CN114797767A - Modified leaf biochar and preparation method and application thereof - Google Patents

Modified leaf biochar and preparation method and application thereof Download PDF

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Publication number
CN114797767A
CN114797767A CN202210278444.6A CN202210278444A CN114797767A CN 114797767 A CN114797767 A CN 114797767A CN 202210278444 A CN202210278444 A CN 202210278444A CN 114797767 A CN114797767 A CN 114797767A
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calcium
magnesium
biochar
modified leaf
modified
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汪义杰
陈文龙
黄伟杰
程帅龙
李丽
罗昊昱
潘少云
唐红亮
龙义海
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Guangdong Shunshui Project Construction Management Co ltd
Urban Construction Water Affairs Comprehensive Affairs Center Shiwan Town Street Chancheng District Foshan City
Pearl River Hydraulic Research Institute of PRWRC
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Guangdong Shunshui Project Construction Management Co ltd
Urban Construction Water Affairs Comprehensive Affairs Center Shiwan Town Street Chancheng District Foshan City
Pearl River Hydraulic Research Institute of PRWRC
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Priority to CN202210278444.6A priority Critical patent/CN114797767A/en
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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
    • 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
    • B01J20/30—Processes for preparing, regenerating, or reactivating
    • B01J20/3078—Thermal treatment, e.g. calcining or pyrolizing
    • 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
    • B01J20/30—Processes for preparing, regenerating, or reactivating
    • B01J20/32—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating
    • B01J20/3231—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating characterised by the coating or impregnating layer
    • B01J20/3234—Inorganic material layers
    • 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
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
    • C10B53/00—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form
    • C10B53/02—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form of cellulose-containing material
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
    • C10B57/00—Other carbonising or coking processes; Features of destructive distillation processes in general
    • C10B57/08—Non-mechanical pretreatment of the charge, e.g. desulfurization
    • 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
    • B01J2220/00—Aspects relating to sorbent materials
    • B01J2220/40—Aspects relating to the composition of sorbent or filter aid materials
    • B01J2220/48—Sorbents characterised by the starting material used for their preparation
    • B01J2220/4812—Sorbents characterised by the starting material used for their preparation the starting material being of organic character
    • B01J2220/4825—Polysaccharides or cellulose materials, e.g. starch, chitin, sawdust, wood, straw, cotton
    • 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
    • C02F2101/20—Heavy metals or heavy metal compounds

Abstract

The invention discloses modified leaf biochar and a preparation method and application thereof. The preparation method comprises the following steps: firstly, putting leaf biomass powder into a strong alkaline solution for modification treatment, and drying to obtain primary modified leaf biomass powder; then placing the mixture into calcium-magnesium mixed salt solution for full dipping, directly drying to obtain secondary modified leaf biomass powder, and then carrying out pyrolysis treatment in an oxygen-free environment to obtain modified leaf biochar; the mass ratio of the total mass of calcium and magnesium elements in the calcium and magnesium mixed salt to the primary modified leaf biomass powder is 1 (5-15), the mass ratio of the calcium elements to the magnesium elements in the calcium and magnesium mixed salt is 1 (0.5-2), the pyrolysis treatment temperature is 500-700 ℃, and the pyrolysis treatment time is 1-3 hours. The modified leaf biochar prepared by the invention can effectively remove phosphate and heavy metal ions in wastewater at the same time.

Description

Modified leaf biochar and preparation method and application thereof
Technical Field
The invention relates to the technical field of environmental pollution treatment, and in particular relates to modified leaf biochar and a preparation method and application thereof.
Background
With the rapid development of industry and agriculture, typical heavy metals (Cu) 2+ 、Pb 2+ 、Ni 2+ And Cd 2+ Etc.) and nutrient elements (phosphate, etc.) enter the water bodies of urban rivers and lakes, causing pollution of different degrees and seriously threatening the human health and the balance of the ecological system. Worker's toolThe commercially common method for removing heavy metal ions is chemical precipitation, which converts heavy metals into hydroxide precipitate for removal; however, this method is expensive and may cause secondary pollution to the adjustment of the pH of the wastewater. When industrial activated carbon is used for adsorption, the adsorption capacity of heavy metal ions is small, and the adsorption of nutrient elements is not ideal; while the reverse osmosis technology can effectively remove heavy metals, phosphate is easy to scale so as to prevent the reverse osmosis technology from stably operating, and the reverse osmosis technology has high operation cost and frequent maintenance.
Biochar has high specific surface area, rich active sites and unique surface chemical characteristics, and often shows certain alkalinity, so that the biochar has better adsorption performance on cationic substances (heavy metal ions), but has weaker adsorption capacity on anionic substances (phosphate radicals), and therefore, the modifying treatment of the biochar to improve the performance of adsorbing the heavy metal ions and the phosphate radicals at the same time becomes a hotspot problem in the adsorption field.
For example, in the prior art, a method for removing phosphorus from phosphorus-containing wastewater and producing a slow-release carbon-based phosphate fertilizer is disclosed, in which forest waste and magnesium oxide powder are mixed and then subjected to oxygen pyrolysis in an isolated manner to obtain magnesium modified biomass carbon, and positive charges on the surface of the modified biomass carbon are increased to realize strong adsorption capacity on anions, but at the same time, the negative charges on the surface are reduced, and the adsorption capacity on cations is reduced, so that heavy metal ions and phosphate radicals in wastewater are difficult to be removed effectively at the same time.
Disclosure of Invention
The invention aims to overcome the defect and the defect that the existing magnesium oxide modified leaf biochar is difficult to simultaneously remove phosphate and heavy metal ions in wastewater, and provides a preparation method of the modified leaf biochar.
Another object of the present invention is to provide a modified leaf biochar.
The invention also aims to provide application of the modified leaf biochar in removing phosphate and heavy metal ions in wastewater.
The above purpose of the invention is realized by the following technical scheme:
a preparation method of modified leaf biochar comprises the following steps:
s1, placing leaf biomass powder in a strong alkaline solution for modification treatment, and drying to obtain primary modified leaf biomass powder;
s2, placing the primary modified leaf biomass powder in the S1 in a calcium-magnesium mixed salt solution for full dipping, and then directly drying to obtain secondary modified leaf biomass powder;
s3, placing the secondary modified leaf biomass powder in the S2 in an oxygen-free environment for pyrolysis treatment to obtain modified leaf biochar;
the mass ratio of the total mass of calcium and magnesium elements in the calcium and magnesium mixed salt to the primary modified leaf biomass powder in S2 is 1 (5-15), and the mass ratio of the calcium element to the magnesium element in the calcium and magnesium mixed salt is 1 (0.5-2); in S3, the pyrolysis treatment temperature is 500-700 ℃, and the pyrolysis treatment time is 1-3 h.
The invention carries out two times of modification treatment on leaf biomass powder:
(1) on one hand, acidic substances in the leaf biomass powder can be neutralized, functional groups on the surface of the leaf biomass can be purified, and alkaline active sites are increased, so that phosphate can be removed; on the other hand, the residual alkali in the leaf biomass powder is subjected to dehydration reaction during pyrolysis treatment to generate water vapor, so that the carbonized product forms more microporous structures; specifically, the strong alkaline solution can be 1-2 mol/L potassium hydroxide or sodium hydroxide solution.
(2) Adopt calcium magnesium mixed salt solution dipping to handle once modified leaf living beings powder, can make calcium magnesium and biological charcoal combine more closely after the pyrolysis, can also realize the multiple absorption to phosphate, its mechanism of action includes: 1) hydrogen bonding: biochar indicates that hydrogen bonds formed by attached functional groups (such as hydroxyl-OH, carboxyl-COOH and the like) and partial magnesium oxide in water can be combined with hydrogen phosphates (including H) 2 PO 4 - 、HPO 4 2- ) Combining; 2) surface precipitation: calcium, magnesium and phosphate radical are combined to form hydroxyapatite, magnesium phosphate and other precipitates; 3) inner sphere complexation: c, Mg in the modified leaf biochar is combined with O element to a high degree, and the O element and P and-OH in phosphate ions form covalent bonds, so that the phosphate is selectively adsorbed.
And the modified leaf biochar has rich pore structures and alkaline active substances, and mainly adopts 1) electrostatic adsorption: the modified leaf biochar has more negative charges in a pore structure and has better electrostatic adsorption performance on heavy metal cations; 2) ion exchange and precipitation reactions: the MgO can form Mg-OH in the wastewater, and can perform ion exchange reaction with heavy metal ions adsorbed to the surface of the modified leaf biochar to form corresponding hydroxide, and the heavy metal ions are removed through further precipitation. Therefore, the modified leaf biochar has great difference on the action mechanism of phosphate and heavy metal ions in the wastewater, namely the modified leaf biochar and the wastewater do not generate obvious competitive adsorption effect, so that the phosphate and the heavy metal ions in the wastewater are effectively removed simultaneously.
In addition, the leaf biomass powder subjected to primary modification is subjected to dipping treatment by using a calcium-magnesium mixed salt solution, and compared with single magnesium salt loading, the formed magnesium oxide crystal grains can be uniformly distributed among the calcium oxide crystal grains by using the calcium-magnesium mixed salt loading, so that the dispersibility of the magnesium oxide is improved, and the agglomeration of the magnesium oxide is further effectively avoided. The time of the dipping treatment can be 10-20 h.
When the mass ratio of the calcium element to the magnesium element in the calcium-magnesium mixed salt is too low, the magnesium oxide on the surface of the modified leaf biochar and in the modified leaf biochar is easy to agglomerate, the uniform dispersibility is reduced, and the removal rate of phosphate is reduced; when the mass ratio of the calcium element to the magnesium element is too large, the amount of main adsorbed substances such as magnesium oxide and the like is reduced, and the removal rate of phosphate by the modified leaf biochar is reduced.
The leaf biomass powder is prepared from Lagerstroemia indica deciduous leaves or dead leaves.
Specifically, the preparation process of the leafy biomass powder is as follows: taking fallen leaves or dead leaves of crape myrtle trees as raw materials, cleaning to remove surface impurities, drying at 60-90 ℃, then crushing, and sieving with a 20-60-mesh sieve to obtain leaf biomass powder.
Preferably, the mass ratio of the calcium element to the magnesium element in the calcium-magnesium mixed salt in S2 is 1 (1-2), and the mass ratio of the calcium element to the magnesium element may be 1:1, 1:1.5 and 1: 2.
Preferably, the mass ratio of the total mass of the calcium and magnesium elements in the calcium and magnesium mixed salt in S2 to the primary modified leaf biomass powder is 1 (5-10).
According to the secondary modification of the leaf biomass powder, the leaf biomass powder after primary modification is placed in a calcium-magnesium mixed salt solution for full dipping, the mixture of the primary modified leaf biomass powder and the calcium-magnesium mixed salt solution is directly dried, and the primary modified leaf biomass powder is not separated from the calcium-magnesium mixed salt solution, so that the solid-liquid ratio of the primary modified leaf biomass powder to the calcium-magnesium mixed salt solution in the step S2 has smaller influence on the loading capacity of calcium and magnesium in the modified leaf biomass, and the solid-liquid ratio can be specifically 1 (5-15).
When the mass ratio of the total mass of the calcium and magnesium elements in the calcium and magnesium mixed salt to the biomass powder of the primary modified leaves reaches 1:10 (namely the mass percentage of the calcium and magnesium elements in the modified leaf biochar is 25 percent), the total mass of the calcium and magnesium elements in the calcium and magnesium mixed salt is continuously increased, although the loading amount of the calcium and magnesium elements in the modified leaf biochar can be increased, the improvement range of the phosphate removal rate is small, and the mass ratio of the total mass of the calcium and magnesium elements in the preferred calcium and magnesium mixed salt to the biomass powder of the primary modified leaves is 1 (5-10) in consideration of other factors.
In a specific embodiment, the calcium-magnesium mixed salt in step S2 of the present invention is calcium acetate-magnesium acetate and/or calcium chloride-magnesium chloride.
In a specific embodiment, the solid-to-liquid ratio (g/mL) of the leafy biomass powder to the strongly alkaline solution in step S1 is 1:5 to 1: 15.
In a specific embodiment, the time of the modification treatment in step S1 is 10 to 15 hours.
The invention also provides the modified leaf biochar prepared by the preparation method of the modified leaf biochar.
The application of the modified leaf biochar in removing phosphate and/or heavy metal ions in wastewater also falls into the protection scope of the invention.
In a specific embodiment, the heavy metal ion of the present invention is Cu 2+ 、Pb 2+ 、Ni 2+ And Cd 2+ One or more of them.
In a specific embodiment, the pH value of the wastewater solution is 3-11.
Compared with the prior art, the invention has the beneficial effects that:
the invention provides a preparation method of modified leaf biochar, which can neutralize acidic substances in leaf biomass powder, purify surface functional groups of the acidic substances and increase alkaline active sites by carrying out alkali modification on the leaf biomass powder; meanwhile, calcium oxide formed after pyrolysis can improve the dispersibility of magnesium oxide, can react with phosphate adsorbed to the surface of the modified leaf biochar by magnesium oxide to a certain extent to generate apatite and other precipitate substances, is beneficial to further improving the removal rate of phosphate, can reach 69.6-91.1% under the condition of different load ratios, can reach 67.3-90.7% of copper ion removal rate, and can effectively remove phosphate and heavy metal ions in wastewater.
Drawings
FIG. 1 is an SEM image of unmodified leafy biomass powder in example 1 of the present invention;
FIG. 2 is an SEM photograph of modified leaf biochar in example 1 of the present invention.
Detailed Description
The present invention will be further described with reference to specific embodiments, but the present invention is not limited to the examples in any way. The starting reagents employed in the examples of the present invention are, unless otherwise specified, those that are conventionally purchased.
Example 1
A preparation method of modified leaf biochar comprises the following steps:
s1, drying and crushing fallen leaves or dead leaves of crape myrtle trees, and screening the crushed fallen leaves or dead leaves through a 40-mesh screen to obtain leaf biomass powder; then placing the mixture into KOH solution with the concentration of 1.5mol/L, stirring for 15 hours, and directly drying to obtain primary modified leaf biomass powder;
s2, placing the primary modified leaf biomass powder in the S1 into a calcium chloride-magnesium chloride mixed salt solution, mixing and stirring for 24 hours, and drying to obtain secondary modified leaf biomass powder;
s3, putting the secondary modified leaf biomass powder in the S2 in a nitrogen atmosphere, pyrolyzing for 2 hours at 600 ℃, and then cleaning and drying to obtain modified leaf biochar;
in the step S2, the mass ratio of the total mass of the calcium and magnesium elements in the calcium and magnesium mixed salt to the primary modified leaf biomass powder is 1:10, the solid-to-liquid ratio (g/mL) of the primary modified leaf biomass powder to the calcium and magnesium mixed salt solution is 1:10, and the mass ratio of the calcium element to the magnesium element in the calcium and magnesium mixed salt is 1:1.
Through digestion and element analysis of the modified leaf biochar, the mass percent of calcium and magnesium elements in the modified leaf biochar obtained by the preparation method is calculated to be 25%.
Example 2
A modified leafy biochar preparation method comprising substantially the same steps as in example 1, except that the mass ratio of the total mass of calcium and magnesium elements in the calcium and magnesium mixed salt to the mass of the primary modified leafy biomass powder in step S2 is 1: 5.
Example 3
A modified leafy biochar preparation method comprising substantially the same steps as in example 1, except that the mass ratio of the total mass of calcium and magnesium elements in the calcium and magnesium mixed salt to the mass of the primary modified leafy biomass powder in step S2 is 1: 15.
Example 4
A modified leaf biochar preparation method, comprising substantially the same steps as in example 1, except that the mass ratio of calcium element to magnesium element in the calcium-magnesium mixed salt in step S2 is 1: 2.
Example 5
A modified leaf biochar preparation method, comprising substantially the same steps as in example 1, except that the mass ratio of calcium element to magnesium element in the calcium-magnesium mixed salt in step S2 is 1: 1.5.
Example 6
A modified leaf biochar preparation method, comprising substantially the same steps as in example 1, except that the mass ratio of calcium element to magnesium element in the calcium-magnesium mixed salt in step S2 is 1: 0.5.
Example 7
A method for preparing modified leaf biochar, comprising substantially the same steps as in example 1, except that the solid-to-liquid ratio (g/mL) of the primary modified leaf biomass powder to the calcium-magnesium mixed salt solution in step S2 is 1: 15.
Example 8
A method for preparing modified leaf biochar, comprising substantially the same steps as in example 1, except that the solid-to-liquid ratio (g/mL) of the primary modified leaf biomass powder to the calcium-magnesium mixed salt solution in step S2 is 1: 5.
Example 9
A method for preparing modified leafy biochar, comprising substantially the same steps as in example 1, except that the pyrolysis temperature is 700 ℃ and the pyrolysis time is 1h in step S3.
Example 10
A method for preparing modified leafy biochar, comprising substantially the same steps as in example 1, except that the pyrolysis temperature is 500 ℃ and the pyrolysis time is 3 hours in step S3.
Example 11
A method for preparing modified leafy biochar comprising substantially the same steps as in example 1, except that the calcium-magnesium mixed salt is calcium acetate-magnesium acetate in step S2.
The main test parameters in examples 1 to 11 are shown in table 1, wherein a is the mass ratio of the total mass of calcium and magnesium elements in the calcium and magnesium mixed salt to the biomass powder of the primary modified leaves; b is the mass ratio of calcium element to magnesium element in the calcium-magnesium mixed salt; c is the solid-to-liquid ratio (g/mL) of the primary modified leaf biomass powder and the calcium-magnesium mixed salt solution; d is the temperature of the heat treatment; e is the time of heat treatment; f is calcium-magnesium mixed salt; g is 25 percent of calcium and magnesium elements in the modified leaf biochar by mass percent.
TABLE 1
Figure BDA0003556845040000061
Figure BDA0003556845040000071
Comparative example 1
A preparation method of modified leaf biochar comprises the following steps:
s1, drying and crushing fallen leaves or dead leaves of crape myrtle trees, and screening the crushed fallen leaves or dead leaves through a 40-mesh screen to obtain leaf biomass powder; then placing the mixture into KOH solution with the concentration of 1.5mol/L for mixing and keeping stirring for 15 hours, and drying to obtain primary modified leaf biomass powder;
s2, placing the primary modified leaf biomass powder in the S1 into a magnesium acetate solution, mixing and stirring for 24 hours, and drying to obtain secondary modified leaf biomass powder;
s3, putting the secondary modified leaf biomass powder in the S2 in a nitrogen atmosphere, pyrolyzing for 2h at 600 ℃, and then cleaning and drying to obtain modified leaf biochar;
wherein the mass ratio of the magnesium element in the magnesium acetate to the biomass powder of the primary modified leaves in the step S2 is 1: 10; the solid-to-liquid ratio (g/mL) of the primary modified leaf biomass powder to the magnesium acetate solution is 1: 10.
Through digestion and element analysis of the modified leaf biochar, the mass percent of calcium and magnesium elements in the modified leaf biochar obtained by the preparation method is calculated to be 25%.
Comparative example 2
A modified leaf biochar preparation method, comprising substantially the same steps as in example 1, except that the mass ratio of calcium element to magnesium element in the calcium-magnesium mixed salt in step S2 is 1: 4.
Comparative example 3
A modified leaf biochar preparation method, comprising substantially the same steps as in example 1, except that the mass ratio of calcium element to magnesium element in the calcium-magnesium mixed salt in step S2 is 1: 0.1.
Comparative example 4
A modified leafy biochar preparation method comprising substantially the same steps as in example 1, except that the mass ratio of the total mass of calcium and magnesium elements in the calcium and magnesium mixed salt to the mass of the primary modified leafy biomass powder in step S2 is 1: 25.
Result detection
(1) SEM test
As can be seen from fig. 1 and fig. 2, the surface of the unmodified leaf biomass powder is relatively flat and has a single structure, the structure types of the modified leaf biochar are relatively rich, and MgO particles are successfully loaded on the surface of the leaf biochar and the structure of the leaf biochar, so that the stability of MgO is significantly improved; meanwhile, the dispersion degree of MgO particles is better, larger specific surface area and more active sites can be brought, and the subsequent catalytic degradation reaction is facilitated.
(2) Adsorption test for phosphate and heavy metal ions
The specific test method and conditions are as follows:
the removal rate is (X initial concentration-X concentration after adsorption)/X initial concentration, and X is phosphate or heavy metal ion.
1, waste water: simulating the simulated composite polluted wastewater with the phosphate concentration of 25mg/L and the copper ion concentration of 10mg/L by using monopotassium phosphate and copper nitrate, and then adjusting the pH of the wastewater to about 5.0 by using hydrochloric acid; the modified leaf biochar of examples 1-11 and comparative examples 1-4 and the modified wood biochar of comparative example 5 were added at 1.5g/L to a reaction flask containing 100mL of phosphate at a concentration of 25mg/L, and then placed in an oscillator and shaken at 125 rpm for 24 hours.
The phosphate before and after the reaction of the wastewater was measured by ammonium molybdate spectrophotometry, the concentration of copper ions in the wastewater was measured by a flame atomic spectrophotometer, and the removal rates of phosphate and copper ions were measured as shown in table 2.
TABLE 2
Numbering Phosphate removal rate Copper ion removal rate
Example 1 90.6％ 89.6％
Example 2 90.8％ 89.5％
Example 3 71.7％ 70.6％
Example 4 73.4％ 75.3％
Example 5 84.0％ 85.3％
Example 6 69.6％ 67.3％
Example 7 91.1％ 90.7％
Example 8 83.8％ 84.1％
Example 9 83.5％ 86.2％
Example 10 75.7％ 79.9％
Example 11 87.0％ 87.4％
Comparative example 1 63.6％ 66.6％
Comparative example 2 56.4％ 63.9％
Comparative example 3 27.5％ 35.4％
Comparative example 4 30.3％ 37.6％
From the examples 1 to 3, when other conditions are the same, the removal rate of phosphate by the modified leaf biochar is increased firstly and then becomes stable along with the increase of the mass ratio of the total mass of calcium and magnesium elements in the calcium and magnesium mixed salt to the mass of the primary modified leaf biomass powder; as can be seen from the examples 1 and 4 to 6, when other conditions are the same, the removal rate of phosphate by the modified leaf biochar is increased firstly and then decreased as the mass ratio of calcium to magnesium in the calcium-magnesium mixed salt is decreased; as can be seen from example 1, example 11 and comparative example 1, when other conditions are the same, the calcium-magnesium mixed salt can significantly improve the removal rate of phosphate by the modified leaf biochar compared with a simple magnesium salt.
Wastewater 2: preparing simulated wastewater with phosphate concentration of 25mg/L by using monopotassium phosphate, and then adjusting the pH of the wastewater to about 3, 4, 5, 6, 7, 8, 9, 10 and 11 by using hydrochloric acid; the modified leaf biochar of example 1 was added at 1.0g/L to a reaction flask containing 100mL of simulated complex contaminated wastewater of different initial pH and then placed in a shaker to shake for 24 hours at 125 rpm.
The ammonium molybdate spectrophotometry is utilized to measure the phosphate before and after the wastewater reaction, and the change of the phosphate concentration is obvious before and after 24 hours of adsorption. When the initial adsorption pH values are respectively 3, 4, 5, 6, 7, 8, 9, 10 and 11, the removal rates of phosphate after 24 hours of reaction respectively reach 85.7%, 85.1%, 86.0%, 85.5%, 84.9%, 86.0%, 84.4%, 85.2% and 84.7%. Therefore, the modified leaf biochar has stable adsorption performance and excellent anti-interference capability in different pH reaction systems.
Wastewater 3: simulating simulated composite polluted wastewater with the phosphate concentration of 25mg/L and the heavy metal ion concentration of 10mg/L by utilizing monopotassium phosphate, lead nitrate, cadmium nitrate and nickel nitrate respectively, then adjusting the pH of the wastewater to about 5.0 by using hydrochloric acid, adding the modified leaf biochar in the embodiment 1 into a reaction bottle filled with 100mL of phosphate and heavy metal composite polluted wastewater according to 1g/L, and then placing the reaction bottle in an oscillator to oscillate for 24 hours at the rotating speed of 125 revolutions per minute.
The phosphate before and after the reaction of the wastewater was measured by ammonium molybdate spectrophotometry, the concentration of heavy metal ions in the wastewater was measured by a flame atomic spectrophotometer, and the removal rates of the phosphate and the heavy metal were measured as shown in table 3.
TABLE 3
Composite pollutants Removal rate of heavy metal ions Phosphate removal rate
Nickel + phosphate salt 83.2％ 87.4％
Cadmium + phosphate 78.7％ 88.2％
Lead + phosphate 86.9％ 86.0％
The above examples of the present invention are merely examples for clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims (10)

1. The preparation method of the modified leaf biochar is characterized by comprising the following steps:
s1, placing leaf biomass powder in a strong alkaline solution for modification treatment, and drying to obtain primary modified leaf biomass powder;
s2, placing the primary modified leaf biomass powder in the S1 in a calcium-magnesium mixed salt solution for full dipping, and then drying to obtain secondary modified leaf biomass powder;
s3, putting the secondary modified leaf biomass powder in the S2 in an oxygen-free environment for pyrolysis treatment to obtain modified leaf biochar;
the mass ratio of the total mass of calcium and magnesium elements in the calcium and magnesium mixed salt to the primary modified leaf biomass powder in S2 is 1 (5-15), and the mass ratio of the calcium element to the magnesium element in the calcium and magnesium mixed salt is 1 (0.5-2); in S3, the pyrolysis treatment temperature is 500-700 ℃, and the pyrolysis treatment time is 1-3 h.
2. The method for preparing modified leaf biochar as claimed in claim 1, wherein the mass ratio of calcium element to magnesium element in the calcium-magnesium mixed salt in S2 is 1 (1-2).
3. The method for preparing modified leaf biochar as claimed in claim 2, wherein the mass ratio of the total mass of calcium and magnesium elements in the calcium and magnesium mixed salt to the primary modified leaf biomass powder in S2 is 1 (5-10).
4. The method for preparing modified leafy biochar as claimed in claim 1, wherein the calcium-magnesium mixed salt in S2 is calcium acetate-magnesium acetate and/or calcium chloride-magnesium chloride.
5. The method for preparing modified leaf biochar as claimed in claim 1, wherein the solid-to-liquid ratio (g/mL) of the leaf biomass powder to the strongly alkaline solution in S1 is 1: 5-1: 15.
6. The method for preparing modified leaf biochar as claimed in claim 1, wherein the time for modification treatment in S1 is 10-15 h.
7. A modified leaf biochar prepared by the preparation method of the modified leaf biochar of any one of claims 1-6.
8. Use of the modified leaf biochar of claim 7 in the removal of phosphate and/or heavy metal ions from wastewater.
9. Use of the modified leafy biochar of claim 7 in removing phosphate and/or heavy metal ions from wastewater, wherein said heavy metal ions are Cu 2+ 、Pb 2+ 、Ni 2+ And Cd 2+ One or more of them.
10. The application of the modified leaf biochar in removing phosphate and/or heavy metal ions in wastewater as claimed in claim 7, wherein the pH value of the wastewater is 3-11.
CN202210278444.6A 2022-03-21 2022-03-21 Modified leaf biochar and preparation method and application thereof Pending CN114797767A (en)

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170282173A1 (en) * 2014-09-24 2017-10-05 Kai-Li HUANG Environment-controlling fibers, method manufacturing the same and fabrics using the same
CN108786738A (en) * 2018-07-03 2018-11-13 西北农林科技大学 A kind of magnesium salts modification biological charcoal and its application
CN109174001A (en) * 2018-10-17 2019-01-11 南方科技大学 A kind of modified method lichee charcoal preparation and reduce oestrone in water body using it of calcium
US20190128604A1 (en) * 2017-10-27 2019-05-02 Larry Baxter Recuperative Heat Exchange for Desiccation of Cold Fluids
CN112624792A (en) * 2020-12-18 2021-04-09 珠江水利委员会珠江水利科学研究院 Ceramsite prepared from byproducts of sludge treatment based on plants, and preparation method and application thereof
CN113828277A (en) * 2021-10-28 2021-12-24 重庆科技学院 Modified biochar and preparation method and application thereof
CN114029035A (en) * 2021-11-18 2022-02-11 河海大学 Preparation method of modified sludge biochar, obtained biochar and application

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170282173A1 (en) * 2014-09-24 2017-10-05 Kai-Li HUANG Environment-controlling fibers, method manufacturing the same and fabrics using the same
US20190128604A1 (en) * 2017-10-27 2019-05-02 Larry Baxter Recuperative Heat Exchange for Desiccation of Cold Fluids
CN108786738A (en) * 2018-07-03 2018-11-13 西北农林科技大学 A kind of magnesium salts modification biological charcoal and its application
CN109174001A (en) * 2018-10-17 2019-01-11 南方科技大学 A kind of modified method lichee charcoal preparation and reduce oestrone in water body using it of calcium
CN112624792A (en) * 2020-12-18 2021-04-09 珠江水利委员会珠江水利科学研究院 Ceramsite prepared from byproducts of sludge treatment based on plants, and preparation method and application thereof
CN113828277A (en) * 2021-10-28 2021-12-24 重庆科技学院 Modified biochar and preparation method and application thereof
CN114029035A (en) * 2021-11-18 2022-02-11 河海大学 Preparation method of modified sludge biochar, obtained biochar and application

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
LE FANG ET AL.: "Use of Mg/Ca modified biochars to take up phosphorus from acidextract of incinerated sewage sludge ash (ISSA) for fertilizer application", 《JOURNAL OF CLEANER PRODUCTION》, vol. 244, pages 1 - 11 *

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