A kind of phosphorus removal filler and its preparation method and application

Abstract

The invention discloses a dephosphorization filler and a preparation method and application thereof, belonging to the technical field of fillers. According to the invention, sulphoaluminate cement, chitosan, sodium alginate and calcium peroxide are uniformly mixed in a nitric acid solution with an amino-containing coupling agent, and then foaming and pore formation is performed under steam, and finally the mixture is uniformly mixed with titanium dioxide, sodium silicate, ferrous sulfate solution and sodium borohydride to obtain a dephosphorization filler with excellent dephosphorization effect. The dephosphorization filler has rich pore structure and adsorption activity, and can fully physically adsorb phosphorus elements. Meanwhile, the dephosphorization filler also has excellent surface complexation activity and photocatalytic effect, and can also generate insoluble salt precipitation through the reaction of iron elements and calcium elements with phosphate in water, thereby realizing the removal of total phosphorus. The material is ground and put into a fish pond as a phosphorus supplement material after adsorption saturation, which can realize resource recycling and has broad application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of fillers, and in particular to a dephosphorization filler and a preparation method and application thereof. Background Art

[0002] At present, local freshwater fish ponds are generally lacking in alkalinity and phosphorus. Maintaining self-purification of the water body mainly relies on regular artificial addition of polybasic organic acids, quicklime, potassium dihydrogen phosphate and other elements to supplement the necessary elements and maintain the basic needs of algae growth.

[0003] At present, rural sewage involves the first-level standard, and usually uses chemical phosphorus removal (addition of phosphorus removal agent) and adsorption phosphorus removal. The former is more common, but it produces chemical sludge. The latter is designed to be adsorbed saturated, and the filler needs to be replaced and treated, and the filler cost is relatively high.

[0004] In view of this, this application is filed. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a dephosphorization filler and a preparation method and application thereof. The dephosphorization filler has an excellent dephosphorization effect.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for preparing a phosphorus removal filler comprises the following steps:

[0008] Adding sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide and an amino-containing coupling agent into a nitric acid solution, stirring evenly, filtering and drying to obtain a mixture;

[0009] The mixed material, the foaming agent and the pore-forming agent are mixed evenly, and steam cured to obtain a precursor material;

[0010] The precursor, titanium dioxide and sodium silicate are added into the ferrous sulfate solution, sodium borohydride is added, stirred evenly, filtered, washed, dried and calcined to obtain the dephosphorization filler.

[0011] The present invention creatively mixes sulphoaluminate cement, chitosan, sodium alginate and calcium peroxide in a nitric acid solution with an amino-containing coupling agent, then foams and forms pores under steam, and finally mixes the mixture with titanium dioxide, sodium silicate, ferrous sulfate solution and sodium borohydride, thereby obtaining a phosphorus removal filler with excellent phosphorus removal effect. The phosphorus removal filler has a rich pore structure and adsorption activity, and can fully physically adsorb phosphorus. Meanwhile, the phosphorus removal filler also has excellent surface complexation activity and photocatalytic effect, and can also generate insoluble salt precipitation through the reaction of iron and calcium elements with phosphate in water, thereby achieving the removal of total phosphorus. The material is ground and put into a fish pond as a phosphorus supplement material after adsorption saturation, which can achieve resource recycling and has broad application prospects.

[0012] Among them, sulphoaluminate cement, chitosan, sodium alginate and calcium peroxide are uniformly mixed in a nitric acid solution with an amino-containing coupling agent, which can effectively improve the adsorption activity of the material. Sulphoaluminate cement is rich in various metal elements, which can react with phosphate in water to form insoluble salt precipitation. The sulphoaluminate cement provides a basic skeleton structure of the filler and can improve the stability of the filler. The sulphoaluminate cement can be hydrated into a gel. Chitosan and sodium alginate enhance the adsorption capacity of phosphorus by providing abundant reactive functional groups, and improve the structure and stability of the filler through gelation. The gelation of chitosan and sodium alginate and the hydration of cement form a tighter structure, provide enough active sites, and improve the overall adsorption activity. Calcium peroxide provides a sufficient amount of calcium element, reacts with phosphate in water to form insoluble salt precipitation, and the addition of the coupling agent increases the reactivity and activity of each component. At the same time, chitosan can also promote the decomposition of calcium peroxide and the reaction with phosphate ions, which significantly improves the reactivity and adsorption performance of the filler.

[0013] Among them, the mixed material, foaming agent and pore-forming agent are mixed evenly, and pores are formed and foamed under steam curing, which is conducive to promoting the formation of pore structures with different pore sizes. Under steam and high temperature, pore formation and foaming are carried out simultaneously, which effectively increases the pore volume and specific surface area and provides more adsorption active sites; the precursor material is mixed evenly with titanium dioxide, sodium silicate, ferrous sulfate solution and sodium borohydride; among them, titanium dioxide and sodium silicate form a small amount of microgel on the surface or in the internal pores of the precursor material, and the titanium dioxide on the surface of the precursor material and the adsorption effect effectively remove the phosphorus element, while the ferrous sulfate solution and sodium borohydride generate zero-valent iron in the pores of the precursor, which effectively improves the removal effect of the phosphorus element.

[0014] As a preferred embodiment of the present invention, the mass ratio of the sulfoaluminate cement, chitosan, sodium alginate, calcium peroxide, amino-containing coupling agent, and nitric acid solution is 1: (0.05~0.15): (0.05~0.15): (0.1~0.2): (0.01~0.02): (8~12), especially when the mass ratio is within this range, the phosphorus removal effect can be further improved.

[0015] As a preferred embodiment of the present invention, the concentration of the nitric acid solution is 0.4-1.2 mol / L.

[0016] As a preferred embodiment of the present invention, the amino-containing coupling agent includes at least one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and N-(2-aminoethyl)-3-aminopropyltriethoxysilane.

[0017] As a preferred embodiment of the present invention, the preparation method of the sulphoaluminate cement is: dihydrate gypsum, fly ash, limestone and bauxite are uniformly mixed, ball-milled, calcined at 1350-1400° C. for 28-40 minutes, and ground to obtain sulphoaluminate cement.

[0018] As a preferred embodiment of the present invention, the mass ratio of dihydrate gypsum, fly ash, limestone and bauxite is (15-22): (8-15): (30-40): (30-40).

[0019] As a preferred embodiment of the present invention, the pore-forming agent includes ammonium bicarbonate and potassium chloride, and the mass ratio of the ammonium bicarbonate to potassium chloride is 1: (0.5-2). Under high-temperature steam, the combined use of the ammonium bicarbonate and potassium chloride promotes the formation of a unique pore structure and effectively improves the phosphorus removal effect.

[0020] As a preferred embodiment of the present invention, the foaming agent includes sodium percarbonate and sodium dodecylbenzene sulfonate, and the mass ratio of the sodium percarbonate to the sodium dodecylbenzene sulfonate is 1:(0.1-0.4).

[0021] As a preferred embodiment of the present invention, the mass ratio of the mixed material, the foaming agent and the pore-forming agent is 1: (0.05-0.15): (0.08-0.15).

[0022] As a preferred embodiment of the present invention, the steam curing temperature is 80-90° C. and the time is 2-5 hours.

[0023] As a preferred embodiment of the present invention, the mass ratio of the precursor, titanium dioxide, sodium silicate, ferrous sulfate solution and sodium borohydride is 1: (0.05-0.12): (0.02-0.06): (2-4): (0.05-0.12).

[0024] As a preferred embodiment of the present invention, the molar concentration of the ferrous sulfate solution is 0.2-0.6 mol / L.

[0025] As a preferred embodiment of the present invention, the calcination temperature is 380-420° C. and the calcination time is 2-4 hours.

[0026] The present invention also provides a phosphorus removal filler, which is prepared by the above-mentioned preparation method.

[0027] The present invention also provides an application of a phosphorus removal filler as a filler for sewage treatment and a filler for artificial wetlands.

[0028] The beneficial effects of the present invention are as follows: the present invention uniformly mixes sulphoaluminate cement, chitosan, sodium alginate and calcium peroxide in a nitric acid solution with an amino-containing coupling agent, then foams and forms pores under steam, and finally uniformly mixes with titanium dioxide, sodium silicate, ferrous sulfate solution and sodium borohydride to obtain a phosphorus removal filler with excellent phosphorus removal effect; the phosphorus removal filler has a rich pore structure and adsorption activity, and can fully physically adsorb phosphorus; at the same time, the phosphorus removal filler also has excellent surface complexation activity and photocatalytic effect, and can also generate insoluble salt precipitation through the reaction of iron elements and calcium elements with phosphate in water, thereby realizing the removal of total phosphorus; the material is ground and put into a fish pond as a phosphorus supplement material after adsorption saturation, which can realize resource recycling and has broad application prospects. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0030] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0031] In this application, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0032] In the present application, there is no particular limitation on the specific dispersion and stirring treatment methods.

[0033] Unless otherwise specified, the components, raw materials or instruments used in the embodiments and comparative examples of the present invention are all commercially available raw materials or instruments, and the components and raw materials used in each parallel experiment are all of the same kind.

[0034] Example 1

[0035] A method for preparing a phosphorus removal filler comprises the following steps:

[0036] (1) Gypsum dihydrate, fly ash, limestone and bauxite were mixed evenly, ball-milled at 500 rpm for 4 h, added to a muffle furnace, calcined at 1360 °C for 30 min, and ground to a specific surface area of ​​500 m 2 / kg, to obtain sulphoaluminate cement.

[0037] The mass ratio of the dihydrate gypsum, fly ash, limestone and bauxite is 20:10:35:35.

[0038] (2) Add sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide and γ-aminopropyltriethoxysilane to 0.5 mol / L nitric acid solution, stir at 100 rpm for 60 min, filter, and dry at 80°C for 2 h to obtain a mixture; the mass ratio of the sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide, γ-aminopropyltriethoxysilane and nitric acid solution is 1:0.1:0.1:0.15:0.02:10.

[0039] (3) The mixed material, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate are mixed evenly, and after mixing evenly, the mixture is placed in a steam curing box and cured at 90° C. for 3 hours to obtain a precursor material;

[0040] The mass ratio of the mixture, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate is 1:0.06:0.06:0.1:0.02.

[0041] (4) The precursor, titanium dioxide and sodium silicate were added to a 0.5 mol / L ferrous sulfate solution, sodium borohydride was added, and the mixture was stirred at 100 rpm for 2 h at 65 °C under nitrogen protection. The mixture was filtered, washed, and dried at 80 °C for 4 h. The mixture was added to a muffle furnace and calcined at 420 °C for 3 h to obtain a dephosphorization filler.

[0042] The mass ratio of the precursor, titanium dioxide, sodium silicate, ferrous sulfate solution and sodium borohydride is 1:0.1:0.05:3:0.1.

[0043] Example 2

[0044] A method for preparing a phosphorus removal filler comprises the following steps:

[0045] (1) Gypsum dihydrate, fly ash, limestone and bauxite were mixed evenly, ball-milled at 500 rpm for 4 h, added to a muffle furnace, calcined at 1360 °C for 30 min, and ground to a specific surface area of ​​500 m 2 / kg, to obtain sulphoaluminate cement.

[0046] The mass ratio of the dihydrate gypsum, fly ash, limestone and bauxite is 20:10:35:35.

[0047] (2) Add sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide and γ-aminopropyltriethoxysilane to 0.5 mol / L nitric acid solution, stir at 100 rpm for 60 min, filter, and dry at 80°C for 2 h to obtain a mixture; the mass ratio of the sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide, γ-aminopropyltriethoxysilane and nitric acid solution is 1:0.05:0.15:0.1:0.02:8.

[0048] (3) The mixed material, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate are mixed evenly, and after mixing evenly, the mixture is placed in a steam curing box and cured at 90° C. for 3 hours to obtain a precursor material;

[0049] The mass ratio of the mixture, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate is 1:0.06:0.06:0.1:0.02.

[0050] (4) The precursor, titanium dioxide and sodium silicate were added to a 0.5 mol / L ferrous sulfate solution, sodium borohydride was added, and the mixture was stirred at 100 rpm for 2 h at 65 °C under nitrogen protection. The mixture was filtered, washed, and dried at 80 °C for 4 h. The mixture was added to a muffle furnace and calcined at 420 °C for 3 h to obtain a dephosphorization filler.

[0051] The mass ratio of the precursor, titanium dioxide, sodium silicate, ferrous sulfate solution and sodium borohydride is 1:0.1:0.05:3:0.1.

[0052] Example 3

[0053] A method for preparing a phosphorus removal filler comprises the following steps:

[0054] (1) Gypsum dihydrate, fly ash, limestone and bauxite were mixed evenly, ball-milled at 500 rpm for 4 h, added to a muffle furnace, calcined at 1360 °C for 30 min, and ground to a specific surface area of ​​500 m 2 / kg, to obtain sulphoaluminate cement.

[0055] The mass ratio of the dihydrate gypsum, fly ash, limestone and bauxite is 20:10:35:35.

[0056] (2) Add sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide and γ-aminopropyltriethoxysilane to 0.5 mol / L nitric acid solution, stir at 100 rpm for 60 min, filter, and dry at 80°C for 2 h to obtain a mixture; the mass ratio of the sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide, γ-aminopropyltriethoxysilane and nitric acid solution is 1:0.15:0.05:0.2:0.01:12.

[0057] (3) The mixed material, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate are mixed evenly, and after mixing evenly, the mixture is placed in a steam curing box and cured at 90° C. for 3 hours to obtain a precursor material;

[0058] The mass ratio of the mixture, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate is 1:0.06:0.06:0.1:0.02.

[0059] (4) The precursor, titanium dioxide and sodium silicate were added to a 0.5 mol / L ferrous sulfate solution, sodium borohydride was added, and the mixture was stirred at 100 rpm for 2 h at 65 °C under nitrogen protection. The mixture was filtered, washed, and dried at 80 °C for 4 h. The mixture was added to a muffle furnace and calcined at 420 °C for 3 h to obtain a dephosphorization filler.

[0060] The mass ratio of the precursor, titanium dioxide, sodium silicate, ferrous sulfate solution and sodium borohydride is 1:0.1:0.05:3:0.1.

[0061] Example 4

[0062] A method for preparing a phosphorus removal filler comprises the following steps:

[0063] (1) Gypsum dihydrate, fly ash, limestone and bauxite were mixed evenly, ball-milled at 500 rpm for 4 h, added to a muffle furnace, calcined at 1360 °C for 30 min, and ground to a specific surface area of ​​500 m 2 / kg, to obtain sulphoaluminate cement.

[0064] The mass ratio of the dihydrate gypsum, fly ash, limestone and bauxite is 20:10:35:35.

[0065] (2) Add sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide and γ-aminopropyltriethoxysilane to 0.5 mol / L nitric acid solution, stir at 100 rpm for 60 min, filter, and dry at 80°C for 2 h to obtain a mixture; the mass ratio of the sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide, γ-aminopropyltriethoxysilane and nitric acid solution is 1:0.1:0.1:0.15:0.02:10.

[0066] (3) The mixed material, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate are mixed evenly, and after mixing evenly, the mixture is placed in a steam curing box and cured at 90° C. for 3 hours to obtain a precursor material;

[0067] The mass ratio of the mixture, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate is 1:0.025:0.025:0.1:0.05.

[0068] (4) The precursor, titanium dioxide and sodium silicate were added to a 0.5 mol / L ferrous sulfate solution, sodium borohydride was added, and the mixture was stirred at 100 rpm for 2 h at 65 °C under nitrogen protection. The mixture was filtered, washed, and dried at 80 °C for 4 h. The mixture was added to a muffle furnace and calcined at 420 °C for 3 h to obtain a dephosphorization filler.

[0069] The mass ratio of the precursor, titanium dioxide, sodium silicate, ferrous sulfate solution and sodium borohydride is 1:0.1:0.05:3:0.1.

[0070] Example 5

[0071] A method for preparing a phosphorus removal filler comprises the following steps:

[0072] (1) Gypsum dihydrate, fly ash, limestone and bauxite were mixed evenly, ball-milled at 500 rpm for 4 h, added to a muffle furnace, calcined at 1360 °C for 30 min, and ground to a specific surface area of ​​500 m 2 / kg, to obtain sulphoaluminate cement.

[0073] The mass ratio of the dihydrate gypsum, fly ash, limestone and bauxite is 20:10:35:35.

[0074] (2) Add sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide and γ-aminopropyltriethoxysilane to 0.5 mol / L nitric acid solution, stir at 100 rpm for 60 min, filter, and dry at 80°C for 2 h to obtain a mixture; the mass ratio of the sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide, γ-aminopropyltriethoxysilane and nitric acid solution is 1:0.1:0.1:0.15:0.02:10.

[0075] (3) The mixed material, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate are mixed evenly, and after mixing evenly, the mixture is placed in a steam curing box and cured at 90° C. for 3 hours to obtain a precursor material;

[0076] The mass ratio of the mixture, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate is 1:0.075:0.075:0.07:0.02.

[0077] (4) The precursor, titanium dioxide and sodium silicate were added to a 0.5 mol / L ferrous sulfate solution, sodium borohydride was added, and the mixture was stirred at 100 rpm for 2 h at 65 °C under nitrogen protection. The mixture was filtered, washed, and dried at 80 °C for 4 h. The mixture was added to a muffle furnace and calcined at 420 °C for 3 h to obtain a dephosphorization filler.

[0078] The mass ratio of the precursor, titanium dioxide, sodium silicate, ferrous sulfate solution and sodium borohydride is 1:0.1:0.05:3:0.1.

[0079] Example 6

[0080] A method for preparing a phosphorus removal filler comprises the following steps:

[0081] (1) Gypsum dihydrate, fly ash, limestone and bauxite were mixed evenly, ball-milled at 500 rpm for 4 h, added to a muffle furnace, calcined at 1360 °C for 30 min, and ground to a specific surface area of ​​500 m 2 / kg, to obtain sulphoaluminate cement.

[0082] The mass ratio of the dihydrate gypsum, fly ash, limestone and bauxite is 20:10:35:35.

[0083] (2) Add sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide and γ-aminopropyltriethoxysilane to 0.5 mol / L nitric acid solution, stir at 100 rpm for 60 min, filter, and dry at 80°C for 2 h to obtain a mixture; the mass ratio of the sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide, γ-aminopropyltriethoxysilane and nitric acid solution is 1:0.1:0.1:0.15:0.02:10.

[0084] (3) The mixed material, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate are mixed evenly, and after mixing evenly, the mixture is placed in a steam curing box and cured at 90° C. for 3 hours to obtain a precursor material;

[0085] The mass ratio of the mixture, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate is 1:0.06:0.06:0.1:0.02.

[0086] (4) The precursor, titanium dioxide and sodium silicate were added to a 0.5 mol / L ferrous sulfate solution, sodium borohydride was added, and the mixture was stirred at 100 rpm for 2 h at 65 °C under nitrogen protection. The mixture was filtered, washed, and dried at 80 °C for 4 h. The mixture was added to a muffle furnace and calcined at 420 °C for 3 h to obtain a dephosphorization filler.

[0087] The mass ratio of the precursor, titanium dioxide, sodium silicate, ferrous sulfate solution and sodium borohydride is 1:0.05:0.06:2:0.05.

[0088] Example 7

[0089] A method for preparing a phosphorus removal filler comprises the following steps:

[0090] (1) Gypsum dihydrate, fly ash, limestone and bauxite were mixed evenly, ball-milled at 500 rpm for 4 h, added to a muffle furnace, calcined at 1360 °C for 30 min, and ground to a specific surface area of ​​500 m 2 / kg, to obtain sulphoaluminate cement.

[0091] The mass ratio of the dihydrate gypsum, fly ash, limestone and bauxite is 20:10:35:35.

[0092] (2) Add sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide and γ-aminopropyltriethoxysilane to 0.5 mol / L nitric acid solution, stir at 100 rpm for 60 min, filter, and dry at 80°C for 2 h to obtain a mixture; the mass ratio of the sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide, γ-aminopropyltriethoxysilane and nitric acid solution is 1:0.1:0.1:0.15:0.02:10.

[0093] (3) The mixed material, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate are mixed evenly, and after mixing evenly, the mixture is placed in a steam curing box and cured at 90° C. for 3 hours to obtain a precursor material;

[0094] The mass ratio of the mixture, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate is 1:0.06:0.06:0.1:0.02.

[0095] (4) The precursor, titanium dioxide and sodium silicate were added to a 0.5 mol / L ferrous sulfate solution, sodium borohydride was added, and the mixture was stirred at 100 rpm for 2 h at 65 °C under nitrogen protection. The mixture was filtered, washed, and dried at 80 °C for 4 h. The mixture was added to a muffle furnace and calcined at 420 °C for 3 h to obtain a dephosphorization filler.

[0096] The mass ratio of the precursor, titanium dioxide, sodium silicate, ferrous sulfate solution and sodium borohydride is 1:0.12:0.02:4:0.12.

[0097] Example 8

[0098] The difference between Example 8 and Example 1 is that the calcination temperature in step (4) is 380° C., and the other conditions are the same.

[0099] Example 9

[0100] The difference between Example 9 and Example 1 is that the calcination temperature in step (4) is 300° C., and the other aspects are the same.

[0101] Example 10

[0102] The difference between Example 10 and Example 1 is that the calcination temperature in step (4) is 500° C., and the other aspects are the same.

[0103] Embodiment 11

[0104] The difference between Example 11 and Example 1 is that the pore-forming agent in this example is a single sodium bicarbonate (the total amount of the pore-forming agent remains unchanged), and the other parts are the same.

[0105] A method for preparing a phosphorus removal filler comprises the following steps:

[0106] (1) Gypsum dihydrate, fly ash, limestone and bauxite were mixed evenly, ball-milled at 500 rpm for 4 h, added to a muffle furnace, calcined at 1360 °C for 30 min, and ground to a specific surface area of ​​500 m 2 / kg, to obtain sulphoaluminate cement.

[0107] The mass ratio of the dihydrate gypsum, fly ash, limestone and bauxite is 20:10:35:35.

[0108] (2) Add sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide and γ-aminopropyltriethoxysilane to 0.5 mol / L nitric acid solution, stir at 100 rpm for 60 min, filter, and dry at 80°C for 2 h to obtain a mixture; the mass ratio of the sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide, γ-aminopropyltriethoxysilane and nitric acid solution is 1:0.1:0.1:0.15:0.02:10.

[0109] (3) The mixed material, ammonium bicarbonate, sodium percarbonate and sodium dodecylbenzene sulfonate are mixed uniformly, and after mixing uniformly, the mixture is placed in a steam curing box and cured at 90° C. for 3 hours to obtain a precursor material;

[0110] The mass ratio of the mixture, ammonium bicarbonate, sodium percarbonate and sodium dodecylbenzene sulfonate is 1:0.12:0.1:0.02.

[0111] (4) The precursor, titanium dioxide and sodium silicate were added to a 0.5 mol / L ferrous sulfate solution, sodium borohydride was added, and the mixture was stirred at 100 rpm for 2 h at 65 °C under nitrogen protection. The mixture was filtered, washed, and dried at 80 °C for 4 h. The mixture was added to a muffle furnace and calcined at 420 °C for 3 h to obtain a dephosphorization filler.

[0112] The mass ratio of the precursor, titanium dioxide, sodium silicate, ferrous sulfate solution and sodium borohydride is 1:0.1:0.05:3:0.1.

[0113] Example 12

[0114] The difference between Example 12 and Example 1 is that the pore-forming agent in this example is potassium chloride alone (the total amount of the pore-forming agent remains unchanged), and the other aspects are the same.

[0115] A method for preparing a phosphorus removal filler comprises the following steps:

[0116] (1) Gypsum dihydrate, fly ash, limestone and bauxite were mixed evenly, ball-milled at 500 rpm for 4 h, added to a muffle furnace, calcined at 1360 °C for 30 min, and ground to a specific surface area of ​​500 m 2 / kg, to obtain sulphoaluminate cement.

[0117] The mass ratio of the dihydrate gypsum, fly ash, limestone and bauxite is 20:10:35:35.

[0118] (2) Add sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide and γ-aminopropyltriethoxysilane to 0.5 mol / L nitric acid solution, stir at 100 rpm for 60 min, filter, and dry at 80°C for 2 h to obtain a mixture; the mass ratio of the sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide, γ-aminopropyltriethoxysilane and nitric acid solution is 1:0.1:0.1:0.15:0.02:10.

[0119] (3) The mixed material, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate are mixed evenly, and after mixing evenly, the mixture is placed in a steam curing box and cured at 90° C. for 3 hours to obtain a precursor material;

[0120] The mass ratio of the mixture, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate is 1:0.12:0.1:0.02.

[0121] (4) The precursor, titanium dioxide and sodium silicate were added to a 0.5 mol / L ferrous sulfate solution, sodium borohydride was added, and the mixture was stirred at 100 rpm for 2 h at 65 °C under nitrogen protection. The mixture was filtered, washed, and dried at 80 °C for 4 h. The mixture was added to a muffle furnace and calcined at 420 °C for 3 h to obtain a dephosphorization filler.

[0122] The mass ratio of the precursor, titanium dioxide, sodium silicate, ferrous sulfate solution and sodium borohydride is 1:0.1:0.05:3:0.1.

[0123] Comparative Example 1

[0124] The difference between Comparative Example 1 and Example 1 is that chitosan and sodium alginate are not added in Comparative Example 1.

[0125] A method for preparing a phosphorus removal filler comprises the following steps:

[0126] (1) Gypsum dihydrate, fly ash, limestone and bauxite were mixed evenly, ball-milled at 500 rpm for 4 h, added to a muffle furnace, calcined at 1360 °C for 30 min, and ground to a specific surface area of ​​500 m 2 / kg, to obtain sulphoaluminate cement.

[0127] The mass ratio of the dihydrate gypsum, fly ash, limestone and bauxite is 20:10:35:35.

[0128] (2) Add sulphoaluminate cement, calcium peroxide and γ-aminopropyltriethoxysilane to a 0.5 mol / L nitric acid solution, stir at 100 rpm for 60 min, filter, and dry at 80° C. for 2 h to obtain a mixture; the mass ratio of the sulphoaluminate cement, calcium peroxide, γ-aminopropyltriethoxysilane and nitric acid solution is 1:0.15:0.02:10.

[0129] (3) The mixed material, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate are mixed evenly, and after mixing evenly, the mixture is placed in a steam curing box and cured at 90° C. for 3 hours to obtain a precursor material;

[0130] The mass ratio of the mixture, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate is 1:0.06:0.06:0.1:0.02.

[0131] (4) The precursor, titanium dioxide and sodium silicate were added to a 0.5 mol / L ferrous sulfate solution, sodium borohydride was added, and the mixture was stirred at 100 rpm for 2 h at 65 °C under nitrogen protection. The mixture was filtered, washed, and dried at 80 °C for 4 h. The mixture was added to a muffle furnace and calcined at 420 °C for 3 h to obtain a dephosphorization filler.

[0132] The mass ratio of the precursor, titanium dioxide, sodium silicate, ferrous sulfate solution and sodium borohydride is 1:0.1:0.05:3:0.1.

[0133] Comparative Example 2

[0134] The difference between Comparative Example 2 and Example 1 is that no calcium peroxide is added in Comparative Example 2.

[0135] A method for preparing a phosphorus removal filler comprises the following steps:

[0136] (1) Gypsum dihydrate, fly ash, limestone and bauxite were mixed evenly, ball-milled at 500 rpm for 4 h, added to a muffle furnace, calcined at 1360 °C for 30 min, and ground to a specific surface area of ​​500 m 2 / kg, to obtain sulphoaluminate cement.

[0137] The mass ratio of the dihydrate gypsum, fly ash, limestone and bauxite is 20:10:35:35.

[0138] (2) Add sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide and γ-aminopropyltriethoxysilane to 0.5 mol / L nitric acid solution, stir at 100 rpm for 60 min, filter, and dry at 80°C for 2 h to obtain a mixture; the mass ratio of the sulphoaluminate cement, chitosan, sodium alginate, γ-aminopropyltriethoxysilane and nitric acid solution is 1:0.1:0.1:0.02:10.

[0139] (3) The mixed material, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate are mixed evenly, and after mixing evenly, the mixture is placed in a steam curing box and cured at 90° C. for 3 hours to obtain a precursor material;

[0140] The mass ratio of the mixture, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate is 1:0.06:0.06:0.1:0.02.

[0141] (4) The precursor, titanium dioxide and sodium silicate were added to a 0.5 mol / L ferrous sulfate solution, sodium borohydride was added, and the mixture was stirred at 100 rpm for 2 h at 65 °C under nitrogen protection. The mixture was filtered, washed, and dried at 80 °C for 4 h. The mixture was added to a muffle furnace and calcined at 420 °C for 3 h to obtain a dephosphorization filler.

[0142] The mass ratio of the precursor, titanium dioxide, sodium silicate, ferrous sulfate solution and sodium borohydride is 1:0.1:0.05:3:0.1.

[0143] Comparative Example 3

[0144] The difference between Comparative Example 3 and Example 1 is that the mass ratio of sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide, γ-aminopropyltriethoxysilane and nitric acid solution in Comparative Example 3 is not within the scope of the present invention, and the others are the same.

[0145] The mass ratio of the sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide, γ-aminopropyltriethoxysilane and nitric acid solution in this comparative example is 1:0.02:0.2:0.05:0.04:20.

[0146] Comparative Example 4

[0147] The difference between Comparative Example 4 and Example 1 is that the mass ratio of sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide, γ-aminopropyltriethoxysilane and nitric acid solution in Comparative Example 4 is not within the scope of the present invention, and the others are the same.

[0148] The mass ratio of the sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide, γ-aminopropyltriethoxysilane and nitric acid solution in this comparative example is 1:0.2:0.02:0.4:0.005:5.

[0149] Comparative Example 5

[0150] The difference between Comparative Example 5 and Example 1 is that Comparative Example 5 does not undergo the pore-forming foaming treatment of step (3).

[0151] A method for preparing a phosphorus removal filler comprises the following steps:

[0152] (1) Gypsum dihydrate, fly ash, limestone and bauxite were mixed evenly, ball-milled at 500 rpm for 4 h, added to a muffle furnace, calcined at 1360 °C for 30 min, and ground to a specific surface area of ​​500 m 2 / kg, to obtain sulphoaluminate cement.

[0153] The mass ratio of the dihydrate gypsum, fly ash, limestone and bauxite is 20:10:35:35.

[0154] (2) Add sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide and γ-aminopropyltriethoxysilane to 0.5 mol / L nitric acid solution, stir at 100 rpm for 60 min, filter, and dry at 80°C for 2 h to obtain a mixture; the mass ratio of the sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide, γ-aminopropyltriethoxysilane and nitric acid solution is 1:0.1:0.1:0.15:0.02:10.

[0155] (3) Add the mixture, titanium dioxide and sodium silicate to a 0.5 mol / L ferrous sulfate solution, add sodium borohydride, stir at 100 rpm at 65 °C for 2 h under nitrogen protection, filter, wash, dry at 80 °C for 4 h, add to a muffle furnace, and calcine at 420 °C for 3 h to obtain a dephosphorization filler.

[0156] The mass ratio of the mixture, titanium dioxide, sodium silicate, ferrous sulfate solution and sodium borohydride is 1:0.1:0.05:3:0.1.

[0157] Comparative Example 6

[0158] The difference between Comparative Example 6 and Example 1 is that Comparative Example 6 adopts ordinary pore-forming foaming treatment.

[0159] A method for preparing a phosphorus removal filler comprises the following steps:

[0160] (1) Gypsum dihydrate, fly ash, limestone and bauxite were mixed evenly, ball-milled at 500 rpm for 4 h, added to a muffle furnace, calcined at 1360 °C for 30 min, and ground to a specific surface area of ​​500 m 2 / kg, to obtain sulphoaluminate cement.

[0161] The mass ratio of the dihydrate gypsum, fly ash, limestone and bauxite is 20:10:35:35.

[0162] (2) Add sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide and γ-aminopropyltriethoxysilane to 0.5 mol / L nitric acid solution, stir at 100 rpm for 60 min, filter, and dry at 80°C for 2 h to obtain a mixture; the mass ratio of the sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide, γ-aminopropyltriethoxysilane and nitric acid solution is 1:0.1:0.1:0.15:0.02:10.

[0163] (3) The mixed material, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate are mixed evenly, placed in a constant temperature box, and maintained at 90° C. for 3 hours to obtain a precursor material;

[0164] The mass ratio of the mixture, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate is 1:0.06:0.06:0.1:0.02.

[0165] (4) The precursor, titanium dioxide and sodium silicate were added to a 0.5 mol / L ferrous sulfate solution, sodium borohydride was added, and the mixture was stirred at 100 rpm for 2 h at 65 °C under nitrogen protection. The mixture was filtered, washed, and dried at 80 °C for 4 h. The mixture was added to a muffle furnace and calcined at 420 °C for 3 h to obtain a dephosphorization filler.

[0166] The mass ratio of the precursor, titanium dioxide, sodium silicate, ferrous sulfate solution and sodium borohydride is 1:0.1:0.05:3:0.1.

[0167] Comparative Example 7

[0168] The difference between Comparative Example 7 and Example 1 is that titanium dioxide and sodium silicate are not added in Comparative Example 7, and the other contents are the same.

[0169] A method for preparing a phosphorus removal filler comprises the following steps:

[0170] (1) Gypsum dihydrate, fly ash, limestone and bauxite were mixed evenly, ball-milled at 500 rpm for 4 h, added to a muffle furnace, calcined at 1360 °C for 30 min, and ground to a specific surface area of ​​500 m 2 / kg, to obtain sulphoaluminate cement.

[0171] The mass ratio of the dihydrate gypsum, fly ash, limestone and bauxite is 20:10:35:35.

[0172] (2) Add sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide and γ-aminopropyltriethoxysilane to 0.5 mol / L nitric acid solution, stir at 100 rpm for 60 min, filter, and dry at 80°C for 2 h to obtain a mixture; the mass ratio of the sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide, γ-aminopropyltriethoxysilane and nitric acid solution is 1:0.1:0.1:0.15:0.02:10.

[0173] (3) The mixed material, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate are mixed evenly, and after mixing evenly, the mixture is placed in a steam curing box and cured at 90° C. for 3 hours to obtain a precursor material;

[0174] The mass ratio of the mixture, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate is 1:0.06:0.06:0.1:0.02.

[0175] (4) The precursor was added into a 0.5 mol / L ferrous sulfate solution, sodium borohydride was added, and the mixture was stirred at 100 rpm for 2 h at 65 °C under nitrogen protection, filtered, washed, and dried at 80 °C for 4 h. The mixture was added into a muffle furnace and calcined at 420 °C for 3 h to obtain a dephosphorization filler.

[0176] The mass ratio of the precursor, ferrous sulfate solution and sodium borohydride is 1:3:0.1.

[0177] Comparative Example 8

[0178] The difference between Comparative Example 8 and Example 1 is that, in Comparative Example 8, ferrous sulfate is replaced by sulfuric acid solution (and no reducing agent is added), and the other contents are the same.

[0179] A method for preparing a phosphorus removal filler comprises the following steps:

[0180] (1) Gypsum dihydrate, fly ash, limestone and bauxite were mixed evenly, ball-milled at 500 rpm for 4 h, added to a muffle furnace, calcined at 1360 °C for 30 min, and ground to a specific surface area of ​​500 m 2 / kg, to obtain sulphoaluminate cement.

[0181] The mass ratio of the dihydrate gypsum, fly ash, limestone and bauxite is 20:10:35:35.

[0182] (2) Add sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide and γ-aminopropyltriethoxysilane to 0.5 mol / L nitric acid solution, stir at 100 rpm for 60 min, filter, and dry at 80°C for 2 h to obtain a mixture; the mass ratio of the sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide, γ-aminopropyltriethoxysilane and nitric acid solution is 1:0.1:0.1:0.15:0.02:10.

[0183] (3) The mixed material, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate are mixed evenly, and after mixing evenly, the mixture is placed in a steam curing box and cured at 90° C. for 3 hours to obtain a precursor material;

[0184] The mass ratio of the mixture, ammonium bicarbonate, potassium chloride, sodium percarbonate and sodium dodecylbenzene sulfonate is 1:0.06:0.06:0.1:0.02.

[0185] (4) The precursor, titanium dioxide and sodium silicate were added to a 0.5 mol / L sulfuric acid solution, stirred at 100 rpm for 2 h at 65 °C under nitrogen protection, filtered, washed, dried at 80 °C for 4 h, added to a muffle furnace, and calcined at 420 °C for 3 h to obtain a dephosphorization filler.

[0186] The mass ratio of the precursor, titanium dioxide, sodium silicate and sulfuric acid solution is 1:0.1:0.05:0.1.

[0187] Test Case

[0188] 150 ml of simulated phosphorus-containing wastewater with a concentration of 60 mg / L was prepared and treated with the fillers of the embodiment and comparative example (the added amount was 2.157 g) respectively (three groups were measured for each embodiment and comparative example, and the average value was taken). The temperature was set to 25°C, the speed was 250 rpm, and the constant temperature oscillation was performed for 2 hours. The supernatant was filtered with a 0.45 μm filter membrane, and the phosphorus removal rate was calculated.

[0189] Table 1

[0190]

[0191] It can be seen from Table 1 that the filler of the present invention has an excellent phosphorus removal effect.

[0192] By comparing Example 1 with Comparative Examples 1-2, it can be seen that the present invention mixes sulphoaluminate cement, chitosan, sodium alginate and calcium peroxide, and the phosphorus removal effect is significantly improved under their combined action.

[0193] By comparing Example 1 with Comparative Examples 3-4, it can be seen that the phosphorus removal effect is effectively improved by controlling the mass ratio of sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide, amino-containing silane coupling agent, and nitric acid solution within the scope of the present invention.

[0194] By comparing Example 1 with Comparative Example 5, it can be seen that the phosphorus removal effect is significantly improved through the pore-forming foaming of the present invention.

[0195] By comparing Example 1 with Comparative Example 6, it can be seen that the use of the steam foaming method of the present invention significantly improves the phosphorus removal effect.

[0196] By comparing Example 1 with Comparative Examples 7-8, it can be seen that the present invention significantly improves the phosphorus removal effect by adding titanium dioxide, sodium silicate, and loading zero-valent iron.

[0197] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a phosphorus removal filler, characterized in that: The following steps are involved: Adding sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide and an amino-containing coupling agent into a nitric acid solution, stirring evenly, filtering and drying to obtain a mixture; The mixed material, the foaming agent and the pore-forming agent are uniformly mixed and steam cured to obtain a precursor material; The precursor, titanium dioxide and sodium silicate are added to the ferrous sulfate solution, sodium borohydride is added, stirred evenly, filtered, washed, dried and calcined to obtain a dephosphorization filler; The mass ratio of the sulphoaluminate cement, chitosan, sodium alginate, calcium peroxide, amino-containing coupling agent and nitric acid solution is 1: (0.05-0.15): (0.05-0.15): (0.1-0.2): (0.01-0.02): (8-12); The pore-forming agent includes ammonium bicarbonate and potassium chloride, and the mass ratio of the ammonium bicarbonate to potassium chloride is 1: (0.5-2); The steam curing temperature is 80-90°C and the time is 2-5h; The calcination temperature is 380-420°C and the calcination time is 2-4 hours; The amino-containing coupling agent includes at least one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and N-(2-aminoethyl)-3-aminopropyltriethoxysilane; The foaming agent includes sodium percarbonate and sodium dodecylbenzene sulfonate, and the mass ratio of the sodium percarbonate to the sodium dodecylbenzene sulfonate is 1:(0.1-0.4).

2. The method for preparing the phosphorus removal filler according to claim 1, characterized in that: The concentration of the nitric acid solution is 0.4-1.2 mol / L.

3. The method for preparing the phosphorus removal filler according to claim 1, characterized in that: The preparation method of the sulphoaluminate cement comprises the following steps: uniformly mixing dihydrate gypsum, fly ash, limestone and bauxite, ball milling, calcining at 1350-1400° C. for 28-40 minutes, and grinding to obtain the sulphoaluminate cement.

4. The method for preparing the phosphorus removal filler according to claim 3, characterized in that: The mass ratio of the dihydrate gypsum, fly ash, limestone and bauxite is (15-22): (8-15): (30-40): (30-40).

5. The method for preparing the phosphorus removal filler according to claim 1, characterized in that: The mass ratio of the mixed material, the foaming agent and the pore-forming agent is 1: (0.05-0.15): (0.08-0.15).

6. The method for preparing the phosphorus removal filler according to claim 1, characterized in that: The mass ratio of the precursor, titanium dioxide, sodium silicate, ferrous sulfate solution and sodium borohydride is 1: (0.05-0.12): (0.02-0.06): (2-4): (0.05-0.12).

7. The method for preparing the phosphorus removal filler according to claim 1, characterized in that: The molar concentration of the ferrous sulfate solution is 0.2-0.6 mol / L.

8. A phosphorus removal filler, characterized in that: The method is prepared by any one of claims 1 to 7.

9. Use of the phosphorus removal filler according to claim 8 as a filler for sewage treatment.

10. Use of the phosphorus removal filler according to claim 8 as a filler for artificial wetlands.

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