| Agricultural straw usually refers to the remaining part of corn, wheat, rice and other crops after people harvested the seed. Straw is an important by-product of crops, at the same time, is also major productive resources of industrial and agricultural production. But a lot of straw is idle or burned as waste in situ. In particular the burning of straw not only brought pollution, has caused many accidents and posed a serious threat to the safety of traffic and transport.The emission of ammonia nitrogen into the lake, the gulf and other water bodies, has proned to multiply algae and other micro-organisms and formed eutrophication. Currently, the treatment teclnology of ammonia nitrogen wastewater at home and abroad are mainly physical and chemical treatment, chemical treatment, biological treatment. Adsorption treatment technology of ammonia nitrogen wastewater as an important means, can be widely used in real life. At present, there has the report of the development of new adsorbents for adsorption of ammonia nitrogen wastewater treatment, while the adsorption treatment technology of the modified stalk on ammonia nitrogen wastewater is rarely reported.Therefore, the ammonia nitrogen adsorbent is made by straw, because of its low cost, can be applied to a large number of eutrophic wastewater treatment, meanwhile, a large number of ammonia nitrogen adsorpted by modified straw will serve as a nitrogen fertilizer, it also do not produce solid waste to fields.In this paper, corn stalks as raw material, through chemical modification, was made into two kinds of modified corn stalks adsorbents. Then I selected the ammonia nitrogen as the purpose of pollutants, adsorption tests were carried out respectively and provided a new approach for the removal of ammonia nitrogen in water.In the modified method of study, the optimal carbonization method is the carbonization in a muffle furnace at 300℃, charring confined 30min. And I selected nitric acid as a modifier, through the study of effects by orthogonal modification effect on the investment ratio, modifier concentration, activation time of the three influential factors, a set of optimum conditions based on ammonia nitrogen removal by nitric acid modification is that putting 2g straw carbon or puffing straw into concentration 6mol/L of 100mL nitric acid solution, activating 3h. The studies through different factors (dosage, adsorption time, temperature, pH, initial concentration) on the modification effect of straw carbon on ammonia nitrogen adsorption have shown that as the dosage increased, the modified straw carbon on the removal rate of ammonia nitrogen also improved, when the dosage of 1Og/L, adsorption of the modification straw carbon on ammonia nitrogen had a good effect. pH value is conducive to the improvement of adsorption on ammonia nitrogen of modified straw carbon, when pH value is 7, its removal rate could reach to 80%. Modified straw carbon can be effective to adsorp ammonia nitrogen within 5min, adsorption equilibrium time is shortened from 6h to 3h than unmodified.2 kinetics and pseudo second order kinetics equation could fit the adsorption kinetics. Langmuir, Freundlich, Linear equations could fit the characteristics of its isotherm adsorption.25℃, the maximum adsorption obtained by Langmuir adsorption equation was 9.08mg/g. The coefficient K of Freundlich adsorption equation increased with increasing temperature, and showed that the adsorption was endothermic reaction, the adsorption increased with increasing temperature.The studies through different factors (dosage, adsorption time, temperature, pH, initial concentration) on the modification effect of puffing straw on ammonia nitrogen adsorption have shown that as the dosage increased, the modified puffing straw on the removal rate of ammonia nitrogen also improved, when the dosage of 12g/L, adsorption of the modification puffing straw on ammonia nitrogen had a good effect. pH value is conducive to the improvement of adsorption on ammonia nitrogen of modified puffing straw, when pH value is 7, its removal rate could be more than 75%. Modified puffing straw can be effective to adsorp ammonia nitrogen within 5min, adsorption equilibrium time is shortened from 7h to 5h than unmodified.2 kinetics and pseudo second order kinetics equation could fit the adsorption kinetics. Langmuir, Freundlich, Linear equations could fit the characteristics of its isotherm adsorption.25℃, the maximum adsorption obtained by Langmuir adsorption equation was 7.53mg/g. The coefficient K of Freundlich adsorption equation increased with increasing temperature, and showed that the adsorption was endothermic reaction, the adsorption increased with increasing temperature.Modified straw carbon and puffing straw had a good effect on ammonia nitrogen removal of the actual domestic wastewater. Tests showed that increasing pH was conducive to modified straw carbon and puffing straw to remove ammonia nitrogen, from the perspective of dealing with actual domestic wastewater, the initial pH in water samples could be transferred to 7-8 for processing, and it can achieve good removal effects. It could also increase the dosage to increase the removal rate. For the modified straw carbon, when the dosage was lOg/L, the ammonia nitrogen removal rate could reach to 80%. For the modified puffing straw, when the dosage was 12g/L, the ammonia nitrogen removal rate could be close to 80%.Finally, the paper pointed out that the following studies should to be further investigated about modified corn stalk adsorbents on the other cationic, for example, the adsorption removal of heavy metals. Under test conditions of the adsorption column it investigated that the adsorption process and operating parameters would be corrected. Increasing research about the technology of putting modified straw to fields, it can make modified straw to be a kind of truly environmentally friendly materials, after used and put modified straw into fields, the technology of putting modified straw to fields will not bring any pollution made by the waste.
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