Treatment method of wastewater containing heterocyclic organics and adsorbing material obtained therefrom

Abstract

The present disclosure relates to a treatment method of wastewater containing heterocyclic organics comprising the following steps: (1) adding a persulfate to the wastewater containing heterocyclic organics in a reaction vessel; (2) heating the reaction vessel to a reaction temperature in an inert atmosphere, then introducing an oxygen-containing gas until a reaction pressure is reached for reaction, and after the reaction is completed, cooling and filtering the reaction resultant to obtain a filtrate as a treated effluent and a filter residue; no catalyst is added to the reaction system. The treatment method provided by the present disclosure not only can significantly reduce the treatment temperature of the conventional wet oxidation, but also can control the amount of generated spherical polymer and the removal efficiency of organic pollutants by control of reaction conditions. Wastewater purification and organics recovery and reuse are achieved at the same time.

Claims

1. A treatment method of wastewater containing heterocyclic organics, wherein the treatment method comprises the following steps: (1) adding a persulfate to the wastewater containing the heterocyclic organics in a reaction vessel; (2) heating the reaction vessel to a reaction temperature in an inert atmosphere, then introducing an oxygen-containing gas until a reaction pressure is reached for reaction, and after the reaction is completed, cooling and filtering a resultant of the reaction to obtain a filtrate as a treated effluent and a filter residue as a polymer; and no catalyst is added to a system of the reaction; wherein the wastewater containing the heterocyclic organics has a COD of 2×10.sup.3 mg/L-1×10.sup.5 mg/L; wherein in the wastewater containing the heterocyclic organics, a content of the heterocyclic organics is 1500 mg/L-7000 mg/L; a COD removal rate of the treated effluent is calculated to be 95%; (3) calcining the filter residue of the step (2) in the inert atmosphere to obtain an adsorbing material; wherein a calcination temperature is 900-1200° C.; wherein the adsorbing material has a hollow spherical structure, the adsorbing material has an external diameter size distribution of 0.5-10 μm and the adsorbing material has a wall thickness size distribution of 50-200 nm.

2. The treatment method according to claim 1, wherein the heterocyclic organics include an aliphatic heterocyclic compound containing hetero atoms and an aromatic heterocyclic compound containing hetero atoms, and the hetero atoms include any one selected from the group consisting of a nitrogen atom, an oxygen atom, a sulfur atom and a combination of at least two selected therefrom.

3. The treatment method according to claim 1, wherein the persulfate of the step (1) comprises any one selected from the group consisting of potassium persulfate, sodium persulfate, ammonium persulfate, potassium monopersulfate, sodium monopersulfate, ammonium monopersulfate, and a combination of at least two selected therefrom.

4. The treatment method according to claim 1, wherein for 1 L of the wastewater, the persulfate is added in the step (1) in a weight of 0.5-5.0 times the chemical oxygen demand (COD) in the wastewater.

5. The treatment method according to claim 1, wherein the reaction in the step (2) is performed at a temperature of 60-320° C.

6. The treatment method according to claim 1, wherein the reaction in the step (2) is performed at an oxygen partial pressure of 0.1-8.0 MPa.

7. The treatment method according to claim 1, wherein the reaction in the step (2) is performed for a time of 0.5-5 h.

8. The treatment method according to claim 1, wherein the oxygen-containing gas in the step (2) comprises any one selected from the group consisting of air, oxygen, an industrial waste gas containing oxygen, and a combination of at least two selected therefrom.

9. The treatment method according to claim 1, wherein the reaction in the step (2) is assisted by agitation.

10. The treatment method according to claim 9, wherein a rate of the agitation is 10-1000 rpm.

11. The treatment method according to claim 1, wherein the treatment method further comprises the following steps: (4) immersing the adsorbing material obtained in the step (3) in an organic wastewater to adsorb and remove pollutants therein.

12. The treatment method according to claim 11, wherein the organic wastewater of the step (4) is the same as or different from the wastewater containing the heterocyclic organics of the step (1).

13. The treatment method according to claim 11, wherein the adsorbing material is added for treating the organic wastewater with a dosage of 0.5-10 g/L in the organic wastewater.

14. The treatment method according to claim 1, wherein the calcination time is 2-4 h.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a SEM image of the adsorbing material described in Application Example 1 (magnified by 2000 times);

(2) FIG. 2 is a SEM image of the adsorbing material described in Application Example 1(magnified by 10000 times);

(3) FIG. 3 is an adsorption effect diagram of the treatment of wastewater by the adsorbing material of Application Example 17.

DETAILED DESCRIPTION

(4) Enumerated below are some examples of the present disclosure in order to facilitate an understanding of the present disclosure. Those skilled in the art shall understand that the examples are set forth to aid in understanding the present disclosure and should not be regarded as specific limitations to the present disclosure.

Example 1

(5) A treatment method of wastewater containing heterocyclic organics, wherein the wastewater is a formulated benzothiazole solution, comprising the following steps:

(6) (1) 1.5 g of potassium persulfate and 500 mL of the benzothiazole solution (1 g/L, a COD of about 2400 mg/L) were added into a reaction kettle, and nitrogen was introduced into the kettle to replace the remaining oxygen therein; then agitation was conducted at a rate of 200 rpm, and the solution in the kettle was heated to 160° C. from room temperature, and then 4.0 MPa of oxygen was introduced. At this point, the timing was started, and after the reaction for 2 h, the agitation was stopped, and the solution in the kettle was rapidly cooled to room temperature to obtain a dark brown suspension liquid.

(7) (2) The dark brown suspension liquid was separated by suction filtration, the COD concentration of the filtrate was determined to be 185 mg/L by potassium dichromate colorimetric method (HJ 828-2017 Water quality—Determination of the chemical oxygen demand—dichromate method), and the COD removal rate was calculated to be 92%.

(8) (3) The filtered black solid was washed and dried repeatedly and then weighed to obtain 0.33 g of solid, and the recovery rate of organics was 66%.

(9) The recovery rate of organics=(the weight of the black solid/the initial weight of the organics in the wastewater)×100%.

Comparison Example 1-1

(10) The difference from Example 1 is that no persulfate was added in step (1). By the same analysis method, the COD removal rate of Comparison Example 1-1 was measured to be only 67%, and no solid was formed.

Comparison Example 1-2

(11) The difference from Example 1 is that oxygen was introduced before heating the solution in step (1), specifically comprising:

(12) 1.5 g of potassium persulfate and 500 mL of the benzothiazole solution (1 g/L) were added into a reaction kettle, and nitrogen was introduced into the kettle to replace the remaining oxygen therein; then 4.0 MPa of oxygen was introduced; thereafter, agitation was conducted at a rate of 200 rpm, and the solution in the kettle was heated to 160° C. from room temperature. At this point, the timing was started, and after the reaction for 2 h, the agitation was stopped, and the solution in the kettle was rapidly cooled to room temperature to obtain a clear liquid. By the same analysis method, the COD removal rate of Comparison Example 1-2 was measured to be 83%, and no solid was formed.

Example 2

(13) A treatment method of wastewater containing heterocyclic organics, wherein the wastewater is a formulated benzothiazole solution, comprising the following steps:

(14) (1) 1.5 g of sodium persulfate and 500 mL of the benzothiazole solution (1.5 g/L, a COD of about 3600 mg/L) were added into a reaction kettle, and nitrogen was introduced into the kettle to replace the remaining oxygen therein. Then agitation was conducted at a rate of 200 rpm, and the solution in the kettle was heated to 220° C. from room temperature, and then 6.0 MPa of oxygen was introduced. After the reaction for 2 h, the agitation was stopped, and the solution in the kettle was rapidly cooled to room temperature to obtain a dark brown suspension liquid.

(15) (2) The dark brown suspension liquid was separated by suction filtration, the COD concentration of the filtrate was determined to be 180 mg/L, and the COD removal rate was calculated to be 95%.

(16) (3) The filtered black solid was washed and dried repeatedly and then weighed to obtain 0.49 g of solid, and the recovery rate of organics was 67%.

Comparison Example 2

(17) The difference from Example 2 is that no persulfate was added in step (1). By the same analysis method, the COD removal rate of Comparison Example 2 was measured to be only 72%, and no solid was formed.

Example 3

(18) A treatment method of wastewater containing heterocyclic organics, wherein the wastewater is a formulated indole solution, comprising the following steps:

(19) (1) 2.5 g of ammonium persulfate and 500 mL of the indole solution (1.5 g/L, a COD of about 4995 mg/L) were added into a reaction kettle, and nitrogen was introduced into the kettle to replace the remaining oxygen therein. Then agitation was conducted at a rate of 200 rpm, and the solution in the kettle was heated to 160° C. from room temperature, and then 4.0 MPa of oxygen was introduced. After the reaction for 2 h, the agitation was stopped, and the solution in the kettle was rapidly cooled to room temperature to obtain a dark brown suspension liquid.

(20) (2) The dark brown suspension liquid was separated by suction filtration, the COD concentration of the filtrate was determined to be 890 mg/L, and the COD removal rate was calculated to be 81%.

(21) (3) The filtered black solid was washed and dried repeatedly and then weighed to obtain 0.24 g of solid, and the recovery rate of organics was 33%.

Comparison Example 3

(22) The difference from Example 3 is that no persulfate was added in step (1). By the same analysis method, the COD removal rate of Comparison Example 3 was measured to be only 46%, and no solid was formed.

Example 4

(23) A treatment method of wastewater containing heterocyclic organics, wherein the wastewater is a formulated benzopyrazole solution, comprising the following steps:

(24) (1) 5 g of potassium persulfate and 500 mL of the benzopyrazole solution (3 g/L, a COD of about 6880 mg/L) were added into a reaction kettle, and nitrogen was introduced into the kettle to replace the remaining oxygen therein. Then agitation was conducted at a rate of 200 rpm, and the solution in the kettle was heated to 200° C. from room temperature, and then 5.0 MPa of oxygen was introduced, and the timing was started at this point. After the reaction for 3 h, the agitation was stopped, and the solution in the kettle was rapidly cooled to room temperature to obtain a dark brown suspension liquid.

(25) (2) The dark brown suspension liquid was separated by suction filtration, the COD concentration of the filtrate was determined to be 890 mg/L, and the COD removal rate was calculated to be 87%.

(26) (3) The filtered black solid was washed and dried repeatedly and then weighed to obtain 0.12 g of solid, and the recovery rate of organics was 8%.

Comparison Example 4

(27) The difference from Example 4 is that no persulfate was added in step (1). By the same analysis method, the COD removal rate of Comparison Example 4 was measured to be only 10%, and no solid was formed.

Example 5

(28) A treatment method of wastewater containing heterocyclic organics, wherein the wastewater is a formulated benzotriazole solution, comprising the following steps:

(29) (1) 1.5 g of potassium persulfate, 1.5 g of sodium persulfate, 1.5 g of ammonium persulfate and 500 mL of the benzotriazole solution (6 g/L, a COD of about 9240 mg/L) were added into a reaction kettle, and nitrogen was introduced into the kettle to replace the remaining oxygen therein; then agitation was conducted at a rate of 200 rpm, and the solution in the kettle was heated to 200° C. from room temperature, and then 5.0 MPa of oxygen was introduced. At this point, the timing was started, and after the reaction for 3 h, the agitation was stopped, and the solution in the kettle was rapidly cooled to room temperature to obtain a dark brown suspension liquid.

(30) (2) The dark brown suspension liquid was separated by suction filtration, the COD concentration of the filtrate was determined to be 1250 mg/L, and the COD removal rate was calculated to be 84%.

(31) (3) The filtered black solid was washed and dried repeatedly and then weighed to obtain 0.30 g of solid, and the recovery rate of organics was 20%.

Comparison Example 5

(32) The difference from Example 5 is that no persulfate was added in step (1). By the same analysis method, the COD removal rate of Comparison Example 5 was measured to be only 30%, and no solid was formed.

Example 6

(33) A treatment method of wastewater containing heterocyclic organics, wherein the wastewater is a formulated benzothiophene solution, comprising the following steps:

(34) (1) 0.5 g of potassium monopersulfate triple salt (2KHSO.sub.5.Math.KHSO.sub.4.Math.K.sub.2SO.sub.4, having potassium monopersulfate as the main active ingredient) and 500 mL of the benzothiophene solution (0.1 g/L, a COD of about 210 mg/L) were added into a reaction kettle, and nitrogen was introduced into the kettle to replace the remaining oxygen therein; then agitation was conducted at a rate of 200 rpm, and the solution in the kettle was heated to 160° C. from room temperature, and then 0.1 MPa of oxygen was introduced. At this point, the timing was started, and after the reaction for 0.5 h, the agitation was stopped, and the solution in the kettle was rapidly cooled to room temperature to obtain a dark brown suspension liquid.

(35) (2) The dark brown suspension liquid was separated by suction filtration, the COD concentration of the filtrate was determined to be 30 mg/L, and the COD removal rate was calculated to be 86%.

(36) (3) The filtered black solid was washed and dried repeatedly and then weighed to obtain 0.008 g of solid, and the recovery rate of organics was 16%.

Comparison Example 6

(37) The difference from Example 6 is that no persulfate was added in step (1).

(38) By the same analysis method, the COD removal rate of Comparison Example 6 was measured to be only 47%, and no solid was formed.

Example 7

(39) A treatment method of wastewater containing heterocyclic organics, wherein the wastewater is a formulated benzimidazole solution, comprising the following steps:

(40) (1) 2.5 g of potassium persulfate, 2.5 g of sodium persulfate, 2.5 g of ammonium persulfate, 2.5 g of potassium monopersulfate triple salt (2KHSO.sub.5.Math.KHSO.sub.4.Math.K.sub.2SO.sub.4) and 500 mL of the benzimidazole solution (7 g/L, a COD of about 14925 mg/L) were added into a reaction kettle, and nitrogen was introduced into the kettle to replace the remaining oxygen therein. Then agitation was conducted at a rate of 200 rpm, and the solution in the kettle was heated to 320° C. from room temperature, and then 8.0 MPa of oxygen was introduced, and the timing was started at this point. After the reaction for 2 h, the agitation was stopped, and the solution in the kettle was rapidly cooled to room temperature to obtain a dark brown suspension liquid.

(41) (2) The dark brown suspension liquid was separated by suction filtration, the COD concentration of the filtrate was determined to be 750 mg/L, and the COD removal rate was calculated to be 95%.

(42) (3) The filtered black solid was washed and dried repeatedly and then weighed to obtain 0.02 g of solid, and the recovery rate of organics was 0.06%.

Comparison Example 7

(43) The difference from Example 7 is that no persulfate was added in step (1). By the same analysis method, the COD removal rate of Comparison Example 7 was measured to be only 92%, and no solid was formed.

Example 8

(44) A treatment method of wastewater containing heterocyclic organics, wherein the wastewater is a pharmaceutical industrial wastewater (mainly composed of benzothiazole, benzimidazole, benzothiophene, thiophene and its substitutes, etc), comprising the following steps:

(45) (1) 7.5 g of sodium persulfate and 500 mL of the pharmaceutical wastewater (having a COD of about 21350 mg/L) were added into a reaction kettle, and nitrogen was introduced into the kettle to replace the remaining oxygen therein. Then agitation was conducted at a rate of 200 rpm, and the solution in the kettle was heated to 160° C. from room temperature, and then 4.0 MPa of oxygen was introduced. At this point, the timing was started, and after the reaction for 2 h, the agitation was stopped, and the solution in the kettle was rapidly cooled to room temperature to obtain a dark brown suspension liquid.

(46) (2) The dark brown suspension liquid was separated by suction filtration, the COD concentration of the filtrate was determined to be 1250 mg/L, and the COD removal rate was calculated to be 94%.

(47) (3) The filtered black solid was washed and dried repeatedly and then weighed to obtain 0.72 g of solid.

Comparison Example 8-1

(48) The difference from Example 8 is that no persulfate was added in step (1). By the same analysis method, the COD removal rate of Comparison Example 8-1 was measured to be only 45%, and no solid was formed.

Comparison Example 8-2

(49) The difference from Example 8 is that the oxygen was introduced before heating the solution in step (1), specifically comprising:

(50) (1) 7.5 g of sodium persulfate and 500 mL of the pharmaceutical wastewater were added into a reaction kettle, and nitrogen was introduced into the kettle to replace the remaining oxygen therein, and then 4.0 MPa of oxygen was introduced. Then agitation at a rate of 200 rpm was conducted, and the solution in the kettle was heated to 160° C. from room temperature. At this point, the timing was started, and after the reaction for 2 h, the agitation was stopped, and the solution in the kettle was rapidly cooled to room temperature to obtain a dark brown suspension liquid.

(51) By the same analysis method, the COD removal rate of Comparison Example 8-2 was measured to be 86%, and no solid was formed.

Application Examples 1-8

(52) (1) The solids obtained in Examples 1-8 were respectively calcined in an inert atmosphere at 600° C. for 4 h to obtain carbonized adsorbing materials; and SEM images of the adsorbing material obtained from the calcination of the solid obtained in Example 1 have been given by FIG. 1 and FIG. 2;

(53) (2) The adsorbing materials were immersed into a benzothiazole wastewater (having a COD of 500 mg/L) in an addition amount of 0.1 g/L, agitated at 20-35° C. for 10 h for wastewater treatment, and the COD concentration and COD removal of the treated water were determined.

Application Examples 9-16

(54) (1) The solids obtained in Examples 1-8 were respectively calcined in an argon atmosphere at 1000° C. for 3 h to obtain carbonized adsorbing materials;

(55) (2) The adsorbing materials were immersed into a benzothiazole wastewater (having a COD of 500 mg/L) in an addition amount of 0.5 g/L, agitated at 20-35° C. for 12 h for wastewater treatment, and the COD concentration and COD removal of the treated water were determined.

Application Examples 17-24

(56) (1) The solids obtained in Examples 1-8 were calcined in an argon atmosphere at 1200° C. for 2 h to obtain carbonized adsorbing materials;

(57) (2) The adsorbing materials were immersed into an actual wastewater containing benzotriazole, indole, thiophene, pyridine, etc. (having a COD of 2230 mg/L) in an addition amount of 10 g/L, agitated at 20-35° C. for 8 h for wastewater treatment, and the COD concentration and COD removal of the treated wastewater were determined.

(58) The adsorption effect diagram of the treatment of wastewater by the adsorbing material of Application Example 17 has been given in FIG. 3.

(59) The COD concentrations and COD removal rates of Application Examples 1-24 have been given in Table 1.

(60) TABLE-US-00001 TABLE 1 Samples COD removal rates Application Example 1 10.4% Application Example 2 10.2% Application Example 3 11.2% Application Example 4 15.1% Application Example 5 16.5% Application Example 6 10.7% Application Example 7 18.4% Application Example 8 16.5% Application Example 9 48.0% Application Example 10 49.5% Application Example 11 54.8% Application Example 12 62.3% Application Example 13 61.3% Application Example 14 46.2% Application Example 15 65.7% Application Example 16 64.0% Application Example 17 98.0% Application Example 18 95.5% Application Example 19 96.5% Application Example 20 99.0% Application Example 21 98.6% Application Example 22 95.3% Application Example 23 98.3% Application Example 24 97.5%

(61) It can be seen from Table 1 that the treatment method of wastewater containing heterocyclic organics provided by the present disclosure can achieve an adsorbing material having adsorption effect while reducing the COD concentration, and the adsorption material has such marked adsorption effect on the pollutants in the wastewater that a usage amount of 0.1 g/L can result in adsorption of 10% or more of the organics in the simulated wastewater, and that a usage amount of 0.5 g/L can result in adsorption of 48% or more of the organics in the simulated wastewater, and that a usage amount of 10 g/L can result in adsorption of 95% or more of the organics in the simulated wastewater.

(62) It can be seen from the test results of the above examples and Comparison examples that the treatment method provided by the present disclosure for treating wastewater, especially wastewater containing heterocyclic organics, can achieve a removal rate of COD in the wastewater of 80% or more, and can also collect the organics in the wastewater in the form of black hollow polymer particles which can be further used for adsorption treatment of wastewater. Of course, the polymer particles can also serve as a catalyst carrier, other adsorbent materials and the like. It can be clarified that in the method of the present disclosure, the heat treatment in prior to the introduction of oxygen can promote the conversion of heterocyclic organics to a polymer. When the oxygen is first introduced and then heated, no solid matter is formed.