CN116282339B - Groundwater treatment method - Google Patents

Groundwater treatment method Download PDF

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CN116282339B
CN116282339B CN202310511761.2A CN202310511761A CN116282339B CN 116282339 B CN116282339 B CN 116282339B CN 202310511761 A CN202310511761 A CN 202310511761A CN 116282339 B CN116282339 B CN 116282339B
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modified
content
ceramsite
parts
solution
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CN116282339A (en
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郜玉楠
黄铿霖
陈忻
徐颂
江学顶
罗英杰
时宛柱
林婧
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Foshan University
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C02F1/288—Treatment of water, waste water, or sewage by sorption using composite sorbents, e.g. coated, impregnated, multi-layered
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/0203—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of metals not provided for in B01J20/04
    • B01J20/0225—Compounds of Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt
    • B01J20/0229—Compounds of Fe
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B01J20/04—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of alkali metals, alkaline earth metals or magnesium
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    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
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    • B01J20/08—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising oxides or hydroxides of metals not provided for in group B01J20/04 comprising aluminium oxide or hydroxide; comprising bauxite
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
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    • B01J20/10—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate
    • B01J20/103—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate comprising silica
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    • B01J20/10—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate
    • B01J20/12—Naturally occurring clays or bleaching earth
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/10—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate
    • B01J20/16—Alumino-silicates
    • B01J20/165—Natural alumino-silicates, e.g. zeolites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01J20/22—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
    • B01J20/24—Naturally occurring macromolecular compounds, e.g. humic acids or their derivatives
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
    • B01J20/28014—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their form
    • B01J20/28016—Particle form
    • B01J20/28021—Hollow particles, e.g. hollow spheres, microspheres or cenospheres
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/105—Phosphorus compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
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    • C02F2101/14—Fluorine or fluorine-containing compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/16—Nitrogen compounds, e.g. ammonia
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/16—Nitrogen compounds, e.g. ammonia
    • C02F2101/163—Nitrates
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/06—Contaminated groundwater or leachate
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00—Technologies relating to the processing of minerals
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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Analytical Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Water Supply & Treatment (AREA)
  • Environmental & Geological Engineering (AREA)
  • Dispersion Chemistry (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Engineering & Computer Science (AREA)
  • Hydrology & Water Resources (AREA)
  • Compositions Of Oxide Ceramics (AREA)

Abstract

The application discloses a groundwater treatment method, and relates to the field of water treatment. Specifically comprises the steps of filtering by adopting modified ceramsite and modified zeolite in turn; the preparation method of the modified ceramsite comprises the following steps: uniformly mixing 20-40 parts of aluminum sludge, 10-20 parts of kaolin, 30-50 parts of papermaking white mud and 5-15 parts of ceramic polishing slag, molding, sintering at 950-1050 ℃, and then immersing in zirconium-containing solution for modification to obtain the modified aluminum-ceramic composite material; the preparation method of the modified zeolite comprises the following steps: loading nano zirconia to zeolite molecular sieve, mixing with sodium alginate solution, and dripping FeCl 3 And (5) crosslinking and solidifying the solution for preset time, and drying to obtain the modified polyvinyl alcohol. By implementing the method, the removal of nitrate nitrogen, ammonia nitrogen, phosphate and fluoride can be simultaneously realized at a lower temperature, and the treatment cost is reduced.

Description

Groundwater treatment method
Technical Field
The application relates to the field of water treatment, in particular to a groundwater treatment method.
Background
Along with the improvement of living standard, the safety awareness of the resident drinking water is also improved. With the development of drinking water nitrate removal technology. For nitrate nitrogen, the existing treatment modes for large-scale application mainly comprise two types: the first type is microbial denitrification, but denitrifying bacteria often need certain temperature conditions, and are difficult to be applied to areas with large four-season temperature differences; and denitrification generally requires anaerobic control, and has high cost; in addition, denitrification often causes secondary pollution, such as methanol production, and if necessary, some organic matters are put in. The other is reverse osmosis, but the equipment requirement is high, the cost is high, and the reverse osmosis is difficult to be adopted for some existing water plants.
On the other hand, in the conventional water works, a coagulant such as aluminum salt or polyaluminium salt is added in the water treatment process to improve the treatment effect, and a large amount of aluminum sludge sediment containing aluminum salt, namely aluminum sludge, is generated in the process. The aluminum sludge can not be directly discharged any more, and the cost of land landfill is high, so the resource utilization of the aluminum sludge is attracting attention.
Disclosure of Invention
The application aims to solve the technical problems of providing a water treatment method which can simultaneously remove phosphate, fluoride, ammonia nitrogen and nitrate nitrogen, and has mild treatment conditions and low maintenance cost.
In order to solve the technical problems, the application provides a groundwater treatment method, which comprises the steps of filtering by adopting modified ceramsite and modified zeolite in sequence;
the preparation method of the modified ceramsite comprises the following steps:
(1) Uniformly mixing 20-40 parts of aluminum sludge, 10-20 parts of kaolin, 30-50 parts of papermaking white mud and 5-15 parts of ceramic polishing slag to obtain a mixture; wherein the total consumption of the aluminum sludge, the kaolin, the papermaking white mud and the ceramic polishing slag is 100 parts;
(2) Molding the mixture to obtain a spherical blank;
(3) Firing the spherical blank at 950-1050 ℃ to obtain a ceramsite matrix;
(4) Immersing the ceramsite matrix into a zirconium-containing solution, and drying and removing solute in the zirconium-containing solution to obtain a ceramsite finished product for groundwater treatment;
the preparation method of the modified zeolite comprises the following steps:
(i) Dispersing nano zirconia and zeolite molecular sieve into water to obtain suspension;
(ii) Uniformly mixing the suspension with sodium alginate solution, and dripping FeCl 3 And (5) crosslinking and solidifying the solution for preset time, and drying to obtain the modified polyvinyl alcohol.
As an improvement of the technical scheme, when the modified ceramsite is adopted for filtration, the filtration temperature is 12-35 ℃;
when the modified zeolite is adopted for filtration, the filtration temperature is 8-35 ℃.
As an improvement of the technical scheme, in the step (i), nano ZrO is firstly treated 2 Placing into water, ultrasonic dispersing, adding zeolite molecular sieve, and ultrasonic dispersing again to obtain suspension, wherein nanometer ZrO 2 And zeolite molecular sieve in a weight ratio of 1: (5-10);
the concentration of zeolite molecular sieve in the suspension is 5-10wt%.
As an improvement of the technical scheme, in the step (ii), the concentration of the sodium alginate solution is 1-5wt%, and the weight ratio of the zeolite molecular sieve to the sodium alginate is (3-5): 1, the FeCl 3 The concentration of the solution is 2-4wt%;
as an improvement of the technical scheme, in the step (ii), feCl 3 The dropping speed of the solution is 30-40 drops/min;
the cross-linking curing comprises cross-linking curing at 30-60 ℃ for 12-36h.
As an improvement of the technical scheme, in the step (i), the zeolite molecular sieve is soaked in hydrochloric acid with the concentration of 4-6wt% for 5-20h, and is cleaned until the pH value is constant.
As an improvement of the technical scheme, the zirconium-containing solution is ZrOCl 2 An aqueous solution having a concentration of 15-30wt%.
As an improvement of the technical proposal, fe in the aluminum sludge 2 O 3 The content of (2) is more than or equal to 10wt percent, the content of CaO is less than or equal to 12wt percent, and Al 2 O 3 The content of (2) is more than or equal to 35 weight percent;
the mass loss rate of the papermaking white mud is more than or equal to 30wt% after the papermaking white mud is burnt to constant weight in an oxidizing atmosphere at 600 ℃;
the mass loss rate of the papermaking white mud is more than or equal to 70wt% after the papermaking white mud is burned to constant weight in an oxidizing atmosphere at 950 ℃.
The content of CaO in the ceramic polishing slag is less than or equal to 1.5wt percent, and SiO is contained in the ceramic polishing slag 2 The content of Al is more than or equal to 63wt percent 2 O 3 The content of (2) is more than or equal to 20wt%.
As an improvement of the technical proposal, fe in the aluminum sludge 2 O 3 The content of (2) is 12-20wt%, the content of CaO is 3-8wt%, and Al 2 O 3 The content of (2) is 38-48wt%;
the mass loss rate of the papermaking white mud is 35-45wt% after the papermaking white mud is burned to constant weight in an oxidizing atmosphere at 600 ℃; burning to constant weight in 950 deg.c oxidizing atmosphere with mass loss rate of 75-85wt%;
the content of CaO in the ceramic polishing slag is 0.3-1.2wt percent, siO 2 The content of (C) is 64-70wt%, al 2 O 3 The content of (C) is 20.5-23wt%.
As an improvement of the above technical scheme, in the step (3), the firing curve is:
the temperature rising rate is 15-20 ℃/min from room temperature to 350 ℃;
preserving heat at 350deg.C for 5-10min;
the temperature rise rate is 8-12 ℃/min from 350 ℃ to 850 ℃;
heating from 850 ℃ to the firing temperature at a heating rate of 5-20 ℃/min;
preserving heat for 10-15min at the firing temperature.
The implementation of the application has the following beneficial effects:
1. according to the treatment method of the underground water, modified ceramsite and modified zeolite are adopted in sequence for filtering treatment. The modified ceramsite is prepared by loading zirconium on a ceramsite matrix prepared from aluminum sludge, kaolin, papermaking white mud and ceramic polishing slag, and can remove a large amount of phosphate, ammonia nitrogen and fluoride at a lower temperature, and meanwhile, nitrate nitrogen is partially removed. Further to load nano ZrO 2 The modified zeolite of the catalyst is filtered, so that the removal efficiency of nitrate nitrogen is greatly improved, and particularly, the removal efficiency of nitrate nitrogen can reach more than 88%. In addition, the treatment method is simple, has low maintenance cost, can be operated at low temperature, is suitable for areas with large four-season temperature difference, is also suitable for reconstruction of old water plants, and does not need to add a large amount of high-price equipment.
2. The modified zeolite of the application loads nano ZrO on zeolite molecular sieve 2 Then sodium alginate and FeCl are also adopted 3 Cross-linking and solidifying to form core-shell structure for loading nano ZrO 2 The zeolite molecular sieve is effectively embedded, so that the problems of dispersion and instability of the nano particles in practical application are solved, and the mechanical strength and stability of the composite microsphere are improved. Furthermore, by FeCl 3 Crosslinking the solution, feCl on the one hand 3 Fe in solution 3+ With Al in zeolite molecular sieves 3+ The ion exchange reaction is carried out to form more firm Si-O-Fe bond, and Fe is combined with zeolite 3+ As an active metal ion, the surface group thereof is capable of adsorbing NO in the form of hydrogen bond 3 - The method comprises the steps of carrying out a first treatment on the surface of the On the other hand, due to FeCl 3 The solution is rich in a large amount of H + Nano ZrO during curing 2 The Br can show the characteristics of a nsted base and can be combined with hydrogen ions, so that hydrogen bonds on the surface of a product are formed, and the Br is favorable for combining with nitrate nitrogen in the adsorption process.
3. The modified ceramsite disclosed by the application is prepared from the ceramsite matrix prepared from aluminum sludge, kaolin, papermaking white mud and ceramic polishing slag with specific chemical components, and is combined with a specific firing curve, so that the apparent porosity and the pore diameter uniformity of the modified ceramsite can be effectively controlled, the good load on zirconium is realized, and the water treatment effect is improved. Meanwhile, the active Al and Fe in the raw materials are more reserved, so that the treatment effect on phosphates and fluorides is enhanced.
4. The modified ceramsite and the modified zeolite are in microsphere form, are easy to separate and recycle, and reduce the water treatment cost.
Drawings
FIG. 1 is N of modified ceramsite in example 3 of the present application 2 Adsorption and desorption isotherm curves;
FIG. 2 is a graph showing the pore size distribution of BJH of the modified ceramic particles in example 3 of the present application;
FIG. 3 is an electron micrograph of the modified zeolite of example 4 of the present application;
FIG. 4 is a graph showing the removal rate and adsorption effect of modified zeolite in example 4 of the present application when the modified zeolite is added to raw water of different nitrate nitrogen;
FIG. 5 is a Langmuir fit plot of the adsorption effect of the modified zeolite of example 4 of the present application;
FIG. 6 is a Freundlich fit plot of the adsorption effect of modified zeolite in example 4 of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be described in further detail with reference to the following detailed description.
The application provides a groundwater treatment method, which comprises the step of filtering by adopting modified ceramsite and modified zeolite. Specifically, when the modified ceramic particles are used for filtration, the filtration temperature is 12-35 ℃, and is exemplified by, but not limited to, 15 ℃, 18 ℃, 20 ℃, 23 ℃, 26 ℃, 28 ℃, 30 ℃ or 33 ℃. Preferably, when the modified ceramsite is adopted for filtration, the filtration temperature is 20-30 ℃; based on the filtering temperature, the modified ceramsite realizes high-efficiency removal of fluoride and phosphate, avoids competitive adsorption of phosphate and fluoride when the modified zeolite filters nitrate nitrogen in the later period, and reduces the adsorption quantity of the nitrate nitrogen. Meanwhile, based on the temperature, the nitrate nitrogen is partially removed, and a good basis is provided for removing the nitrate nitrogen from the late-stage modified zeolite.
When the modified zeolite is used for filtration, the filtration temperature is 8 to 35 ℃, and is exemplified by, but not limited to, 10 ℃, 15 ℃, 20 ℃, 24 ℃, 28 ℃, 30 ℃ or 34 ℃. Preferably, when modified zeolite is used for filtration, the filtration temperature is 8-15 ℃. Based on the filtration temperature, one reduces adsorption of anions such as phosphates, fluorides, etc., reducing its adverse effect on nitrate nitrogen adsorption. In both cases, the modified zeolite has a high adsorption amount of nitrate nitrogen in this temperature range. In addition, it should be noted that, because the modified ceramsite is adopted for filtering in the early stage, a great amount of competitive anion phosphate radical and fluoride ion are removed, so that the high-efficiency removal of nitrate nitrogen can be realized when the modified zeolite is adopted in the later stage. The initial concentration of the nitrate nitrogen is relatively low (8-12 mg/L) when the modified zeolite is adopted for filtering in the later stage, so that the effect of removing the nitrate nitrogen by the modified zeolite is better exerted.
The preparation method of the modified ceramsite comprises the following steps:
(1) Uniformly mixing 20-40 parts of aluminum sludge, 10-20 parts of kaolin, 30-50 parts of papermaking white mud and 5-15 parts of ceramic polishing slag to obtain a mixture;
wherein the aluminum sludge is solid waste of water plants, contains amorphous iron and aluminum hydroxide, and also contains SiO 2 Minerals such as kaolinite and feldspar. The aluminum sludge is introduced, so that not only is an Al source necessary for the ceramsite provided, but also an Fe source is provided, and the pore channel structure of the ceramsite can be optimized by the gas released by Fe at high temperature, so that the apparent porosity is improved. Preferably, in one embodiment of the present application, fe in the aluminum sludge is controlled 2 O 3 The content of (2) is more than or equal to 10wt percent, the content of CaO is less than or equal to 12wt percent, and Al 2 O 3 The content of (2) is more than or equal to 35 weight percent. Based on the control, the apparent porosity of the ceramsite matrix can be improved, more active Al can be reserved, and the subsequent adsorption effect on phosphate, fluoride and ammonia nitrogen can be improved. In addition, the ceramic particle substrate is not sintered too early, so that the apparent porosity is greatly reduced. Further preferably, fe in the aluminum sludge is controlled 2 O 3 The content of (2) is 12 to 20wt%, and is exemplified by 13wt%, 15wt%, 17wt%, 18.5wt% or 19wt%, but not limited thereto. Control deviceThe CaO content of the aluminum sludge is 3 to 8 wt.%, and is exemplified by 3.5 wt.%, 4.5 wt.%, 5.5 wt.%, 6.5 wt.%, or 7 wt.%, but not limited thereto. Control of Al in aluminum sludge 2 O 3 The content of (C) is 38-48wt%, and is exemplified by 39wt%, 41wt%, 43wt%, 45wt% or 47wt%, but not limited thereto.
The aluminum sludge is used in an amount of 20 to 40 parts by weight, and is exemplified by 22 parts, 26 parts, 30 parts, 34 parts, 38 parts, or 39 parts, but not limited thereto.
Wherein, the kaolin can provide plasticity and is convenient for molding. Preferably, in one embodiment of the application, al in the kaolin is controlled 2 O 3 The kaolin of the component has better plasticity, and can form partial columnar mullite in the firing process, thereby improving the mechanical properties (such as barrel pressure strength and the like) of the ceramsite matrix.
The kaolin is used in an amount of 10 to 20 parts by weight, and is exemplified by 11 parts, 13 parts, 15 parts, 17 or 19 parts, but not limited thereto.
The papermaking white mud is waste residue obtained by a paper mill, contains a large amount of paper fibers and also contains a certain amount of calcium carbonate. By introducing papermaking white mud, the performance of a formed blank body can be improved, the use of kaolin is reduced, and the cost of raw materials is reduced. And a large number of paper fibers can be decomposed to form a large number of pore channels, so that the adsorption performance of the ceramsite is improved. Furthermore, by controlling the firing curve, the paper fiber still can be decomposed and released at a higher temperature (about 900 ℃), so that the decomposed gas can be wrapped on the surfaces of other particles in the formula, and other particles (such as SiC and Fe in ceramic polishing residues) are regulated 2 O 3 Etc.) release gas, thereby ensuring the uniformity of the ceramsite pores and improving the adsorption effect. The firing temperature of the papermaking white mud is reduced, the conversion of active Al is reduced, and the adsorption effect is improved. The calcium carbonate can be decomposed at high temperature, so that the apparent porosity of the ceramsite is further improved, and the adsorption performance of a ceramsite matrix is improved. Preferably, in one embodiment of the application, the mass loss rate of the papermaking white mud is more than or equal to 30wt% after the papermaking white mud is burned to constant weight in an oxidizing atmosphere at 600 ℃; the papermaking white mud is burned to constant weight in an oxidizing atmosphere at 950 ℃,the mass loss rate is more than or equal to 70 weight percent. Based on this control, the treatment effect on phosphates and fluorides can be further improved. It is further preferred that the mass loss rate of the papermaking white mud after being burned to a constant weight in an oxidizing atmosphere at 600 c is 35 to 45wt%, and exemplary is 37wt%, 39wt%, 41wt% or 43wt%, but not limited thereto. The mass loss rate of the papermaking white mud after being burned to a constant weight in an oxidizing atmosphere at 950 ℃ is 75-85wt%, and is exemplified by 77wt%, 79wt%, 81wt% or 83wt%, but not limited thereto.
The papermaking white mud is used in an amount of 30 to 50 parts by weight, and exemplified by 33 parts, 35 parts, 37 parts, 39 parts, 41 parts, 43 parts, 45 parts or 47 parts, but not limited thereto.
Wherein the ceramic polishing slag is waste obtained by polishing ceramic polishing bricks. The ceramic polishing slag contains a grinding head substance SiC, which can be foamed at high temperature, so that the open porosity of the ceramic matrix is improved. Meanwhile, because the papermaking white mud with high Ca content is introduced into the formula, the viscosity can be reduced at high temperature, and the white mud can corrode SiO formed in the reaction process of SiC 2 The film is then decomposed and foamed at a lower temperature (about 1000 ℃). Whereas conventional SiC and O 2 The reaction temperature is about 1200 ℃. The ceramic polishing slag contains a large amount of active substances which are sintered at high temperature (1150-1250 ℃), and the adsorption capacity of phosphate and ammonia nitrogen can be improved. Preferably, in one embodiment of the application, the CaO content of the ceramic polishing residues is less than or equal to 1.5wt percent, siO 2 The content of Al is more than or equal to 63wt percent 2 O 3 The content of (2) is more than or equal to 20wt%. Further preferred ceramic polishing residues have a CaO content of 0.3 to 1.2 wt.%, and exemplary ones are 0.5 wt.%, 0.7 wt.%, 0.9 wt.%, or 1.1 wt.%, but are not limited thereto. SiO in ceramic polishing slag 2 The content of (2) is 64 to 70wt%, and is exemplified by 65wt%, 67wt%, 68wt%, or 69wt%, but not limited thereto. Al in ceramic polishing slag 2 O 3 The content of (2) is 20.5 to 23wt%, and is exemplified by 21wt%, 21.5wt%, 22wt%, or 22.5wt%, but not limited thereto.
The ceramic polishing residue is used in an amount of 5 to 15 parts by weight, and is exemplified by 6 parts, 8 parts, 10 parts, 12 parts, or 14 parts, but not limited thereto.
Wherein, a small amount of water can be added in the mixing process, so that the mixture has certain fluidity, and the subsequent molding is convenient. The mixing may be performed by using a mixer commonly used in the art, or may be performed by using a ball mill, but is not limited thereto.
(2) Molding the mixture to obtain a spherical blank;
specifically, the mixture may be molded by a disk granulator, but is not limited thereto. And (5) drying the spherical blank at 80-100 ℃ after molding.
(3) Firing the spherical blank at 950-1050 ℃ to obtain a ceramsite matrix;
specifically, firing can be performed using a firing profile conventional in the art, but is not limited thereto. Preferably, in one embodiment of the present application, the firing profile is: the temperature rising rate is 15-20 ℃/min from room temperature to 350 ℃; preserving heat at 350deg.C for 5-10min; the temperature rise rate is 8-12 ℃/min from 350 ℃ to 850 ℃; the temperature rising rate is 5-20 ℃/min from 850 ℃ to the firing temperature (950-1050 ℃); preserving heat for 10-15min at the firing temperature. Based on the firing curve, the content of active Al and Fe in the ceramsite matrix can be effectively improved, and the efficiency of treating phosphate, fluoride and ammonia nitrogen is improved. Meanwhile, the active Al and Fe can also improve the load capacity of zirconium and the treatment capacity of nitrate nitrogen.
Specifically, the ceramic matrix obtained based on the formula and the preparation method has apparent porosity of more than or equal to 55%, cylinder pressure of more than or equal to 5MPa and bulk density of more than or equal to 0.9g/cm 3 。
(4) Immersing the ceramsite matrix into a zirconium-containing solution, and drying and removing solute in the zirconium-containing solution to obtain a ceramsite finished product for groundwater treatment.
The zirconium-containing solution may be, but not limited to, an aqueous solution of zirconium chloride, an aqueous solution of zirconium acetate, an aqueous solution of zirconium nitrate, an aqueous solution of zirconyl nitrate, or an aqueous solution of zirconyl chloride. Preferably, in one embodiment of the present application, the zirconium-containing solution is ZrOCl 2 An aqueous solution having a concentration of 15-30wt%.
Further, before soaking the zirconium-containing solution, the ceramsite can be soaked for 10-30 hours by adopting dilute hydrochloric acid (5-12 wt%) and then rinsed until the pH value is constant. After soaking the zirconium-containing solution, naOH solution (5-15 wt%) is used for soaking for 1-5h, then the solution is rinsed until the pH value is constant. Based on the technology, zr can be loaded on the surface of the ceramsite matrix, so that the adsorption quantity of fluoride, phosphate and nitrate nitrogen is effectively improved.
Wherein the preparation method of the modified zeolite comprises the following steps:
(i) Dispersing nano zirconia and zeolite molecular sieve into water to obtain suspension;
wherein nano ZrO is firstly treated 2 Placing into water, ultrasonic dispersing, adding zeolite molecular sieve, and ultrasonic dispersing again to obtain suspension, wherein nanometer ZrO 2 And zeolite molecular sieve in a weight ratio of 1: (5-10); when nano ZrO 2 When the weight ratio of the zeolite molecular sieve to the zeolite molecular sieve is more than 0.2, agglomeration is easy to cause, mesopores are reduced, and the adsorption quantity is reduced. When nano ZrO 2 When the weight ratio of the nano ZrO and the zeolite molecular sieve is less than 0.1, the nano ZrO is loaded 2 The amount is small, and the adsorption effect on nitrate nitrogen is poor. Exemplary, nano ZrO 2 And zeolite molecular sieve in a weight ratio of 1: 6. 1:7, 1:8, 1:8.5 or 1:9, more preferably 1:8.
Wherein the concentration of zeolite molecular sieve in the suspension is 5-10wt%, and exemplary is 6wt%, 7.5wt%, 8wt% or 9wt%, but is not limited thereto.
Preferably, in one embodiment of the present application, the zeolite molecular sieve is first soaked with 4-6wt% hydrochloric acid for 5-20 hours and washed to a constant pH. Specifically, the zeolite molecular sieve has stronger negative charge and weaker adsorption effect on anions, so that the effective space of the internal pores of the zeolite is widened and the non-polar characteristic is shown after the modification by adopting hydrochloric acid in the preparation process, and the ion exchange capacity and the affinity to anions of the zeolite molecular sieve are improved. Wherein, the concentration of hydrochloric acid is 4-6wt%, when the concentration of hydrochloric acid is too high, the pore canal structure of zeolite molecular sieve can be destroyed, resulting in nano ZrO 2 Is reduced, resulting in a partial nano ZrO 2 The adsorption particles are free in the gel solution, so that the porosity of the adsorption particles is reduced, and the adsorption sites are likely to be masked due to irregular dispersion; the modification process of hydrochloric acid also reduces the cation exchange capacity of zeolite molecular sieve, and forms water condensation in sodium alginateFe also occurs in the course of the glue 3+ Ion exchange with zeolite molecular sieves, fe 3+ The zeolite molecular sieve skeleton can form hydrated hydroxide in water environment to raise electrostatic adsorption effect of nitrate nitrogen, and hydrochloric acid with too high concentration obviously damages nano ZrO 2 Load of (2) and Fe 3+ Balance of ion exchange. When the hydrochloric acid concentration is too low, the widening effect on the internal pores of the zeolite is poor.
(ii) Uniformly mixing the suspension with sodium alginate solution, and dripping FeCl 3 And (5) crosslinking and solidifying the solution for preset time, and drying to obtain the modified polyvinyl alcohol.
Wherein the concentration of the sodium alginate solution is 1-5wt%, and is exemplified by 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, or 4wt%, but not limited thereto.
Wherein, the weight ratio of the zeolite molecular sieve to the sodium alginate is (3-5): 1, when zeolite molecular sieve and nano zirconia are added too much, the zeolite molecular sieve and the nano zirconia are difficult to uniformly distribute in a sodium alginate solution, the prepared gel microsphere has obvious tailing, is in a shape of tadpole, and can be accompanied with damage of structural morphology in the drying and adsorption processes, so that adsorption sites are damaged, and the removal efficiency is reduced. When the zeolite molecular sieve and the nano zirconia are added too little, the load sites are fewer, the cation exchange capacity is weak, and the later Fe is not favored 3+ And (3) modification.
Wherein FeCl 3 The concentration of the solution is 2-4wt%. When FeCl 3 Higher concentrations of the solution reduce the gel network space formed on the particle surface. In addition, a large amount of Fe 3+ and-COOH groups in sodium alginate, which is accompanied by reduction of excessive-COOH groups, resulting in weakening of electrostatic repulsive force between-COOH groups, which reduces the porosity of the microspheres.
FeCl 3 The dropping speed of the solution is 30 to 40 drops/min, and exemplary is 32 drops/min, 34 drops/min, 36 drops/min or 38 drops/min, but is not limited thereto.
Wherein the cross-linking curing comprises cross-linking curing at 30-60 ℃ for 12-36h. When the crosslinking temperature is too high, sodium alginate is degraded. When the temperature is too low, the distribution uniformity of sodium alginate is low, which is unfavorable for crosslinking and curing.
The application is illustrated below by means of specific examples:
the raw water in each of the following examples of the present application was simulated water prepared in a laboratory, and had a fluorine concentration of 10mg/L, a phosphate concentration of 20mg/L, a nitrate nitrogen concentration of 30mg/L, and an ammonia nitrogen concentration of 5mg/L.
Example 1
The embodiment provides a groundwater treatment method, which comprises the steps of filtering by adopting modified ceramsite and modified zeolite in sequence; wherein, when the modified ceramsite is filtered, the input amount is 15g/L, the filtering temperature is 20 ℃ (the filtration is performed in a constant-temperature oscillator at 140rpm for 1 h). When the modified zeolite was filtered, the input was 2g/L and the filtration temperature was 10deg.C (shaking at 140rpm in a constant temperature shaker for 1 h).
The preparation method of the modified ceramsite comprises the following steps:
the embodiment provides a preparation method of ceramsite for groundwater treatment, which comprises the following steps:
(1) Uniformly mixing 24 parts of aluminum sludge, 15 parts of kaolin, 49 parts of papermaking white mud and 12 parts of ceramic polishing slag to obtain a mixture;
wherein Fe in the aluminum sludge 2 O 3 13.5 wt.%, caO 4.3 wt.%, al 2 O 3 The content of (2) was 42.5% by weight. Al of Kaolin 2 O 3 The content is 38.3wt%; the mass loss rate of the papermaking white mud is 25.4wt% after the papermaking white mud is burned to constant weight in an oxidizing atmosphere at 600 ℃. The mass loss rate of the papermaking white mud is 76.3wt% after the papermaking white mud is burned to constant weight in an oxidizing atmosphere at 950 ℃. The content of CaO in the ceramic polishing slag is 1.4wt percent, siO 2 The content of (C) is 66.8wt%, al 2 O 3 21.8wt%.
(2) Shaping the mixture by adopting a disc granulator to obtain a spherical blank, and drying at 85 ℃;
(3) Firing the spherical blank to obtain a ceramsite matrix;
wherein, the firing curve is: the temperature is kept for 20min at 300 ℃ from room temperature to 300 ℃ at a heating rate of 30 ℃/min; heating up at a rate of 20 ℃/min from 300 ℃ to 1020 ℃; the temperature is kept at 1020℃for 15min.
(4) The ceramsite substrate is soaked in dilute hydrochloric acid (10 wt%) for 24h, and then rinsed with water until the pH is constant. Then immerse ZrOCl 2 And (3) evaporating the mixture in a water bath (80 ℃) in the water solution (20 wt%) to dryness, soaking the mixture in a NaOH solution (8 wt%) for 3 hours, and rinsing the mixture with water until the pH is constant, thus obtaining the product.
The preparation method of the modified zeolite comprises the following steps:
(1) Nano ZrO 2 Placing in water, ultrasonic dispersing for 90min, adding 4A type zeolite molecular sieve with 200 mesh size, ultrasonic dispersing for 90min again to obtain suspension, adding zeolite molecular sieve and nano ZrO 2 The mass ratio of (2) is 10:1, and nano ZrO is obtained 2 The particle size of (2) was 50nm.
(2) Slowly adding sodium alginate into water, and stirring at 60 ℃ for 1h to prepare sodium alginate solution with the mass concentration of 2%; mixing the sodium alginate solution with the suspension, and stirring for 4 hours at 60 ℃ to obtain a mixed solution. Wherein the mass ratio of the zeolite molecular sieve to the sodium alginate is 4:1,
(3) 2wt% FeCl was added dropwise at a rate of 35 drops/min 3 After the solution is dripped, crosslinking and curing are carried out for 24 hours at 50 ℃ to obtain gel microspheres;
(4) Washing gel microspheres with water until the washing liquid is neutral, and drying in a constant temperature drying oven at 60 ℃ for 10 hours to obtain the gel microspheres.
Example 2
The embodiment provides a groundwater treatment method, which comprises the steps of filtering by adopting modified ceramsite and modified zeolite in sequence; wherein, when the modified ceramsite is filtered, the input amount is 15g/L, the filtering temperature is 20 ℃ (the filtration is performed in a constant-temperature oscillator at 140rpm for 1 h). When the modified zeolite was filtered, the input was 2g/L and the filtration temperature was 10deg.C (shaking at 140rpm in a constant temperature shaker for 1 h).
The preparation method of the modified ceramsite comprises the following steps:
the embodiment provides a preparation method of ceramsite for groundwater treatment, which comprises the following steps:
(1) Uniformly mixing 24 parts of aluminum sludge, 15 parts of kaolin, 49 parts of papermaking white mud and 12 parts of ceramic polishing slag to obtain a mixture;
wherein Fe in the aluminum sludge 2 O 3 13.5 wt.%, caO 4.3 wt.%, al 2 O 3 The content of (2) was 42.5% by weight. Al of Kaolin 2 O 3 The content is 38.3wt%; the mass loss rate of the papermaking white mud is 37.4wt% after the papermaking white mud is burned to constant weight in an oxidizing atmosphere at 600 ℃. The mass loss rate of the papermaking white mud is 80.5wt% after the papermaking white mud is burned to constant weight in an oxidizing atmosphere at 950 ℃. The content of CaO in the ceramic polishing slag is 1.4wt percent, siO 2 The content of (C) is 66.8wt%, al 2 O 3 21.8wt%.
(2) Shaping the mixture by adopting a disc granulator to obtain a spherical blank, and drying at 85 ℃;
(3) Firing the spherical blank to obtain a ceramsite matrix;
wherein, the firing curve is: the temperature is kept for 20min at 300 ℃ from room temperature to 300 ℃ at a heating rate of 30 ℃/min; heating up at a rate of 20 ℃/min from 300 ℃ to 1020 ℃; the temperature is kept at 1020℃for 15min.
(4) The ceramsite substrate is soaked in dilute hydrochloric acid (10 wt%) for 24h, and then rinsed with water until the pH is constant. Then immerse ZrOCl 2 And (3) evaporating the mixture in a water bath (80 ℃) in the water solution (20 wt%) to dryness, soaking the mixture in a NaOH solution (8 wt%) for 3 hours, and rinsing the mixture with water until the pH is constant, thus obtaining the product.
The preparation method of the modified zeolite comprises the following steps:
(1) Nano ZrO 2 Placing in water, ultrasonic dispersing for 90min, adding 4A type zeolite molecular sieve with 200 mesh size, ultrasonic dispersing for 90min again to obtain suspension, adding zeolite molecular sieve and nano ZrO 2 The mass ratio of (2) is 10:1, and nano ZrO is obtained 2 The particle size of (2) was 50nm.
(2) Slowly adding sodium alginate into water, and stirring at 60 ℃ for 1h to prepare sodium alginate solution with the mass concentration of 2%; mixing the sodium alginate solution with the suspension, and stirring for 4 hours at 60 ℃ to obtain a mixed solution. Wherein the mass ratio of the zeolite molecular sieve to the sodium alginate is 4:1,
(3) 2wt% FeCl was added dropwise at a rate of 35 drops/min 3 The solution is crosslinked and solidified for 24 hours at 50 ℃ after the dripping is completed,obtaining gel microspheres;
(4) Washing gel microspheres with water until the washing liquid is neutral, and drying in a constant temperature drying oven at 60 ℃ for 10 hours to obtain the gel microspheres.
Example 3
The embodiment provides a groundwater treatment method, which comprises the steps of filtering by adopting modified ceramsite and modified zeolite in sequence; wherein, when the modified ceramsite is filtered, the input amount is 15g/L, the filtering temperature is 20 ℃ (the filtration is performed in a constant-temperature oscillator at 140rpm for 1 h). When the modified zeolite was filtered, the input was 2g/L and the filtration temperature was 10deg.C (shaking at 140rpm in a constant temperature shaker for 1 h).
The preparation method of the modified ceramsite comprises the following steps:
the embodiment provides a preparation method of ceramsite for groundwater treatment, which comprises the following steps:
(1) Uniformly mixing 24 parts of aluminum sludge, 15 parts of kaolin, 49 parts of papermaking white mud and 12 parts of ceramic polishing slag to obtain a mixture;
wherein Fe in the aluminum sludge 2 O 3 13.5 wt.%, caO 4.3 wt.%, al 2 O 3 The content of (2) was 42.5% by weight. Al of Kaolin 2 O 3 The content is 38.3wt%; the mass loss rate of the papermaking white mud is 37.4wt% after the papermaking white mud is burned to constant weight in an oxidizing atmosphere at 600 ℃. The mass loss rate of the papermaking white mud is 80.5wt% after the papermaking white mud is burned to constant weight in an oxidizing atmosphere at 950 ℃. The content of CaO in the ceramic polishing slag is 1.4wt percent, siO 2 The content of (C) is 66.8wt%, al 2 O 3 21.8wt%.
(2) Shaping the mixture by adopting a disc granulator to obtain a spherical blank, and drying at 85 ℃;
(3) Firing the spherical blank to obtain a ceramsite matrix;
wherein, the firing curve is: the temperature rising rate is 16.5 ℃/min from room temperature to 350 ℃; preserving heat at 350 ℃ for 8min; the temperature rising rate is 11 ℃/min from 350 ℃ to 850 ℃; heating from 850 ℃ to 1020 ℃ at a heating rate of 15 ℃/min; the temperature is kept at 1020 ℃ for 12min.
The preparation method of the modified zeolite comprises the following steps:
(1) Nano ZrO 2 Placing in water, ultrasonic dispersing for 90min, adding 4A type zeolite molecular sieve with 200 mesh size, ultrasonic dispersing for 90min again to obtain suspension, adding zeolite molecular sieve and nano ZrO 2 The mass ratio of (2) is 10:1, and nano ZrO is obtained 2 The particle size of (2) was 50nm.
(2) Slowly adding sodium alginate into water, and stirring at 60 ℃ for 1h to prepare sodium alginate solution with the mass concentration of 2%; mixing the sodium alginate solution with the suspension, and stirring for 4 hours at 60 ℃ to obtain a mixed solution. Wherein the mass ratio of the zeolite molecular sieve to the sodium alginate is 4:1,
(3) 2wt% FeCl was added dropwise at a rate of 35 drops/min 3 After the solution is dripped, crosslinking and curing are carried out for 24 hours at 50 ℃ to obtain gel microspheres;
(4) Washing gel microspheres with water until the washing liquid is neutral, and drying in a constant temperature drying oven at 60 ℃ for 10 hours to obtain the gel microspheres.
Example 4
The embodiment provides a groundwater treatment method, which comprises the steps of filtering by adopting modified ceramsite and modified zeolite in sequence; wherein, when the modified ceramsite is filtered, the input amount is 15g/L, the filtering temperature is 20 ℃ (the filtration is performed in a constant-temperature oscillator at 140rpm for 1 h). When the modified zeolite was filtered, the input was 2g/L and the filtration temperature was 10deg.C (shaking at 140rpm in a constant temperature shaker for 1 h).
The preparation method of the modified ceramsite comprises the following steps:
the embodiment provides a preparation method of ceramsite for groundwater treatment, which comprises the following steps:
(1) Uniformly mixing 24 parts of aluminum sludge, 15 parts of kaolin, 49 parts of papermaking white mud and 12 parts of ceramic polishing slag to obtain a mixture;
wherein Fe in the aluminum sludge 2 O 3 13.5 wt.%, caO 4.3 wt.%, al 2 O 3 The content of (2) was 42.5% by weight. Al of Kaolin 2 O 3 The content is 38.3wt%; the mass loss rate of the papermaking white mud is 37.4wt% after the papermaking white mud is burned to constant weight in an oxidizing atmosphere at 600 ℃. Firing the papermaking white mud to constant weight at 950 ℃ in an oxidizing atmosphereThe loss rate was 80.5wt%. The content of CaO in the ceramic polishing slag is 1.4wt percent, siO 2 The content of (C) is 66.8wt%, al 2 O 3 21.8wt%.
(2) Shaping the mixture by adopting a disc granulator to obtain a spherical blank, and drying at 85 ℃;
(3) Firing the spherical blank to obtain a ceramsite matrix;
wherein, the firing curve is: the temperature rising rate is 16.5 ℃/min from room temperature to 350 ℃; preserving heat at 350 ℃ for 8min; the temperature rising rate is 11 ℃/min from 350 ℃ to 850 ℃; heating from 850 ℃ to 1020 ℃ at a heating rate of 15 ℃/min; the temperature is kept at 1020 ℃ for 12min.
The preparation method of the modified zeolite comprises the following steps:
(1) Nano ZrO 2 Placing in water, ultrasonic dispersing for 90min, adding 4A type zeolite molecular sieve with 200 mesh size, ultrasonic dispersing for 90min again to obtain suspension, adding zeolite molecular sieve and nano ZrO 2 The mass ratio of (2) is 8:1, and nano ZrO 2 The particle size of (2) was 50nm.
(2) Slowly adding sodium alginate into water, and stirring at 60 ℃ for 1h to prepare sodium alginate solution with the mass concentration of 2%; mixing the sodium alginate solution with the suspension, and stirring for 4 hours at 60 ℃ to obtain a mixed solution. Wherein the mass ratio of the zeolite molecular sieve to the sodium alginate is 4:1,
(3) 3wt% FeCl was added dropwise at a rate of 35 drops/min 3 After the solution is dripped, crosslinking and curing are carried out for 24 hours at 50 ℃ to obtain gel microspheres;
(4) Washing gel microspheres with water until the washing liquid is neutral, and drying in a constant temperature drying oven at 60 ℃ for 10 hours to obtain the gel microspheres.
Comparative example 1
This comparative example provides a groundwater treatment method which differs from example 1 in that: the formulation of the ceramsite matrix does not include aluminum sludge, and all the other components are the same as in example 1.
Comparative example 2
This comparative example provides a groundwater treatment method which differs from example 1 in that: the formulation of the ceramsite matrix does not include papermaking white mud, and all the other components are the same as in the example 1.
Comparative example 3
This comparative example provides a groundwater treatment method which differs from example 1 in that: ceramic polishing residues are not included in the ceramsite matrix formulation, and all the other components are the same as in example 1.
Comparative example 4
This comparative example provides a groundwater treatment method which differs from example 1 in that: the formulation of the ceramic matrix does not include aluminum sludge and papermaking white mud, and the other components are the same as in example 1.
Comparative example 5
This comparative example provides a groundwater treatment method which differs from example 1 in that: the formulation of the ceramic matrix does not include aluminum sludge and ceramic polishing slag, and the other components are the same as in example 1.
Comparative example 6
This comparative example provides a groundwater treatment method which differs from example 1 in that: the formulation of the ceramic aggregate matrix does not include papermaking white mud and ceramic polishing slag, and the other components are the same as in example 1.
Comparative example 7
This comparative example provides a groundwater treatment method which differs from example 1 in that: the substrate containing no ceramsite was not immersed in the zirconium-containing solution, and the rest was the same as in example 1.
Comparative example 8
This comparative example provides a groundwater treatment method which differs from example 1 in that: the filtration was carried out using only modified ceramsite (15 g/L input, filtration temperature 20 ℃, shaking in a constant temperature shaker at 140rpm for 1 h) without using modified zeolite.
Comparative example 9
This comparative example provides a groundwater treatment method which differs from example 1 in that: the filtration was carried out using only modified zeolite (input 2g/L, filtration temperature 10 ℃, shaking in a constant temperature shaker at 140rpm for 1 h) without using modified ceramsite.
Comparative example 10
This comparative example provides a groundwater treatment method which is different from example 1 in that filtration is performed by using modified zeolite (input amount is 2g/L, filtration temperature is 10 ℃, vibration is performed at 140rpm in a constant temperature vibrator for 1 h), and then filtration is performed by using modified ceramic particles (input amount is 15g/L, filtration temperature is 20 ℃, vibration is performed at 140rpm in a constant temperature vibrator for 1 h).
The experimental results are shown in the following table:
the modified ceramsite obtained in example 3 was subjected to adsorption/desorption experiments and pore diameter measurement, as shown in fig. 1 and 2. Wherein FIG. 1 is N of modified ceramsite 2 Adsorption and desorption isotherms, as can be seen, when p/p 0 Lower, for N 2 The adsorption amount of (2) increases slowly, indicating fewer micropores. Thereafter at N 2 Gradually adsorbed from a single layer to multiple layers on the inner surface of the porous structure. Thereafter N 2 The adsorption capacity of (2) increases rapidly in the range of 0.6 to 1, producing a distinct hysteresis loop, but the increase in adsorption capacity does not end when the relative pressure reaches 1.0, reflecting the presence of mesopores and macropores. According to ICUPA classification, the adsorption isotherm is an IV type isotherm with an H1 type hysteresis loop, the IV type isotherm can be usually observed in mesoporous materials, and the H1 hysteresis loop can reflect that the adsorption material is spherical particles with uniform size and belongs to mesoporous materials with uniform pore size distribution. FIG. 2 is a graph showing that the BJH pore size distribution diagram of the modified ceramsite shows that the pore size has an obvious peak value at the position of 2.750nm, so that most of the pore size is concentrated in the range and accords with the structural characteristics of mesopores (2-50 nm), and the pore size can well absorb fluoride, ammonia nitrogen, phosphate and nitrate nitrogen.
Further, electron microscopic scanning was performed on the modified zeolite prepared in example 4, and the results are shown in FIG. 3. The porous sandwich structure on the surface of the adsorbent can be obviously seen, the pores on the surface have peeling phenomenon, clear lamellar lines appear, the structural phenomenon is formed on the surface of the modified zeolite, the water absorption and swelling of the microspheres are facilitated, the utilization of functional groups in the composite structure is further brought into play, the adsorption is facilitated, and the adsorption performance of the nitrate nitrogen is improved.
The modified zeolite prepared in example 4 was then taken and placed in 100mL of raw water having nitrate nitrogen concentrations of 10mg/L, 15mg/L, 20mg/L, 25mg/L, 30mg/L, 35mg/L, 40mg/L, 50mg/L, 70mg/L and 100mg/L, respectively, in an amount of 5g/L, and the adsorption amounts were measured under the above conditions, and the results are shown in FIG. 4. As can be seen in the figure: under the condition of low initial concentration, namely when the concentration of the nitrate nitrogen in raw water is 10mg/L, the modified zeolite still keeps higher removal rate up to 88.11 percent, and the adsorption quantity is 1.78mgN/g, so that the modified zeolite provided by the application has higher sensitivity in the treatment of the nitrate nitrogen raw water with low concentration. In addition, at high concentration, when the nitrate nitrogen concentration of raw water is increased to 100mg/L, the removal rate is 36.28%, and the adsorption capacity is increased to 7.33mgN/g.
Model fitting of adsorption fitting curve is carried out on the test result, langmuir fitting curve (shown in figure 5) and Freundlich fitting curve (shown in figure 6) are respectively drawn, and adsorption NO is obtained by integration 3 - The fitting curve adsorption model parameters of (2) are detailed in the following table.
As can be seen by comparing the fitted curves of FIGS. 5 and 6, R is compared with the Freundlich fitted curve 2 R of langmuir fitted curve =0.9677 2 The case of = 0.9943 indicates that the modified zeolite has a monolayer adsorption effect during the adsorption of nitrate nitrogen, and the maximum monolayer adsorption amount is 8.06mg/g.
Wherein the value of the Freundlich fitted curve n should be between 1 and 10, which is a condition under which adsorption can occur. The results of the above table additionally show that the modified zeolite has n=2.67, which is seen for NO 3 - Has high-efficiency adsorption effect. Furthermore, when n > 0.5, it is considered that the adsorption of the adsorbent by the adsorbent is easy to proceed, and thus n=2.67 also indicates NO 3 - Is susceptible to adsorption behavior.
While the foregoing is directed to the preferred embodiments of the present application, it will be appreciated by those skilled in the art that changes and modifications may be made without departing from the principles of the application, such changes and modifications are also intended to be within the scope of the application.

Claims (9)

1. The groundwater treatment method is characterized by comprising the step of filtering by sequentially adopting modified ceramsite and modified zeolite;
the preparation method of the modified ceramsite comprises the following steps:
(1) Uniformly mixing 20-40 parts by weight of aluminum sludge, 10-20 parts by weight of kaolin, 30-50 parts by weight of papermaking white mud and 5-15 parts by weight of ceramic polishing slag to obtain a mixture; wherein the total amount of the aluminum sludge, the kaolin, the papermaking white mud and the ceramic polishing slag is 100 parts by weight;
fe in the aluminum sludge 2 O 3 The content of (2) is more than or equal to 10wt percent, the content of CaO is less than or equal to 12wt percent, and Al 2 O 3 The content of (2) is more than or equal to 35 weight percent;
the mass loss rate of the papermaking white mud is more than or equal to 30wt% after the papermaking white mud is burnt to constant weight in an oxidizing atmosphere at 600 ℃;
the mass loss rate of the papermaking white mud is more than or equal to 70wt% after the papermaking white mud is burned to constant weight in an oxidizing atmosphere at 950 ℃;
the content of CaO in the ceramic polishing slag is less than or equal to 1.5wt percent, and SiO is contained in the ceramic polishing slag 2 The content of Al is more than or equal to 63wt percent 2 O 3 The content of (2) is more than or equal to 20wt%;
(2) Molding the mixture to obtain a spherical blank;
(3) Firing the spherical blank at 950-1050 ℃ to obtain a ceramsite matrix;
(4) Immersing the ceramsite matrix into a zirconium-containing solution, and drying and removing solute in the zirconium-containing solution to obtain a ceramsite finished product for groundwater treatment;
the preparation method of the modified zeolite comprises the following steps:
(i) Dispersing nano zirconia and zeolite molecular sieve into water to obtain suspension;
(ii) Uniformly mixing the suspension with sodium alginate solution, and dripping FeCl 3 Solution, cross-linking and solidifying pre-treatmentSetting time and drying to obtain the final product.
2. The groundwater treatment method according to claim 1, wherein the filtration temperature is 12-35 ℃ when the modified ceramsite is used for filtration;
when the modified zeolite is adopted for filtration, the filtration temperature is 8-35 ℃.
3. The method for groundwater treatment according to claim 1, wherein in step (i), nano ZrO is first used 2 Placing into water, ultrasonic dispersing, adding zeolite molecular sieve, and ultrasonic dispersing again to obtain suspension, wherein nanometer ZrO 2 And zeolite molecular sieve in a weight ratio of 1: (5-10);
the concentration of zeolite molecular sieve in the suspension is 5-10wt%.
4. The groundwater treatment method according to claim 1, wherein in step (ii), the concentration of the sodium alginate solution is 1-5wt%, and the weight ratio of zeolite molecular sieve to sodium alginate is (3-5): 1, the FeCl 3 The concentration of the solution is 2-4wt%.
5. The groundwater treatment method according to claim 1 wherein in step (ii), feCl 3 The dropping speed of the solution is 30-40 drops/min;
the cross-linking curing comprises cross-linking curing at 30-60 ℃ for 12-36h.
6. The groundwater treatment method according to any one of claims 1 to 5, wherein in step (i), zeolite molecular sieve is soaked with hydrochloric acid having a concentration of 4-6wt% for 5-20 hours and washed to a constant pH.
7. The groundwater treatment method according to claim 1 wherein the zirconium containing solution is ZrOCl 2 An aqueous solution having a concentration of 15-30wt%.
8. As claimed inThe method for treating groundwater according to claim 1, wherein Fe in the aluminum sludge is 2 O 3 The content of (2) is 12-20wt%, the content of CaO is 3-8wt%, and Al 2 O 3 The content of (2) is 38-48wt%;
the mass loss rate of the papermaking white mud is 35-45wt% after the papermaking white mud is burned to constant weight in an oxidizing atmosphere at 600 ℃; burning to constant weight in 950 deg.c oxidizing atmosphere with mass loss rate of 75-85wt%;
the content of CaO in the ceramic polishing slag is 0.3-1.2wt percent, siO 2 The content of (C) is 64-70wt%, al 2 O 3 The content of (C) is 20.5-23wt%.
9. The groundwater treatment method according to claim 1, wherein in the step (3), a firing profile is:
the temperature rising rate is 15-20 ℃/min from room temperature to 350 ℃;
preserving heat at 350deg.C for 5-10min;
the temperature rise rate is 8-12 ℃/min from 350 ℃ to 850 ℃;
heating from 850 ℃ to the firing temperature at a heating rate of 5-20 ℃/min;
preserving heat for 10-15min at the firing temperature.
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