The Preparation And The Removal Algae Characteristic Of The Quaternized Organic Clay Minerals

With the city’s development and the improvement of people’s living standards, the eutrophication problem of urban landscape water is getting worse. The high efficiency and no secondary pollution technigues to recover landscape water have attracted people’s attention. This paper not only studied effects of smectites(MMT) modified by quaternary ammonium compound cation surfactant(CTAB, cetyltrimethyl ammonium bromide and DTAC, dodecyl trimethyl ammonium chlorid) to remove the algae in landscape water using three kinds of algaes: Cyanobacteria, Green algae, Diatoms, isolated from Xi’an Xingqing Lake in where they are dominant species, but also investigated the optimal conditions to prepare organic-modified smectites. The following conclusions are drawn.(1)The CTAB-modified MMT and DTAC-modified MMT were prepared at the optimum conditions: 60℃/1h/p H≥7, and 50℃/1h/p H≥7, respectively. For both CTAB and DTAC, their usage amount was the main influence factor to affect the exchange capacity of modified MMT.(2) For CTAB-modification and DTAC-modification, MMTs with the quaternary ammonium salt exchange capacity of 1.5CEC have the highest algae removal rate.(3)The optimal conditions of modified MMT to remove algae were studied.CTAB-modified MMT and DTAC-modified MMT showed the the best algae removal rate against Chlorella at the concentration of 30mg/L, 20℃, p H=7 and 24 h. But under the optimal conditions, the difference of their algae removal rates against Chlorella was not observed comparing with that of MMT.CTAB-modified MMT and DTAC-modified MMT showed the the best algae removal rate against Diatoms at the concentration of 30mg/L, 25℃, p H=6 and 36 h, at which the algae removal rate against Diatoms of CTAB-modified MMT and DTAC-modified MMT are higher 20.75% and 25.85% than that of MMT, respectively. At the natural temperature and p H>6, modified MMT is more efficient to remove Diatoms than unmodified MMT, which shows that the removal of green algae by organic modified clay is suitable for practical application.CTAB-modified MMT and DTAC-modified MMT showed the the best algae removal rate against Cyanobacteria at the concentration of 40mg/L, 35℃, p H=7 and 24 h at which the algae removal rate against Cyanobacteria of CTAB-modified MMT and DTAC-modified MMT are higher 22.89% and 24.99% than that of MMT, respectively. When temperature is lower than 35℃ and p H>7, modified MMT is more efficient to remove Cyanobacteria than unmodified MMT, which shows that the removal of green algae by organic modified clay is suitable for practical application.The study provides a theoretical basis for the control of eutrophication caused by different algae species in various seasons. There are 28 charts, 20 tables and 104 references in this paper.