阅读说明：本技术 一种羟基磷灰石/桑树杆生物炭的制备方法及其应用 (Preparation method and application of hydroxyapatite/mulberry tree stalk biochar ) 是由 梁美娜 李净溪 王敦球 芦琳 曹海燕 阮麟乔 于 2021-08-16 设计创作，主要内容包括：本发明公开一种羟基磷灰石/桑树杆生物炭的制备方法及其应用。先将桑树杆磨碎、炭化得桑树杆生物炭粉末；往硝酸钙溶液中,加入桑树杆生物炭,再加入磷酸氢二铵溶液,在搅拌下加入氨水；过滤、洗涤、干燥、过筛,得羟基磷灰石/桑树杆生物炭。本发明易操作,成本低；本发明工艺设备简单,成本低,易操作；所制备的羟基磷灰石/桑杆生物炭应用于含铅废水的吸附处理,最大吸附量达到312.5 mg/g。(The invention discloses a preparation method and application of hydroxyapatite/mulberry tree stalk biochar. Grinding mulberry stems and carbonizing to obtain mulberry stem charcoal powder; adding mulberry tree stalk biochar into the calcium nitrate solution, adding a diammonium hydrogen phosphate solution, and adding ammonia water under stirring; filtering, washing, drying and sieving to obtain the hydroxyapatite/mulberry stalk biochar. The invention is easy to operate and low in cost; the invention has simple process equipment, low cost and easy operation; the prepared hydroxyapatite/mulberry stem biochar is applied to the adsorption treatment of lead-containing wastewater, and the maximum adsorption capacity reaches 312.5 mg/g.)

1. A preparation method of hydroxyapatite/mulberry stalk biochar is characterized by comprising the following specific steps:

(1) peeling mulberry stems, crushing the mulberry stems into powder by using a universal crusher, sieving the powder by using a 20-mesh sieve, and drying the powder in an oven at the temperature of 60-80 ℃ for later use;

(2) placing the powdery mulberry stems obtained in the step (1) into a crucible, placing the crucible containing the mulberry stems into a muffle furnace, heating to 600-800 ℃ at a heating rate of 10 min/DEG C, keeping for 2-6 hours to obtain mulberry stem biochar, grinding, sieving with a 100-mesh sieve, and sealing for storage;

(3) adding 500mL of a calcium nitrate solution with the concentration of 0.1-0.5 mol/L into a 2000mL beaker according to the molar ratio of Ca/P =1.67, then adding 50g of the mulberry stem biochar obtained in the step (2) into the beaker, and then continuing to add 300mL of a diammonium hydrogen phosphate solution with the concentration of 0.1-0.5 mol/L into the beaker;

(4) rapidly adding an ammonia water solution with the volume percentage concentration of 8-10% into the mixed suspension solution obtained in the step (3) under stirring, and adjusting the pH value of the solution to 8.0-10.0;

(5) after the pH value of the mixed suspension in the step (4) is kept stable and unchanged, stirring the mixed suspension in the step (4) for 30 minutes at room temperature by using a magnetic stirrer at a rotating speed of 200r/min, and then performing water bath aging for 3-6 hours at 70 ℃;

(6) naturally cooling the mixed suspension in the step (5), measuring the pH value of the supernatant, centrifugally separating the mixed suspension at the rotating speed of 4000r/min for 5-15 minutes, washing the mixed suspension for many times by using ultrapure water after solid-liquid separation until the pH value is about 7.0, washing by using absolute ethyl alcohol, and filtering;

(7) and (4) drying the product obtained in the step (6) at 80 ℃ for 24-30 hours, naturally cooling, grinding, and sieving by a 100-mesh sieve to obtain the hydroxyapatite/mulberry stem biochar.

2. The application of the hydroxyapatite/mulberry stem biochar prepared by the preparation method according to claim 1 is characterized in that the hydroxyapatite/mulberry stem biochar is applied to the adsorption treatment of lead-containing wastewater.

Technical Field

The invention relates to a preparation method and application of hydroxyapatite/mulberry stalk biochar²⁺The adsorption performance of (3).

Background

Pb²⁺Is a highly toxic heavy metal pollutant, Pb, widely existing in industrial wastewater²⁺With Hg²⁺、Cd²⁺、As³⁺And Cr⁶⁺Is listed as heavy metal pollutants which are preferentially controlled and discharged in 5 water bodies by the national environmental protection department. Due to Pb²⁺Biological accumulation can be carried out through a food chain, and even lead with low concentration in natural water can cause great harm to human health and ecological environment, so lead-containing wastewater must be effectively treated before being discharged. The minimum limit of lead concentration in drinking water by the world health organization (WTO) is 10 mug/L.

Lead pollution in water mainly refers to lead enrichment in water caused in human production activities. Mainly comprises the combustion of fossil fuel, the smelting of sulfur-containing minerals, the discharge of waste water of acid mines and the like. These factors can cause serious pollution to the water environment. Lead is not only toxic to organisms but also can be accumulated in animals and plants, and even threatens the health and safety of human beings. Therefore, the control of lead pollution in water and the reduction of the harm of lead pollution to human beings are currently an important problem.

At present, the method for treating lead pollution of water bodies at home and abroad mainly comprises an adsorption method, a chemical precipitation method, an ion exchange technology, a membrane separation technology, a photocatalysis technology, a biological treatment technology and the like. Wherein, the adsorption method has simple process, low cost and good treatment effect, and is widely applied to the treatment of the lead-containing wastewater. The currently used adsorbents include active zeolite, chitosan, biochar and the like. The biochar is widely applied to treatment of lead-containing wastewater due to the advantages of high stability, strong adsorption capacity and the like, and particularly, the biochar composite material with good adsorption performance is prepared by physical and chemical modification and loading of other substances on the surface of the biochar composite material, so that the removal efficiency of the biochar composite material on heavy metal ions is improved to a great extent.

The single charcoal has poor adsorption performance and limited treatment effect. The biochar has a developed pore structure, rich surface functional groups and good heavy metal adsorption performance. In order to enable the biochar to achieve a better effect of adsorbing heavy metals, the biochar is modified to achieve the performance of enhancing the adsorption effect. Therefore, the invention uses the mulberry stem biochar to load hydroxyapatite to prepare the hydroxyapatite/mulberry stem biochar, enhances the adsorption effect, and is used for adsorbing and removing lead in water.

Disclosure of Invention

The invention aims to provide a method for preparing mulberry tree extract by using waste mulberry stems as main raw materials and calcium nitrate tetrahydrate (Ca (NO)₃)₂·4H₂O) and diammonium hydrogen phosphate ((NH)₄)₂HPO₄) A method for preparing hydroxyapatite/mulberry stalk biochar by a sol-gel method as an auxiliary material and application thereof.

The method comprises the following specific steps:

(1) the mulberry stems are peeled, crushed into powder by a universal crusher, sieved by a 20-mesh sieve, and placed in an oven to be dried at 60-80 ℃ for later use.

(2) And (2) placing the powdery mulberry stems obtained in the step (1) into a crucible, placing the crucible containing the mulberry stems into a muffle furnace, heating to 600-800 ℃ at a heating rate of 10 min/DEG C, keeping for 2-6 hours to obtain the mulberry stem biochar, grinding, sieving with a 100-mesh sieve, and sealing for storage.

(3) Adding 500mL of calcium nitrate solution with the concentration of 0.1 mol/L-0.5 mol/L into a 2000mL beaker according to the molar ratio of Ca/P being 1.67, then adding 50g of the mulberry stem biochar obtained in the step (2) into the beaker, and then continuing to add 300mL of diammonium hydrogen phosphate solution with the concentration of 0.1 mol/L-0.5 mol/L into the beaker.

(4) And (3) rapidly adding an ammonia water solution with the volume percentage concentration of 8-10% into the mixed suspension solution obtained in the step (3) under stirring, and adjusting the pH value of the solution to 8.0-10.0.

(5) And (3) after the pH value of the mixed suspension in the step (4) is kept stable and unchanged, stirring the mixed suspension in the step (4) for 30 minutes at room temperature by using a magnetic stirrer at the rotating speed of 200r/min, and then aging in a water bath for 3-6 hours at 70 ℃.

(6) And (5) naturally cooling the mixed suspension, measuring the pH value of the supernatant, centrifugally separating the mixed suspension at the rotating speed of 4000r/min for 5-15 minutes, washing the mixed suspension for many times by using ultrapure water until the pH value is about 7.0 after solid-liquid separation, washing the mixed suspension by using absolute ethyl alcohol, and filtering.

(7) And (3) drying the product obtained in the step (6) at 80 ℃ for 24-30 hours, naturally cooling, and grinding (sieving by a 100-mesh sieve) to obtain the hydroxyapatite/mulberry stem biochar (HMp).

The prior composite material for adsorbing lead is hydroxyapatite/Fe₃O₄Nano composite material, tricalcium aluminate/biochar composite material, magnesium-calcium hydroxyapatite material, strontium-doped carbon hydroxyapatite material and the like. The invention provides a composite material for effectively adsorbing lead, namely hydroxyapatite/mulberry stem biochar. The obtained biological carbon contains hydroxyapatite, and has improved adsorption capacity. When the initial lead ion concentration in the solution is 300mg/L, the removal rate of lead is more than 99.5 percent, the total lead concentration in the adsorption equilibrium solution is lower than 1.0mg/L, and the lead content in the adsorption equilibrium solution reaches the national comprehensive sewage discharge standard (GB 8978-2002); when the initial lead concentration in the solution is 100mg/L, the lead ion concentration in the adsorption equilibrium solution is lower than the limit value of lead in the Water quality Standard of Drinking of the world health organization of 0.01 mg/L.

The invention has simple process equipment, low cost and easy operation. Mainly takes mulberry stems as main raw materials. The prepared hydroxyapatite/mulberry stem biochar has a good adsorption effect on lead in an aqueous solution, the maximum adsorption capacity reaches 312.5mg/g, and the hydroxyapatite/mulberry stem biochar is applied to adsorption treatment of lead-containing wastewater.

Drawings

Fig. 1 is a graph showing the influence of hydroxyapatite/mulberry stem biochar prepared by the embodiment of the invention on the adsorption effect of different initial lead concentrations.

FIG. 2 is an infrared spectrum of the mulberry stalk charcoal and hydroxyapatite/mulberry stalk charcoal prepared according to the embodiment of the present invention.

Fig. 3 is an XRD pattern of the mulberry stalk biochar and hydroxyapatite/mulberry stalk biochar prepared by the embodiment of the invention.

Fig. 4 is SEM images of the mulberry stem biochar and hydroxyapatite/mulberry stem biochar prepared according to the embodiment of the present invention.

Detailed Description

Example (b):

(1) peeling mulberry stems, crushing into powder by a universal crusher, sieving by a 20-mesh sieve, and drying in an oven at 80 ℃ for later use.

(2) Placing the powdery mulberry stems obtained in the step (1) into a crucible, placing the crucible containing the mulberry stems into a muffle furnace, heating to 700 ℃ at a heating rate of 10 min/DEG C, keeping for 2 hours to obtain the mulberry stem biochar, grinding, sieving with a 100-mesh sieve, and sealing for storage.

(3) 500mL of 2000mL of a 0.2mol/L calcium nitrate solution was added to a beaker at a molar ratio of Ca/P of 1.67, followed by adding 50g of the mulberry stalk biochar obtained in step (2) to the beaker, and then adding 300mL of a 0.2mol/L diammonium hydrogen phosphate solution to the beaker.

(4) And (4) rapidly adding an ammonia water solution with the volume percentage concentration of 8% into the mixed solution obtained in the step (3) under stirring, and adjusting the pH value of the solution to 10.0.

(5) After the pH value of the mixed suspension in the step (4) is kept stable, stirring the mixed suspension in the step (4) for 30 minutes at room temperature by using a magnetic stirrer at the rotating speed of 200r/min, and then aging in a water bath for 4 hours at 70 ℃.

(6) And (5) naturally cooling the mixed suspension, measuring the pH value of the supernatant, centrifugally separating the mixed suspension at the rotating speed of 4000r/min for 5 minutes, washing the mixed suspension for many times by using ultrapure water until the pH value is about 7.0 after liquid separation, and then washing by using absolute ethyl alcohol.

(7) And (3) drying the product obtained in the step (6) at the temperature of 80 ℃ for 24 hours, naturally cooling, grinding, and sieving by using a 100-mesh sieve to obtain the hydroxyapatite/mulberry stem biochar (HMp).

The hydroxyapatite/mulberry stalk biochar prepared by the embodiment is applied to the adsorption treatment of the lead-containing wastewater.

0.1g of the hydroxyapatite/mulberry stem biochar prepared in the example was weighed into a series of 100mL polyethylene plastic centrifuge tubes, and the pH was adjusted to 5.0 with 0.1mol/L NaOH solution or HCl solution, the volume was 50mL, Pb²⁺Pb-containing solution with concentrations of 10, 50, 100, 300, 400, 500, and 600mg/L, respectively²⁺The solution is added toThe plastic centrifuge tube. Oscillating and adsorbing for 24 hours at the temperature of 25 ℃ and the oscillating rotation speed of 200 r/min. The plastic centrifuge tube was then placed in a centrifuge, centrifuged at 4000r/min for 5 minutes, the supernatant was filtered using a syringe filter (0.22 μm filter), and the remaining total Pb concentration in the filtrate was measured using an inductively coupled plasma emission spectrometer (ICP-OES), the experimental results being shown in fig. 1.

The phase structure and the composition were measured by a fourier spectrometer and an X-ray diffractometer, and the results are shown in fig. 2 and 3. The morphology of the hydroxyapatite/mulberry stalk biochar is analyzed by a field emission scanning electron microscope, and the result is shown in figure 4.