CN101716491B - Method for preparing heavy metal adsorbent by carbonizing lakebed sludge - Google Patents
Method for preparing heavy metal adsorbent by carbonizing lakebed sludge Download PDFInfo
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- CN101716491B CN101716491B CN2009102183453A CN200910218345A CN101716491B CN 101716491 B CN101716491 B CN 101716491B CN 2009102183453 A CN2009102183453 A CN 2009102183453A CN 200910218345 A CN200910218345 A CN 200910218345A CN 101716491 B CN101716491 B CN 101716491B
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Abstract
The invention discloses a method for preparing heavy metal adsorbent by carbonizing lakebed sludge, which comprises the steps of: washing the lakebed sludge with distilled water and drying, adding phosphoric acid solution (activator) and heating by means of water bath, drying, putting into a quartz tube of a high-temperature furnace, flowing with CO2 to carbonize by means of pyrolyzation to obtain adsorbent. The method takes the phosphoric acid with low price as chemical activator, thereby reducing cost; combines a physical activation method with a chemical activation method, thereby having good activation effect, improving the performance of adsorbent, having good absorption effect, and having iodine absorption value which is larger than 350mg/g; and completely uses organic matters in the lakebed sludge, thereby providing an approach for disposing the lakebed sludge by means of stabilization and resource utilization.
Description
Technical field
The present invention relates to the recycling of bottom mud in lake, particularly relate to the method for utilizing the bottom mud in lake charing to prepare heavy metal absorbent.
Background technology
Industries such as plating, process hides, smelting will be discharged the waste water that contains heavy metal in a large number every year.The processing method of heavy metal-containing waste water mainly contains ion-exchange, air supporting method, chemical precipitation method, electrolysis, absorption method etc.Wherein, the waste water that absorption method is handled can reach discharge standard, and the surplus sludge volume of generation is less, and therefore the heavy metal of absorption is considered to a kind of than effective method through the recyclable utilization of desorb.The adsorbent that this method adopted is generally absorbent charcoal material, high adsorption capacity, but price is more expensive.
On the other hand, in recent years, along with development of industry and agriculture, water body in lake receives pollution in various degree, and bed mud is the important component part in lake, and lake ecosystem is being brought into play important effect.
Bottom mud in lake is the remittance of pollutant: bottom mud in lake is one of place, the main home to return to of all contaminations that enters the lake water system; Pass through atmospheric sedimentation; Discharge of wastewater, rainwater leaching and variety of way such as wash away; A large amount of pollutants gets into water body in lake, and wherein a part deposits in the bed mud and enrichment gradually, and bed mud is polluted; Simultaneously bed mud is again the source of pollutant: the pollutant in the bed mud through and overlying water between physics, chemistry and biological exchange interaction, all kinds of inorganic and organic pollution that accumulates in the bed mud can discharge under certain condition again, the pollution overlying water.
In order to control the endogenous pollution in lake, the many places of China are all in a planned way carried out desilting to the lake and are dredged.A large amount of bottom mud in lake of dredging out are deposited in bank or fixing yard, land occupation not only, and have secondary pollution hidden danger.Bottom mud in lake how that output is huge, complicated component is handled through science, makes its stabilisation, minimizing, innoxious, resource, has become an environmental problem that needs to be resolved hurrily.
A kind of preparation method of wet sludge carbonizing adsorbent, publication number is disclosed in being the patent of CN100418621C.This method is raw material with the excess sludge of municipal sewage plant, and it is dewatered to moisture content 70～90%, and adding concentration is 20～60% liquor zinci chloridi; Drying and other treatment is carried out in activation 4～24 hours after the activation, make moisture percentage in sewage sludge reduce to 10～15%; Mud after the mummification is placed the high temperature carbonization stove; Heating rate with 5～40 ℃ of per minutes is warming up to 450～700 ℃, feeds water vapour simultaneously and does protection gas, charing 30～60 minutes.Adopt the washing of hydrochloric acid solution and distilled water, oven dry promptly gets carbonizing adsorbent.This invents activation under the situation of not mummification of mud (moisture content 70～90%), has reduced cost, has realized the recycling of mud.The deficiency that exists is that the application of the adsorbent of preparation is not illustrated, and uses heavy-metal residual that zinc chloride makees activator that the influence of finished product is still waiting research.
A kind of preparation method of mud adsorbent, publication number is disclosed in being the patent of CN101559354A.The processing step of this method is following: at first under 400～600 ℃; In protective atmosphere, dewatered sludge is carried out the pyrolysis first time; Adding solid sodium bicarbonate in the first time in the pyrolyzing sludge product then mixes; Under 400～800 ℃ nitrogen atmosphere, solid mixture is carried out the pyrolysis second time again, mixture difference water, weak acid scrubbing and dry to the pyrolysis second time obtain the mud adsorbent product.This invention has adopted cheap sodium acid carbonate as chemical activating agent, and the adsorbent that obtains has good effect to heavy metal in the water and pentavalent arsenic removal.The deficiency that exists mainly is to carry out twice pyrolysis, has increased energy consumption.
Bottom mud in lake contains a large amount of carbonaceous organic materials, for charing prepares adsorbent certain prerequisite is provided, and the report that at present both at home and abroad prepares adsorbent about bottom mud in lake seldom.Existing research proof, the municipal sludge of handling through pyrolysis charring can be converted into sorbing material preferably, and heavy metal is had stronger absorption property.Carbonaceous organic material content in the bottom mud in lake is taller than in the mud sometimes, if can effectively utilize, makes it become a kind of adsorbent source, not only can realize the resource of bed mud, and the improvement that can be heavy metal wastewater thereby again provides a kind of comparatively cheap adsorbent.
Summary of the invention
The purpose of this invention is to provide a kind of charring process that utilizes is that raw material is produced the adsorbent that can handle heavy metal wastewater thereby with the bottom mud in lake.
Mechanism of the present invention: bottom mud in lake contains a large amount of carbonaceous organic materials, and under anaerobic or anoxia condition, the bottom mud in lake of heat drying is to uniform temperature, the organic matter generation thermal decomposition in the bed mud, and solid product is carbon-bearing adsorbent.
Technical scheme of the present invention is: bottom mud in lake with distilled water washing back oven dry, is carried out the water-bath heating behind the adding phosphoric acid solution (as activator), the quartz ampoule of high temperature furnace is put in oven dry more then, and feeds CO
2Carry out pyrolysis charring, thereby obtain adsorbent.
Method of the present invention is accomplished according to the following steps:
(1) sampling
Bottom mud in lake is through deposition, and the supernatant that inclines washs 3 times with distilled water, and the 8～10h that at room temperature dewaters in advance puts into drying box then, dry 12h under 105 ℃.The bed mud of drying is ground, cross 60 mesh sieves, get sieve subordinate and divide use.
(2) chemical activation
Got the bottom mud in lake of 60 mesh sieves, joined in 1: 3～1: 5 in the 5mol/L phosphoric acid solution, put into 60 ℃ of waters bath with thermostatic control then, behind the heating 12h, removed supernatant liquid, and put into baking oven and dry 24h down at 105 ℃ by the solid-liquid mass ratio.
(3) physically activated, charing
Putting into the quartz tube reactor of high temperature carbonization stove after the taking-up, is the CO of 80mL/min at flow
2Under (physically activated atmosphere) atmosphere, pyrolysis charring 40～70min under 500 ℃～700 ℃ temperature.
(4) washing, drying, screening
The pyrolysis charring product is cleaned repeatedly with the HCl solution of 3mol/L earlier; Remove the impurity in the carbonizing production, use pH＞6 of rinsed with deionized water to the water more than 70 ℃ again, again at 105 ℃ of oven dry 24h; The cooling back is ground, is crossed 60 mesh sieves and promptly gets adsorbent, iodine sorption value＞350mg/g.
(5) heavy metal adsorption experiment
Adopt static method at room temperature to carry out.Accurately measuring the concentration that 100mL prepares is the cadmium (Cd of 40mg/L
2+) water sample puts into the 250mL beaker, adds 1.5g bed mud carbonizing adsorbent, is placed on the constant temperature oscillator behind the speed oscillation 60min with 120r/min, the water sampling centrifugation is with the Cd of atomic absorption spectrophotometer supernatant
2+Concentration is calculated clearance.
Major advantage of the present invention has:
(1) adopts comparatively cheap phosphoric acid to make chemical activating agent, reduced cost;
(2) physical activation method is combined with chemical activation method, activation effect is better, has improved the performance of adsorbent, and adsorption effect is better, iodine sorption value＞350mg/g;
(3) make full use of organic matter in the bottom mud in lake, for the stabilisation and the disposal of resources of bottom mud in lake provides approach.
Description of drawings
Fig. 1 prepares the adsorbent process chart for the bottom mud in lake charing.
The specific embodiment
Further specify flesh and blood of the present invention with instance below, but content of the present invention is not limited to this.
Bottom mud in lake is taken from the plateau lake, Yunnan, and under the empty butt condition, the mass fraction of carbon is 22.4 ~ 27.8%, and hydrogen is 1.9 ~ 2.6%, and oxygen is 13.6 ~ 17.0%, and full sulphur is 0.41 ~ 0.67%.
(1) sampling
Bottom mud in lake is through deposition, and the supernatant that inclines washs 3 times with distilled water, and the 8～10h that at room temperature dewaters in advance puts into drying box then, dry 12h under 105 ℃.The bed mud of drying is ground, cross 60 mesh sieves, get sieve subordinate and divide use.
(2) chemical activation
Got the bottom mud in lake of 60 mesh sieves, joined in 1: 3～1: 5 in the 5mol/L phosphoric acid solution, put into 60 ℃ of waters bath with thermostatic control then, behind the heating 12h, removed supernatant liquid, and put into baking oven and dry 24h down at 105 ℃ by the solid-liquid mass ratio.
(3) physically activated, charing
Putting into the quartz tube reactor of high temperature carbonization stove after the taking-up, is the CO of 80mL/min at flow
2Under (physically activated atmosphere) atmosphere, pyrolysis charring 40～70min under 500 ℃～700 ℃ temperature.
(4) washing, drying, screening
The pyrolysis charring product is cleaned repeatedly with the HCl solution of 3mol/L earlier; Remove the impurity in the carbonizing production, use pH＞6 of rinsed with deionized water to the water more than 70 ℃ again, again at 105 ℃ of oven dry 24h; The cooling back is ground, is crossed 60 mesh sieves and promptly gets adsorbent, iodine sorption value＞350mg/g.
(5) heavy metal adsorption experiment
Adopt static method at room temperature to carry out.Accurately measuring the concentration that 100mL prepares is the cadmium (Cd of 40mg/L
2+) water sample puts into the 250mL beaker, adds 1.5g bed mud carbonizing adsorbent, is placed on the constant temperature oscillator behind the speed oscillation 60min with 120r/min, the water sampling centrifugation is with the Cd of atomic absorption spectrophotometer supernatant
2+Concentration is calculated clearance.
Embodiment 1:
Fetch bottom mud in lake through deposition, the supernatant that inclines, with distilled water washing 3 times, 8h in advance at room temperature dewaters; Dry 12h under 105 ℃ again with its grinding, crosses 60 mesh sieves then, gets the bottom mud in lake 20g that sieve subordinate divides; Joining 60g concentration is in the 5mol/L phosphoric acid solution, puts into 60 ℃ of water-baths and heats 12h, removes supernatant liquid; Being put in the inherent 105 ℃ of oven dry 24h of baking oven then, putting into the quartz tube reactor of high temperature furnace after the taking-up, is the CO of 80mL/min at flow
2Under the atmosphere, pyrolysis charring 60min under 500 ℃ temperature.The pyrolysis charring product is cleaned repeatedly with the HCl solution of 3mol/L earlier; Remove the impurity in the carbonizing production, use pH＞6 of rinsed with deionized water to the water more than 70 ℃ again, again at 105 ℃ of oven dry 24h; The cooling back is ground, is crossed 60 mesh sieves and promptly gets adsorbent, and iodine sorption value is 350.2mg/g.Carry out adsorption experiment by above-mentioned steps (5), clearance reaches 90%.
Embodiment 2:
Fetch bottom mud in lake through deposition, the supernatant that inclines, with distilled water washing 3 times, 8h in advance at room temperature dewaters; Dry 12h under 105 ℃ again with its grinding, crosses 60 mesh sieves then, gets the bottom mud in lake 20g that sieve subordinate divides; Joining 80g concentration is in the 5mol/L phosphoric acid solution, puts into 60 ℃ of water-baths and heats 12h, removes supernatant liquid; Being put in the inherent 105 ℃ of oven dry 24h of baking oven then, putting into the quartz tube reactor of high temperature furnace after the taking-up, is the CO of 80mL/min at flow
2Under the atmosphere, pyrolysis charring 60min under 600 ℃ temperature.The pyrolysis charring product is cleaned repeatedly with the HCl solution of 3mol/L earlier; Remove the impurity in the carbonizing production, use pH＞6 of rinsed with deionized water to the water more than 70 ℃ again, again at 105 ℃ of oven dry 24h; The cooling back is ground, is crossed 60 mesh sieves and promptly gets adsorbent, and iodine sorption value is 370.1mg/g.Carry out adsorption experiment by above-mentioned steps (5), clearance reaches 91.3%.
Embodiment 3:
Fetch bottom mud in lake through deposition, the supernatant that inclines, with distilled water washing 3 times, 8h in advance at room temperature dewaters; Dry 12h under 105 ℃ again with its grinding, crosses 60 mesh sieves then, gets the bottom mud in lake 20g that sieve subordinate divides; Joining 100g concentration is in the 5mol/L phosphoric acid solution, puts into 60 ℃ of water-baths and heats 12h, removes supernatant liquid; Being put in the inherent 105 ℃ of oven dry 24h of baking oven then, putting into the quartz tube reactor of high temperature furnace after the taking-up, is the CO of 80mL/min at flow
2Under the atmosphere, pyrolysis charring 60min under 700 ℃ temperature.The pyrolysis charring product is cleaned repeatedly with the HCl solution of 3mol/L earlier; Remove the impurity in the carbonizing production, use pH＞6 of rinsed with deionized water to the water more than 70 ℃ again, again at 105 ℃ of oven dry 24h; The cooling back is ground, is crossed 60 mesh sieves and promptly gets adsorbent, and iodine sorption value is 365.8mg/g.Carry out adsorption experiment by step of the present invention (5), clearance reaches 90.6%.
Claims (3)
1. method of utilizing the bottom mud in lake charing to prepare heavy metal absorbent is characterized in that containing following steps: (1) sampling:
Bottom mud in lake is through deposition, and the supernatant that inclines washs with distilled water, and the 8～10h that at room temperature dewaters in advance puts into the drying box drying then, with the bed mud grinding of drying, crosses 60 mesh sieves, gets sieve subordinate and divides use;
(2) chemical activation:
Got the bottom mud in lake of 60 mesh sieves, joined in the phosphoric acid solution in 1: 3～1: 5, put into water bath with thermostatic control then, behind the heating 12h, removed supernatant liquid, and put into baking oven and dry 24h down at 105 ℃ by the solid-liquid mass ratio;
(3) physically activated, charing:
Put into the quartz tube reactor of high temperature carbonization stove after the taking-up, under physically activated atmosphere, pyrolysis charring 40～70min under 500 ℃～700 ℃ temperature;
(4) washing, drying, screening:
The pyrolysis charring product is cleaned with HCl solution earlier repeatedly, remove the impurity in the carbonizing production, use pH＞6 of rinsed with deionized water to the water more than 70 ℃ again, at 105 ℃ of oven dry 24h, the cooling back is ground, is crossed 60 mesh sieves and promptly gets adsorbent again;
The concentration of the phosphoric acid solution in the described step (2) is 5mol/L, and the temperature of water bath with thermostatic control is 60 ℃;
Physically activated atmosphere in the described step (3) is that flow is the CO of 80mL/min
2
2. the method for utilizing the bottom mud in lake charing to prepare heavy metal absorbent according to claim 1 is characterized in that the drying in the described step (1) is meant: dry 12h under 105 ℃.
3. the method for utilizing the bottom mud in lake charing to prepare heavy metal absorbent according to claim 1, the concentration that it is characterized in that the HCl solution in the described step (4) is 3mol/L.
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| CN102553514A (en) * | 2012-02-28 | 2012-07-11 | 昆明理工大学 | Preparation method for porous adsorption material |
| CN103145226B (en) * | 2013-03-01 | 2014-06-11 | 溧阳市天目湖保健品有限公司 | Method for preparing flocculant by using substrate sludge from river bottom or pond bottom |
| CN104355355B (en) * | 2014-11-06 | 2016-09-14 | 中国环境科学研究院 | A kind of porous adsorbing material processing organic wastewater |
| CN104437374B (en) * | 2014-11-27 | 2016-08-24 | 昆明理工大学 | A kind of Sediments of Dian Chi Lake prepares method and the application of adsorbent |
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| CN105903443A (en) * | 2016-06-14 | 2016-08-31 | 百色学院 | Method for preparing hexavalent chromium adsorbing agent from lychee exocarp |
| CN106566554B (en) * | 2016-10-17 | 2017-12-29 | 长江水利委员会长江科学院 | A kind of method that desilting sediment is disposed using livestock and poultry dung recovery |
| CN106564872A (en) * | 2016-11-09 | 2017-04-19 | 深圳市深港产学研环保工程技术股份有限公司 | Charcoal and preparation method and application thereof |
| CN113735405A (en) * | 2020-05-29 | 2021-12-03 | 南京林业大学 | Continuous composite remediation method for heavy metal polluted bottom mud |
| CN112516960B (en) * | 2020-10-23 | 2022-05-24 | 华南理工大学 | Sludge-based carbon material based on surface modification and preparation method thereof |
| CN112811785A (en) * | 2020-12-30 | 2021-05-18 | 中国葛洲坝集团生态环境工程有限公司 | Preparation method of sludge drying agent |
| CN114524434A (en) * | 2022-04-09 | 2022-05-24 | 李立欣 | Method for preparing activated carbon by utilizing cavitated sludge |
| CN115304080B (en) * | 2022-08-29 | 2024-03-12 | 华南农业大学 | Bottom mud-based zeolite molecular sieve and preparation method and application thereof |
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