poor degradability by microorganism, chroma can be reduced from 980PCU to 50PCU,...