CN104118892A - Method for preparing nano magnesium hydroxide from microplasma seawater - Google Patents

Abstract

The invention discloses a method and device for preparing nano-magnesium hydroxide from micro-plasma seawater. The specific steps include pouring seawater into a micro-plasma reactor, adding NaOH to adjust the initial pH value of the solution to a certain value; opening the argon gas bottle, and adjusting the flow rate. The gas flow is controlled by the meter, and the DC high-voltage power supply is turned on after the gas flow is stable. When the voltage reaches about 2500V, the gas is broken down to form a micro-plasma; then the voltage is adjusted immediately to stabilize the micro-plasma at a certain voltage and current level, and the reaction officially begins ; Discharge treatment for 5-20 minutes to complete the preparation of nano-magnesium hydroxide. The invention can complete the preparation process of nano-magnesium hydroxide according to actual requirements, and prepares nano-magnesium hydroxide simply, at low cost and with high efficiency, and has potential development prospects.

Description

A method for preparing nano-magnesium hydroxide from micro-plasma seawater

technical field

The invention relates to the technical field of nanomaterial preparation, in particular to a method and a device for preparing nano magnesium hydroxide from micro-plasma seawater. the

Background technique

Seawater comprehensive utilization technology is developing rapidly, and the combination of seawater desalination and comprehensive utilization is the direction of future seawater utilization. Magnesium hydroxide is an important inorganic compound, which can be widely used in the fields of flame retardant for plastics, resins and other organisms, lead-containing wastewater treatment, flue gas desulfurization and medicine. Nano-scale magnesium hydroxide is the development direction of flame retardants in recent years due to the characteristics of nano-materials. It has multiple functions such as flame retardant, smoke elimination, anti-drip, filling, etc. It is an environmentally friendly green flame retardant. The market The prospects are broader. At present, the most basic method for preparing nano-magnesium hydroxide from seawater is the direct precipitation method, adding alkali to concentrated seawater to precipitate magnesium hydroxide, but the product of this method has large particle size, wide distribution, low purity, and serious agglomeration. Therefore, to economically, efficiently, and highly purely prepare nano-magnesium hydroxide from seawater, in addition to improving existing technologies, new technologies still need to be developed. the

Contents of the invention

In order to solve the above problems, the present invention proposes a method and device for preparing nano-magnesium hydroxide from micro-plasma seawater. The method and device have the advantages of simple, high-efficiency, and low-consumption preparation of nano-magnesium hydroxide, and have potential development prospects. the

The present invention is to achieve above object, realizes by following technical scheme:

A method for preparing nano-magnesium hydroxide from micro-plasma seawater is provided. 1) Pour seawater into a micro-plasma reactor, add NaOH to adjust the initial pH value of the solution to a certain value; 2) open the argon gas bottle, and adjust the flow meter to control the gas Flow rate, after the air flow is stable, turn on the DC high-voltage power supply. When the voltage reaches about 2500V, the gas is broken down to form a micro-plasma; then immediately adjust the voltage to stabilize the micro-plasma at a certain voltage and current level, and the reaction officially begins; discharge treatment 5-20 minutes to complete the preparation of nano-magnesium hydroxide. the

A device for preparing nano-magnesium hydroxide from micro-plasma seawater is provided, comprising a micro-plasma reactor, a DC high-voltage power supply (1) for powering the micro-plasma reactor and an argon bottle (1) for supplying gas to the micro-plasma reactor 9); the micro-plasma reactor adopts a glass reactor (5), the solution is stirred by a magnetic stirrer (8), the anode body is a capillary stainless steel tube (3), and the argon gas is injected into the stainless steel electrode from the argon gas bottle through the glass rotameter Inside the body to the reactor; the stainless steel electrode is placed vertically above the reaction solution, and the gas outlet of the electrode is 2mm away from the surface of the solution; the cathode is a thin tungsten rod (4); the tungsten rod is connected to the ground terminal of the DC high voltage power supply through a series ballast resistor (2) ; After starting the DC high-voltage power supply, micro plasma (6) is generated between the stainless steel electrode and the liquid surface, and the system forms a path. the

The principle of preparing nano-magnesium hydroxide in the present invention: the present invention uses micro-plasma as the cathode, which is connected with the anode through an electrolytic medium to form a micro-plasma electrochemical system. After gas breakdown produces micro-plasma, a large amount of high-energy Electrons enter the reaction medium, and the following reactions occur:

Mg ²⁺ +2OH→Mg(OH) ₂ ↓

The invention can complete the preparation process of nano-magnesium hydroxide according to actual requirements, and can prepare nano-magnesium hydroxide simply, at low cost and with high efficiency. the

Description of drawings

Fig. 1 is the device schematic diagram of the method of the present invention. the

In the figure: 1. DC high voltage power supply, 2. Ballast resistor, 3. Stainless steel tube, 4. Tungsten rod, 5. Glass reactor, 6. Micro plasma, 7. Magnetic stirrer, 8. Glass rotameter, 9. Argon cylinder. the

Detailed ways

Example

As shown in Figure 1, the micro-plasma reactor is a glass reactor with a height of 8.5 cm and an inner diameter of 5.5 cm. The main body of the anode is a stainless steel tube with a length of 8 cm and an inner diameter of 0.7 mm. Argon gas is injected from the argon cylinder through the glass rotameter into the stainless steel electrode body until it reaches the reactor. The stainless steel electrode is placed vertically above the reaction solution, and the gas outlet of the electrode is 2mm away from the solution surface. The cathode is a tungsten rod with a length of 15cm and a diameter of 2mm. The tungsten rod is connected to the ground terminal of the DC high-voltage power supply through a 10kΩ ballast resistor in series. The two electrodes were kept at a distance of 3 cm. After starting the DC high-voltage power supply, micro-plasma is generated between the stainless steel electrode and the liquid surface, and the system forms a path. The solution was stirred using a digital constant temperature magnetic stirrer. the

Take a certain amount of seawater and mix well with 0.5mol/L NaOH, take 40mL of the solution and pour it into the reactor, and add ethylene glycol. Pass argon gas into the stainless steel needle tube, and its flow rate is controlled at 60 mL/min by a glass rotameter. After the device is connected, turn on the DC high-voltage power supply. When the voltage reaches about 2500V, the gas between the solution and the stainless steel tube is broken down to generate bright micro-plasma. Then adjust the voltage immediately to make the discharge run stably, and the preparation of nano-magnesium hydroxide begins. , react for 20min. After the discharge, the precipitated product was centrifuged and filtered, washed several times with ethanol and deionized water, and finally dried in a vacuum oven at 60°C for 6 hours. The obtained product was analyzed for purity, XRD and TEM. The XRD pattern of the product is compared with the standard pattern of Mg(OH) ₂ , and the intensity and position of each peak are consistent with the standard diffraction pattern, which proves that the product is Mg(OH) ₂ . TEM analysis shows that the product has a regular hexagonal sheet structure with a particle size of about 60-200nm, good dispersion and uniform distribution.

Claims (2)

1. A method for preparing nano-magnesium hydroxide from micro-plasma seawater is characterized in that the steps of the method are as follows: seawater is poured into a micro-plasma reactor, and NaOH is added to adjust the initial pH value of the solution to a certain value; the argon cylinder is opened , adjust the flowmeter to control the gas flow, and turn on the DC high-voltage power supply after the air flow is stable. When the voltage reaches about 2500V, the gas is broken down to form a micro plasma; then immediately adjust the voltage to stabilize the micro plasma at a certain voltage and current level, The reaction officially starts; the discharge treatment is 5-20 minutes, and the preparation of nano-magnesium hydroxide is completed. 2. according to the device that a kind of micro-plasma seawater of method according to claim 1 prepares nano-magnesium hydroxide, it is characterized in that comprising micro-plasma reactor, the DC high-voltage power supply (1) that supplies power to micro-plasma reactor and power supply The argon bottle (9) for gas supply to the micro-plasma reactor; the micro-plasma reactor adopts a glass reactor (5), the solution is stirred using a magnetic stirrer (8), the anode body is a capillary stainless steel tube (3), and the argon gas The argon gas bottle is injected into the stainless steel electrode body through the glass rotameter to the reactor; the stainless steel electrode is placed vertically above the reaction solution, and the gas outlet of the electrode is 2mm away from the surface of the solution; the cathode is a thin tungsten rod (4); the tungsten rod is ballasted in series The resistor (2) is connected to the ground terminal of the DC high-voltage power supply; after the DC high-voltage power supply is started, micro-plasma (6) is generated between the stainless steel electrode and the liquid surface, and the system forms a path.