CN101823777B

CN101823777B - Method for removing phenol in aqueous solution with magnetic mesoporous carbon material

Info

Publication number: CN101823777B
Application number: CN201010152347XA
Authority: CN
Inventors: 胡龙兴; 党松涛
Original assignee: University of Shanghai for Science and Technology
Current assignee: University of Shanghai for Science and Technology
Priority date: 2010-04-20
Filing date: 2010-04-20
Publication date: 2011-12-21
Anticipated expiration: 2030-04-20
Also published as: CN101823777A

Abstract

The invention relates to a method for absorbing and catalyzing phenol in aqueous solution with mesoporous carbon CMK-3 of load magnetic Fe3O4 particles, which belongs to the technical field of catalyst loading and application. The method takes the mesoporous carbon material CMK-3 as a carrier, takes magnetic active metal oxide Fe3O4 as a load object and takes glycol as reducer, loads the Fe3O4 particles into a mesoporous channel of the mesoporous carbon CMK-3, and synchronizes Fe3O4/CMK-3 which has absorption, catalysis and oxidation functions to the phenol in aqueous solution. The Fe3O4/CMK-3 is characterized by easy separation from water, has good absorption, catalysis and oxidation effect to the phenol in aqueous solution, has better reusability, and has the absorption capability to the phenol in the water still up to 52mg/g after being reused for 15 times. The method has potential actual application prospect.

Description

Remove the method for phenol in aqueous solution with magnetic mesoporous carbon material

Technical field

The present invention relates to remove the method for phenol in the aqueous solution, metal catalyst load and application with a kind of magnetic mesoporous carbon material.

Background technology

Ryoo in 1999 etc. are template with meso pore silicon oxide material MCM-48 first, and sucrose is that carbon source has been synthesized ordered mesoporous carbon material CMK-1.This is the important breakthrough on the porous carbon materials development history.Ordered mesoporous carbon material has higher specific surface area, adjustable hole dimension, the duct that is interconnected and modifiable surface nature usually, is with a wide range of applications in various fields such as chemical industry, energy and environment, biotechnology, adsorbing separation, catalysis and light, electricity, magnetic.In traditional catalyst application, by using the discrete catalyst of active carbon immobilization, utilize the absorption property enrichment catalysis matter of active carbon, again the catalytic action by catalyst reach the purpose of catalysis be one than popular topic.Activated carbon supported catalyst with traditional exists some inherent shortcoming.At first, the aperture of active carbon is less, how in range of micropores, is difficult to macromolecular catalyst of load and the macromolecular catalysis matter of absorption.Secondly, traditional active carbon specific area and pore volume are all less, and be limited to the adsorbance of adsorbate.Simultaneously, in some cases, aperture that active carbon is less and pore volume are unfavorable for the mass transfer of liquids and gases to a certain extent, thereby hinder the carrying out of catalytic reaction.In addition, because carbon powder is not easily separated in water, can increase extra cost when using it in the wastewater treatment.Therefore, in order to improve to the load capacity of catalyst and the adsorbance of adsorbate, improve the catalytic efficiency of catalyst and increase its easily separated property, adopt new catalyst carrier with larger aperture and specific area, strengthen its recycling simultaneously, reduce the use cost of catalyst, meaningful and press for.Mesoporous carbon has the adjustable mesoporous aperture of homogeneous, the inner surface that is easy to modify, the stable and agraphitic carbon skeleton that is easy to mix, and attributes such as high-specific surface area and pore volume, makes it can be used for absorption and as catalyst carrier.Use mesoporous carbon to be as the advantage of catalyst carrier: (1) mesoporous carbon has higher specific surface area, can have very big adsorbance and load capacity; (2) duct of mesoporous carbon is controlled, can strengthen the catalytic activity of catalyst in catalytic process; (3) mesoporous carbon has the surface nature of the pore passage structure and the homogeneous of high-sequential, the behavior of measurable catalyst in loading process; (4) operating process of supported active metal oxide catalyst is very simple and reliable.Simultaneously, the load of magnetisable material helps the separation of mesoporous carbon and recycling.

Summary of the invention

The invention provides a kind of magnetic mesoporous material Fe for preparing ₃O ₄/ CMK-3 also removes the method for phenol in aqueous solution take it as absorption-catalyst.Take meso-porous carbon material CMK-3 as carrier, reactive metal oxides tri-iron tetroxide (Fe ₃O ₄) be the load object, made magnetic mesoporous material Fe ₃O ₄/ CMK-3.Utilize adsorption experiment and recycled experimental verification Fe ₃O ₄/ CMK-3 has good absorption and catalytic oxidation performance to phenol in aqueous solution.

For achieving the above object, the present invention adopts following technical proposals:

A. the load of reactive metal oxides tri-iron tetroxide: Fe ₃O ₄Load be by with metal precursor Fe (NO ₃) ₃Aqueous solution dipping CMK-3, dry after take ethylene glycol as reducing agent, what roasting realized in inert atmosphere at a certain temperature; Be about to 5g and be dissolved with 1.44g Fe (NO ₃) ₃9H ₂The aqueous solution of O and 1g CMK-3 fully mix, prior to 350K baking 15h, again in inert atmosphere nitrogen under 520K roasting 2h, naturally cool off, obtain magnetic mesoporous material Fe ₃O ₄/ CMK-3.In the mass fraction of Fe, this moment Fe ₃O ₄/ CMK-3 is 20% to the load capacity of tri-iron tetroxide;

B.Fe ₃O ₄/ CMK-3 is to absorption and the catalytic performance of phenol in aqueous solution: be 20～80mgL with 100mL concentration ^-1Phenol solution put into tool plug triangular flask, add the Fe of 0.03～0.07g ₃O ₄The magnetic mesoporous carbon dust of/CMK-3 adsorbs 1h in 30 ℃ of constant temperature in the gas bath constant temperature oscillator.After absorption finishes, absorption there is the Fe of phenol by the method for externally-applied magnetic field ₃O ₄/ CMK-3 separates from water, is dried to constant weight in 30 ℃ and obtains adsorption sample.Adsorption sample is placed porcelain boat, put into tube type resistance furnace, in 220～250 ℃ of catalytic oxidation 1h, heating rate is 3～5 ℃ of min under air atmosphere ^-1Carry out the absorption-catalytic oxidation circulation experiment of next round again through the adsorption sample of catalytic oxidation experiment.

Characteristics of the present invention are: take meso-porous carbon material CMK-3 as carrier, Fe (NO ₃) ₃9H ₂O is that predecessor, ethylene glycol are reducing agent, utilizes a kind of easy method with metal oxide Fe ₃O ₄Load enters among the duct of CMK-3, has formed a kind of effective absorption-catalytic oxidant to phenol in aqueous solution.At load Fe ₃O ₄Process in, adopted the method for equi-volume impregnating and roasting in inert gas, so that the Fe that in the CMK-3 duct, forms ₃O ₄Particle has little, the dispersed strong advantage of crystal grain, is conducive to the catalytic oxidation phenol in aqueous solution.Because the mesoporous material Fe that makes ₃O ₄/ CMK-3 has magnetic, so that can utilize easily the method for externally-applied magnetic field to separate with the aqueous solution after adsorbing phenol.Absorption-catalyst Fe ₃O ₄/ CMK-3 has the good effect that recycles, and after multiple adsorb-catalytic oxidation circulation, still phenol in aqueous solution is had good absorption property.

Description of drawings

Fig. 1 is preparation CMK-3 and Fe ₃O ₄The little angle XRD figure of/CMK-3.

Fig. 2 is the Fe of preparation ₃O ₄The big angle XRD figure of/CMK-3.

Fig. 3 is the Fe of preparation ₃O ₄The transmission electron microscope picture of/CMK-3.

Fig. 4 is the Fe of preparation ₃O ₄/ CMK-3 is to the adsorbance of phenol in aqueous solution.

Fig. 5 is for using externally-applied magnetic field with Fe ₃O ₄/ CMK-3 separates schematic diagram with the aqueous solution.

Fig. 6 is Fe ₃O ₄/ CMK-3 is to the multiple adsorb of phenol in aqueous solution-catalytic oxidation effect.

The specific embodiment

Details are as follows in conjunction with the accompanying drawings for the preferred embodiments of the present invention:

Embodiment one: Fe ₃O ₄Load be by with metal precursor Fe (NO ₃) ₃Aqueous solution dipping CMK-3, dry after take ethylene glycol as reducing agent, what roasting realized in inert atmosphere at a certain temperature.5g is dissolved with 1.44g Fe (NO ₃) ₃9H ₂The aqueous solution of O and 1g CMK-3 fully mix, prior to 350K baking 15h, again in inert atmosphere (nitrogen) under 520K roasting 2h, naturally cool off, just obtained magnetic mesoporous material Fe ₃O ₄/ CMK-3.In the mass fraction of Fe, this moment Fe ₃O ₄/ CMK-3 is 20% to the load capacity of catalyst.

Load Fe ₃O ₄After, can be found out Fe by accompanying drawing 1 ₃O ₄The diffraction maximum that belongs to (100) plane in the XRD curve of/CMK-3 broadens and strength decreased, shows that magnetic particle has entered among the duct of CMK-3.The nitrogen adsorption test shows Fe ₃O ₄Specific area and the pore volume of/CMK-3 all decrease, and are respectively the 1196m from CMK-3 ²/ g and 0.98cm ³/ g is reduced to 916.2m ²/ g and 0.82cm ³/ g, this proves that further magnetic particle has entered CMK-3 inside.

Fig. 2 is Fe ₃O ₄The wide-angle XRD diffraction pattern of/CMK-3 as seen from the figure, has a wide diffraction maximum when 2 θ are 25 °, the corresponding disperse diffraction maximum of amorphous carbon; Be respectively 30.1 ° at 2 θ, 35.4 °, 43.1 °, 57.0 °, locate also can see very strong diffraction maximum that this is corresponding to face-centered cubic Fe for 62.6 ° ₃O ₄Characteristic diffraction peak. show that under current experiment condition that produce mainly is Fe in the duct of CMK-3 ₃O ₄Magnetic particle.Fig. 3 is Fe ₃O ₄The TEM figure of/CMK-3. as seen from the figure, Fe ₃O ₄/ CMK-3 has the meso-hole structure of long-range order, Fe ₃O ₄(black particle among the figure) is present in the duct of mesoporous carbon with the form of nanocrystal, and particle diameter is about 10nm.

As seen from Figure 4, in initial 20min, the Adsorption of Phenol amount in time growth and increase fast, in 40min, substantially reach poised state. adsorb and when recycling experiment, fully adsorb in order to make mesoporous carbon, the setting adsorption time is 60min.Fe ₃O ₄/ CMK-3 Pyrogentisinic Acid's adsorbance is bigger, reaches the initial adsorption amount and reaches 60mg/g, shows that it is a kind of novel sorbing material.

The separating effect of magnetic mesoporous material from water.Work as Fe ₃O ₄/ CMK-3 behind the adsorbing phenol, because it has stronger magnetic, can separate it easily, thereby carry out follow-up catalytic oxidation from water with the aqueous solution. by Fig. 5 (A) as seen, and at the time spent of doing that does not have externally-applied magnetic field, Fe ₃O ₄/ CMK-3 can be scattered in the aqueous solution well; And adding magnetic field only behind the 5min, most Fe ₃O ₄/ CMK-3 particle has been adsorbed in (Fig. 5 B) on the chamber wall, through 10min good solid-liquid separation effect (Fig. 5 C) has been arranged.

Fe ₃O ₄/ CMK-3 is to the effect that recycles of phenol in aqueous solution.Be the phenol solution of 50mg/L and the Fe of 0.05g with 100mL concentration ₃O ₄/ CMK-3 puts into tool plug triangular flask, adsorbs 1h in 30 ℃ in the air bath constant temperature oscillator.After absorption finishes, by the method recovery Fe of externally-applied magnetic field ₃O ₄/ CMK-3 is dried to constant weight in 30 ℃, puts into porcelain boat, carries out catalytic oxidation in tube furnace under air atmosphere.Be warming up to 250 ℃ and lasting 1h under room temperature, heating rate is 5 ℃/min.Sample through catalytic can enter next round absorption-catalytic.And maintenance Fe ₃O ₄/ CMK-3 is 0.1g: 200mL with the ratio of phenol solution.The concentration of phenol solution is measured by tetramino antipyrine method, and the phenol adsorbance is by the change calculations of phenol solution concentration before and after the absorption.

Fig. 6 is Fe ₃O ₄The variation of/CMK-3 Pyrogentisinic Acid's adsorbance in 15 absorption-catalytic oxidation circulations wherein represents Fe 0 time ₃O ₄The original adsorbance of/CMK-3.As seen from the figure, Fe ₃O ₄/ CMK-3 has the good performance that recycles.In front 5 times circulation, lose about 1.5% Adsorption of Phenol amount at every turn, after 6 circulations, Fe ₃O ₄/ CMK-3 Pyrogentisinic Acid's adsorbance tends towards stability, about 53mg/g.

Claims

1. remove the method for phenol in the aqueous solution with magnetic mesoporous carbon material for one kind, it is characterized in that this method has following technical process:

A. the load of reactive metal oxides tri-iron tetroxide: Fe ₃O ₄Load be by with metal precursor Fe (NO ₃) ₃Aqueous solution dipping CMK-3, dry after take ethylene glycol as reducing agent, what roasting realized in inert atmosphere at a certain temperature; Be about to 5g and be dissolved with 1.44g Fe (NO ₃) ₃9H ₂The aqueous solution of O and 1g CMK-3 fully mix, prior to 350K baking 15h, again in inert atmosphere nitrogen under 520K roasting 2h, naturally cool off, obtain magnetic mesoporous material Fe ₃O ₄/ CMK-3;

B.Fe ₃O ₄/ CMK-3 is to the absorption of phenol in aqueous solution: be 20～80mgL with 100mL concentration ^-1Phenol solution put into tool plug triangular flask, add the Fe of 0.03～0.07g ₃O ₄The magnetic mesoporous carbon dust of/CMK-3 adsorbs 1h in 30 ℃ of constant temperature in the air bath constant temperature oscillator.