| Adsorption process which is the most basic and common water treatment process, has advantages of simple structure and convenient use operation simple and convenient maintenance, low cost advantages. But the downside is also very obvious that covers an area of big, long processing time, water quality is not stable. Ultrafiltration technology in recent years, with the energy conservation and environmental protection, green high efficiency become the theme of the mainstream technology, this technology has a fast and efficient, stable discharging water, saving land, easy automation and miniaturization. Defect is equipment operation maintenance complex, high cost. This experiment combined with two kinds of process characteristics, the adsorption in the filter process combination, make it both run maintenance cost, water quality, fast and efficient, and the advantages of miniaturization.This article explores the common adsorptive fluorine technology combined with the emerging of ultrafiltration technology, by combining the advantages of two kinds of research of the fluorine ion removal. This experiment USES the engineering of the most commonly used adsorbent activated carbon, daily fluoride ion removal with adsorbent activated alumina and emerging fluorine ion adsorbent adsorption process hydroxyapatite material, experiment. In the adsorbent physical characterization, can observe the three have large specific surface area. There should be a fairly adhesion ability of physics. With respect to its physical characterization of speculation out except for:hydroxyapatite> activated alumina> activated carbon.The adsorption experiment is in ion concentration of lOmg/L. Based on the optimal adsorbent dosage, we focused on testing the condition such as temperature, pH value, adsorption time for the effects of fluoride removal. We obtained that with the change of temperature, the fluorine ion removal efficiency change accordingly, they present positive correlation; with the increase of pH, the fluoride removal rate fell significantly; activated carbon does not have the typical of removing fluorine. The adsorbent for fluoride removal in 90 min after gradually to reach equilibrium. The adsorption capacity of activated carbon/activated alumina and hydroxyapatite is 0.7mg/g,1.02mg/g and 2.02mg/g.Based on the analysis of adsorption thermodynamics and adsorption kinetics which reaction is in solid-liquid heterogeneous to remove fluorine ion. We know that adsorption thermodynamic test of fluorine ion adsorption reaction conform Langmuir isothermal formula. Adsorption thermodynamics test shows that fluorine ion adsorption is given priority to with chemical adsorption.The intermittent dynamic adsorption experiment with the equipment combined ultrafiltration concluded that the recovery rate of the three adsorbent are hydroxyapatite 88.79%, activated alumina87.32% and activated carbon 91.23%, respectively.Based on the removal efficiency of three kinds of selected adsorbent, we carried out the test of fluoride ion removal effect by different cycle and aeration. The results confirmed that: the emerging adsorbent hydroxyatite has a better adsorption ability and process stability than the adsorbent activated alumina in fluorine ion. Both above two types of adsorbent have very significant removal efficiency than traditional adsorbent activated carbon in fluorine ion removed.Because activated carbon does not have obvious fluorine removal characteristics, and activated alumina has part problems of aluminum ions residue. Therefore hydroxyapatite has a significant advantage of all there adsorbents without problems mentioned above. Adsorption of ultrafiltration coupled devices running stability is better, and the operation simple and convenient, has a certain feasibility. |
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