CN105152261B - A kind of preparation of ammonia nitrogen waste water adsorbent that can be recycled and regeneration application method - Google Patents

Abstract

The invention relates to a method for preparing and regenerating a recyclable ammonia-nitrogen wastewater adsorbent. Phosphate, silicate, and magnesium salt are mixed in a certain proportion, reacted for 10 to 30 minutes, centrifuged and precipitated, and can be obtained after drying. Recycled ammonia nitrogen wastewater adsorbent. When in use, directly add the recyclable ammonia nitrogen wastewater adsorbent into the ammonia nitrogen wastewater with a pH of 9 to 10, stir for 10 to 40 minutes, let stand for 10 to 100 minutes, collect the sediment, and bake at 100 to 120°C for 3 to 5 minutes. Hours, the regenerated adsorbent powder is obtained, and the regenerated adsorbent powder is recycled for the adsorption treatment of ammonia nitrogen wastewater, and the continuous cycle is 3 times or more. The adsorption performance of the regenerated adsorbent powder is very close to the initial adsorption performance of the recyclable ammonia nitrogen wastewater adsorbent . The invention has the advantages of simple preparation process, readily available raw materials, low cost, large adsorption capacity of ammonia nitrogen, short time, high regeneration efficiency, etc., and has valuable economic and social benefits.

Description

A method for the preparation and regeneration of a recyclable ammonia nitrogen wastewater adsorbent

technical field

The invention relates to a method for preparing and regenerating a recyclable ammonia nitrogen wastewater adsorbent, belonging to the technical field of environmental pollution control.

Background technique

Ammonia nitrogen in water comes from, first, the decomposition products of nitrogen-containing organic matter in domestic sewage by microorganisms, and second, certain industrial wastewater, such as coking wastewater and synthetic ammonia, wastewater from chemical fertilizer plants, farmland drainage, and excess feed in aquaculture water and excessive fertilization. High ammonia nitrogen content in water will cause eutrophication of the water body, leading to the proliferation of aquatic plants, blue-green algae and other organisms, destroying the ecological balance, causing a series of environmental problems, and seriously endangering ecological security. Under aerobic conditions, nitrosifying bacteria and nitrifying bacteria will oxidize ammonia nitrogen in the water body into nitrate and nitrite, which will cause great harm to drinking water and aquatic organisms.

At present, the domestic and foreign high-concentration ammonia nitrogen wastewater treatment technologies can be mainly divided into biological methods, physical and chemical methods and methods combined with various technologies. The biological method is to use the life activities of microorganisms to convert the ammonia nitrogen in the wastewater into harmless nitrogen gas through a series of reactions such as ammonification, nitrification, and denitrification. Biological methods mainly include traditional biological nitrification and denitrification technology, simultaneous nitrification and denitrification technology, short-range nitrification and denitrification technology, anaerobic ammonium oxidation technology, etc. The effluent quality of the biological method is relatively stable, the operating cost is low, and it is easy to manage, but the operating cycle is long, the nitrogen removal efficiency is low, it is easily affected by the influent water quality and environmental factors, and it is easy to cause secondary pollution. It is suitable for large-scale low-ammonia nitrogen wastewater treatment project. The physical and chemical method is to use the comprehensive effect of physics and chemistry to purify ammonia nitrogen wastewater. It mainly includes blow-off method, break point chlorination method, ion exchange method, magnesium ammonium phosphate precipitation method and other treatment technologies. The magnesium ammonium phosphate precipitation method (MAP method) is to remove the ammonia in the water by adding magnesium salt and phosphate to the wastewater to generate magnesium ammonium phosphate crystal precipitation under alkaline conditions. Ammonium magnesium phosphate precipitation method has the advantages of quick response, simple process, not affected by temperature and toxins in water, and high removal rate, and is suitable for the treatment of high-concentration wastewater. However, this method needs to add a large amount of phosphate, and the residual phosphate, magnesium ions, chloride ions and sulfate ions in the wastewater have brought a burden to the subsequent treatment, and sodium hydroxide needs to be added to adjust the pH, which is costly. Moreover, during the use of regenerated MAP, the phosphate radicals are seriously lost due to dissolution, and the adsorption performance and adsorption efficiency of the regenerated materials are greatly reduced, which is limited in industrial applications.

The adsorption method to treat high-concentration ammonia nitrogen wastewater is to use the exchangeable ions in the ion exchanger (insoluble ionic compound) to exchange with the same-sex cation (NH ₄ ⁺ ) in the solution, and absorb a large amount of NH ₄ ⁺ to the insoluble ionic compound surface, thereby achieving the removal of ammonia nitrogen. Commonly used adsorbents can be roughly divided into three categories: ① mineral adsorbents, mainly including zeolite, attapulgite, bentonite, vermiculite, rare earth and sepiolite, etc.; ② waste residue adsorbents, mainly including fly ash, peanut Shells, etc., ③ bamboo charcoal adsorbents, such as activated carbon, bamboo charcoal, carbonized bagasse, etc. Tong Xiaowei and others found that when using inorganic salts to modify zeolite, NaCl modified zeolite has the best adsorption effect on ammonia nitrogen, and the adsorption capacity of ammonia nitrogen can reach 887mg/kg, which is 3.84 times that of natural zeolite (Tong Xiaowei, Zhu Yinian, Journal of Environmental Engineering, 2009,3 :635-638). Zhang Lindong and others modified the purified sepiolite by hydrothermal activation, acid activation and sodium ion exchange. When the pH was 6, the concentration of ammonia nitrogen was 500 mg/L, and the adsorption time was 8 hours, the saturated adsorption capacity of ammonia nitrogen was 8.89 mg/g (Zhang Lindong, Wang Xiannian, Li Jun et al., Chemical Environmental Protection, 2006, 26:67-69). Liu Tong and others found that the salt-modified zeolite has a high removal rate for ammonia nitrogen. For source water with an ammonia nitrogen concentration of 4.43mg/L, the concentration of ammonia nitrogen decreased after 15 minutes of contact at 25°C with a particle size of 0.8-1.7mm. To 0.3mg/L, the removal rate is 93.2% (Liu Tong, Yan Gang, Yao Lirong, Hydrogeology and Engineering Geology, 2011, 38:97-101). Research by Zheng Yue et al. found that the adsorption capacity of fly ash to ammonia nitrogen increases with the increase of ammonia nitrogen concentration in water. The ammonia nitrogen concentration is 500 mg/L, and the adsorption capacity of fly ash to ammonia nitrogen is as high as 0.68 mg/g (Zheng Yue, Liu Fang, Wu Yonggui, Environmental Science and Technology, 2011, 34:4-7). Zhou Shan and others modified bamboo charcoal with nitric acid. When the pH was 7, the concentration of ammonia nitrogen was 50 mg/L, the dosage was 3.0 g/100 mL, and the equilibrium adsorption time was 4 hours, the saturated adsorption capacity of ammonia nitrogen reached 0.30 mg/g (Zhou Shan, Chen Bin, Wang Jiaying, etc., Journal of Zhejiang University-Agriculture and Life Sciences, 2007, 33:584-590). In summary, the above-mentioned adsorbents have disadvantages such as long adsorption time, small adsorption capacity, and low regeneration efficiency. Therefore, the research and development of ammonia-nitrogen adsorbents with simple process, large adsorption capacity, and regenerability have important application value.

Contents of the invention

The object of the present invention is to disclose a preparation method of a recyclable ammonia nitrogen wastewater adsorbent, which is mainly used for the treatment of high concentration ammonia nitrogen wastewater in industrial wastewater.

In order to achieve the above object, the present invention is based on the reaction principle of magnesium hydrogen phosphate adsorbing ammonia to generate insoluble water-soluble magnesium ammonium phosphate, and adopts the doping of silicate to reduce the loss of phosphorus (fix phosphorus), and combine phosphate, silicon Ammonia nitrogen wastewater adsorbent is prepared by mixing reaction with acid salt, magnesium salt, etc. in a certain proportion. The ammonia nitrogen wastewater adsorbent is added to ammonia nitrogen wastewater, precipitated, separated, heated, dried and regenerated to obtain recyclable ammonia nitrogen wastewater adsorption. The adsorption performance of the adsorbent in three consecutive cycles is very close to that of the initial adsorbent.

The specific preparation and use process is as follows:

A preparation method of a recyclable ammonia nitrogen wastewater adsorbent is as follows: firstly measure phosphate:silicate:magnesium salt=20:1～20:10～100 parts according to the mass ratio, then add water and stir for 10～30 minutes, Stand still for 0.5 to 2 hours , and centrifuge to obtain a recyclable ammonia nitrogen wastewater adsorbent;

Above-mentioned phosphate is commercially available industrial grade disodium hydrogen phosphate, or dipotassium hydrogen phosphate;

Above-mentioned silicate is commercially available technical grade sodium silicate, or potassium silicate;

Above-mentioned magnesium salt is commercially available technical grade magnesium chloride, or magnesium sulfate.

The preparation method of the recyclable ammonia nitrogen waste water adsorbent is: firstly add water to the metered phosphate to prepare a phosphate solution with a molar concentration of 0.2mol/L, and add water to the silicate to prepare a molar concentration of 0.1mol/L Silicate solution, the magnesium salt is added with water to prepare a magnesium salt solution with a molar concentration of 0.5mol/L, then the silicate solution is added to the phosphate solution, and then the magnesium salt solution is slowly added while stirring, and stirred for 10-30 minute, stand still for 0.5-2 hours, and centrifuge to obtain a recyclable ammonia nitrogen wastewater adsorbent.

A method of using the recyclable ammonia nitrogen wastewater adsorbent is: adding the recyclable ammonia nitrogen wastewater adsorbent into the ammonia nitrogen wastewater with a pH of 9 to 10 to be treated, and the amount of the recyclable ammonia nitrogen wastewater adsorbent is the amount to be treated 0.5% to 3% of the mass of ammonia nitrogen wastewater; stir for 10 to 40 minutes, let stand for 10 to 100 minutes, remove the supernatant, collect the lower sediment, and dry at 100 to 120°C for 3 to 5 hours to obtain regeneration Adsorbent powder, then add the obtained regenerated adsorbent powder into the ammonia nitrogen wastewater to be treated, stir for 10-40 minutes according to the above, let stand for 10-100 minutes, remove the supernatant, collect the lower layer of sediment, at 100-120 Drying at ℃ for 3 to 5 hours to obtain regenerated adsorbent powder, cycle continuously for 3 times or more, the adsorption performance of regenerated adsorbent powder is very close to that of recyclable ammonia nitrogen wastewater adsorbent;

The amount of the above regenerated adsorbent powder added is 0.5% to 3% of the quality of the ammonia nitrogen wastewater to be treated;

The wastewater to be treated above is industrial wastewater with an ammonia nitrogen concentration greater than 500 mg/L.

The ammonia nitrogen wastewater adsorbent of the present invention has the following advantages:

1. Since the adsorbent of the present invention is doped with silicate that can reduce the loss of phosphorus, the adsorption efficiency is significantly improved. The ammonia adsorption capacity of the adsorbent of the present invention exceeds 80g/kg, which is the largest with the existing adsorption capacity Compared with other adsorbents, the adsorption performance is obviously improved, and the adsorption time is short, the application range is wide, and it is suitable for the treatment of various ammonia nitrogen wastewater.

2. Since the adsorbent of the present invention is doped with silicate that can reduce the loss of phosphorus, compared with the existing magnesium ammonium phosphate precipitation method, it does not need to add a large amount of phosphate and magnesium salt reagents, and the residues in the wastewater There are few phosphate, magnesium, chloride and sulfate ions, and the follow-up treatment is simple, which greatly reduces the treatment cost.

3. Since the adsorbent of the present invention is doped with silicate that can reduce the loss of phosphorus, the regeneration effect is good, and phosphorus supplementation is not required, and it can be used for the adsorption treatment of ammonia nitrogen wastewater for more than 3 consecutive regeneration cycles. The adsorption performance is very close to that of the initial adsorbent.

4. The preparation process of the adsorbent of the present invention is simple, the production raw materials are easy to obtain, the price is cheap, and the secondary pollution is also reduced, which has valuable economic and social benefits.

detailed description

Example 1

Preparation of Recyclable Adsorbent for Ammonia Nitrogen Wastewater

In 100ml of 0.2mol/L disodium hydrogen phosphate solution, add 100ml of 0.1mol/L sodium silicate solution, under stirring condition, slowly add 100ml of 0.5mol/L magnesium chloride solution, stir for 30min, let stand for 1 hour, centrifuge, collect The recyclable ammonia nitrogen wastewater adsorbent was obtained by precipitation, and baked at 110° C. for 4 hours to obtain 3.5 g of a solid recyclable ammonia nitrogen wastewater adsorbent powder product.

Example 2

Ammonia nitrogen wastewater adsorbent regeneration cycle for circuit board dismantling ammonia nitrogen wastewater treatment

Take 50ml of wastewater from a circuit board dismantling factory in a beaker, adjust the pH to 9-10 with dilute alkali, add 1g of the recyclable ammonia nitrogen wastewater adsorbent prepared in Example 1, stir for 20min, and let stand for 20min. The test results showed that the concentration of ammonia nitrogen decreased from 1856 mg/L to 184 mg/L after adsorption, and the removal rate of ammonia nitrogen was 90%. Dry the precipitated sludge at 110°C for 3 hours to regenerate to obtain 0.87g of regenerated adsorbent powder. Add 0.87g of regenerated adsorbent powder to 50ml of this wastewater. The test shows that the concentration of ammonia nitrogen in the wastewater after adsorption is reduced from 1856mg/L to 423mg /L. Recirculate once according to the regeneration method, add 0.73g of the regenerated adsorbent powder obtained twice to 50ml of this wastewater again, and the test shows that the concentration of ammonia nitrogen in the wastewater after adsorption is reduced from 1856mg/L to 612mg/L. The calculated adsorption capacity of the adsorbent to ammonia in three cycles is 100-102g/kg. Therefore, in addition to the gradual decrease in the yield of the regenerated adsorbent powder (add 1g, regenerate to obtain 0.87g, add 0.87g to regenerate to obtain 0.73g), continuous regeneration The adsorption performance after use is very close to the initial adsorption performance.

Example 3

Ammonia nitrogen wastewater adsorbent regeneration cycle for coking plant ammonia nitrogen wastewater treatment

Take 50ml of wastewater from a coking plant in a beaker, adjust the pH to 9-10 with dilute alkali, add 1g of the ammonia nitrogen wastewater adsorbent prepared in Example 1, stir for 20min, and let stand for 10min. The test results showed that the concentration of ammonia nitrogen decreased from 1620 mg/L to 236 mg/L after adsorption, and the removal rate of ammonia nitrogen was 85%. The precipitated sludge was regenerated by baking at 110°C for 3 hours to obtain 0.85g of regenerated adsorbent, which was added to 50ml of this coking wastewater again. The test showed that the concentration of ammonia nitrogen in the wastewater dropped from 1620mg/L to 389mg/L after adsorption. Recirculate once according to the regeneration method, and add 0.75g of the secondary regeneration adsorbent to 50ml of this coking wastewater again. The test shows that the concentration of ammonia nitrogen in the wastewater after adsorption is reduced from 1620mg/L to 572mg/L. Calculate the effect of the adsorbent on ammonia after three cycles The adsorption capacity is 85-88g/kg. Therefore, except that the yield of regenerated adsorbent powder decreases each time (add 1g, regenerate to get 0.85g, add 0.85g to regenerate to get 0.75g), the adsorption performance after continuous regeneration is similar to that of The initial adsorption performance is very close.

Claims (3)

1. a kind of preparation method for the ammonia nitrogen waste water adsorbent that can be recycled, it is characterised in that：First phosphoric acid is measured in mass ratio Salt：Silicate：Magnesium salts=20：1~20：10~100 parts, the stirring reaction that then adds water 10~30 minutes stands 0.5~2 hour, Centrifuge, the ammonia nitrogen waste water adsorbent that can be recycled；

Above-mentioned phosphate is commercially available PHOSPHORIC ACID TECH.GRADE disodium hydrogen, or dipotassium hydrogen phosphate；

Above-mentioned silicate is commercially available technical grade sodium metasilicate, or potassium silicate；

Above-mentioned magnesium salts is commercially available industrial grade magnesium chloride, or magnesium sulfate.

2. a kind of preparation method of ammonia nitrogen waste water adsorbent that can be recycled according to claim 1, it is characterised in that： The preparation method of the ammonia nitrogen waste water adsorbent that can be recycled is, first being added water in the phosphate of metering, it is mole dense to be prepared into Spend for 0.2mol/L phosphate solutions, silicate is added water the silicate solutions for being prepared into that molar concentration is 0.1mol/L, by magnesium Salt add water be prepared into molar concentration be 0.5mol/L magnesium salt solution, then by silicate solutions add phosphate solution in, so It is slowly added to magnesium salt solution while stirring afterwards, stirs 10~30 minutes, stand 0.5~2 hour, centrifuges, produce recyclable The ammonia nitrogen waste water adsorbent used.

3. a kind of application method for the ammonia nitrogen waste water adsorbent that can be recycled that claim 1 methods described is obtained, its feature It is：The ammonia nitrogen waste water adsorbent that can be recycled is added in the ammonia nitrogen waste water of pending pH9~10, be can be recycled The addition of ammonia nitrogen waste water adsorbent is the 0.5%~3% of pending ammonia nitrogen waste water quality；Stirring 10~40 minutes, stands 10~100 minutes, supernatant is removed, lower sediment thing is collected, is dried 3~5 hours at 100~120 DEG C, produces regenerative adsorption Agent powder, then adds obtained reproducing adsorbent powder in pending ammonia nitrogen waste water, quiet according to above-mentioned stirring 10~40 minutes Put 10~100 minutes, remove supernatant, collect lower sediment thing, dried 3~5 hours at 100~120 DEG C, obtain regeneration and inhale Attached dose of powder, detection calculates the absorption property that uses of circulation cyclic regeneration and initial absorption property very close to for 85~102g/kg；

The addition of above-mentioned reproducing adsorbent powder is the 0.5%~3% of pending ammonia nitrogen waste water quality；

Above-mentioned pending waste water is the industrial wastewater that ammonia nitrogen concentration is more than 500mg/L.