CN114132992A

CN114132992A - Sound-driven iron-based and derivative material activated peroxide oxidation system and method for treating wastewater

Info

Publication number: CN114132992A
Application number: CN202111436840.9A
Authority: CN
Inventors: 尤宏; 徐祺辉; 王树涛; 柳锋; 李昊阳
Original assignee: Harbin Institute of Technology
Current assignee: Harbin Institute of Technology
Priority date: 2021-11-29
Filing date: 2021-11-29
Publication date: 2022-03-04

Abstract

The invention provides an oxidation system of an acoustic drive iron-based and derivative material activated peroxide and a method for treating wastewater. The oxidation system is composed of ultrasound, iron-based and derivative materials and peroxide-like compounds, wherein the peroxide-like compounds can form composite oxidants through different molar ratios, the reaction process is controlled and the activation efficiency is improved by introducing the ultrasound, the iron-based and derivative materials, and the reaction conditions are optimized by adjusting factors such as pH, stirring and temperature. The invention widens the oxidation utilization rate of the oxidant; ultrasonic cleaning of iron base and derivative material surface passivation is utilized to provide a fresh zero-valent iron source and a continuous activation source; adjusting the cyclic utilization by using an intermediate oxidant; the coupled acoustic/iron combined action activates the oxidant to generate stronger active intermediate, including free radical process and non-free radical process, and the catalytic/activation effect is widened in various aspects.

Description

Sound-driven iron-based and derivative material activated peroxide oxidation system and method for treating wastewater

Technical Field

The invention belongs to the technical field of pollutant treatment, and particularly relates to an oxidation system for acoustically driving iron-based and derivative material activated peroxides and a method for treating wastewater.

Background

A series of triphenylmethane derivatives such as malachite green, crystal violet, etc. are well known for use in the chemical industry. In recent years, however, the triphenylmethane derivatives are gradually presented in the water environment and the aquatic environment as emerging pollutants, and research shows that the triphenylmethane derivatives with low concentration are frequently detected in the aquatic environment, have enrichment property, can be adsorbed on the surface of the aquatic organism or enter the body of the aquatic organism, and are considered as persistent pollutants. A plurality of reports indicate that the triphenylmethane derivatives in the series can stimulate the skin, the digestive tract, the respiratory tract and the like, have carcinogenic, mutagenic and teratogenic effects, harm the health of aquatic animals and human beings, and are easy to transform or metabolize into fat-soluble recessive compounds which are more toxic and more difficult to degrade in the natural aquatic environment or organism and have larger masking property. For the treatment of the organic pollutants, conventional methods such as biological methods have not been satisfactory, and Advanced Oxidation Processes (AOPs) may be satisfactory. Among them, the activation of peroxides is of wide interest, including covalent type peroxides such as hydrogen peroxide, metallic type peroxides such as calcium peroxide, organic type peroxides such as peracetic acid, and peroxosulfates such as persulfate, wherein Persulfate (PS) oxidation mainly includes Peroxymonosulfate (PMS) and Peroxydisulfate (PDS). Persulfate radicals (SO) are generated after persulfate activation₄·^-) In which E⁰(SO₄·^-/SO₄ ^2-)＝2.60 ～3.10V_NHE>E⁰(·OH/OH^-)＝1.90-2.80V_NHEComparable to OH, and SO₄·^-Has longer service life and can maintain continuous oxidation. The persulfate catalyst activation mainly comprises carbon base, metal, organic covalent metal compound, oxidant and the like. Wherein the metal-based iron-based catalyst is derived fromThe iron-based heterogeneous catalysis has the advantages that the iron-based heterogeneous catalysis is wide in application range and low in price, but iron-based heterogeneous catalysis has two problems, namely iron-based surface passivation and insufficient utilization rate of ionic iron.

Disclosure of Invention

In view of the above, the present invention provides an oxidation system for acoustically driving iron-based and derivative materials to activate peroxides and a method for treating wastewater, so as to solve the technical problems in the prior art.

In order to achieve the above purpose of the present invention, the following technical solutions are adopted:

an oxidation system for activating peroxide by sound-driven iron base and derivative materials is composed of physical field ultrasonic wave, iron base and derivative materials and peroxide.

Physical field ultrasound or iron-based and derived materials can respectively activate peroxide-like compounds to generate synergistic effect.

The physical field ultrasonic wave can cooperate with the iron base and the derivative material to co-activate the peroxide to generate a synergistic effect.

Further, the ultrasonic source of the physical field ultrasonic waves used in the present invention includes an ultrasonic transducer or an ultrasonic vibrating rod.

Further, the iron-based and derived materials include iron-based or iron-carbon-based composites.

Further, the iron base is zero-valent iron; such as zero-valent iron powder, waste scrap iron, foam zero-valent iron and the like.

The iron-carbon-based compound is a zero-valent iron/hydrothermal carbon compound, namely, the iron-carbon-based compound is obtained by co-hydrothermal derivatization of glucose and ferric salt and high-temperature heat treatment.

Further, the peroxide (oxidant) is one or more of hydrogen peroxide, chlorite and persulfate. The compound oxidant is obtained by combining a plurality of components.

The activation performance of the composite oxidant (persulfate and chlorite) with equal molar concentration is better than that of the persulfate with equal molar concentration, and the molar ratio of the persulfate to the chlorite in the composite oxidant is controlled between (11:1) and (1: 2).

Further, the chlorite is sodium chlorite.

Further, the persulfate is one or two of sodium persulfate and potassium persulfate. Wherein the price of the sodium persulfate is more favorable for industrial application.

The invention also provides a wastewater treatment method, which utilizes the oxidation system to treat wastewater and comprises the following steps:

and (3) placing the oxidation system in wastewater, and reacting for 15-40min at 25 (room temperature) -50 ℃, wherein in the reaction process, the pH is controlled to be less than 7, the ultrasonic frequency is more than or equal to 28kHz, and the ultrasonic intensity is more than or equal to 30W/L.

Further, the pH is 2.0 to 4.5. The pH value is controlled in a weak acid range. The pH regulation can be as follows: (1) the ionic iron is prevented from precipitating at high pH value to influence the activation effect; (2) the acid can properly utilize iron dissolution to accelerate the reaction process, but the pH value is not suggested to be too low, on one hand, the acid is additionally consumed, on the other hand, the effluent quality is influenced, and therefore, the pH value is controlled to be weak acid.

The invention forms composite oxidant (such as persulfate and chlorite) by different molar ratios, and improves the activity utilization rate of the oxidant by mutual activation of the composite oxidant and the chlorite; ultrasound as a physical field can be used to activate peroxide-like compounds; the iron base and derivative materials are used as catalytic sources to activate peroxide, so that the multi-element synergistic effect is achieved, the utilization rate of an oxidant is improved, the treatment efficiency is improved, and the treatment cost and time are reduced.

The invention can generate active intermediates by acoustically driving iron-based and derivative material peroxides, including free radical processes (hydroxyl free radicals and sulfate free radicals) and non-free radical processes (high valence iron); a plurality of oxidizer compounding forms can be adopted, and particularly, the oxidation effect is improved by adjusting the proportion of the composite oxidizer; the reaction process including the release of an iron source in an activating agent driven by a sound field, forced movement of the activating agent under the sound field, mass transfer promotion of the sound field and the like is controlled by introducing ultrasound, an iron base and derivative materials, so that the activation efficiency is further improved; reaction conditions are optimized by adjusting factors such as pH, stirring, temperature and the like, and the removal of pollutants is accelerated.

The iron base and derivative materials used in the invention include but are not limited to foam zero-valent iron and hydrothermal carbon-loaded micro-nano iron base materials. In order to solve the problem of surface passivation in the iron system activation process, the system utilizes the physicochemical characteristic of an ultrasonic field to self-clean a passivation oxide layer on the surface of the foamed iron.

The oxidation system of the sound-driven iron-based and derivative material activation peroxide provided by the invention has the synergistic effect of co-catalysis/activation, and the feasibility of the co-driven activation of the composite oxidant and the sound-iron is discovered and proved through system experiments.

Compared with the prior art, the invention has the beneficial effects that:

the prepared iron base and derivative materials can be used for activating various peroxides to generate active intermediates under ultrasonic drive, and the processes comprise a free radical process and a non-free radical process; the method utilizes ultrasonic cleaning of the iron-based surface to continuously provide a fresh iron source, and solves the problem of surface passivation of system materials; the composite can be compounded with an oxidant, such as persulfate/chlorite, and can play a role in oxidation-reduction recycling by using intermediate valence chlorine of chlorite, so that the utilization rate of the oxidant is greatly improved; the method provided by the invention can realize high-efficiency and deep degradation of the organic wastewater, and has wide application prospect.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a scanning electron microscope image of a foam iron of the present invention;

FIG. 2 is a scanning electron micrograph of a self-made iron-carbon based composite of the present invention.

Detailed Description

Reference will now be made in detail to various exemplary embodiments of the invention, the detailed description should not be construed as limiting the invention but as a more detailed description of certain aspects, features and embodiments of the invention.

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Further, for numerical ranges in this disclosure, it is understood that each intervening value, between the upper and lower limit of that range, is also specifically disclosed. Every smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in a stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference herein for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control.

It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the present disclosure without departing from the scope or spirit of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification. The specification and examples are exemplary only.

As used herein, the terms "comprising," "including," "having," "containing," and the like are open-ended terms that mean including, but not limited to.

Example 1

(1) Selection of oxidizing agents

The composite oxidant selected in this example is potassium persulfate and sodium chlorite.

(2) Selection of sound sources

The sound source selected by the embodiment is a bath type ultrasonic generator made of an ultrasonic transducer.

(3) The specific degradation process (wastewater treatment) is implemented according to the following steps:

taking a triphenylmethane derivative crystal violet solution as organic wastewater, adding potassium persulfate and sodium chlorite (the molar ratio is 5:1) into the solution with the initial pH value of 6-7 and the near neutrality, wherein the total adding amount is 6mmol/L, the initial temperature is 30 ℃, the pH value is not regulated in the reaction process, treating the solution for a certain time under the ultrasonic action frequency of 28kHz and the intensity of 30W/L (the same below), and after sampling, measuring and calculating, the result shows that the treatment time is 35-40min when the crystal violet removal rate reaches 90% under the conditions of the embodiment.

Example 2

(1) Selection of oxidizing agents

(2) Selection of sound sources

(3) Selection of activating agents

The activator selected in this example is foamed zero-valent iron as shown in FIG. 1.

(4) The specific degradation process (wastewater treatment) is implemented according to the following steps:

taking a triphenylmethane derivative crystal violet solution as organic wastewater, wherein the initial pH of the solution is 6-7, the solution is nearly neutral, potassium persulfate and sodium chlorite (the molar ratio is 5:1) are added, the total adding amount is 6mmol/L, 20mg/L of foam zero-valent iron (as shown in figure 1, the foam zero-valent iron is of a porous honeycomb structure) is added, the initial temperature is 28 ℃, the pH is not adjusted in the reaction process, the solution is treated for a certain time under the action of ultrasonic waves, and after sampling measurement and calculation, the result shows that the treatment time is 20-25min when the crystal violet removal rate reaches 90% under the conditions of the embodiment. Comparative example 1 found that without addition of an activator: 6mmol/L of composite oxidant is needed, and the action time is 35-40 min. Comparative example 1 shows that the reaction time can be shortened although the amount of the composite oxide is the same when the foam zero-valent iron activator is added.

Example 3

(1) Selection of oxidizing agents

(2) Selection of sound sources

(3) Selection of activating agents

The activating agent selected in this example is a self-made iron-carbon-based compound as shown in fig. 2, and is hydrothermally derived from glucose and iron salt and subjected to high-temperature heat treatment, and the specific preparation method is as follows: dissolving 2g of ferric chloride hexahydrate, 2.5g of urea and 2.5g of glucose in 30mL of deionized water, carrying out hydrothermal treatment at 180 ℃ for 18h, and then placing the dried product in a tubular furnace for carrying out thermal treatment at 800 ℃ for 1h to obtain the final product iron-based/hydrothermal carbon. As can be seen from fig. 2, the self-made iron-carbon based composite material comprises iron-based and hydrothermal carbon, in which the iron-based and hydrothermal carbon microspheres are tightly bound together.

taking a triphenylmethane derivative crystal violet solution as organic wastewater, adding potassium persulfate and sodium chlorite (the molar ratio is 5:1) into the solution with the initial pH value of 6-7 and the near neutrality, wherein the total adding amount is 3mmol/L, adding 20mg/L of iron-carbon-based compound, the initial temperature is 28 ℃, the pH value is not adjusted in the reaction process, treating for a certain time under the ultrasonic action, and after sampling measurement and calculation, the result shows that the treatment time is 17.5-22.5min when the crystal violet removal rate reaches 90% under the conditions of the embodiment. Comparative example 2 it can be seen that the use of the homemade activator reduces the amount of complex oxidant by half.

Example 4

(1) Selection of oxidizing agents

(2) Selection of sound sources

(3) Selection of activating agents

The activator chosen in this example was a homemade iron-carbon based composite (same as example 3).

taking a triphenylmethane derivative crystal violet solution as organic wastewater, adjusting the initial pH of the solution to be 4.6, adding potassium persulfate and sodium chlorite (the molar ratio is 5:1), adding 3mmol/L of total dosage, adding 20mg/L of iron-carbon-based compound, treating for a certain time under the action of ultrasonic waves at the initial temperature of 28 ℃, and after sampling, measuring and calculating, the result shows that the treatment time is 10-15min when the crystal violet removal rate reaches 90% under the conditions of the embodiment, and the treatment time is reduced compared with that of example 3.

Example 5

The difference from example 4 is that the oxidizing agent is sodium chlorite. When the crystal violet removal rate reaches 90% under the conditions of the embodiment, the treatment time is 12.5-17.5 min.

Example 6

The difference from example 4 is that the oxidizing agent is hydrogen peroxide. When the crystal violet removal rate reaches 90% under the conditions of the embodiment, the treatment time is 20-25 min.

Example 7

The difference from example 3 is that the pH is 2.9. When the crystal violet removal rate reaches 90% under the conditions of the embodiment, the treatment time is 7-10 min.

Example 8

The difference from example 3 is that the initial temperature is 40 ℃. When the crystal violet removal rate reaches 90% under the conditions of the embodiment, the treatment time is 12.5-15 min.

Comparative example 1

The difference from example 1 is that the oxidizing agent is potassium persulfate alone. When the treatment time is 35-40min, the removal rate of the crystal violet is about 70%.

Comparative example 2

The difference from example 2 is that the initial temperature is 16 ℃. When the crystal violet removal rate reaches 90%, the treatment time is 30-35 min.

Comparative example 3

The difference from example 4 is that the oxidizing agent is potassium persulfate alone. When the treatment time is 25-30min, the removal rate of the crystal violet is about 80%.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included therein.

Claims

1. The sound-driven oxidation system for activating the peroxide-like substances by the iron base and the derivative materials is characterized by consisting of physical field ultrasonic waves, the iron base and the derivative materials and the peroxide-like substances.

2. An oxidation system according to claim 1, wherein the iron-based and derived materials comprise iron-based or iron-carbon-based composites.

3. An oxidation system according to claim 2, wherein the iron base is zero valent iron; the iron-carbon-based compound is obtained by co-hydrothermal derivatization of glucose and iron salt and high-temperature heat treatment.

4. An oxidation system according to claim 1, wherein the peroxide-like compound is one or more of hydrogen peroxide, chlorite, persulfate.

5. An oxidation system according to claim 4, wherein the chlorite is sodium chlorite.

6. An oxidation system according to claim 4, wherein the persulfate is one or both of sodium persulfate and potassium persulfate.

7. A method for treating wastewater, characterized in that the wastewater is treated by the oxidation system according to any one of claims 1 to 6, comprising the steps of:

and (3) placing the oxidation system in wastewater, and carrying out ultrasonic reaction for 15-40min at 25-50 ℃, wherein in the reaction process, the pH is controlled to be less than 7, the ultrasonic frequency is not less than 28kHz, and the ultrasonic intensity is not less than 30W/L.

8. The treatment process according to claim 7, wherein the pH is from 2.0 to 4.5.