| Currently,coagulation/flocculation is one of the most commonly methods used for landscape water restoration.Development of new efficient quality flocculants to improve flocculation effect in water treatment has become the focus of research in water treatment field.In this paper,a new type flocculant which can improve the turbidity and phosphorus removal efficiency was developed.At first,the flocculants which was screened from commonly used inorganic flocculants and organic flocculants with better turbidity and phosphorus removal efficiency were mixed to treat kaolinite water samples.By means of comparison,the difference in turbidity and phosphorus removing of single flocculant and composite flocculant was analyzed.According to the experimental results,the CTS-AM graft copolymer were synthesizedand by chitosan and acrylamide.Then a novel PAFC-(CTS-AM)composite flocculant was prepared by compounding CTS-AM graft copolymer with self-made polymerized aluminum-iron,and the optimum conditions for the flocculant,flocculation performance for the removal of turbidity and phosphorus,structural characterization and floc properties were systematically studied.At last,a new type of flocculant was prepared by compounding PAFC-(CTS-AM)composite flocculant with oxygenating agent,of which the floating efficiency and the reaction mechanism were studied.The main research contents and conclusions are as follows:(1)The flocculation performance of four kinds of flocculants such as organic flocculant,inorganic flocculant,inorganic-organic complex flocculant and organic-organic flocculant is:inorganic-organic flocculant>inorganic flocculant>organic-organic compound Flocculants>Organic flocculants.(2)The optimal reaction conditions of CTS-AM graft copolymer were as follows:the initiator mass fraction was 0.03%,the monomer mass ratio of AM to CTS was 1:4,the pH value was 2,the reaction temperature was 60 ?,and reaction time was 5 h.Under this condition,the intrinsic viscosity of CTS-AM graft copolymer is 4.65 dL/g.(3)The flocculation performance of the PAFC-(CTS-AM)composite flocculant was influenced by factors such as pH,dosing ratio,mixing time,settling time and the addition of fly ash.When the reaction conditions were as follows:pH 9,PAFC:CTS-AM of 5:1,stirring time of 4min and settling time of more than 9min,flocculants had the best turbidity and phosphorus removal efficiencies of 93.27%and 53.31%respectively.(4)The structure characterization of the PAFC-(CTS-AM)and the fly ash/PAFC-(CTS-AM)was investigated by infrared spectroscopy,scanning electron microscopy and X-ray diffraction.The FT-IR results showed that the hydroxyl bridged iron salt polymer was present in the flocculants.And the XRD results showed that the two kinds of complex flocculants both had good crystal structure.The results of SEM showed that the cross-linked structure of PAFC and CTS-AM graft copolymer appeared,which enhanced the adsorption and net-capture performance of the flocculants.The particle size of the two flocculants was measured on-line with the laser particle analyzer.The results showed that the floc size of PAFC-(CTS-AM)was larger than that of fly ash/PAFC-(CTS-AM)The average floc size of PAFC-(CTS-AM)increased by 128.9 um,while that of fly ash/PAFC-(CTS-AM)increased only by 38.34 um.The flotation performance of aerobic agent A was significant.Only 0.05 g of the oxygenating agent A can make the flocculant flocs completely floated.The performance of flocculant floating was ranked as inorganic-organic complex flocculant>inorganic flocculant,of which the flocculant performancet of both PAFC-(CTS-AM)and fly ash/PAFC-(CTS-AM)was superior. |
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