The Application Of The Modified Bentonite In The Treatment Of Oily Waste Water

The density of the oil in oily wastewater from oil tanker washing is the same as water, and is difficult to be separated from water. The existing methods of oily wastewater treatment have many problems, such as large floor space, high operation cost, instable effluent, and so on. Therefore, it needs to develop more perfect technology of oily wastewater treatment. Bentonite has good adsorption, cation exchange and larger specific surface area, cheap price and is abundant in China, however, the surface silica structure of natural bentonite with strong hydrophilic and interlayer exchangeable cations hydrolysis, makes its surface to form a layer of water film, which results in poor adsorption capacity of hydrophobic organic compounds. Therefore, in order to effectively apply bentonite to deal with oily wastewater, it is necessary to modified bentonite to make its surface from hydrophilicity converted to hydrophilic. Specific content is as follows:Bentonite of natrium and organic bentonite was prepared used cetyl trimethyl ammonium chloride and sodium carbonate as modifier, respectively. The morphology and structure have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and infrared spectrum (FT-IR). SEM and TEM results showed that the surface morphology of bentonite changed, layer spacing increased after modified. XRD results further proved that the layer spacing of organic bentonite increased significantly compared with bentonite and bentonite of natrium. FT-IR results indicated that the basic crystal structure of montmorillonite is no obvious influence after the organic modified and only organic functional group was introduced into montmorillonite interlayer.The different types of bentonite were applied to the treatment of actual oily wastewater as adsorbent materials, and the influence of adsorbent types and the addition of bentonite on the removal efficiency were investigated by the determination of the decolorization rate, COD removal rate and the change of the uv-vis spectra. The results indicated the removal efficiency of oil increased with the increase of amount of bentonite added using the same bentonite for oily wastewater treatment. Under the same conditions, organic bentonite showed the strong decoloring performance and the performance of the removal of organic matter compared with bentonite and bentonite of natrium. The removal rate of COD reached54.62%when1.5g/50ml the quantity of bentonite was added and further increased the addition of organic bentonite; the removal rate remained no change.