[Ten years of major development in chemical technology] 051-2019 Polytetrafluoroethylene (PTFE) hollow fiber membrane contactor for high-concentration ammonia nitrogen removal

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Chemical science and technology has developed greatly in the past ten years. Praise for China's prosperity and strength in the prosperous age. It will be more lively and exciting with everyone's participation. Everyone is welcome to participate in more forum exchanges and discussions. Everyone pays attention to safety and knows how to respond to emergencies. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * In January 2019, after 120 hours of continuous operation, the polytetrafluoroethylene (PTFE) hollow fiber membrane contactor technology developed by Cao Yiming's research team at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, was successfully used in a high-concentration ammonia nitrogen removal treatment project in vanadium extraction wastewater. This is the first time in the world that new membrane technology has been successfully applied in wastewater treatment in the vanadium extraction industry. On-site operation data shows that the ammonia nitrogen concentration of the treated vanadium extraction wastewater is stable at 2-7mg/L, which meets the requirements of the vanadium industrial pollution discharge standard (10mg/L) and the national sewage discharge standard Level 1 A (8mg/L). The wastewater treatment capacity reaches 50 tons/day. As we all know, nitrosamines are strong carcinogens, and ammonia nitrogen is an important source of nitrosamines. High-concentration ammonia nitrogen wastewater is mainly discharged by production companies such as steel, pharmaceuticals, fertilizers, petrochemicals, aquaculture, and domestic sewage. If not treated, it can cause peculiar smell in the water body, and in severe cases can cause fish poisoning and death. In the past, high-concentration ammonia nitrogen wastewater was mainly treated by blowing off method, steam stripping method, etc. However, there are common problems such as high energy consumption, low efficiency and secondary pollution. The new "membrane deamination" technology developed by the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, uses a hydrophobic porous membrane to provide a mass transfer interface, and then the ammonia nitrogen wastewater after alkali adjustment and absorbent such as dilute acid flow through both sides of the membrane respectively. The ammonia in the sewage will be absorbed by the dilute acid, thereby reducing the ammonia nitrogen value in the wastewater to meet the emission standards. The core of the "membrane deamination" technology developed by the Dalian Institute of Chemical Physics, Chinese Academy of Sciences is a high-performance, highly hydrophobic porous hollow fiber membrane, and the characteristics of polytetrafluoroethylene make it an ideal membrane material. Polytetrafluoroethylene, also known as the "King of Plastics", has excellent chemical stability, hydrophobicity and mechanical properties. After years of research and development, the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, has developed a polytetrafluoroethylene hollow fiber microporous membrane with an inner/outer diameter of 0.4/0.8mm respectively. It has now achieved large-scale and stable production and has excellent hydrophobicity and anti-pollution properties. In addition, in the process of high-concentration nitrogen and ammonia sewage treatment, low-cost lime is used instead of liquid alkali to adjust the pH value, which greatly reduces the cost of high-concentration sewage treatment and forms sewage treatment advantages such as low energy consumption, high deamination efficiency, low operating costs, and compact equipment. It is reported that the project was jointly completed by the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Nanjing Bidun New Membrane Technology Co., Ltd., and Panzhihua Biyuan Technology Co., Ltd. At present, this new membrane technology has been promoted and applied in the fields of natural gas or biogas purification, membrane distillation, wastewater treatment such as deamination of ammonia nitrogen from garbage permeate, and sulfur-containing tail gas treatment.