Preparation Of Modified Starch Composite Flocculant And Its Properties

With the rapid development of modern industry, the wastewater dischargepollution problem by many production enterprises is getting worse. Among them, theagricultural products, food processing industry discharge caused by highconcentration organic wastewater treatment of water pollution problem is moreserious. Potato starch wastewater belong to high concentration organic wastewater,the wastewater containing starch, sugars, amino acids, fat, organic acids, vitamins andenzymes, etc. If arbitrary discharge of high nutrition wastewater will cause the oxygendeficiency in the water; make aquatic organisms died of asphyxiation, great harm tothe environment. Therefore, these harmful wastewater treatments appears very urgent,chemical flocculation is one kind of important processing method,there are theinfrastructure less investment, simple process, easy operation and low energyconsumption. Inorganic polymer has been an important role in wastewater treatment,simple process and low price. Potato starch, which has a wide range of advantages,such as from large resources, innocuous, biodegradability, cheap and so on, is widelyused in the study in wastewater treatment, due to the higher the chemical andbiological stability, easy to regeneration. In this thesis, a new type ofinorganic/organic polymer composite flocculant, modified starch composite flocculantwere prepared using inorganic polymer, potato starch which was modified forcarboxymethyl potato starch, and removal rate of chemical oxygen demand (COD)were investigated from potato starch wastewater which a typical high concentrationorganic one.Firstly, to composite flocculant in starch wastewater treatment of the applicationis reviewed in this paper. And summarized starch wastewater treatment and theproblems in the various methods.Secondly, the polyaluminium chloride-carboxymethyl potato starch (PAC-CMPS)composite flocculant was prepared using aluminium chloride and carboxymethylstarch. Using orthogonal experimental design, the optimum conditions for preparationof PAC-CMPS were given based on the removal rates of COD in high concentrationorganic wastewater (potato starch wastewater). The structure and apparentmorphology of PAC-CMPS were characterized by FTIR, TG and SEM. Study on theflocculation performance of potato starch wastewater, the investigation of the effect of flocculation temperature, time, pH and dosage on the removal rate of COD, under thecondition, the removal rate reached to87.8%。Thirdly, the polymeric ferric sulfate-carboxymethyl potato starch (PFS-CMPS)composite flocculant was prepared using ferrous sulfate heptahydrate andcarboxymethyl starch. Using orthogonal experimental design, the optimum conditionsfor preparation of PFS-CMPS were given based on the removal rates of COD in highconcentration organic wastewater (potato starch waste water). The structure andapparent morphology of PFS-CMPS were characterized by FTIR, TG and SEM.Study on the flocculation performance of potato starch wastewater, the investigationof the effect of flocculation temperature, time, pH and dosage on the removal rate ofCOD, under the condition, the removal rate reached to82.4%。Fourthly, the polymeric aluminum ferric chloride-carboxymethyl potato starch(PAFC-CMPS) composite flocculant was prepared using aluminium chloride, ferricchloride hexahydrate and carboxymethyl starch.. Using orthogonal experimentaldesign, the optimum conditions for preparation of PAFC-CMPS were given based onthe removal rates of COD in high concentration organic wastewater (potato starchwaste water). The structure and apparent morphology of PAFC-CMPS werecharacterized by FTIR, TG and SEM. Study on the flocculation performance of potatostarch wastewater, the investigation of the effect of flocculation temperature, time, pHand dosage on the removal rate of COD, under the condition, the removal rate reachedto77.9%。...