Dephenolization method for phenol-containing wastewater by extraction

Abstract

The invention provides a dephenolization method for phenol-containing wastewater by extraction. The dephenolization method comprises the following step: subjecting the phenol-containing wastewater to multistage countercurrent extraction with an extractant at 20 to 35 DEG C so as to obtain an extraction phase and a raffinate phase, wherein the extractant is cyclic ketone, and the pH value of the phenol-containing wastewater is 6 to 7. The dephenolization method by extraction provided by the invention has the following advantages: the removal rate of phenol in the phenol-containing wastewater can reach 96.5% or above, and more phenols can be recycled; meanwhile, the removal rate of polyphenol in phenols is significant; the concentration of residual phenol in wastewater is greatly reduced, thereby facilitating subsequent biochemical treatment; the quality of biochemical effluent is improved; the difficulty of reusing treatment of the wastewater is greatly reduced; and the change to operating conditions of equipment is small, thereby facilitating rapid application to the process of dephenolization by extraction.

Description

technical field

[0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a method for extracting and dephenolizing wastewater containing phenol. Background technique

[0002] Phenols are oxygen-containing derivatives of aromatic hydrocarbons. They are highly toxic and difficult to degrade. Direct discharge will cause serious pollution to water bodies. Phenol-containing wastewater mainly comes from the production processes of coal chemical industry, petrochemical industry, dyestuffs, organic pesticides, etc., especially coal chemical industry, which not only has a large amount of wastewater, but also has high phenol content. At home and abroad, the treatment of phenol-containing wastewater is very important, and a lot of research has been done, but the extraction method is mainly used in industry.

[0003] Extraction dephenolization includes physical extraction and complex extraction. There are many kinds of extractants availa...

Examples

Embodiment 1

[0023] A method for extracting and removing phenols from wastewater containing phenols, comprising the following steps: using cyclohexanone as an extractant at a temperature of 30° C. Perform three-stage countercurrent extraction to obtain an extract phase and a raffinate phase. Among them, the pH value of the phenolic wastewater is 6.5, and the volume ratio of the extractant to the phenolic wastewater is 1:6.

[0024] The raffinate phase was detected, and the residual concentration of unit phenols was 85mg / L, the residual concentration of polyphenols was 180mg / L, and the concentration of total phenols was 265mg / L. The calculation shows that the removal rate of unit phenols is 98.5%, the removal rate of polyphenols is 96.0%, and the removal rate of total phenols is 97.4%.

Embodiment 2

[0026] A method for extracting and removing phenols from wastewater containing phenols, comprising the following steps: using cyclohexanone as an extractant at a temperature of 25° C. Perform three-stage countercurrent extraction to obtain an extract phase and a raffinate phase. Among them, the pH value of the phenolic wastewater is 7, and the volume ratio of the extractant to the phenolic wastewater is 1:7.

[0027] The raffinate phase was detected, and the residual concentration of unit phenols was 130mg / L, the residual concentration of polyphenols was 350mg / L, and the concentration of total phenols was 480mg / L. The calculation shows that the removal rate of unit phenols is 98.4%, the removal rate of polyphenols is 96.2%, and the removal rate of total phenols is 97.2%.

Embodiment 3

[0029] A method for extracting and removing phenols from wastewater containing phenols, comprising the following steps: using cyclohexanone as an extractant at a temperature of 25° C. Perform three-stage countercurrent extraction to obtain an extract phase and a raffinate phase. Among them, the pH value of the phenolic wastewater is 6, and the volume ratio of the extractant to the phenolic wastewater is 1:5.

[0030] The raffinate phase was detected, and the residual concentration of unit phenol was 75mg / L, the residual concentration of polyphenol was 130mg / L, and the concentration of total phenol was 205mg / L. The calculation shows that the removal rate of unit phenols is 98.4%, the removal rate of polyphenols is 96.3%, and the removal rate of total phenols is 97.5%.

technical field

[0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a method for extracting and dephenolizing wastewater containing phenol. Background technique

[0002] Phenols are oxygen-containing derivatives of aromatic hydrocarbons. They are highly toxic and difficult to degrade. Direct discharge will cause serious pollution to water bodies. Phenol-containing wastewater mainly comes from the production processes of coal chemical industry, petrochemical industry, dyestuffs, organic pesticides, etc., especially coal chemical industry, which not only has a large amount of wastewater, but also has high phenol content. At home and abroad, the treatment of phenol-containing wastewater is very important, and a lot of research has been done, but the extraction method is mainly used in industry.

[0003] Extraction dephenolization includes physical extraction and complex extraction. There are many kinds of extractants availa...

Examples

Embodiment 1

[0023] A method for extracting and removing phenols from wastewater containing phenols, comprising the following steps: using cyclohexanone as an extractant at a temperature of 30° C. Perform three-stage countercurrent extraction to obtain an extract phase and a raffinate phase. Among them, the pH value of the phenolic wastewater is 6.5, and the volume ratio of the extractant to the phenolic wastewater is 1:6.

[0024] The raffinate phase was detected, and the residual concentration of unit phenols was 85mg / L, the residual concentration of polyphenols was 180mg / L, and the concentration of total phenols was 265mg / L. The calculation shows that the removal rate of unit phenols is 98.5%, the removal rate of polyphenols is 96.0%, and the removal rate of total phenols is 97.4%.

Embodiment 2

[0026] A method for extracting and removing phenols from wastewater containing phenols, comprising the following steps: using cyclohexanone as an extractant at a temperature of 25° C. Perform three-stage countercurrent extraction to obtain an extract phase and a raffinate phase. Among them, the pH value of the phenolic wastewater is 7, and the volume ratio of the extractant to the phenolic wastewater is 1:7.

[0027] The raffinate phase was detected, and the residual concentration of unit phenols was 130mg / L, the residual concentration of polyphenols was 350mg / L, and the concentration of total phenols was 480mg / L. The calculation shows that the removal rate of unit phenols is 98.4%, the removal rate of polyphenols is 96.2%, and the removal rate of total phenols is 97.2%.

Embodiment 3

[0029] A method for extracting and removing phenols from wastewater containing phenols, comprising the following steps: using cyclohexanone as an extractant at a temperature of 25° C. Perform three-stage countercurrent extraction to obtain an extract phase and a raffinate phase. Among them, the pH value of the phenolic wastewater is 6, and the volume ratio of the extractant to the phenolic wastewater is 1:5.

[0030] The raffinate phase was detected, and the residual concentration of unit phenol was 75mg / L, the residual concentration of polyphenol was 130mg / L, and the concentration of total phenol was 205mg / L. The calculation shows that the removal rate of unit phenols is 98.4%, the removal rate of polyphenols is 96.3%, and the removal rate of total phenols is 97.5%.