Treatment method of organic dye in waste water

[0022]

[0023] The sponge is soaked in the graphene oxide suspension emulsion to obtain a graphene oxide composite sponge; the graphene oxide composite sponge is placed in a mixture of nano-level photocatalyst and reducing agent to obtain a photocatalyst modified graphene composite sponge hydrogel ; The photocatalyst modified graphene composite sponge hydrogel is washed and dried to prepare a photocatalyst modified graphene composite sponge.

[0024] In the present invention, the sponge may be one of polyurethane sponge, melamine sponge, polyester sponge, polyether sponge or polyvinyl alcohol sponge. Preferably, the sponge is a polyurethane sponge or a melamine sponge. According to a specific embodiment of the present invention, the sponge is a polyurethane sponge. The volume of the sponge is 20~500cm 3. Preferably, the volume of the sponge is 100~400cm 3. More preferably, the volume of the sponge is 150~300cm 3. The shape of the sponge can be a cuboid or a cube. Preferably, the shape of the sponge is a rectangular parallelepiped. In this way, the graphene oxide can be better coated on the sponge, so that the prepared photocatalyst modified graphene composite sponge has stronger adsorption capacity and higher photocatalytic degradation performance.

[0025] In the present invention, the sponge can be ultrasonically cleaned, washed and dried before being soaked. The lotion for ultrasonic cleaning can be water or alcohol solution. Preferably, the alcohol solution is ethanol. According to a specific embodiment of the present invention, the sponge is ultrasonically cleaned twice, the first washing liquid is absolute ethanol, and the second washing liquid is deionized water. The washing liquid used in the washing process can be water or alcohol solvent. Preferably, the lotion is water or ethanol. More preferably, the lotion is water. According to a specific embodiment of the present invention, the washing process is to soak the washing sponge with distilled water. The drying temperature is 50-100°C. Preferably, the drying temperature is 60 to 80°C. More preferably, the drying temperature is 60 to 70°C. In this way, the sponge can achieve a better coating effect, and the prepared photocatalyst modified graphene composite sponge has stronger adsorption capacity and higher photocatalytic degradation performance.

[0026] In the present invention, the sheet diameter of graphene oxide may be 1-50 μm; preferably 5-35 μm; more preferably 20-25 μm. The oxygen to carbon molar ratio of graphene oxide may be 0.3 to 0.8, preferably 0.5 to 0.7, and more preferably 0.6 to 0.7. Examples of graphene oxide include, but are not limited to, graphene oxide from Changzhou Sixth Element Material Technology Co., Ltd. The graphene oxide sheet diameter is 20-25 μm, and the oxygen-carbon molar ratio is 0.6.

[0027] In the present invention, the concentration of graphene oxide in the graphene oxide suspension emulsion is 2-15 mg/ml. Preferably, the concentration of graphene oxide is 2-10 mg/ml. More preferably, the concentration of graphene oxide is 3 to 5 mg/ml.

[0028] In the present invention, the nano-level photocatalyst is nano-titanium dioxide, nano-zinc oxide or nano-tin oxide. Preferably, the nano-level photocatalyst is nano-titanium dioxide or nano-zinc oxide. According to a specific embodiment of the present invention, the nano-level photocatalyst is nano-titanium dioxide. In this way, the nano-level photocatalyst can be better distributed on the graphene oxide, and the prepared photocatalyst-modified graphene composite sponge has stronger adsorption capacity and higher photocatalytic degradation performance.

[0029] In the present invention, the reducing agent is hydrazine hydrate, ascorbic acid or ammonia. Preferably, the reducing agent is hydrazine hydrate or ascorbic acid. More preferably, the reducing agent is ascorbic acid. In this way, the nano-level photocatalyst can be better distributed on the graphene oxide, and the prepared photocatalyst-modified graphene composite sponge has stronger adsorption capacity and higher photocatalytic degradation performance.

[0030] In the present invention, the mass ratio of the nano-level photocatalyst to the reducing agent is 1:5-30. Preferably, the mass ratio of the nano-level photocatalyst to the reducing agent is 1:10-30. More preferably, the mass ratio of the nano-scale photocatalyst to the reducing agent is 1:15-25.

[0031] In the present invention, in the mixture of nano-scale photocatalyst and reducing agent, the concentration of nano-scale photocatalyst is 0.2-1 mg/ml, and the concentration of reducing agent is 2-10 mg/ml. Preferably, the concentration of the nano-level photocatalyst is 0.2-0.7 mg/ml. More preferably, the concentration of the nano-level photocatalyst is 0.2-0.5 mg/ml. Preferably, the concentration of the reducing agent is 5-10 mg/ml. More preferably, the concentration of the reducing agent is 5-7 mg/ml. In this way, the prepared photocatalyst-modified graphene composite sponge has stronger adsorption capacity and higher photocatalytic degradation performance.

[0032] In the present invention, the reaction temperature of the graphene oxide composite sponge, the mixed solution of the nano-level photocatalyst and the reducing agent is 50-150°C. Preferably, the reaction temperature is 70 to 120°C. More preferably, the reaction temperature is 70-100°C. The reaction time is 8-20h. Preferably, the reaction time is 10-18h. More preferably, the reaction time is 10-15h. In this way, the nano-level photocatalyst can be better distributed on the graphene oxide, and the prepared photocatalyst-modified graphene composite sponge has stronger adsorption capacity and higher photocatalytic degradation performance.

[0033] In the present invention, the washing liquid for washing the photocatalyst modified graphene composite sponge hydrogel is an ethanol aqueous solution. Preferably, the ethanol concentration of the ethanol aqueous solution is 1-20 vol%. More preferably, the ethanol concentration of the ethanol aqueous solution is 3-10 vol%. The washing time is 15~36h. Preferably, the washing time is 20 to 36 hours. More preferably, the washing time is 24 to 36 hours. The temperature for drying the photocatalyst modified graphene composite sponge hydrogel is 50-100°C. Preferably, the drying temperature is 50-80°C. More preferably, the drying temperature is 60 to 75°C. The drying time is 5-20h. Preferably, the drying time is 10-20h. More preferably, the drying time is 15-20h. In this way, the prepared photocatalyst-modified graphene composite sponge has stronger adsorption capacity and higher photocatalytic degradation performance.

[0034] In the present invention, the weight of nanometer titanium dioxide in the photocatalyst modified graphene composite sponge is 0.1-5 wt% of the total weight of the composite sponge. Preferably, the weight of the nano titanium dioxide is 1 to 5 wt% of the total weight of the composite sponge. More preferably, the weight of the nano titanium dioxide is 2 to 4 wt% of the total weight of the composite sponge.

[0035]

[0036] The wastewater containing organic dyes is passed through an adsorption reactor equipped with a photocatalyst modified graphene composite sponge to adsorb the organic dyes in the wastewater.

[0037] In the present invention, the wastewater containing organic dyes is subjected to 3 or more adsorption treatments. Preferably, the wastewater containing organic dyes is subjected to 5 or more adsorption treatments. More preferably, the waste water containing organic dyes is treated by adsorption of more than 7 levels. For example, it can be 7 to 10 stages of adsorption treatment. This can more fully adsorb the organic dyes in the wastewater.

[0038] In the present invention, the organic dye may be selected from one or more of methyl orange, methylene blue, rhodamine B, methyl violet, and neutral red. Preferably, the organic dye may be selected from one or more of methyl orange, methylene blue, and rhodamine B. More preferably, the organic dye is methylene blue.

[0039] In the present invention, the photocatalyst modified graphene composite sponge can be made into an adsorption fitting and loaded into the adsorption reactor. According to a specific embodiment of the present invention, the photocatalyst modified graphene composite sponge is fixed in a stretchable network barrier and loaded into an adsorption reactor.

[0040]

[0041] The adsorbed saturated photocatalyst modified graphene composite sponge is taken out, and the organic dye is catalytically decomposed under light to obtain a regenerated photocatalyst modified graphene composite sponge.

[0042] In the present invention, when the difference between the concentration of organic dyes in the wastewater at the inlet and the outlet of the adsorption reactor is less than 50 mg/ml, the photocatalyst modified graphene composite sponge is adsorbed saturated, and a new photocatalyst modified graphene composite sponge is replaced. Saturated photocatalyst modified graphene composite sponge for regeneration.

[0043] In the present invention, photocatalysis can be carried out under natural light. The time of photocatalysis is 36~80h. Preferably, the time for photocatalysis is 36-60h. More preferably, the time for photocatalysis is 48-60h. This can increase the photocatalytic degradation rate of organic dyes.

[0045] Example 1

[0046] The polyurethane sponge with a volume of 10cm×10cm×2cm was first placed in absolute ethanol for ultrasonic cleaning, and then placed in deionized water for ultrasonic cleaning. The polyurethane sponge after ultrasonic cleaning was soaked and washed with distilled water, and dried at 65°C. The dried polyurethane sponge is soaked in a graphene oxide suspension emulsion with a concentration of 2 mg/ml, squeezed and soaked for several times, and then centrifuged to obtain a graphene oxide composite sponge. The graphene oxide composite sponge is placed in a mixture of nano-titanium dioxide and ascorbic acid (the concentration of nano-titanium dioxide is 0.2mg/ml, the concentration of ascorbic acid is 5mg/ml), and the reaction is carried out at 80℃ for 12h to obtain photocatalytically modified graphene Composite sponge hydrogel. The photocatalyst modified graphene composite sponge hydrogel was immersed and washed in 1 vol% ethanol aqueous solution for 24 hours, and dried at 65°C for 10 hours to prepare a photocatalyst modified graphene composite sponge. The photocatalyst modified graphene composite sponge was The weight of the nano titanium dioxide is 1.4 wt% of the total weight of the composite sponge.

[0047] The photocatalyst modified graphene composite sponge is fixed in the stretchable network compartment to form an adsorption accessory, and the adsorption accessory is put into the adsorption reactor. The waste water containing organic dyes is passed through an adsorption reactor equipped with adsorption accessories to absorb the organic dyes in the waste water and undergoes a three-stage adsorption treatment.

[0048] Detect the concentration of organic dyes in the wastewater at the outlet of the adsorption reactor. When the concentration difference of the organic dyes in the wastewater at the inlet and outlet of the adsorption reactor is less than 50mg/ml, the photocatalyst modified graphene composite sponge is saturated with adsorption and replaced with a new photocatalyst Modified graphene composite sponge. The adsorbed saturated photocatalyst modified graphene composite sponge is exposed to natural light for 48 hours to catalyze the decomposition of organic dyes to obtain a regenerated photocatalyst modified graphene composite sponge.

[0049] Example 2

[0050] The polyurethane sponge with a volume of 10cm×10cm×2cm was first placed in absolute ethanol for ultrasonic cleaning, and then placed in deionized water for ultrasonic cleaning. The polyurethane sponge after ultrasonic cleaning was soaked and washed with distilled water, and dried at 65°C. The dried polyurethane sponge is soaked in a graphene oxide suspension emulsion with a concentration of 4 mg/ml, squeezed and soaked several times, and then centrifuged to obtain a graphene oxide composite sponge. The graphene oxide composite sponge is placed in a mixture of nano-titanium dioxide and ascorbic acid (the concentration of nano-titanium dioxide is 0.2mg/ml, the concentration of ascorbic acid is 5mg/ml), and the reaction is carried out at 80℃ for 12h to obtain photocatalytically modified graphene Composite sponge hydrogel. The photocatalyst modified graphene composite sponge hydrogel was immersed and washed in 1 vol% ethanol aqueous solution for 24 hours, and dried at 65°C for 10 hours to prepare a photocatalyst modified graphene composite sponge. The photocatalyst modified graphene composite sponge was The weight of nano titanium dioxide is 2.6% by weight of the total weight of the composite sponge.

[0051] The photocatalyst modified graphene composite sponge is fixed in the stretchable network compartment to form an adsorption accessory, and the adsorption accessory is put into the adsorption reactor. The waste water containing organic dyes is passed through an adsorption reactor equipped with adsorption accessories to absorb the organic dyes in the waste water and undergoes a three-stage adsorption treatment.

[0052] Detect the concentration of organic dyes in the wastewater at the outlet of the adsorption reactor. When the concentration difference of the organic dyes in the wastewater at the inlet and outlet of the adsorption reactor is less than 50mg/ml, the photocatalyst modified graphene composite sponge is saturated with adsorption and replaced with a new photocatalyst Modified graphene composite sponge. The adsorbed saturated photocatalyst modified graphene composite sponge is exposed to natural light for 48 hours to catalyze the decomposition of organic dyes to obtain a regenerated photocatalyst modified graphene composite sponge.