A solid-phase liquid membrane process for treating phenol-containing wastewater from coal tar deep processing

Abstract

The invention belongs to the field of industrial wastewater treatment, and specifically relates to a process for treating phenol-containing wastewater from coal tar deep processing by a solid-phase liquid membrane method. The process for treating phenol-containing wastewater from coal tar deep processing by a solid-phase liquid membrane method combines solid-phase adsorption and emulsion liquid membrane, with solid-phase adsorption as a supplement, and combines emulsion liquid membrane with porous solid adsorption material to treat phenol-containing wastewater. The process can effectively avoid the problem of unsatisfactory treatment effect of a single treatment method, and can effectively respond to sudden situations such as changes in phenol content in wastewater and liquid membrane rupture, thereby ensuring the treatment effect of volatile phenols in wastewater and improving the ability to respond to situations such as changes in incoming water quality or liquid membrane swelling and rupture. The process is combined into a process package, which is simple to operate and manage, can complete the absorption and release of phenolic substances in wastewater in one step, has simple treatment equipment and process, and has high liquid membrane penetration speed and selectivity, low energy consumption, greatly saves the consumption of extraction solvent, and reduces the treatment cost of phenol-containing wastewater.

Description

Technical Field

[0001] The invention belongs to the field of industrial wastewater treatment, and particularly relates to a process for treating phenol-containing wastewater from coal tar deep processing by a solid-phase liquid membrane method. Background Art

[0002] Phenolic wastewater primarily originates from coal tar deep processing, as well as industrial processes such as coking, petrochemicals, and gas-fired power plants. The primary pollutants in phenolic wastewater are phenolic compounds, such as phenol, cresols, xylenols, and nitrocresols. Phenolic concentrations can reach as high as 2,000-20,000 mg / L. This high phenol concentration, high variability, complex water quality, and significant hazards make it one of the most challenging types of wastewater to treat in industrial wastewater treatment.

[0003] Phenol and other phenolic compounds in phenolic wastewater are highly structurally stable, making them difficult to degrade using conventional treatment methods. Furthermore, the high phenol content in such wastewater can lead to environmental pollution and resource waste if not recovered. Currently, extraction + back-extraction or extraction + distillation are the most common treatment methods in the industry. However, the complex process chain, high chemical consumption, large equipment investment, and high operating costs of these methods have limited their widespread application.

[0004] The solid-phase liquid membrane process is a novel wastewater treatment and separation technology that combines physical adsorption with membrane separation. During the separation process, the substance being separated (phenol) is simultaneously extracted and stripped, transferring the substance through the liquid membrane to achieve separation and concentration. This process offers advantages such as simplicity and efficiency, high selectivity, high separation efficiency, and the ability to reuse the emulsion after demulsification. Summary of the Invention

[0005] The present invention provides a solid-phase liquid membrane process for treating phenol-containing wastewater from coal tar deep processing, which is used to solve the problems of complex extraction process, small extraction agent distribution coefficient and low extraction efficiency in the existing extraction process.

[0006] The present invention is achieved through the following technical solutions:

[0007] A process for treating phenol-containing wastewater from coal tar deep processing using a solid-phase liquid membrane method mainly comprises the following steps:

[0008] S1: Phenol-containing wastewater is temporarily stored in a temporary storage tank, and the clarification and separation device removes suspended solids with relatively large particle sizes in the wastewater. The treated wastewater enters the reaction tower;

[0009] S2: adding one of kerosene, isopropyl ether, methyl isobutyl ketone, dimethylformamide and dimethyl sulfoxide into the reaction tower, followed by adding sodium hydroxide solution, surfactant, stabilizer and carrier;

[0010] S3: A flat-plate cyclone agitator is installed in the reaction tower. The solvent, sodium hydroxide solution, surfactant, stabilizer and carrier are formed into a liquid film by the flat-plate cyclone agitator. The liquid film is impregnated on the porous solid material with a high specific surface area to form a liquid film layer.

[0011] S4: The porous solid material loaded with the liquid membrane layer is in full contact with the phenol-containing wastewater, and a large amount of phenolic substances in the phenol-containing wastewater are captured by utilizing the good mass transfer rate of the liquid membrane and the pore enrichment of the porous solid material;

[0012] S5: When the porous solid material loaded with the liquid film layer is saturated with the adsorption of the phenolic substance, it is repeatedly washed with clean water in the water storage tank to make the saturated liquid film fall off from the surface of the porous solid material;

[0013] S6: The saturated liquid film is sent to the subsequent demulsifier for demulsification. The sodium phenolate in the inner phase wrapped by the emulsion film is released, and the emulsion returns to the front-end reaction tower to form a film again for the next round of absorption of phenolic substances. The treated wastewater is discharged through the drain pipe;

[0014] S7: The porous solid material after adsorption saturation enters the regeneration tank and is regenerated by the solvent. The regenerated porous solid material can be recycled again.

[0015] The concentration of the sodium hydroxide solution is 10-20%; the surfactant is a mixture of anionic polymer surfactant LMS-3 and nonionic polymer surfactant LMA-1 in a molar ratio of 1.5-3:1; the stabilizer is one of polyethylene oxide, polyoxypropylene polyol, epoxidized ethylene polyol, polycaprolactone and polyethylene terephthalate; the carrier is one of polyethylene glycol complex, polypropylene alcohol complex, polyaminoethanol complex and polyethylene glycol polypropylene alcohol copolymer; and the mass ratio of the solvent, surfactant, stabilizer and carrier is 75-90%: 4-10%: 0.1-3%: 2-15%.

[0016] The flat plate cyclone in step S3 comprises a flat plate and a central shaft, wherein the central shaft rotates at a speed of 1000-3000 r / min; and the mass ratio of the liquid film to the porous solid material is 2-10:1.

[0017] A solid-phase liquid membrane is mainly prepared by forming a liquid membrane with droplet diameter small enough to be emulsified by a water-in-oil-in-water (W / O / W) system through a flat cyclone and a porous solid adsorption material. The solid adsorption material is one of activated carbon fiber, macroporous resin, zeolite, molecular sieve or activated alumina, which can play the role of immobilizing the liquid membrane and make the liquid membrane uniformly dispersed on the surface of the porous material. At the same time, the porous material can use its own huge specific surface area and structural characteristics such as micropores and mesopores as a supplementary process to further adsorb phenolic substances in wastewater, ensure the treatment effect of phenol-containing wastewater and make up for the shortcomings of the single liquid membrane in the process of absorbing phenolic substances in wastewater; the composite effect of the two is used to further reduce the surface tension of the liquid membrane, making the liquid membrane more stable.

[0018] The flat-plate cyclone agitator can form the liquid into a spiral annular flow. The liquid film formed under the stirring of the flat-plate cyclone has a small thickness distribution range, small liquid film volatility, and good stability of the spiral annular flow liquid film. The surfactant is a mixture obtained by mixing the anionic polymer surfactant LMS-3 and the non-ionic polymer surfactant LMA-1. The composite effect of the two is utilized to further reduce the surface tension of the liquid film, making the liquid film more stable. The stabilizer can reduce the swelling of the liquid film. The carrier has a hydrophobic group and a hydrophilic group, and can shuttle back and forth between the two interfaces of the liquid film to transfer phenolic substances in the wastewater. Through the selective reaction between the carrier and the phenolic substance, the effective solubility of the phenolic substance in the liquid film is greatly improved.

[0019] Beneficial effects of the present invention:

[0020] The present invention combines solid-phase adsorption and emulsion liquid membrane, with solid-phase adsorption as a supplement, and combines emulsion liquid membrane and porous solid adsorption material to treat phenol-containing wastewater, which can effectively avoid the problem of unsatisfactory treatment effect of a single treatment method. At the same time, it can effectively respond to changes in the phenol content in the wastewater and sudden situations such as liquid membrane rupture, ensure the treatment effect of volatile phenol in the wastewater, and improve the ability to respond to changes in incoming water quality or liquid membrane swelling and rupture.

[0021] The process of the present invention is combined into a process package, which is easy to operate and manage and can complete the absorption and release of phenolic substances in wastewater in one step. The treatment equipment and process are simple, and the liquid membrane penetration speed and selectivity are high, the energy consumption is low, the consumption of extraction solvent is greatly saved, and the treatment cost of phenol-containing wastewater is reduced.

[0022] The sodium phenol salt liberated by the method can be sold after being recovered, thereby reducing resource waste, improving the economic benefit of sewage treatment, and realizing the harmlessness and resource utilization of phenol-containing wastewater in coal chemical industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a schematic diagram of a process flow for treating phenol-containing wastewater from coal tar deep processing by a solid-phase liquid membrane method.

[0024] Figure numbers: 1: temporary storage tank; 2: phenol-containing wastewater inlet pipe; 3: clarification and separation device inlet pipe; 4: clarification and separation device; 5: clarification and separation device outlet pipe; 6: reaction tower; 7: porous solid material combined with liquid film; 8: flat-plate cyclone agitator; 9: NaOH addition pipe; 10: solvent addition pipe; 11: surfactant and stabilizer addition pipe; 12: carrier addition pipe; 13: emulsion liquid film collection pipe; 14: demulsifier; 15: emulsion circulation pipe; 16: drain pipe; 17: water storage tank; 18: lifting pump; 19: regeneration tank. DETAILED DESCRIPTION

[0025] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below with reference to specific embodiments and illustrations.

[0026] Unless otherwise specified, the experimental methods in the following examples are conventional methods and were performed according to the techniques or conditions described in literature in the field or according to product specifications. The materials and reagents used in the following examples are all commercially available unless otherwise specified.

[0027] The present invention will be further described below in conjunction with the accompanying drawings and Examples:

[0028] Example 1

[0029] See also Figure 1 , this embodiment specifically includes the following steps:

[0030] 1: Wastewater containing 22,000 mg / L of phenol enters temporary storage tank 1 through phenolic wastewater inlet pipe 2. It then enters clarification and separation device through clarification and separation device inlet pipe 3 to remove large suspended particles in the wastewater, laying the foundation for subsequent wastewater treatment. The clarified water enters reaction tower 6 through clarification and separation device outlet pipe 5;

[0031] 2: In the reaction tower 6, 25 L of 40 wt% sodium hydroxide solution was added through the sodium hydroxide solution addition pipe 9, 40 L of dimethyl sulfoxide was added through the solvent addition pipe 10, 1.5 kg of LMS-3, 1 kg of LMA-1, and 1 kg of polyethylene oxide were added through the surfactant and stabilizer addition pipe 11, and 5 kg of polyethylene glycol complex was added through the carrier addition pipe 12;

[0032] 3: A flat-plate cyclone stirrer 8 is installed in the reaction tower 6. Dimethyl sulfoxide, 15 wt% sodium hydroxide solution, LMS-3, LMA-1, polyethylene oxide, and polyethylene glycol complex are stirred by the flat-plate cyclone stirrer 8 at 3000 r / min, 35° C., and for 30 min to form a liquid film. The liquid film formed by stirring the flat-plate cyclone stirrer 8 in the reaction tower 6 and the activated carbon fiber loaded with the liquid film is impregnated on the activated carbon fiber with a high specific surface area to form a liquid film layer;

[0033] 4: The activated carbon fiber loaded with the liquid film layer in the reaction tower 6 is in full contact with the phenol-containing wastewater, and a large amount of phenolic substances in the phenol-containing wastewater are captured by utilizing the good mass transfer rate of the liquid film and the pore enrichment of the activated carbon fiber;

[0034] 5: When the activated carbon fiber loaded with the liquid film layer is saturated with the adsorption of phenolic substances, it is repeatedly washed with clean water in the water storage tank 17 to make the saturated liquid film fall off from the surface of the porous solid material;

[0035] 6: The emulsion film enriched with a large amount of sodium phenolate is discharged into the demulsifier 14 through the emulsion film collecting pipe 13 for demulsification. The sodium phenolate in the inner phase wrapped by the emulsion film is released and recovered. The emulsion returns to the front-end reaction tower 6 through the circulation pipe 15 for reuse and re-film formation for the next round of absorption of phenolic substances. The treated wastewater is discharged through the drain pipe 16;

[0036] 7: The activated carbon fibers after adsorption saturation enter the regeneration tank 19 and are regenerated by solvent. The regenerated activated carbon fibers can be recycled and returned to the reaction tower 6 for the next round of adsorption.

[0037] Table 1, parameter table of reagents used in Example 1

[0038]

[0039] Table 2, Treatment results of phenolic wastewater in Example 1

[0040]

[0041] From the analysis of Table 2, it can be seen that the wastewater with a phenol content of 22,000 mg / L is treated in a phenol-containing wastewater treatment process used in this embodiment after being treated by the clarification and separation device 4 and entering the reaction tower 6. In the reaction tower 6, the phenolic substances in the wastewater are absorbed by the porous solid material 7 combined with the liquid membrane. The phenol content in the water discharged through the drain pipe 16 is reduced to 200 mg / L, and the removal rate reaches 99.1%.

[0042] The present invention combines solid-phase adsorption and emulsion liquid membrane, with solid-phase adsorption as a supplement, and combines emulsion liquid membrane and porous solid adsorption material to treat phenol-containing wastewater, which can effectively avoid the problem of unsatisfactory treatment effect of a single treatment method, and at the same time can effectively deal with changes in phenol content in wastewater and sudden situations such as liquid membrane rupture, ensure the treatment effect of volatile phenol in wastewater, and improve the ability to deal with changes in incoming water quality or liquid membrane swelling and rupture.

[0043] Example 2

[0044] See also Figure 1 , this embodiment specifically includes the following steps:

[0045] 1: Phenolic wastewater enters phenolic wastewater temporary storage tank 1 through phenolic wastewater inlet pipe 2 for temporary storage, then enters clarification separation device through clarification separation device inlet pipe 3 to remove large suspended particles in the wastewater, laying a foundation for subsequent wastewater treatment. The clarified water enters reaction tower 6 through clarification separation device outlet pipe 5;

[0046] 2: In the reaction tower 6, 25 L of 40 wt% sodium hydroxide solution was added through the sodium hydroxide solution addition pipe 9, 40 L of polypropylene ether was added through the solvent addition pipe 10, 1.5 kg of LMS-3, 1 kg of LMA-1, and 1 kg of polyoxypropylene polyol were added through the surfactant and stabilizer addition pipe 11, and 5 kg of polyaminoethanol complex was added through the carrier addition pipe 12;

[0047] 3: A flat-plate cyclone stirrer 8 is installed in the reaction tower 6. Polypropylene ether, 40 wt% sodium hydroxide solution, LMS-3, LMA-1, polyoxypropylene polyol, and polyaminoethanol complex are stirred by the flat-plate cyclone stirrer 8 at 3000 r / min, 35° C., for 30 minutes to form a liquid film. The liquid film formed by stirring the flat-plate cyclone stirrer 8 in the reaction tower 6 containing activated alumina supporting the liquid film is impregnated on the activated alumina with a high specific surface area to form a liquid film layer;

[0048] 4: The activated alumina loaded with a liquid film layer in the reaction tower 6 is in full contact with the phenol-containing wastewater, and a large amount of phenolic substances in the phenol-containing wastewater are captured by utilizing the good mass transfer rate of the liquid film and the pore enrichment of the activated alumina;

[0049] 5: When the activated alumina loaded with the liquid film layer is saturated with the adsorption of phenolic substances, it is repeatedly washed with clean water in the water storage tank 17 to make the saturated liquid film fall off from the surface of the porous solid material;

[0050] 6: The emulsion film enriched with a large amount of sodium phenolate is discharged into the demulsifier 14 through the emulsion film collecting pipe 13 for demulsification. The sodium phenolate in the inner phase wrapped by the emulsion film is released and recovered. The emulsion returns to the front-end reaction tower 6 through the circulation pipe 15 for reuse and re-film formation for the next round of absorption of phenolic substances. The treated wastewater is discharged through the drain pipe 16;

[0051] 7: The activated alumina after adsorption saturation enters the regeneration tank 19 and is regenerated by solvent. The regenerated activated carbon fiber can be recycled and returned to the reaction tower 6 for the next round of adsorption.

[0052] Table 3, parameter table of reagents used in Example 2

[0053]

[0054] Table 4, phenol-containing wastewater treatment results in Example 2

[0055]

[0056] From the analysis in Table 4, it can be seen that the wastewater with a phenol content of 22,000 mg / L is treated in a phenol-containing wastewater treatment process used in this embodiment after being treated by the clarification and separation device 4 and entering the reaction tower 6. In the reaction tower 6, the phenolic substances in the wastewater are absorbed by the porous solid material 7 combined with the liquid membrane. The phenol content in the water discharged through the drain pipe 16 is reduced to 200 mg / L, and the removal rate reaches 99.18%.

[0057] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A process for treating phenol-containing wastewater from coal tar deep processing by a solid-phase liquid membrane method, characterized in that: The following steps are involved: S1: Phenol-containing wastewater is temporarily stored in a temporary storage tank, and the clarification and separation device removes suspended solids with relatively large particle sizes in the wastewater. The treated wastewater enters the reaction tower; S2: adding one of kerosene, isopropyl ether, methyl isobutyl ketone, dimethylformamide and dimethyl sulfoxide into the reaction tower, followed by adding sodium hydroxide solution, surfactant, stabilizer and carrier; S3: A flat-plate cyclone agitator is installed in the reaction tower. The solvent, sodium hydroxide solution, surfactant, stabilizer and carrier are formed into a liquid film by the flat-plate cyclone agitator. The liquid film is impregnated on the porous solid material with a high specific surface area to form a liquid film layer. S4: The porous solid material loaded with the liquid membrane layer is in full contact with the phenol-containing wastewater, and a large amount of phenolic substances in the phenol-containing wastewater are captured by utilizing the good mass transfer rate of the liquid membrane and the pore enrichment of the porous solid material; S5: When the porous solid material loaded with the liquid film layer is saturated with the adsorption of the phenolic substance, it is repeatedly washed with clean water in the water storage tank to make the saturated liquid film fall off from the surface of the porous solid material; S6: The absorbed saturated liquid film enters the subsequent demulsifier for demulsification. The sodium phenolate in the inner phase wrapped by the emulsion liquid film is released, and the emulsion returns to the front-end reaction tower to form a film again for the next round of absorption of phenolic substances. The completed wastewater is discharged through the drain pipe; S7: The porous solid material after adsorption saturation enters the regeneration tank and is regenerated by the solvent. The regenerated porous solid material can be recycled again.

2. The process for treating phenol-containing wastewater from coal tar deep processing by a solid-phase liquid membrane method according to claim 1, characterized in that: The concentration of the sodium hydroxide solution described in step S2 is 10-20%.

3. The process for treating phenol-containing wastewater from coal tar deep processing by a solid-phase liquid membrane method according to claim 1, characterized in that: The surfactant described in step S2 is a mixture obtained by mixing anionic polymer surfactant LMS-3 and nonionic polymer surfactant LMA-1 in a molar ratio of 1.5-3:

1.

4. The process for treating phenol-containing wastewater from coal tar deep processing by a solid-phase liquid membrane method according to claim 1, characterized in that: The stabilizer in step S2 is one of polyethylene oxide, polyoxypropylene polyol, epoxidized ethylene polyol, polycaprolactone and polyethylene terephthalate.

5. The process for treating phenol-containing wastewater from coal tar deep processing by a solid-phase liquid membrane method according to claim 1, characterized in that: The carrier described in step S2 is one of polyethylene glycol complex, polypropylene alcohol complex, polyaminoethanol complex and polyethylene glycol polypropylene alcohol copolymer.

6. The process for treating phenol-containing wastewater from coal tar deep processing by a solid-phase liquid membrane method according to claim 1, characterized in that: The mass ratio of the solvent, surfactant, stabilizer and carrier in step S2 is 75-90%: 4-10%: 0.1-3%: 2-15%.

7. The process for treating phenol-containing wastewater from coal tar deep processing by a solid-phase liquid membrane method according to claim 1, characterized in that: The flat plate cyclone in step S3 comprises a flat plate and a central shaft, wherein the central shaft has a rotational speed of 1000-3000 r / min.

8. The process for treating phenol-containing wastewater from coal tar deep processing by a solid-phase liquid membrane method according to claim 1, characterized in that: The porous solid material in step S3 is one of activated carbon fiber, macroporous resin, zeolite, molecular sieve and activated alumina.

9. The process for treating phenol-containing wastewater from coal tar deep processing by a solid-phase liquid membrane method according to claim 1, characterized in that: The mass ratio of the liquid film to the porous solid material in step S3 is 2-10:1.

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