| Flocculants are widely used in water treatment. Due to the high cost and resistdegradation of synthetic polymer flocculant, and it also has a certain amount ofresidual monomers that inevitably bring toxic. So the application subject to certainrestrictions. However, natural polymer flocculants have rich source of rawmaterial with low cost, large selectivity, little dosage, less sludge, safe and non-toxic, completely biodegradable, and they can get rid of secondary pollution.Therefore, researchers have paid a great attention to natural polymer flocculant.Research and development of new water treatment agent develop forward to moreefficiency, low toxicity, pollution-free.The resource of Koelreuteria paniculata Laxm seeds is rich. In this paper, weused Koelreuteria paniculata Laxm seeds as a raw material to study the conditionof preparation, the flocculating properties, the influencing factors of flocculatingeffect and application in order to develop a new natural polymer flocculant withthe low-cost，safe-used, non-toxic and efficiency. Not only to promote thecomprehensive utilization of resources of Koelreuteria paniculata Laxm, as wellas a wide variety of natural polymer flocculant to contribute. The main contentsare as follows:(1) By determination of the basic physical and chemical properties ofKoelreuteria paniculata Laxm seeds, we knew that Koelreuteria paniculata Laxmseeds has a high content of fat and protein. The crude fat contents of Koelreuteriapaniculata Laxm seeds(Weiyang school district of Shaanxi university of scienceand technology) and Koelreuteria paniculata Laxm seeds(Xianyang schooldistrict of Shaanxi university of science and technology) were respectively27.8%and37.2%, the crude protein contents were respectively19.342%and23.472%,and the isoelectric points were respectively3.2and2.8. Higher protein contentprovided the theoretical basis for using Koelreuteria paniculata Laxm seeds asflocculant. FT-IR spectra also confirmed that Koelreuteria paniculata Laxm seeds were rich in fat.(2) Koelreuteria paniculata Laxm seeds were produced as dry powderflocculant, water extract flocculant and salt extract flocculant. Combined theflocculant dosage, pH, temperature these three factors, found water extractflocculant was the most viable option.(3) Using Kaolin suspension as the simulate water sample, the studyinvestigated the influence of pH, temperature, dosage on flocculanting activity ofKoelreuteria paniculata Laxm seeds flocculant. By single factor test andorthogonal test, it showed the most important factor was pH. The experimentalresults showed that for100mL mass concentration of5g/L Kaolin suspension, at30℃,0.6mL5g/L Koelreuteria paniculata Laxm seeds water extract (Weiyangschool district), and pH of2.6, the best flocculating effect was obtained,92.98%removal in turbidity occurred. Also at50℃,1.0mL5g/L Koelreuteria paniculataLaxm seeds water extract (Xianyang school district), and pH of3.8, the bestflocculating effect was obtained, up to94.72%removal in turbidity occurred.(4) Several kinds of metal ions played a facilitating role on the flocculantingeffect. The promoting effects of Al3+and Fe3+are very significant.(5) The flocculating effect of Koelreuteria paniculata Laxm seeds flocculant-Fe3+was better than Fe3+alone. It got the same treatment effect with less amountof Fe3+. By single factor test and response surface method to determine the bestflocculation condition. The experimental results showed that0.75mmol/L Fe3+concentration,0.3mL5g/L Koelreuteria paniculata Laxm seeds water extract(Xianyang school district), and pH of10, the best flocculating effect was obtained,more than99%removal in turbidity occurred. The result was similar with themodel prediction.(6) Koelreuteria paniculata Laxm seeds flocculant were used to treat Cr6+andCr3+solution. That had achieved a certain effect. When the concentration of5g/Lflocculant dose was6mL, pH=2, it obtained the maximum Cr6+removal of91.25%,when the concentration of5g/L flocculant dose was8mL, pH=6, the maximumCr3+removal reached81.56%. |
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