Surface Modification Of Ceramics Filters And Experiment Research In The Pretreatment Of Light Polluted Water

Alongside the sources of drinking water are polluted increasingly, traditional water treatment technology can hardly reach the national hygiene standard of drinking water, so it is necessary to develop new water treatment technology. Coating of iron-oxide can improve the surface characters of original filter media ,and will then enhance the ability of filter media to remove contaminant such as organic matter.The experiment used a kind of ceramics filters which was produced by the red grain of Shandong Alum Corporation as the carrier, using Fe(NO₃)₃ as the modifying agent, we assumed the way of heating vaporization to modify ceramics preparation. After The modified ceramics filters in different modifying conditions were shaked three hours in light polluted water, the removing rates of COD were mensurated, and the highest removing rate would confirm the best modifying condition, which contained pH value at seven, Fe(NO₃)₃ with the density of 2mol/L,roasting temperature at 550 centigrade, the times of modifying for four times. Compared with the numerical value using ceramics filters, the rate of removing COD was enhanced six to eight times.The surface area after modified was 4.987 times as large as that of original ceramics filters; The matter species of iron oxide film were analyzed by XRD, which showed that it containsα-Fe₂O₃ andα-FeOOH, and they were helpful for removing organic matter; The surface morphologies of the modified filter medium were observed by SEM, which indicated that iron oxide film being fine particle was covered on original ceramics filters orderly and well-proportionedly, and it was benefit for enhancing adsorption capability.Filter experiment with model filter pillar indicated that they all had good effects on removing suspended matters under different velocities(5m/h,10 m/h,15 m/h); The removing rate of organic matter became worse and worse with the filter velocity increasing; In addition, it was unconspicuous for modified ceramics filters to remove the TN, but the TP removing rate was much better.At last, the mechanism of removing contamination with modified ceramics filters was analyzed in this paper, which were showed in the following four facets: (1)Increasing the surface area would enhance adsorption capability; (2)The pH value at zero point of charge on oxide was enhanced, and the contamination could be removed by electric charge attraction; (3)Hydroxide ion attached to metal ion could be exchanged by organic negative ion in light polluted water; (4)Absord point(tiny finestra and middle finestra)was increased on the surface.