Modified coal ash used for treating ammonia nitrogen waste water and preparation method thereof

Abstract

The invention relates to modified coal ash used for treating ammonia nitrogen waste water, which is prepared by the following steps of: calcining NaOH and coal ash at a low temperature after NaOH and coal ash are uniformly mixed in proportion, cooling, grinding and sieving, then adding 1-5 times of water by weight, mixing, stirring, heating to the temperature of 70 DEG C and stopping stirring, gelling for 1.5-2 hours at constant temperature, then heating to the temperature of 100 DEG C, crystallizing for 3-4 hours at constant temperature, carrying out suction filtering, washing to be neutral with water, drying, cooling and then grinding and sieving, thus the modified coal ash is obtained. In the invention, NaOH low temperature calcining hydrothermal synthesis is adopted to modify the coal ash, the physical structure of the coal ash is destroyed, the modification time is shortened and a new zeolite mineral phase is generated under the condition of low alkali addition amount, the specific area of the coal ash is increased, and the cation exchange performance of the coal ash is improved. The modified coal ash provided by the invention is used for treating the ammonia nitrogen waste water, and the removing effect is obvious. By adopting the modified coal ash provided by the invention, wastes are treated with wastes, the resource utilization of wastes is realized, and the utilization factor of the coal ash is improved.

Description

technical field [0001] The invention relates to solid waste resource utilization and water treatment technology, in particular to a modified fly ash for treating ammonia nitrogen wastewater and a preparation method thereof. Background technique [0002] Ammonia nitrogen is one of the important pollutants in water, mainly from urban domestic sewage, industrial wastewater from various industries and fertilizers used in agricultural production. Excessive nitrogen content in water bodies will not only deteriorate the quality of the water environment, cause eutrophication of water bodies, but also cause serious harm to humans and animals. At present, the methods of treating ammonia nitrogen wastewater at home and abroad mainly include stripping method, chemical precipitation method, ion exchange method and so on. The ion exchange method is a method in which the exchangeable ions on insoluble ionic compounds exchange with the same ions in the solution to remove harmful ions. It i...

AI Technical Summary

Problems solved by technology

[0005] However, the modification time of the above-mentioned modification processes is too long. Document 3 added a calcination process in the modification process, which can shorten the modification time appropriately, but the calcination temperature is too high at 850°C for 2 hours, which consumes more energy and uses There are few reports on fly ash modification methods for treating ammonia nitrogen wastewater, and the removal effect of modified fly ash on ammonia nitrogen is not ideal, such as the literature: Surface modification of fly ash and its removal of ammonia nitrogen in water. Suzhou School of Science and Technology.2008.22

Stir fly ash with different concentrations of sodium hydroxide at a constant temperature of 85°C for 4 hours, then wash with distilled water until neutral, filter, dry and modify, the removal rate of fly ash to ammonia nitrogen increases from 29% to 47%, with lower removal rates