CN103143318A - Preparation method for siliceous earth/FeOOH composite materials in micro-nano structure - Google Patents

Abstract

The invention discloses a preparation method for siliceous earth/FeOOH composite materials in a micro-nano structure. The preparation method comprises the steps of evenly attaching FeOOH obtained by a water-bath method to the surface of siliceous earth, respectively characterizing prepared products by a field emission scanning electronic microscope and an X-ray diffraction instrument, and knowing that alpha-FeOOH is of an orthorhombic system structure, evenly distributed on the surface of the siliceous earth and even in morphological structure. The alpha-FeOOH of the composite materials is of a nano structure and has higher crystallinity and purity. During a preparation process, due to the fact that substances like templates are not added, follow-up processing is convenient to achieve, reaction temperature is low, reaction time is short, processes are simple, cost is low, and the preparation method is potentially applied to the field of environment.

Description

A kind of diatomite with micro-nano structure/FeOOH composite manufacture method

Technical field

The present invention relates generally to a kind of diatomite with micro-nano structure/FeOOH composite manufacture method, belongs to the adsorbent application.

Background technology

In inorganic natural minerals, the biological silicalite that diatomite is comprised of the siliceous remains of diatom and other microorganism.Its mineralogical composition is mainly opal (SiO ₂H ₂O) and mutation.Diatomite light weight, porous, relative density are little, also have simultaneously many good performances such as unique microcellular structure, specific area are large, bulk density is little, acidproof, the surface is covered by a large amount of silicon hydroxyls, usually its particle surface is with negative electrical charge, therefore, its application pay attention to day by day aspect wastewater treatment gets up, especially for the heavy metal cation pollutant.

Because diatomite has microcellular structure and with effectively removing contained most of impurity after acid treatment, obtains stable inside cavernous structure, can become a kind of good carrier material.Therefore be a good selection to the diatomite modifying metallic oxide, negative electrical charge absorption by the hot method metal cation of aqueous solvent after by the dehydrogenation of diatomite surface deposits to the diatomite surface, obtain having the composite of little/micro-nano structure, having overcome so diatomaceous settling property hangs down and the long shortcoming of hydraulic detention time (HRT), simultaneously the volume of structures required also greatly to reduce, strengthen the adsorption capacity to heavy metal.On the other hand in metal oxide FeOOH have higher charge density, than bigger serface, distinctive crystal property, so counterweight metal adsorption performance is stronger, but easily reunites, and not easily separated.Therefore after by the aqueous solvent method, alpha-feooh being assembled into the diatomite surface, bring into play on the one hand the effect of the unique microcellular structure of diatomite, enriched diatomaceous microcellular structure, improved the character of diatomite in the aqueous solution; Because the nano-hydroxy iron oxide is deposited on diatomaceous micropore, stop the reunion of nano particle on the other hand, be of value to increase material surface electric charge and surface area, can strengthen the absorption property to heavy metal contaminants, reached the structural reinforcing characterization of adsorption; Simultaneously because the integral composite macro manifestations is micrometer structure, institute so that composite separate from solution.Therefore through after assembling little/composite of receiving gives full play to diatomaceous microcellular structure and surface charge effect, strengthens the structure characterization of adsorption.Take full advantage of the advantage of bi-material for this composite, both organically assembled, obtain a kind of green, cheapness, high absorption property and have the structural reinforcing absorption property little/the micro-nano structure composite.

Summary of the invention

The object of the invention just is to provide a kind of diatomite with micro-nano structure/FeOOH composite manufacture method.

The present invention is achieved by the following technical solutions:

A kind of diatomite with micro-nano structure/FeOOH composite manufacture method is characterized in that comprising the following steps:

(1) take a certain amount of diatomite, join in the 2-4M hydrochloric acid solution, be heated to 90-95 ^oC, and after carrying out mechanical agitation 20-25h, be neutral with deionized water and absolute ethyl alcohol cyclic washing to the aqueous solution, suction filtration is also dried stand-by;

(2) deionized water and ethylene glycol are prepared and ultrasonic 5-10 minute according to the ratio of 0.8 ~ 1.2:0.8 ~ 1.2, then be divided into two parts and be respectively charged in two volumetric flasks of size;

(3) add FeSO in large volumetric flask ₄7H ₂Diatomite after O and step (1) are processed adds urea in the low capacity bottle, then distinguish ultrasonic 5-15 minute; Described diatomite, FeSO ₄7H ₂The mass ratio of O and urea is 2-5:1:1-1.5; Diatomite and ionized water and ethylene glycol gross mass volume ratio are 1g:15-30mL;

(4) mixture in large volumetric flask is poured in there-necked flask, being put into temperature is 90-95 ^oIn the C Water Tank with Temp.-controlled, stirred 5-15 minute;

(5) by peristaltic pump, the solution in the low capacity bottle is injected above-mentioned there-necked flask with 0.8-1.1mL/min speed, treat that in the low capacity bottle, the solution injection is complete, change speed into 2.8-3mL/min, air is passed in above-mentioned there-necked flask;

(6) after 3-4 hour, take out product, be neutral with deionized water and absolute ethyl alcohol cyclic washing to the aqueous solution, at last centrifugal being deposited in baking oven of obtaining dried, obtain the compound of diatomite/FeOOH.

Advantage of the present invention is:

(1) alpha-feooh that obtains of immersion method is attached to the diatomite surface uniformly, use respectively field emission scanning electron microscope and x-ray diffractometer to characterize the product that makes, alpha-feooh is orthorhombic structure as can be known, is evenly distributed in diatomite surface and pattern homogeneous;

(2) alpha-feooh of above-mentioned composite presents nanostructured, has higher crystallinity and higher purity;

(3) the method is in preparation process, owing to not adding the material such as template, makes subsequent treatment convenient, and reaction temperature is low, the time is short, technique is simple, cheap;

(4) any poisonous and hazardous source of iron is not used in the preparation process environmental protection of the method.

(5) whole course of reaction is controlled by peristaltic pump, realizes accurate, automation control; Select simultaneously urea as precipitating reagent, and slowly inject copperas solution by peristaltic pump, slowly decompose, controlled pH value uniformity in solution, prevent that simultaneously the hydroxyl excessive concentration from causing product to reunite.This process synergic dispersant ethylene glycol is the important guarantee of controlling alpha-feooh appearance and size homogeneity, can guarantee that alpha-feooh is in the growth of diatomite surface uniform simultaneously.

Description of drawings

Fig. 1 takes the photo obtain to diatomite/alpha-feooh after with scanning electronic microscope observation, Fig. 1 (a) is the diatomite of unmodified, Fig. 1 (b) ~ (d) is the diatomite after modifying, as seen from Figure 1, to prepare in diatomite with micro-nano structure/alpha-feooh composite alpha-feooh be needle-shaped nano-structure and be evenly distributed in the diatomite surface.

Fig. 2 is observed outside de-carbon by the X ray electron spectrum, and remaining only have iron, oxygen and silicon (because instrument reason hydrogen can't detect), shows that by table one main component of this composite is silicon, iron, oxygen, so this product has higher degree.

Fig. 3 uses Phlips X ' Pert type X-ray diffraction instrument to record the XRD spectra of composite to Fig. 1, from XRD spectra as can be known, except the diatomite characteristic peak, also has the characteristic peak of obvious FeOOH at composite; By infrared can find out equally in composite also have the characteristic peak of FeOOH, therefore products therefrom is diatomite/alpha-feooh compound except the diatomite characteristic peak.

Fig. 4 carries out thermogravimetric analysis to institute's synthetic sample; By Fig. 4 a as can be known before diatomite is modified without the obvious characteristic peak; By Fig. 4 b as can be known, modification is rear 246 ^oHave comparatively significantly characteristic peak near C, this peak produces mainly due to the FeOOH after modifying, and is present in composite by the above results explanation alpha-feooh.

Fig. 5 carries out specific surface and heavy metal adsorption to the iron carbonyl in Fig. 1, and Fig. 5 a is 90.3m by the specific surface that nitrogen adsorption and desorption record institute's diatomite/alpha-feooh composite ²/ g is than modifying front 51.9 m ²/ g is greatly improved; By Fig. 5 b as can be known composite (oxalic acid modification) adsorption process of heavy metal lead is met the langmuir equation, and the diatomite (adsorbance is 210.1 mg/g) after modifying has obvious raising with respect to (165.6 mg/g) adsorbance before modifying, illustrate that it is aspect environmental improvement, especially to the heavy metal adsorption aspect, there is potential application.

The specific embodiment

Embodiment 1

A kind of diatomite with micro-nano structure/FeOOH composite manufacture method comprises the following steps:

(1) at first take the former diatomite of 10g, add in 150mL 2M hydrochloric acid solution, be transferred in the there-necked flask of 250mL heating water bath to 90 ^oC and stir 24h after, repeatedly clean until solution is neutral with deionized water and ethanol, suction filtration is dry.

(2) at first deionized water and the 60mL ethylene glycol of 60mL evenly is blended in the volumetric flask of 250mL, then gets the volumetric flask that 90mL injects 250mL, and take 1.98 gram FeSO ₄7H ₂O, the diatomite after 5 grams clean adds in volumetric flask, ultrasonic 5 minutes;

[0015] in the conical flask that (3) are injected into 50mL with deionized water and the ethylene glycol mixture of remaining 30mL, then add 1.5 gram urea and ultrasonic 10 minutes;

(4) with Water Tank with Temp.-controlled Temperature Setting to 90 degree centigrade, ferrous sulfate and diatomite mixed solution poured in the there-necked flask of 250mL after temperature arrives 90 degrees centigrade and be put in Water Tank with Temp.-controlled, stirred 5 minutes;

After (5) 5 minutes, urea liquid is squeezed in there-necked flask with the speed of 1mL/min by peristaltic pump; Treat that the urea liquid input is complete, peristaltic pump speed is changed into 3mL/min and passes into air to solution;

After (6) 3 hours, close the peristaltic pump stopped heating, take out reactant and repeatedly clean until solution is neutral with deionized water and ethanol, at last centrifugal being deposited in vacuum drying chamber of obtaining dried, obtain diatomite/hydroxyl oxidize iron complexes, pattern as shown in Figure 1.

Embodiment 2

(1) at first take the former diatomite of 10g, add in 150mL 2M hydrochloric acid solution, be transferred in the there-necked flask of 250mL heating water bath to 90 ^oC and stir 24h after, repeatedly clean until solution is neutral with deionized water and ethanol, suction filtration is dry;

(2) at first deionized water and the 60mL ethylene glycol of 60mL evenly is blended in the volumetric flask of 250mL, then gets the volumetric flask that 90mL injects 250mL, and take 0.99 gram FeSO ₄7H ₂O, the diatomite after 5 grams clean adds in volumetric flask, ultrasonic 5 minutes;

(3) in the conical flask that deionized water and the ethylene glycol mixture of remaining 30mL is injected into 50mL, then add 0.75 gram urea and ultrasonic 10 minutes;

(4) with Water Tank with Temp.-controlled Temperature Setting to 95 ^oC treats that temperature arrives 95 ^oAfter C, ferrous sulfate and diatomite mixed solution poured in the there-necked flask of 250mL and be put in Water Tank with Temp.-controlled, stirring 5 minutes;

After (5) 5 minutes, urea liquid is squeezed in there-necked flask with the speed of 1mL/min by peristaltic pump; Treat that the urea liquid input is complete, peristaltic pump speed is changed into 3mL/min and passes into air to solution;

After (6) 3 hours, close the peristaltic pump stopped heating, take out reactant and repeatedly clean until solution is neutral with deionized water and ethanol, at last centrifugal being deposited in vacuum drying chamber of obtaining dried, obtain diatomite/hydroxyl oxidize iron complexes, pattern as shown in Figure 1.

Claims (1)

1. the diatomite with micro-nano structure/FeOOH composite manufacture method is characterized in that comprising the following steps:

(1) take a certain amount of diatomite, join in the 2-4M hydrochloric acid solution, be heated to 90-95 ^oC, and after carrying out mechanical agitation 20-25h, be neutral with deionized water and absolute ethyl alcohol cyclic washing to the aqueous solution, suction filtration is also dried stand-by;

(2) deionized water and ethylene glycol are prepared and ultrasonic 5-10 minute according to the ratio of 0.8 ~ 1.2:0.8 ~ 1.2, then be divided into two parts and be respectively charged in two volumetric flasks of size;

(3) add FeSO in large volumetric flask ₄7H ₂Diatomite after O and step (1) are processed adds urea in the low capacity bottle, then distinguish ultrasonic 5-15 minute; Described diatomite, FeSO ₄7H ₂The mass ratio of O and urea is 2-5:1:1-1.5; Diatomite and ionized water and ethylene glycol gross mass volume ratio are 1g:15-30mL;

(4) mixture in large volumetric flask is poured in there-necked flask, being put into temperature is 90-95 ^oIn the C Water Tank with Temp.-controlled, stirred 5-15 minute;

(5) by peristaltic pump, the solution in the low capacity bottle is injected above-mentioned there-necked flask with 0.8-1.1mL/min speed, treat that in the low capacity bottle, the solution injection is complete, change speed into 2.8-3mL/min, air is passed in above-mentioned there-necked flask;

(6) after 3-4 hour, take out product, be neutrality with deionized water and absolute ethyl alcohol cyclic washing to the aqueous solution, at last centrifugal being deposited in baking oven of obtaining dried, obtain having the diatomite of micro-nano structure/hydroxyl oxidize iron complexes.

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