Design And Preparation Of Ceramic Matrix Porous Materials And Its Application In The Sewage

Nowadays, with the progress of science and technology and industry development, the environmental pollution is increasingly conspicuous. Especially water pollution, has bought great influence on the national economical development and our everyday life. Coke plant wastewater is a kind of intractable waste water during the process of making hard coke. The components of coke plant wastewater are complex. In the treatment of coke plant wastewater by traditional integrated technique, the oil removal efficiency is too low so that the ammonia still is blocked up by coke tar, and the PAHs reduce the activity of bacterium during the following bio-treatment. Therefore, in order to meet the requirement of strict ecological environment quality standards, the advanced technologies should be adopted to upgrade their existing equipment and technologies.In this paper, the porous ceramic filter was used to remove the coking tars for the pre-treatment of coking wastewater. Ceramic filtration could reduce the quantity of tars that feed to post-treatment process, thus decrease the adverse effect to post-biological treatment and the diffusion rate of polycyclic aromatic hydrocarbons(PAHs). After the biological treatment, enhanced treatment measures, such as activated carbon adsorption and advanced oxidation processes, were adopted to adapt criterion for sewage discharge. The preparation and adsorptive properties of activated carbon and ceramic/acticarbon composites were mainly studied. Moreover, the absorption removal of heavy metal ions on low silica X-zeolite and ceramic/low silica X-zeolite composite materials were also discussed in this paper.The ceramic filtration for the pretreatment of coking wastewater was investigated. The optimization of operating conditions were obtained, including the filtration pressure, filtration flow, regeneration of filter backwash mode of operation, and the backwash time. The results showed that the pollutants in coking wastewater, such as suspended solids, oils substances and PAH, could be removed effectively by ceramic filter pretreatment. It was very beneficial to avoid reducing biological activity in biological processes by hazardous pollutants, and control the diffusion rate of PAHs successfully. Through the development of effective oil removal equipment in ceramic filter, the operation period of filtration material could be prolonged 20%,and the removal rate of tars improved by 10%.According to the characteristics of higher concentration of phenols in coking wastewater after ceramic filtration, the sorption action of activated carbon absorbing the phenols has been mainly discussed. By discussing and comparing the absorptive function of different modified activated carbon, we have come to the conclusion that adsorption ability of activated carbon for phenols not only depend on the specific surface area, but also the surface groups. Adsorption capacity for phenols of activated carbon modified by alkaline functional groups, especially oxygen containing groups, was better than which modified by acidic groups. Activated carbon obtained from coal tar pitch could considerably adsorb phenolic compounds.Ceramic/carbon composite material has been prepared by in situ carbonization and activation from coal tar pitch. The composite material shows the smaller pore size and higher hydrophobic surface than ceramic, so that the composite material had more powerful adsorption and filtration capabilities. The composite material may be used as catalyst carrier for wastewater treatment by advanced oxidation process owing to its excellent properties in mechanical strength and hydrophobic surface.In addition, low-silica X zeolite was utilized for the adsorption of heavy metals. Under the optimized conditions, the heavy metals in the solution were efficiently removed. Furthermore, the low-silica zeolite was embedded into ceramics to function as ceramic-zeolite composites. Such composite materials can also be used for the removal of heavy metals and, more importantly, they can be regenerated for further use with good adsorption ability. Compared with sole zeolite, the composites possessed several advantages such as easy operation, no need of filtration and the feasibility of regeneration.