CN103657681A - Preparation method of catalytic wet oxidation catalyst composited by precious metal, transition metal and rare earth - Google Patents

Abstract

The invention discloses a preparation method of a catalytic wet oxidation catalyst composited by precious metal, transition metal and rare earth. The preparation method comprises the following steps: (1) preparing a gamma-Al2O3 carrier for later use; (2) preparing 20.0 weight parts of impregnation liquid containing Pd<3+>, Fe<3+>, Co<3+> and Ce<3+>; (3) impregnating the gamma-Al2O3 carrier prepared in the step (1) into the impregnation liquid prepared in the step (2), and performing dynamic impregnation; (4) taking out the gamma-Al2O3 carrier which is dynamically impregnated, drying the gamma-Al2O3 carrier, and putting the dried gamma-Al2O3 carrier into a muffle furnace for roasting to obtain the catalytic wet oxidation catalyst. According to the prepared catalytic wet oxidation catalyst, the oxidative decomposition capability can be improved, the reaction speed is increased, and the removal rate and the biodegradability of organic matters in waste water are greatly improved.

Description

The CWO method for preparing catalyst that a kind of noble metal-transition metal-rare earth is compound

Technical field

The present invention relates to catalyst field, specifically the preparation method of a kind of " noble metal-transition metal-rare earth " compound CWO catalyst.

Background technology

Ceramic printing waste water comprises waste water, printing table flushing water, ground flushing water and the combined sewage in marble paper production process, its COD _cr(bichromate index) is 500～20,000mg/L, BOD ₅be about 100～3,000mg/L, colourity 500～10,000 times, pH value approximately 7.0; The biodegradability index B/C of waste water is about 0.15, is less than the biodegradability index critical value 0.3 of waste water.Ceramic printing waste water belongs to high concentration and refractory organic wastewater.

Catalytic wet air oxidation (Catalytic Wet Air Oxidation, abbreviation CWAO) technology is under catalyst action, under the condition that is 30～120min at 150～315 ℃ of reaction temperatures, reaction pressure 2～15MPa, reaction time, it by organic substance decomposing, is the chemical process of carbon dioxide and water.The adding of suitable catalyst in reaction, has changed the course of chemical reaction, has reduced the activation energy of reaction, thereby has made reaction temperature and pressure decreased, improves organic oxidative decomposition capacity and fast reaction speed.And ceramic printing waste water belongs to high concentration and refractory organic wastewater, with biochemical process or the plural serial stage method of conventional sewage disposal, process ceramic printing waste water, the floor space of its device is large, and investment cost and operating cost are high, and poor processing effect.CWAO technology is applied to the processing of the difficult biochemical ceramic printing waste water of high concentration, has the high obvious advantage of organic removal rate; CWAO technology is usually used in the pre-treatment of the biochemical treatment of high concentration and refractory organic wastewater.

Active component for loaded catalyst, there are 3 types of noble metal, rare earth metal and transition metal, noble metal active is high, stable performance but expensive, and rare earth metal relative intensity is low but can improve catalyst activity and stability, the active high but poor stability of transition metal; Current domestic researcher is all usingd in noble metal, rare earth metal and transition metal a kind or 2 kinds as active component; In research, we are compound by noble metal, rare earth metal and transition metal, and expectation obtains the composite catalyst that activity is high, stability is strong, cost is low.

Summary of the invention

The preparation method who the object of this invention is to provide a kind of " noble metal-transition metal-rare earth " compound CWO catalyst.

The preparation method of the CWO catalyst that " noble metal-transition metal-rare earth " of the present invention is compound, comprises the following steps:

(1) by clover shape γ-Al ₂o ₃till washing clarification first with clear water washing 2～3 times, then with distilled water, in 105 ℃ of oven dry 7～9h, finally, at 500～600 ℃ of roasting 2～4h, make γ-Al ₂o ₃carrier is standby;

(2) accurately take palladium nitrate solution 1.3333 weight portions, ferric nitrate 1.4472 weight portions, cobalt nitrate 0.9877 weight portion, cerous nitrate 1.8593 weight portions and be dissolved in 14.3725 weight portion distilled water, make and contain Pd ³⁺, Fe ³⁺, Co ²⁺, Ce ³⁺maceration extract 20.0 weight portions;

(3) then get γ-Al that step (1) makes ₂o ₃carrier 10.00 weight portions are impregnated in the maceration extract that step (2) makes, and are then placed in constant-temperature table, dynamic dipping 7～9h under 35 ℃, the condition of 150rpm;

(4) take out the dynamically complete γ-Al of dipping ₂o ₃carrier and drain away the water after, under 105 ℃ of ventilation conditions by γ-Al ₂o ₃carrier is dried 7～9h, finally puts into Muffle furnace in 500～600 ℃ of constant temperature calcining 2～4h, makes CWO catalyst.

The CWO catalyst that the present invention makes, can improve oxidative decomposition capacity and fast reaction speed, significantly improves organic removal rate and biodegradability in waste water.

The specific embodiment

Below by embodiment, the present invention is done to further specific descriptions, but embodiments of the present invention are not limited to this.

Embodiment: (1) is by clover shape γ-Al ₂o ₃till washing clarification first with clear water washing 3 times, then with distilled water, in 105 ℃ of oven dry 8h, finally, at 550 ℃ of roasting 3h, make γ-Al ₂o ₃carrier is standby;

(2) accurately take palladium nitrate solution 1.3333g, ferric nitrate 1.4472g, cobalt nitrate 0.9877g, cerous nitrate 1.8593g are dissolved in 14.3725g distilled water, make and contain Pd ³⁺, Fe ³⁺, Co ²⁺, Ce ³⁺maceration extract 20.0g;

(3) then get γ-Al that step (1) makes ₂o ₃carrier 10.00g is impregnated in the maceration extract that step (2) makes, and is then placed in constant-temperature table, dynamic dipping 8h under 35 ℃, the condition of 150rpm;

(4) take out the dynamically complete γ-Al of dipping ₂o ₃carrier and drain away the water after, under 105 ℃ of ventilation conditions by γ-Al ₂o ₃carrier is dried 8h, finally puts into Muffle furnace in 550 ℃ of constant temperature calcining 3h, makes the CWO catalyst " Pd-Ce-Fe-Co/ γ-Al of the present embodiment ₂o ₃".

Under the condition of the CWO catalyst amount 6.0g/L making at 180 ℃ of reaction temperatures, partial pressure of oxygen 3.0MPa, the present embodiment, process COD _crfor 6800mg/L, colourity are 1500 times, BOD ₅for the ceramic printing waste water that 1020mg/L, B/C are 0.15, choose the waste water of reaction 120min, monitoring COD _cr(national standard Cr method), colourity (extension rate method), BOD ₅(instrument rapid method) characterizes the activity of catalyst, and the stability of catalyst characterizes to process the catalytic component concentration of stripping in water outlet, and monitoring method is inductively coupled plasma emission spectrography (ICP), and result is as table 1:

Table 1 catalyst " Pd-Ce-Fe-Co/ γ-Al ₂o ₃" CWAO result to ceramic printing waste water

Result	Catalyst-free	There is catalyst
			COD CrClearance/%	53.2	92.0
Percent of decolourization/%	56.1	97.9
			BOD 5Clearance/%	43.6	81.4
C[Pd 3+]/(mg/L)	0	0.0016
			C[Fe 3+]/(mg/L)	0	6.8781
C[Co 2+]/(mg/L)	0	0.0721
			C[Ce 3+]/(mg/L)	0	0.0615

So far, ceramic printing waste water carries out after group technology processing through the CWO catalyst that uses the present embodiment to make, and index COD is controlled in the main pollution of waste water _crfor 544mg/L, colourity is 30 times, reaches three grades and the primary standard of < < integrated wastewater discharge standard > > (GB8978-1996).And the BOD of processed waste water ₅for 190mg/L, the B/C value of waste water brings up to 0.35 by 0.15 before processing.Visible after the CWO catalyst that uses the present embodiment to make is processed, the biodegradability of waste water obviously improves, and available biochemical treatment process further reduces the COD of waste water _cr, BOD ₅, reached the object of CWAO method for the biochemical treatment pre-treatment of high concentration and refractory organic wastewater.

Claims (1)

1. the preparation method of " noble metal-transition metal-rare earth " compound CWO catalyst, comprises the following steps:

(1) by clover shape γ-Al ₂o ₃till washing clarification first with clear water washing 2～3 times, then with distilled water, in 105 ℃ of oven dry 7～9h, finally, at 500～600 ℃ of roasting 2～4h, make γ-Al ₂o ₃carrier is standby;

(2) accurately take palladium nitrate solution 1.3333 weight portions, ferric nitrate 1.4472 weight portions, cobalt nitrate 0.9877 weight portion, cerous nitrate 1.8593 weight portions and be dissolved in 14.3725 weight portion distilled water, make and contain Pd ³⁺, Fe ³⁺, Co ²⁺, Ce ³⁺maceration extract 20.0 weight portions;

(3) then get γ-Al that step (1) makes ₂o ₃carrier 10.00 weight portions are impregnated in the maceration extract that step (2) makes, and are then placed in constant-temperature table, dynamic dipping 7～9h under 35 ℃, the condition of 150rpm;

(4) take out the dynamically complete γ-Al of dipping ₂o ₃carrier and drain away the water after, under 105 ℃ of ventilation conditions by γ-Al ₂o ₃carrier is dried 7～9h, finally puts into Muffle furnace in 500～600 ℃ of constant temperature calcining 2～4h, makes CWO catalyst.