| China is a country which is rich of coal, short of oil and contained with gas. The total coal reserve which is widely distributed and has complete varieties reaches 114.5 billion tons. The lignite holds a large proportion of the total coal. Because of the disadvantages of the lignite on low calorific value, high humidity, low ignition point and large amounts of carbon dioxide emissions, using lignite gasification process, especially the Lurgi process, to prepare gas can effectively alleviate the current problem about energy shortage. But using lignite gasification process will generate a large amount of typical refractory organic industry wastewater which has complex quality, high ammonia content, large phenol content, high COD, poor biodegradability, high toxicity and great chroma. The polycyclic aromatic hydrocarbons, phenols and ammonia in the wastewater will do serious harm to humans and the environment. In recent years, lignite gasification wastewater has become a bottleneck of restricting the development of lignite gasification technology. Thus, finding an efficient and economical method of treating the wastewater has great significance for society, environment and economy.Compared with traditional resin, the magnetic resin has smaller particle size and faster mass transfer, is easy to separate and difficult to drain with water, has not only the ion exchange, but also hydrogen bonding, π-π effect and cation-π:effect. In recent years, more and more scholars committed to the development and research of magnetic resin, but most of works are applied to remove macromolecular pollutants in low concentration water. Based on the advantages of magnetic resin, it should also have greater potential in removing macromolecular pollutants in high concentration water. This study is to explore the potential applications of magnetic resin in high concentration water.In this study, we use magnetic resin NDMP which is developed independently by Nanjing University to research the main organics in actual wastewater, the adsorption mechanism of chromogenic materials and the treatment of the actual wastewater. Theoretical results show that adsorption of NDMP resin to phenol, m-cresol. quinoline, pyridine reached equilibrium within 5min, the time of potassium ferricyanide is 10min. The five substances can be better described by using Freundlich model. PH has greater impact on phenol and m-cresol, but it almost has no effect on the quinoline and pyridine, and ii has little effect on potassium ferric>anide. There is a competitive adsorption between phenol, m-cresol, quinoline and pyridine. NDMP resin has a good bleaching performance on potassium ferricyanide. Different renewable liquid has different effects on regeneration of NDMP resin, of which 1% NaCl mixing 1% NaOH is the best.The tests of actual wastewater show that NDMP resin can well remove the COD of lignite gasification wastewater, PH has greater impact on the removal efficiency which increased first and then decreased, and reached maximum at PH=11. Dosage and adsorption time of NDMP resin is proportional to the removal amount of COD. NDMP resin can not only adsorb molecules in wastewater, but also effectively remove the macromolecules. NDMP resin can remove chroma in wastewater significantly. For the actual wastewater, its chroma can drop from 3200 to 400. For wastewater after 5000D ultrafiltration, its chroma can drop to 64. When using NDMP resin to treat lignite gasification wastewater, it has good stability and larger removal of COD, and the average removal of COD is 2845mg/L. |
PDF Full Text Request