Study On The Coagulation Performances Of Cucurbituril On The Removal Of Typical Organic Matters From Water

Coagulation-precipitation technology is a common unit operation process. The type of the coagulants determine the coagulation performance. Therefore, researches on the development and application of coagulants having been conducting extensively. In this paper, a mixed cucurbiturils are made using microwave radiation technology. Its physical and chemical properties were assessed, and the effects of pH, co-existing materials, and coagulant dosage on the removal of humic acids, dye water and different coagulation process of actual water. Study its mechanism of cucurbiturils and organic matter through scanning electron microscope(SEM) and infrared spectroscopy(IR).It was determined that HCl could improve the solubility of cucurbituril notably, and the floc particles formed during coagulation also get denser. Most of the organic matters were removal in physical processes, without new chemical bond formation. When the dosage of cucurbituril was 500 mg/L, the removal rate of humic acid was above 90%. Compared with traditional coagulants, solution pH showed little affects on the removal performances of humic acids during coagulation. Even at pH = 2, the removal rate of humic acid was still as high as 92.54%. Further study showed that exept for calcium and magnesium salts, the co-existance of inorganic salts, would not inhibit the removal of humic acid, but promote the coagulation process for the raw waters with 5 mg/L and 15 mg/L of humic acids, respectively.Compared with the removal performances of humic acids, the removal rates of all the three types of dyes were much higher, approximately 98%. However, coagulation performances of PACl on the removal of dyes were much weaker. The removal rate of acid red G was the highest, but still lower than 70%. Again, the coagulation performance of cucuriturils also showed good adaptability to the variation of pH for the removal of dyes. At pH 2-9, cucuriturils showed a good decolorization effect. Compared with cucuriturils, the decolorization performance of PACl was highly affected by solution pH and co-existing salt concentration. When the dosage of cucurituril was more than 400mg/L, the removal rates of dissolved organic matters were 20% and 25% for the secondary treated wastewater with initial TOC content at 6.0 mg/L and 9.2 mg/L, respectively.The removal rate of selected organic matters were all higher at both low and normal pH values using cucuriturils than that of traditional coagulants. Compared with traditional coagulant, pH has slight affect on the coagulation performance of cucurbiturils. The removal mechanisms of different organic matters are similar. Under the effects of neutralization and compression of electrical double-layer, colloids get destabilized, and finially removal through the effects of bridge connection. In the process of precipitation, parts of the suspended and colloidal solids were swept out. In summary, the cucurbiturils, developed in our study, has research value and good application prospect a novel water treatment material.