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Do you know what adsorption methods are available for ammonia nitrogen removal?

by:BOQU     2023-03-20
In terms of adsorption and denitrification treatment of wastewater, a lot of research has been carried out at home and abroad, and a variety of feasible processes have been proposed. The focus is on the study of adsorption mechanism, adsorbent performance comparison and regeneration method. There are many studies on zeolite, fly ash, and bentonite. The removal principle of ammonia nitrogen is mainly the adsorption of non-ionic ammonia and ion exchange with ionic ammonia. The main factors affecting the removal of ammonia nitrogen include the reaction time with the adsorbent solution, the amount of adsorbent used, the concentration of ammonia nitrogen in the solution, the particle size of the adsorbent, and the temperature of the solution. Several common ammonia nitrogen adsorbents 1. Activated carbon Activated carbon (AC) is a common adsorption material, its adsorption is mainly physical adsorption, but due to the existence of surface oxides, some chemical selective adsorption. Activated carbon is a commonly used adsorbent in wastewater treatment. Among them, granular carbon is used in the largest amount because of its simple process, convenient operation, and large amount. The granular carbon used abroad is mostly coal or shell amorphous carbon, and the domestic one is mostly columnar coal. Activated carbon mainly adsorbs nitrogen in water in the form of ammonia molecules, which has no selectivity and limited adsorption capacity, so the denitrification efficiency is very low. 2. Activated carbon fiber Activated carbon fiber (ACF) is a new type of adsorption functional material, which is made of lignin, cellulose, phenolic fiber, polypropylene fiber, pitch fiber, etc. through carbonization and activation. Compared with activated carbon, ACF has a unique microporous structure, higher external surface area and specific surface area, as well as a variety of functional groups, and the average pore size is also smaller. It has been widely used in the fields of water treatment and water purification. The desorption and regeneration speed of activated carbon fiber is fast, the time is short, and the performance is unchanged, which is better than activated carbon. 3. Zeolite Zeolite (Zeolite) is a widely distributed and mined natural and cheap ion exchange material. Zeolite has a large specific surface area (400-800m2/g zeolite), second only to activated carbon, and can be used as an adsorbent, ion exchanger, etc. Zeolite has preferential and selective adsorption for polar, unsaturated and easily polarized molecules. Zeolite has acid resistance, alkali resistance, thermal stability and other properties, and is often used in industrial wastewater treatment. In terms of ion exchange and quantitative treatment, clinoptilolite has good selectivity to NH4+-N, so it can be used in the deammonization nitrogen treatment process of engineering sewage, and the denitrification rate can reach 90% to 97%. The industrial zeolite ammonia removal device is relatively simple, generally a cylindrical filter. 4. Humic acid adsorbent Humic acid is a negatively charged polyelectrolyte and an organic substance with a large molecular weight. The nature and structure of humic acid itself determine its ability to adsorb cations. The adsorption of humic acid on cations, including ion exchange, integration, surface adsorption, condensation, etc., has both chemical adsorption and physical adsorption. There are two types of humic acid substances used as adsorbents: one is weathered coal, peat, lignite, etc., which are naturally rich in humic acid, which are directly used as adsorbents or after simple treatment; the other is the use of humic acid-rich substances , with appropriate binders, made into humic acid resin, granulated, and used in tubular or tower adsorption devices. 5. Coal-based adsorbent Coal-based adsorbent has the function of removing metal ions, cyanide, volatile phenol, etc. in wastewater. It has strong adsorption capacity, low price, and does not need to be regenerated. Coal reacts with concentrated sulfuric acid or oleum to produce sulfonated coal, which can be used to treat TNT wastewater. After adsorption, it can be easily desorbed with acetone or ethyl acetate and ethanol, and can be reused.
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