Based On The Application Of Membrane Separation Technology In Production Of Polyaluminum And Desalination Of Acid Blue 9

Environmental protection is paid more and more attention with the deteriorating living environment. The treatment of three-waste production cost enterprises a great investment. Green, environmental friendly product technologies develop quickly. The membrane separation technology because of its low energy consumption, easy operation, long lifespan, and has a wide application in production. This article consists of two parts: the production of polymerization aluminum chloride and dye purification:1. Polyaluminum with high basicity is a kind of important industrial products, is produced by oxidation of the aluminum metal with acid. Aluminum atoms were reduced from alumina to aluminum metal and then formed the polyaluminum by oxidation. The preparation process of polyaluminum is not economic and chemical efficiency is low. In this work, a system of bipolar membrane electrodialysis coupled with ultrafiltration was designed to get polyaluminium salt including polyaluminum chloride, polymaluminum sulfate and polymaluminum nitrate from aluminum hydroxide and the corresponding acid. And it was under normal temperature and pressure. Aluminium hydroxide and acid react as aluminum salt in the mix reactor, separated as aluminum salt pure solutions via ultrafiltration system, then basified in bipolar membrane electrodialysis, the corresponding acid was produced as byproduct and the acid is recycled to react with aluminum hydroxide. In the whole process, aluminum atoms are without deoxidize process or oxidize process, obtained polymaluminium directly. The system works with maximization of atomic economy, and the cost is low. It is a green production process of polymaluminium.2. The concentrations of inorganic salts in dye is high during the synthesis, currently nanofiltration technology is widely used in the desalting and purification. Nanofiltration technology desalt effectively in dye purification. But when the salt concentration is low, nanofiltration technology is difficult to desalt and with a high energy consumption. An optimization of ED desalting process was design in dye purification, it overcomes the defect of nanofiltration desalination. The interaction of dye and ion exchange membrane was researched, including the mechanism of dye adsorption and desorption. After continuous desalting process, the system shows a good stability. SO42- was almost removel, the concentration of Cl- is only 130mg/L(about 96% removed). The purification cost of overall is 0.43 yuan /kg Acid Blue 9 solid. It provides another alternative methods in dye purification.