CN113502685A

CN113502685A - Polyacrylonitrile pulp, preparation method thereof and application thereof in preparation of carbon rod filter element

Info

Publication number: CN113502685A
Application number: CN202110701634.XA
Authority: CN
Inventors: 王习文; 计园火
Original assignee: South China University of Technology SCUT
Current assignee: South China University of Technology SCUT
Priority date: 2021-06-23
Filing date: 2021-06-23
Publication date: 2021-10-15
Anticipated expiration: 2041-06-23
Also published as: CN113502685B

Abstract

The invention discloses a polyacrylonitrile pulp and its preparation method and its application in the preparation of a carbon rod filter element; the invention adopts a new type of grinding disc for double-disc grinding, which is used for high-concentration disc grinding, combined with chemical treatment, The rapid and energy-saving preparation of polyacrylonitrile pulp is realized; specifically, the polyacrylonitrile fiber is pretreated with a surface treatment agent, and the polyacrylonitrile pulp is obtained by dispersing and grinding. The pulp prepared by the invention has good fibrillation effect, good fiber binding force, good dispersibility and uniform structure, and the new type of refining sheet can reduce the energy consumption of refining and improve the production efficiency. The polyacrylonitrile pulp provided by the invention can be used as a binder to realize the wet manufacturing of the carbon rod filter element. The prepared carbon rod filter element has the advantages of low cost, good adsorption effect, acid and alkali resistance, high temperature resistance, high strength, and water immersion. It does not loosen for 1 year, and the activated carbon rod filter element added with pulp has the characteristics of low density, which can save raw materials and reduce production costs.

Description

Polyacrylonitrile pulp, preparation method thereof and application thereof in preparation of carbon rod filter element

Technical Field

The invention belongs to the technical field of polyacrylonitrile pulp, and particularly relates to polyacrylonitrile pulp, a preparation method thereof and application thereof in preparation of a carbon rod filter element.

Background

The polyacrylonitrile fiber has high elasticity, high strength, excellent heat resistance and optical rotation resistance, and good acid resistance, oxidant resistance and common organic solvent resistance. The polyacrylonitrile pulp can well maintain the excellent performances of polyacrylonitrile fibers, contains rich polar groups-CH, has excellent bonding performance and easy processing, also has the advantages of high fibrillation degree, good dispersibility, good fiber bonding force and the like, can replace asbestos to be used in a plurality of fields of friction, sealing materials, papermaking, non-woven fabrics and the like, and has very wide application range. Compared with the aramid fiber pulp which is the main material for replacing asbestos at present, the polyacrylonitrile pulp has lower production cost and high cost performance.

The preparation technology of the polyacrylonitrile pulp in China mostly adopts low-concentration pulp grinding, so that pulp fibers are cut excessively, and because the polyacrylonitrile has strong hydrophobicity, the fiber fibrillation degree is difficult to control, the bonding force of the polyacrylonitrile pulp is not high, and the power consumption in the pulp grinding process is high and the yield is low.

The existing activated carbon filter element needs to be added with a binder, a forming agent and the like, the binder used by the activated carbon filter element in the existing market is mostly resin and inorganic binder, and the binder can cause the filter holes of the activated carbon filter element to be blocked and reduce the efficiency of the filter element.

The existing production technology of the active carbon filter element is dry type forming technology, sintering forming or extrusion forming technology, the produced filter element has poor adsorption capacity, and a micro filter element manufacturing process is lacked; the filter is only suitable for granular filter materials, like some fibrous filter materials, cannot be realized at all, the energy consumption is high, and the manufactured filter element has low functionality.

At present, some preparation techniques of polyacrylonitrile pulp and forming techniques of activated carbon filter elements are related.

Application publication No. CN 103437233A discloses a polyacrylonitrile pulp-like fiber and a preparation method thereof, the method cuts acrylic filaments into short fibers with certain length, the short fibers are dispersed in water and mechanically knocked and ground, the fibers are torn and fibrillated, and microfibrillar hairiness is generated on the surface of the fibers to form highly fibrillated PAN pulp, the pulp fiber prepared by the method is short, and the bonding force is insufficient.

Application publication No. CN 107175071A discloses a sintered activated carbon molding filter element, coconut shell activated carbon powder 45-65%, ultra-high molecular weight polyethylene 25-50%, sodium hexametaphosphate 1-5%, polyepoxysuccinic acid 0.5-3%, sodium polyacrylate 0.1-2%, sodium molybdate 0.1-1%, and sodium lignosulfonate 0.1-1%. The mixed active carbon, scale inhibition component and ultra-high molecular weight polyethylene powder are poured into a special forming die, pressurized at 1-5Mpa, and sintered and formed at the high temperature of 150-. The filter element prepared by the method has high cost, the activated carbon filter holes are easy to block, and the adsorption performance is not excellent enough.

Disclosure of Invention

In order to solve the problems, the invention mainly aims to provide a novel preparation method of polyacrylonitrile pulp and application of the polyacrylonitrile pulp in preparation of a carbon rod filter element. The pulp can control the fibrillation degree of fibers and keep the fiber length through a disc grinding process and a designed high-concentration disc grinding plate, the bonding force, the dispersity and the uniformity of the fibers are improved, the pulp grinding energy consumption is reduced, and the pulp yield is improved. The binder of the carbon rod filter element for water treatment also has an adsorption effect.

The purpose of the invention is realized by the following technical scheme:

a preparation method of polyacrylonitrile pulp comprises the following steps:

the polyacrylonitrile fiber is pretreated by adopting a surface treating agent, and the polyacrylonitrile pulp is obtained by dispersing and grinding.

Preferably, the polyacrylonitrile chopped fiber has the fineness of 1.5-2.0detx and the length of 3-10 mm.

Preferably, the surface treating agent is a sodium hydroxide aqueous solution with the mass concentration of 10% -30%, the pretreatment time is 12-24h, and the pretreated polyacrylonitrile fiber is washed to be neutral by clear water. The polyacrylonitrile fiber has strong hydrophobicity, so the surface pretreatment by the alkali solution enhances the hydrophilicity, and is beneficial to the fiber fibrillation.

Preferably, the polyacrylonitrile fiber is dispersed in water to form a suspension with the mass concentration of 5-20%.

Preferably, the grinding is carried out by three double-disc grinder series disc grinding systems; the pumping flow rate of the grinding is 2-5 t/h.

Further preferably, the grinding process comprises the steps that the first disc grinding gap is 0.4-0.5mm and is 1-3 times longer, the second disc grinding gap is 0.2-0.3mm and is 1-3 times longer, and the third disc grinding gap is 0.1-0.15mm and is 1-3 times longer.

Further preferably, the double-disc grinder is a double-disc grinder with the diameter of 305-600 mm; the grinding sheet tooth shape of the double-disc grinder is an open grinding sheet; the open type grinding plate is a disc-shaped grinding plate consisting of fan-shaped grinding plates, the material is stainless steel, each fan-shaped grinding plate is divided into a disintegration area, a coarse grinding area and a fine grinding area, the disintegration area is wide-groove coarse grinding teeth, the coarse grinding area and the fine grinding area are fine-groove fine grinding teeth, the width of each grinding tooth is 1-3mm, the height of each grinding tooth is 2-3mm, and the width of each groove is 3-5 mm. The grinding plate can reduce the retention time of the pulp in the grinding plate gap and improve the pulp grinding pressure, and can reduce the energy consumption and improve the production efficiency when processing the same amount of pulp.

The polyacrylonitrile pulp prepared by the preparation method has the fiber length of 1.5-3mm, the length-diameter ratio of 100-150: 1, the surface of the polyacrylonitrile pulp is provided with microfiber; the polyacrylonitrile pulp has a Shore D beating degree of 25-51 DEG SR and a Canadian freeness of 180-680 mL. The fibrillation effect is good, the number of hydrogen bonds of the pulp is large, and the bonding force of pulp fibers is improved.

The polyacrylonitrile pulp is applied to the preparation of the activated carbon rod filter element. The prepared carbon rod filter core has good bonding performance, high strength and adsorption effect.

Preferably, the polyacrylonitrile pulp is used as an activated carbon rod filter element binder;

preferably, the activated carbon rod filter element is prepared by a wet forming technology;

preferably, the wet-process forming technology comprises the steps of mixing the polyacrylonitrile pulp and the activated carbon fiber with the diameter of 5-20 microns in a groove type mixing tank, adding water after mixing to form suspension with the mass concentration of 5-10%, pumping the suspension into a former for forming, dehydrating and drying after forming, and cooling to obtain the filter element; more preferably, the mass ratio of the polyacrylonitrile pulp to the activated carbon fiber is 5-15: 85-95.

The pulp obtained by the method can be used as a good binder in the preparation process of a carbon rod filter element for wastewater treatment, such as the pulp, wherein the pulp is treated by 20 percent sodium hydroxide solution for 24 hours, and the pulp with 20 percent pulp concentration is treated by three serially-connected disc mills to be optimal.

The filter element prepared by the method has the best effect of preparing 10% pulp and 90% activated carbon fiber with the diameter of 10 microns by mass, and has the advantages of low preparation cost, good adsorption effect, good water flux and density of 0.4g/cm³The adsorption rate for 5mg/L methylene blue is 100 percent, and the adsorption rate for 10mg/L methylene blue is 98 percent; adsorbing potassium permanganate of 10mg/L by 99 percent; adsorbing 98% of Congo red of 10 mg/L; adsorbing 99% of residual chlorine at 5 mg/L.

Compared with the prior art, the invention has the following beneficial effects:

the pulp prepared by the invention has good fibrillation effect, the fiber length is kept between 1.5 and 3mm, the length-diameter ratio is 100-150: 1, the pulp has a large number of hydrogen bonds, good fiber bonding force, good dispersibility and uniform structure, and the novel grinding plate can reduce grinding energy consumption and improve production efficiency;

the polyacrylonitrile pulp can be used as a binder to realize wet manufacturing of the carbon rod filter element, and the prepared carbon rod filter element has the advantages of low cost, good adsorption effect, good water flux, acid and alkali resistance, high temperature resistance, high strength, no loose property after being soaked in water for 1 year, effective removal of residual chlorine, peculiar smell and dye, and no black water generation; and the activated carbon rod filter element added with the pulp has the characteristic of low density, so that the raw materials can be saved, and the production cost can be reduced.

Drawings

FIG. 1 is a diagram of a disc refiner plate used in a disc refining process; comprises a defibering area-1, a rough grinding area-2 and a fine grinding area-3, wherein the defibering area-1 comprises grinding teeth-4 and a baffle-5, and the rough grinding area-2 comprises grinding teeth-6 and a pulp mixing cavity-7; the refining zone-3 comprises grinding teeth-8 and a baffle-9.

FIG. 2 is a process flow diagram of a disc grinding system.

FIG. 3 is an electron micrograph of polyacrylonitrile pulp prepared in example 8.

FIG. 4 is a diagram of a process for preparing a carbon rod filter core by using pulp; wherein, the water supply tower-1, the mixer-2, the pulp tower-3, the proportioning tank-4, the forming machine-5, the backwater tower-6, the oven-7, the storage tower-8 and the raw material tower-9.

Fig. 5 is a diagram of a wet forming machine.

Detailed Description

The invention is illustrated below with reference to specific embodiments. So that those skilled in the art can clearly understand that these examples are only intended to illustrate the invention and do not limit the scope of the invention in any way.

Pulp preparation examples

Pulp preparation referring to the process flow diagram of the disc mill system shown in fig. 2, polyacrylonitrile short fibers are pretreated and then mixed in a pulp tank to form pulp with mass concentration of 5-10%, and the pulp is pumped to three disc mills connected in series for disc milling. The diameter of the grinding disc chassis is 305mm, and the diameter of the grinding disc is 305 mm.

Wherein a disc refiner plate for use in a disc refining process is shown in figure 1; the device comprises a defibering area 1, a rough grinding area 2 and a fine grinding area 3, wherein the defibering area 1 comprises grinding teeth 4 and a pulp baffle plate 5, and the rough grinding area 2 comprises grinding teeth 6 and a pulp mixing cavity 7; the refining zone 3 comprises grinding teeth 8 and a baffle 9; s is the face width of the grinding tooth 4 is 3 mm; a is the width of the tooth surface of the grinding tooth 6 is 2 mm; b is the width of the tooth surface of the grinding tooth 8 of 1 mm.

Example 1

Weighing 5kg of polyacrylonitrile chopped fiber with the length of 6mm, pretreating the polyacrylonitrile chopped fiber with a 10% sodium hydroxide solution for 24h, cleaning the polyacrylonitrile chopped fiber to be neutral, dispersing the polyacrylonitrile chopped fiber in 95kg of water to form a 5% suspension, pumping the suspension into a disc mill at the flow rate of 2t/h for grinding, wherein the first disc mill has a gap of 0.5mm for 1 time, the second disc mill has a gap of 0.3mm for 1 time, and the third disc mill has a gap of 0.15mm for 1 time. Dewatering and drying the pulp to obtain polyacrylonitrile pulp, passing through a gap of 0.5mm and a Shore 15 degree SR, passing through a gap of 0.3mm and a Shore 18 degree SR, passing through a gap of 0.15mm and a Shore 25 degree SR, and obtaining the polyacrylonitrile pulp with the Canadian freeness of 680mL, the surface fiber length of 2.0 +/-0.5 mm and the length-diameter ratio of 150: 1, consuming 83KWh of energy.

Example 2

Weighing 5kg of polyacrylonitrile chopped fiber with the length of 6mm, pretreating the polyacrylonitrile chopped fiber with a sodium hydroxide solution with the concentration of 20% for 24h, cleaning the polyacrylonitrile chopped fiber to be neutral, dispersing the polyacrylonitrile chopped fiber in 95kg of water to form a suspension with the concentration of 5%, pumping the suspension into a disc mill at the flow rate of 2t/h for grinding, wherein the clearance of a first disc mill is 0.5mm for 1 time, the clearance of a second disc mill is 0.3mm for 1 time, and the clearance of a third disc mill is 0.15mm for 1 time. And (3) dewatering and drying the pulp to obtain polyacrylonitrile pulp, wherein the Shore degree of beating of the pulp is 16 degrees SR at the position of 0.5mm through a gap, the Shore degree of beating of the pulp is 20 degrees SR at the position of 0.3mm through a gap, the Shore degree of beating is 0.15mm through a gap, the Shore degree of beating is 28 degrees SR, the Canadian freeness is 600mL, the surface fiber length is 1.9 +/-0.5 mm, and the length-diameter ratio is 140: energy consumption 81 KWh.

Example 3

Weighing 5kg of polyacrylonitrile chopped fiber with the length of 6mm, pretreating the polyacrylonitrile chopped fiber with 30% sodium hydroxide solution for 24h, cleaning the polyacrylonitrile chopped fiber to be neutral, dispersing the polyacrylonitrile chopped fiber in 95kg of water to form 5% suspension, pumping the suspension into a disc mill at the flow rate of 2t/h for grinding, wherein the first disc mill has a gap of 0.5mm for 1 time, the second disc mill has a gap of 0.3mm for 1 time, and the third disc mill has a gap of 0.15mm for 1 time. Dewatering and drying the pulp to obtain polyacrylonitrile pulp, wherein the Shore degree of beating of the pulp is 15 degrees SR at the position of 0.5mm through the gap, the Shore degree of beating of the pulp is 20 degrees SR at the position of 0.3mm through the gap, the Shore degree of beating is 0.15mm through the gap, the Shore degree of beating is 30 degrees SR, the Canadian freeness is 550mL, the surface fiber length is 1.6 +/-0.5 mm, and the length-diameter ratio is 135: energy consumption 84 KWh.

Example 4

Weighing 10kg of polyacrylonitrile chopped fiber with the length of 6mm, pretreating the polyacrylonitrile chopped fiber with a sodium hydroxide solution with the concentration of 5% for 24h, cleaning the polyacrylonitrile chopped fiber to be neutral, dispersing the polyacrylonitrile chopped fiber in 90kg of water to form a suspension with the concentration of 10%, pumping the suspension into a disc mill at the flow rate of 2t/h for grinding, wherein the clearance of a first disc mill is 0.5mm for 1 time, the clearance of a second disc mill is 0.3mm for 1 time, and the clearance of a third disc mill is 0.15mm for 1 time. And dewatering and drying the pulp to obtain the polyacrylonitrile pulp, wherein the Shore degree of beating of the pulp is 16 degrees SR at the gap of 0.5mm, the Shore degree of beating of the pulp is 24 degrees SR at the gap of 0.3mm, the Shore degree of beating of the pulp is 0.15mm, the Shore degree of beating is 35 degrees SR, the Canadian freeness is 500mL, the surface fiber length is 1.8 +/-0.5 mm, the length-diameter ratio is 130:1, and the energy consumption is 85.5 KWh.

Example 5

Weighing 10kg of polyacrylonitrile chopped fiber with the length of 6mm, pretreating the polyacrylonitrile chopped fiber with a sodium hydroxide solution with the concentration of 20% for 12h, cleaning the polyacrylonitrile chopped fiber to be neutral, dispersing the polyacrylonitrile chopped fiber in 90kg of water to form a suspension with the concentration of 10%, pumping the suspension into a disc mill at the flow rate of 2t/h for grinding, wherein the clearance of a first disc mill is 0.5mm for 1 time, the clearance of a second disc mill is 0.3mm for 1 time, and the clearance of a third disc mill is 0.15mm for 1 time. And (3) dehydrating and drying the pulp to obtain polyacrylonitrile pulp, wherein the Shore degree of beating of the pulp is 17 DEG SR at the position of 0.5mm through the gap, the Shore degree of beating of the pulp is 25 DEG SR at the position of 0.3mm through the gap, the Shore degree of beating is 0.15mm through the gap, the Shore degree of beating is 36 DEG SR, the Canadian freeness is 480mL, the surface fiber length is 1.7 +/-0.5 mm, and the length-diameter ratio is 125: energy consumption 83 KWh.

Example 6

Weighing 10kg of polyacrylonitrile chopped fiber with the length of 6mm, pretreating the polyacrylonitrile chopped fiber with 30% sodium hydroxide solution for 12h, cleaning the polyacrylonitrile chopped fiber to be neutral, dispersing the polyacrylonitrile chopped fiber in 90kg of water to form 10% suspension, pumping the suspension into a disc mill at the flow rate of 2t/h for grinding, wherein the first disc mill has a gap of 0.5mm for 1 time, the second disc mill has a gap of 0.3mm for 1 time, and the third disc mill has a gap of 0.15mm for 1 time. And (3) dewatering and drying the pulp to obtain the polyacrylonitrile composite pulp, wherein the Shore degree of beating of the pulp is 18 degrees SR at the position of 0.5mm through the gap, the Shore degree of beating of the pulp is 27 degrees SR at the position of 0.3mm through the gap, the Shore degree of beating of the pulp is 0.15mm through the gap, the Shore degree of beating is 38 degrees SR, the Canadian freeness is 450mL, the length of a surface fiber is 1.6 +/-0.5 mm, and the length-diameter ratio: 125: energy consumption 86 KWh.

Example 7

Weighing 20kg of polyacrylonitrile chopped fiber with the length of 6mm, pretreating the polyacrylonitrile chopped fiber with a 10% sodium hydroxide solution for 24h, cleaning the polyacrylonitrile chopped fiber to be neutral, dispersing the polyacrylonitrile chopped fiber in 80kg of water to form a 20% suspension, pumping the suspension into a disc mill at a flow rate of 2t/h for grinding, wherein the first disc mill has a clearance of 0.5mm for 1 time, the second disc mill has a clearance of 0.3mm for 1 time, and the third disc mill has a clearance of 0.15mm for 1 time. And (3) dewatering and drying the pulp to obtain polyacrylonitrile pulp, wherein the Shore degree of beating of the pulp is 18 degrees SR at the position of 0.5mm through the gap, the Shore degree of beating of the pulp is 30 degrees SR at the position of 0.3mm through the gap, the Shore degree of beating is 0.15mm through the gap, the Shore degree of beating is 49 degrees SR, the Canadian freeness is 250mL, the surface fiber length is 1.5 +/-0.5 mm, and the length-diameter ratio is 120: 1, energy consumption 82.5KWh

Example 8

Weighing 20kg of polyacrylonitrile chopped fiber with the length of 6mm, pretreating the polyacrylonitrile chopped fiber with a sodium hydroxide solution with the concentration of 20% for 24h, cleaning the polyacrylonitrile chopped fiber to be neutral, dispersing the polyacrylonitrile chopped fiber in 80kg of water to form a suspension with the concentration of 20%, pumping the suspension into a disc mill at the flow rate of 2t/h for grinding, wherein the clearance of a first disc mill is 0.5mm for 1 time, the clearance of a second disc mill is 0.3mm for 1 time, and the clearance of a third disc mill is 0.15mm for 1 time. And (3) dewatering and drying the pulp to obtain polyacrylonitrile pulp, wherein the Shore degree of beating of the pulp is 19 degrees SR per 0.5mm of clearance, the Shore degree of beating of the pulp is 31 degrees SR per 0.3mm of clearance, the Shore degree of beating is 0.15mm of clearance, the Shore degree of beating is 51 degrees SR, the Canadian freeness is 210mL, the surface fiber length is 1.6 +/-0.5 mm, and the length-diameter ratio is 110: energy consumption 85 KWh.

The obtained polyacrylonitrile pulp has an electron microscope image (figure 3), high degree of fiber fibrillation, many micro fibers on the fiber surface, fiber length maintenance and large specific surface area.

Example 9

Weighing 20kg of acrylonitrile chopped fibers with the length of 6mm, pretreating the acrylonitrile chopped fibers for 24h by a sodium hydroxide solution with the concentration of 30%, cleaning the acrylonitrile chopped fibers to be neutral, dispersing the acrylonitrile chopped fibers in 80kg of water to form a suspension with the concentration of 20%, pumping the suspension into a disc mill at the flow rate of 2t/h for grinding, wherein the clearance of a first disc mill is 0.5mm and 1 time is passed, the clearance of a second disc mill is 0.3mm and 1 time is passed, and the clearance of a third disc mill is 0.15mm and 1 time is passed. And (3) dewatering and drying the pulp to obtain polyacrylonitrile pulp, wherein the pulp has a Shore degree of 19 DEG SR of 0.5mm clearance, a Shore degree of 31 DEG SR of 0.3mm clearance, a Shore degree of 51 DEG SR of 0.15mm clearance, a Canadian freeness of 180mL, a surface fiber length of 1.4 +/-0.5 mm, and a length-diameter ratio of 100: energy consumption 88 KWh.

Table 1: pulp Performance and energy consumption for examples 1-9

Example of production of carbon rod Filter core

The pulp prepared by the method of pulp preparation example 8 is selected, the pulp has a Shore beating degree of 51 degrees SR, a Canadian freeness of 210mL, a surface fiber length of 1.6 +/-0.5 mm, an aspect ratio of 110: 1.

carbon rod cartridge preparation reference is made to the process flow diagram of fig. 4; a water supply tower 1, a mixing tank 2, a pulp tower 3, a batching tank 4, a forming machine 5, a water return tower 6, an oven 7, a storage tower 8 and a raw material tower 9; wherein the molding machine-5 is a wet molding machine shown in fig. 5.

The method specifically comprises the following steps: mixing (2) polyacrylonitrile pulp and activated carbon fiber with the diameter of 5-20 microns in a groove type mixing tank, adding water to form suspension with the mass concentration of 5-10%, pumping the suspension into a former to be formed (5), feeding the formed suspension into a storage tower (8), and drying and cooling the formed suspension by an oven (7) to obtain the filter element.

Example 10

Weighing 5% by mass of pulp and 95% of carbon fiber with the diameter of 20 microns, mixing in a trough type mixing tank, adding water to form 10% suspension, pumping the suspension into a former for forming, dehydrating and drying after forming, and cooling to obtain a filter element;

the density of the obtained filter element is 0.5g/cm³The adsorption rate for 5mg/L methylene blue is 100 percent, and the adsorption rate for 10mg/L methylene blue is 97 percent; adsorbing potassium permanganate of 10mg/L by 99 percent; adsorbing 98% of Congo red of 10 mg/L; 98 percent of residual chlorine with the concentration of 5mg/L

Example 11

Weighing 5% by mass of pulp and 95% of carbon fiber with the diameter of 10 microns, mixing in a trough type mixing tank, adding water to form 10% suspension, pumping the suspension into a former for forming, dehydrating and drying after forming, and cooling to obtain a filter element;

the density of the obtained filter element is 0.5g/cm³The adsorption rate for 5mg/L methylene blue is 100 percent, and the adsorption rate for 10mg/L methylene blue is 97 percent; adsorbing potassium permanganate of 10mg/L by 99 percent; adsorbing 10mg/L Congo red by 99%; 98.5 percent of residual chlorine with the concentration of 5mg/L is absorbed.

Example 12

Weighing 10% by mass of pulp and 90% of carbon fiber with the diameter of 20 microns, mixing in a trough type mixing tank, adding water to form 10% suspension, pumping the suspension into a former for forming, dehydrating and drying after forming, and cooling to obtain a filter element;

the density of the obtained filter element is 0.45g/cm³The adsorption rate for 5mg/L methylene blue is 100 percent, and the adsorption rate for 10mg/L methylene blue is 96 percent; adsorbing potassium permanganate of 10mg/L by 99 percent; adsorbing 10mg/L Congo red by 97 percent; 98% of residual chlorine of 5mg/L is adsorbed.

Example 13

Weighing 10% by mass of pulp and 90% of carbon fiber with the diameter of 10 microns, mixing in a trough type mixing tank, adding water to form 10% suspension, pumping the suspension into a former for forming, dehydrating and drying after forming, and cooling to obtain a filter element;

the density of the obtained filter element is 4.5g/cm³The adsorption rate for 5mg/L methylene blue is 100 percent, and the adsorption rate for 10mg/L methylene blue is 98 percent; adsorbing potassium permanganate of 10mg/L by 99 percent; adsorbing 98% of Congo red of 10 mg/L; adsorbing 99% of residual chlorine at 5 mg/L.

Example 14

Weighing pulp with the mass of 15% and carbon fiber with the diameter of 20 microns of 85% in a tank type mixing tank, mixing and adding water to form suspension with the concentration of 10%, pumping the suspension into a former for forming, dehydrating and drying after forming, and cooling to obtain a filter element;

the density of the obtained filter element is 0.4g/cm³The adsorption rate for 5mg/L methylene blue is 100 percent, and the adsorption rate for 10mg/L methylene blue is 95 percent; 98 percent of potassium permanganate with the concentration of 10mg/L is absorbed; adsorbing Congo red of 10mg/L by 96 percent; adsorbing 5mg/L residual chlorine by 97 percent.

Example 15

Weighing pulp with the mass of 15% and carbon fiber with the diameter of 10 microns of 85% in a tank type mixing tank, mixing and adding water to form suspension with the concentration of 10%, pumping the suspension into a former for forming, dehydrating and drying after forming, and cooling to obtain a filter element;

the density of the obtained filter element is 0.4g/cm³The adsorption rate for 5mg/L methylene blue is 100 percent, and the adsorption rate for 10mg/L methylene blue is 96 percent; adsorbing 98.5 percent of potassium permanganate with the concentration of 10 mg/L; adsorbing Congo red of 10mg/L by 96 percent;adsorbing 5mg/L residual chlorine by 97.5 percent.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims

1. a preparation method of polyacrylonitrile pulp, is characterized in that, comprises the following steps:

The polyacrylonitrile fiber is pretreated with a surface treatment agent, and the polyacrylonitrile pulp is obtained by dispersing and grinding.

2 . The method for preparing polyacrylonitrile pulp according to claim 1 , wherein the length of the polyacrylonitrile fiber is 3-10 mm. 3 .

3. the preparation method of a kind of polyacrylonitrile pulp according to claim 1, is characterized in that, described surface treatment agent is the sodium hydroxide aqueous solution of mass concentration 10%-30%, and the time of described pretreatment is 12 -24h, the pretreated polyacrylonitrile fibers are washed with water until neutral.

4 . The method for preparing polyacrylonitrile pulp according to claim 1 , wherein the polyacrylonitrile fibers are dispersed in water to form a suspension with a mass concentration of 5-20%. 5 .

5. the preparation method of a kind of polyacrylonitrile pulp according to claim 1, is characterized in that, described grinding is to grind by three double disc mills series disc milling system; The pumping flow rate of described grinding is 2- 5t/h.

6. the preparation method of a kind of polyacrylonitrile pulp according to claim 5 is characterized in that, the process of described grinding is that the first disc grinding gap is 0.4-0.5mm for 1-3 times, and the second disc The grinding gap is 0.2-0.3mm for 1-3 times, and the third disc grinding gap is 0.1-0.15mm for 1-3 times.

7 . The method for preparing polyacrylonitrile pulp according to claim 5 , wherein the double-disc refiner is a double-disc refiner with a diameter of 305-600 mm; The shape is an open grinding piece; the open grinding piece is a disc-shaped grinding piece composed of a fan-shaped grinding piece, and the material is stainless steel. For the wide groove rough grinding teeth, the rough grinding area and the fine grinding area are fine groove grinding teeth, the grinding tooth width is 1-3mm, the grinding tooth height is 2-3mm, and the groove width is 3-5mm.

8. The polyacrylonitrile pulp prepared by the preparation method according to any one of claims 1-7, wherein the fiber length of the polyacrylonitrile pulp is 1.5-3 mm, and the aspect ratio is 100-150:1 , the surface of the polyacrylonitrile pulp has microfibers; the Shore beating degree of the polyacrylonitrile pulp is 25-51°SR, and the Canadian freeness is 180-680mL.

9. the application of the polyacrylonitrile pulp according to claim 8 in the preparation of activated carbon rod filter element.

10 . The application according to claim 9 , wherein the polyacrylonitrile pulp is used as a binder for activated carbon rod filter elements; the activated carbon rod filter elements are prepared by wet molding technology; the wet molding technology In order to mix the polyacrylonitrile pulp and activated carbon fibers with a diameter of 5-20 microns in a tank-type mixing tank, add water after mixing to form a suspension with a mass concentration of 5-10%, and the suspension is pumped to the molding machine. The filter element is formed after forming, dewatering and drying after forming, and cooling to obtain a filter element; the mass ratio of the polyacrylonitrile pulp to the activated carbon fiber is 5-15:85-95.