CN105498691A - Method for preparing ramie biochar for treating hexavalent chromium wastewater - Google Patents
Method for preparing ramie biochar for treating hexavalent chromium wastewater Download PDFInfo
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- CN105498691A CN105498691A CN201610039748.1A CN201610039748A CN105498691A CN 105498691 A CN105498691 A CN 105498691A CN 201610039748 A CN201610039748 A CN 201610039748A CN 105498691 A CN105498691 A CN 105498691A
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- ramie
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- hexavalent chromium
- biological carbon
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- 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
- B01J20/20—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising free carbon; comprising carbon obtained by carbonising processes
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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
- C02F1/283—Treatment of water, waste water, or sewage by sorption using coal, charred products, or inorganic mixtures containing them
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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
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/20—Heavy metals or heavy metal compounds
- C02F2101/22—Chromium or chromium compounds, e.g. chromates
Abstract
The invention relates to a method for preparing ramie biochar for treating hexavalent chromium wastewater. The preparation method is used for performing resource utilization on ramie waste in farmlands to prepare a hexavalent chromium wastewater adsorbent. The preparation comprises the particular steps: removing non-biomass including sediment in raw material ramie stems with ramie husk and leaf removed, withering naturally, milling and sieving; putting the sieved ramie particles into a tubular furnace, warming at even speed under the anaerobic condition (pre-introducing nitrogen), and after reaching the set temperature, keeping the temperature for a period of time under high-temperature and anaerobic conditions so as to obtain ramie biochar. The ramie biochar prepared by the method has a good adsorption effect to the hexavalent chromium ion, has the characteristics of low cost, high yield, simple preparation, high adsorption capacity and the like, and is an environment-friendly adsorption material. The ramie biochar can be used for treating hexavalent chromium wastewater in smelting plants, chemical plants, electroplating plants and the like so as to achieve the dual effects of removal of hexavalent chromium and resource utilization of waste.
Description
Technical field
The invention belongs to contaminated wastewater control technology field, be specifically related to a kind of ramie biological carbon preparation method for the treatment of hexavalent chromium wastewater.
Background technology
Along with mining, metal smelt, developing rapidly of the industry such as intermetallic composite coating and Chemical Manufacture, plurality of heavy metal pollutant emission is in water body, these pollutants directly or indirectly enter human body by food chain, put aside in vivo, concentrated thus cause the harm such as teratogenesis, carcinogenic, mutagenesis.Therefore, heavy metal pollution becomes the larger water pollution problems of harm.Chromium (Cr) is one of heavy metal contaminants common in water body, mostly comes from process hides, waste water that plating, intermetallic composite coating, mining, textile industry are discharged.Usually in water environment, there are two kinds of valence states in chromium, is Cr (VI) and Cr (III) respectively.Cr (III) is comparatively stable in the environment, and toxicity is low; And Cr (VI) has high toxicity, be strong oxidizer and potential carcinogen.Cr (VI) dissolubility is strong, mainly with CrO
4 2-, HCrO
4 -and Cr
2o
7 2-exist Deng anion.Therefore be badly in need of finding a kind of efficient and technology of economy to process the hexavalent chromium wastewater that enterprise discharges.At present, the processing method of chromate waste water has ion-exchange, chemical precipitation, electro-deposition, filtration, absorption, infiltration, redox etc.Wherein, absorption method has easy to operate, and equipment is simple, the low and removal efficiency advantages of higher of cost, existing application in the waste water treatment project of reality.But kind and the adsorption efficiency of the adsorbent used at present are all very limited.Therefore, research and develop the novel adsorbent with high-adsorption-capacity, high efficiency and cheapness practicality, just become the key matter of science and technology further developing and apply absorption method.
Biological carbon refers to that living beings are in low temperature (being less than 700 DEG C) and anaerobic environment, the rich carbon solid product generated after incomplete thermal cracking.Existing multinomial research shows, biomass carbonization has many benefits for earth environment.One, biomass carbonization effectively can realize carbon fixation, thus decreases CO2 emissions, alleviates global warming; Its two, biological carbon can be used as soil conditioner, increases soil fertility, Promoting plant growth.In addition, compared with active carbon, biological carbon has fine and close microcellular structure and abundant oxygen-containing functional group, has stronger adsorption capacity for heavy metal and ionic organic pollution.In recent years, domestic and international researcher is devoted to, by all kinds of agriculture and forestry by-product or agricultural wastes carbonization, to make the adsorbent of different qualities, difference in functionality, such as straw, bagasse, municipal sludge, peanut shell etc.But the adsorption capacity of above-mentioned biological carbon to Cr (VI) is often limited, cannot realize large-scale practical application.Researchers modify by the functional group of chemical modification method to biological carbon surface usually, strengthen the adsorption capacity of its heavy metal ion, but but considerably increase cost of manufacture and the environmental protection cost of biological carbon.Therefore, select the living beings raw material of high-efficiency and economic, preparation has characteristic group, be applicable to the biological carbon adsorbent of hexavalent chromium wastewater process and seem particularly important.
Ramie, Urticaceae Section of Genus Boehmeria semishrub plant is one of important fiber crop.Ramie originates in In Southwest China, and cultivation history was apart from modern existing more than 4700.Husks can come unstuck extraction fiber, for weaving and paper grade (stock).But the ramie stalk after shelling usually is regarded as agricultural wastes and arbitrarily loses and put.According to statistics, China's ramie discarded object annual production is about 450,000 ton.General employing on-site incineration or directly landfill ramie discarded object, the not only manpower and materials of at substantial, and bring serious ecological environment problem.Therefore, by discarded ramie stalk recycling, turn waste into wealth, there is important practicality meaning.Containing a large amount of high-quality porous fibres in ramie stalk, the biological carbon of function admirable can be made, for realizing the approach that ramie changing rejected material to useful resource provides new on a large scale.At present, ramie is adopted to be that the document that raw material makes high-quality biological carbon have not been reported.The invention provides a kind of biological carbon sorbent preparation method for the treatment of hexavalent chromium wastewater, to improve the efficiency that biological carbon repairs chromium pollution water.
Summary of the invention
The present invention is directed to the deficiency that prior art exists, propose a kind of biological carbon preparation method for hexavalent chromium wastewater process.Described preparation method carries out recycling to farmland ramie discarded object, and obtained biological carbon adsorbent has good treatment effect to hexavalent chromium wastewater, and possesses that cost is low, preparation is simple and the advantage such as output is large.Invention achieves the double effects of hexavalent chromium removal and twice laid.
A kind of ramie biological carbon preparation method for the treatment of hexavalent chromium wastewater that the present invention proposes, comprises the following steps:
(1) collect ramie stalk discarded in farmland, namely remove the aerial stem of plant part after numb shell, numb leaf.Discarded ramie stalk is cleaned with clear water repeatedly, natural air drying 6-8 days after the abiotic matter such as removal silt;
(2) the ramie stalk chopping after air-dry is placed in pulverizer, is crushed to particle diameter and is less than 0.147mm and crosses 100 mesh sieves;
(3) opened by tube furnace, pre-logical nitrogen 15 minutes, maintenance nitrogen rate is 50ml/min, to discharge furnace air;
(4) be placed in by ramie particle in the tube furnace of pre-logical nitrogen, setting carburizing temperature 300-600 DEG C, the setting heating-up time, makes heating rate remain on 5-10 DEG C/min, setting constant temperature time 120 minutes;
(5), after pyrolysis completes, isolated air, Temperature fall, obtains ramie biological carbon.Ramie biological carbon is taken out, spends deionized water 2-4 time, be placed in 60 DEG C of drying in oven 24h stand-by.
Described preparation method, meets energy-conservation to the full extent and reduces preparation process greenhouse Gas Emission, effectively improve biological carbon productive rate.
The ramie biological carbon utilizing the inventive method to prepare is rich in oxygen-containing functional group and dense micro-hole structure, has stronger absorption, reducing power for hexavalent chromium.Therefore, the biological carbon that the ramie stalk utilizing farmland to discard by the method is prepared into, can be used for the adsorption treatment of hexavalent chromium pollutant in water body.
In above-mentioned application, the preferred 2g/L of described adsorbent consumption in waste water.
In above-mentioned application, the condition of described adsorption reaction is preferably: pH value is 2 ~ 4, and the reaction time is 12 ~ 24 hours.
Compared with prior art, the invention has the advantages that:
1. use raw material sources extensive, and feature is the good fiber structure making full use of discarded ramie stalk, makes it turn waste into wealth.
2. ramie biological carbon preparation technology of the present invention and simple to operate, preparation is fast, with short production cycle, does not need special chemical industry equipment, is easy to realize suitability for industrialized production.
3. ramie biological carbon adsorbent oxygen-containing functional group of the present invention is abundant, adsorption site is many, high to the removal efficiency of hexavalent chromium.
4. product is nontoxic, environmentally friendly, also can be used as additive for compound fertilizer and soil conditioner.
Accompanying drawing explanation
Fig. 1 is the transmission electron microscope schematic diagram of the embodiment of the present invention 1 ramie biological carbon;
Fig. 2 is the infrared spectrogram of the embodiment of the present invention 1 ramie biological carbon.
Detailed description of the invention
Below with reference to Figure of description and specific embodiment, the present invention is described in further details.
Embodiment 1:
Gather the ramie stalk discarded in farmland, only get its aerial stem of plant part, with clear water, its surface impurity is cleaned up, in ventilation natural drying 8 days.Chopping ramie stem, and be placed in pulverizer, degree of grinding is 0.147mm, by 100 mesh sieves.Dropped in tube furnace by ramie particle after pulverizing, before heating, in stove, logical 15 minutes gas speed is the nitrogen of 50ml/min, to keep oxygen free condition in stove.Setting reaction temperature is respectively 300 DEG C, 450 DEG C and 600 DEG C, and setting accordingly reaches target temperature in 55 minutes, 85 minutes and 115 minutes, keeps constant temperature time 120 minutes.After isothermal pyrolysis completes, keep tube furnace closed state, isolated air, Temperature fall.Taken out by ramie biological carbon, spend deionized water 2-4 time, 60 DEG C of drying in oven 24h, are placed in drier and keep in Dark Place.Obtained ramie biological carbon numbering is respectively RB300, RB450 and RB600, and its physicochemical properties are as shown in table 1.As shown in Figure 1, surface functional group composition as shown in Figure 2 for the pore structure of ramie biological carbon.
The ramie biological carbon physicochemical properties of table 1 different temperatures
Analysis of physical and chemical property result shows, raise with pyrolysis temperature, biological carbon productive rate and oxygen content reduce gradually, and phosphorus content improves.Compared with RB300, RB450, RB600 specific area is maximum, and aperture is minimum.Shown in Fig. 1, transmission electron microscope picture shows, RB300 rough surface is without type, and raise with pyrolysis temperature, ramie biological carbon surface pore structure is tending towards regular.Infrared shown in Fig. 2 (FTIR) Spectrum Analysis result shows, ramie biological carbon oxygen-containing functional group enriches, and quantity reduces with the rising of pyrolysis temperature.
Embodiment 2:
Ramie biological carbon adsorbent of the present invention is used for the hexavalent chromium in adsorption treatment constant temperature waste water, comprises the following steps: get the Cr that 50mL initial concentration is 100mg/L
6+solution, the pH value regulating solution is 2.0, add the RB300 that embodiment 1 is obtained, RB450 or RB600, the consumption of adsorbent is 2g/L, carry out vibration adsorption reaction at 30 DEG C of air bath constant temperature oscillators, with qualitative filter paper, this adsorbent be separated from waste water after 24 hours, with in flame atomic absorption spectrometry waste water not by the Cr adsorbed
6+and total cr content, the adsorbance result of calculating is as shown in table 1:
Table 1: the adsorbance of different ramie biological carbon
As shown in Table 1, at Cr
6+initial concentration is the adsorbance that under the condition of 100mg/L, RB300, RB450 and RB600 have 47.5mg/g, 39.8mg/g and 31.4mg/g, corresponding Cr
6+clearance is respectively 95%, 79.5% and 62.8%.As can be seen here, RB300 is the best ramie biological carbon of adsorption effect.
Embodiment 3:
Ramie biological carbon adsorbent of the present invention is used for the hexavalent chromium in adsorption treatment different condition waste water, comprises the following steps: get the Cr that 50mL initial concentration is respectively 20,50,80,100,200,250,400,500 and 800mg/L
6+solution, the pH value regulating solution is 2.0, add the RB300 that embodiment 1 is obtained, the consumption of this adsorbent is 2g/L, vibration adsorption reaction is carried out at 20,30 and 40 DEG C of water-bath constant temperature oscillators, after 24 hours, this adsorbent is separated from waste water, with in flame atomic absorption spectrometry waste water not by the Cr adsorbed
6+content, the Cr VI adsorbance of calculating.Be that under the condition of 20mg/L, this adsorbent all has the adsorbance of 10mg/g at initial concentration, and increase with initial concentration and increase, substantially reach stable after being increased to certain value.Meanwhile, temperature has obvious effect to ramie biological carbon process hexavalent chromium solution, and when temperature is 40 DEG C, its clearance is best, and maximal absorptive capacity can reach 84.74mg/g; Along with temperature reduces, Cr VI adsorbance reduces to some extent.
Below be only the preferred embodiment of the present invention, protection scope of the present invention be not only confined to above-described embodiment, conceives various process programs without substantial differences all in protection scope of the present invention with the present invention.
Claims (8)
1., for the treatment of a ramie biological carbon preparation method for hexavalent chromium wastewater, comprise the following steps:
(1) cleaned by discarded ramie stalk, after removing the abiotic matter such as silt, natural wind dry doubling pulverizes and sieves;
(2) be placed in by ramie particle in the tube furnace of pre-logical nitrogen, at the uniform velocity heat up, after arriving design temperature, constant temperature certain hour under high temperature, oxygen free condition, obtains ramie biological carbon.
2. preparation method according to claim 1, wherein, discarded ramie stalk is the aerial stem of plant part after removing numb shell, numb leaf.
3. preparation method according to claim 1, wherein, the powder particle diameter of ramie is less than 0.147mm.
4. preparation method according to claim 1, wherein, nitrogen rate is 50ml/min, before heating, pre-logical nitrogen 15 minutes.
5. preparation method according to claim 1, wherein, heating rate is 5-10 DEG C/min, and design temperature is 300-600 DEG C.
6. preparation method according to claim 1, wherein, keeps constant temperature time 120 minutes, after pyrolysis completes, and isolated air, Temperature fall.
7. preparation method according to claim 1, wherein, ramie biological carbon spends deionized water 2-4 time before use, and it is stand-by to dry 24h at being placed in 60 DEG C.
8. preparation method according to claim 1, wherein, ramie biological carbon is applicable to the sewage discharged by hexavalent chromium polluted surface water body or industrial and mining enterprises, and chromic maximal absorptive capacity can reach 84.74mg/g.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106902738A (en) * | 2017-03-10 | 2017-06-30 | 扬州大学 | A kind of wooden sub- shell base ecological restoration material and its application |
| CN111939872A (en) * | 2020-08-12 | 2020-11-17 | 华南农业大学 | Preparation method and application of activated hemp carbon adsorbent |
| CN111974352A (en) * | 2020-08-21 | 2020-11-24 | 湖南农业大学 | Ramie leaf silicon-based biochar and preparation method and application thereof |
| CN111974351A (en) * | 2020-08-21 | 2020-11-24 | 湖南农业大学 | Ramie biochar for purifying cadmium-containing wastewater and preparation method and application thereof |
| CN113695383A (en) * | 2020-05-23 | 2021-11-26 | 中国环境科学研究院 | Plant restoration device and restoration method for heavy metal pollution of soil |
| CN114653340A (en) * | 2022-04-12 | 2022-06-24 | 四川文理学院 | Ramie biochar and preparation method and application thereof |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106902738A (en) * | 2017-03-10 | 2017-06-30 | 扬州大学 | A kind of wooden sub- shell base ecological restoration material and its application |
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| CN111939872A (en) * | 2020-08-12 | 2020-11-17 | 华南农业大学 | Preparation method and application of activated hemp carbon adsorbent |
| CN111939872B (en) * | 2020-08-12 | 2021-11-02 | 华南农业大学 | Preparation method and application of activated hemp carbon adsorbent |
| CN111974352A (en) * | 2020-08-21 | 2020-11-24 | 湖南农业大学 | Ramie leaf silicon-based biochar and preparation method and application thereof |
| CN111974351A (en) * | 2020-08-21 | 2020-11-24 | 湖南农业大学 | Ramie biochar for purifying cadmium-containing wastewater and preparation method and application thereof |
| CN114653340A (en) * | 2022-04-12 | 2022-06-24 | 四川文理学院 | Ramie biochar and preparation method and application thereof |
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Application publication date: 20160420 |