CN111170525A

CN111170525A - Treatment method of antibiotic wastewater

Info

Publication number: CN111170525A
Application number: CN202010054226.5A
Authority: CN
Inventors: 傅敏; 陈正波; 王瑞琪; 卢鹏; 王小平
Original assignee: Chongqing Technology and Business University
Current assignee: Chongqing Technology and Business University
Priority date: 2020-01-17
Filing date: 2020-01-17
Publication date: 2020-05-19

Abstract

The invention discloses a method for treating antibiotic wastewater, and belongs to the technical field of wastewater treatment. The method comprises the following steps: soaking the iron-carbon filler in the solution for 0.5-1 h to reach adsorption saturation, and then cleaning the iron-carbon filler with distilled water; adding iron-carbon filler into the antibiotic wastewater, adjusting the pH value of the antibiotic wastewater to be acidic, simultaneously switching on a micro-nano bubble reactor, ventilating until the solution is milky, and reacting for 1-2 h. The method for treating the antibiotic wastewater has the advantages of simple operation, mild and easily-controlled conditions, safety, environmental protection and good repeatability, and has great industrial popularization and application values in the antibiotic wastewater treatment process.

Description

Treatment method of antibiotic wastewater

Technical Field

The invention belongs to the technical field of wastewater treatment, and particularly relates to a method for treating antibiotic wastewater.

Background

Tetracycline hydrochloride (TC) is a common antibiotic, has large production capacity and wide application range, causes large pollution area, and has a content of 0.07-1.34ug/L detected in surface water, thereby causing high social attention. At present, the methods for degrading and removing antibiotics in water mainly comprise an activated sludge method, an adsorption method, a chlorination method, a deep oxidation method, a photolysis/photooxidation method and an acoustic catalysis method. However, due to the biological activity, polarity and persistence of antibiotics, most biological processes and advanced oxidative treatments are insufficient to degrade and mineralize them.

The traditional micro-electrolysis technology is firstly used for wastewater pretreatment in the last century, and is widely applied to removal of various pollutants due to the advantages of low cost, simple operation, high efficiency and the like, and particularly has great potential for treatment of benzene ring-containing wastewater and heavy metal organic pollutants. In microelectrolytic systems, iron (anode), carbon (cathode) and wastewater (electrolyte) are mixed and brought into contact, forming a mass of galvanic micro cells between them, in which the mechanisms of electron transfer, coagulation, deposition and adsorption occur simultaneously, removing the contaminants. The defects are that the problems of easy inactivation of electrode materials, hardening and blockage of fillers, low gas-liquid mass transfer efficiency and the like exist in an iron-carbon micro-electrolysis system.

In recent years, micro-nano bubbles make great progress in the field of water treatment. Micro-nano bubbles (MNBs) are bubbles with the diameter of dozens of nanometers to dozens of micrometers, compared with the conventional bubbles, the micro-nano bubbles have the characteristics of large specific surface area, long retention time, high mass transfer efficiency, high interface zeta potential and the like, and when micro bubbles are broken, the gas-liquid interface is violently changed to quickly release chemical energy accumulated by high-concentration ions, so that a large number of hydroxyl radicals are generated. The micro-nano bubbles are combined with solid or colloid pollutants in the floating process, the pollutants are removed after being brought to the water surface, and the process of combining the bubbles and the pollutants is an important link, so that the gas-liquid mass transfer efficiency can be effectively improved. The microbubbles can also promote the decomposition of ozone to generate hydroxyl radicals, and the microbubbles and the ozone oxidation technology are combined to be beneficial to the degradation of organic matters in the wastewater. In the prior art, when the phenol solution is treated by microbubbles for 2 hours, the content of phenol is reduced by 60 percent, and the result shows that hydroxyl radicals generated by breaking the microbubbles play an important role in the decomposition process of phenol; the acid scarlet 3R wastewater is treated by using ozone micro-nano bubbles, the decolorization rate and the removal rate of the wastewater are far higher than those of a traditional bubble system, and the ozone decomposition coefficient of a micro-bubble system is 6.2 times that of the traditional bubble system; the industrial granular Activated Carbon (AC) catalytic Microbubble (MB) ozonation method for treating and synthesizing the acidic scarlet 3R wastewater has an effect obviously superior to that of a pure Conventional Bubble (CB) and Microbubble (MB) ozonation method, because the micro-nano bubbles obviously promote chemical reaction, physical adsorption and mass transfer of a gas-liquid interface.

Disclosure of Invention

In view of the above, the present invention aims to provide a method for treating antibiotic wastewater.

In order to achieve the above purpose, the inventor of the present invention has made a long-term study and a large number of practices to obtain the technical scheme of the present invention as follows:

1. a method for treating antibiotic wastewater comprises the following steps:

s1, soaking the iron-carbon filler in the solution for 0.5-1 h, and then cleaning with water;

s2, adding the cleaned iron-carbon filler into the antibiotic wastewater, adjusting the pH value of the antibiotic wastewater to be acidic, simultaneously switching on the micro-nano bubble reactor, ventilating until the antibiotic wastewater is milky, and reacting for 1-2 hours.

In S1, the iron-carbon filler is immersed in the solution for the purpose of maintaining adsorption equilibrium of the activated carbon on the surface, and the water used for cleaning is ultrapure water and is rinsed many times. Through detection and analysis, when the solution is milky white in S2, the particle size of micro-nano bubbles existing in the antibiotic wastewater is 30-40 um, and the particle size of the nano bubbles is 90-100 nm.

Preferably, in the iron-carbon filler, the mass ratio of iron to carbon is 1: 1. Wherein, the iron-carbon filler is in a spherical shape, and the chemical components comprise iron, carbon, silicon dioxide and other catalytic elements.

Preferably, the adding amount of the iron carbon filler in S2 is 50-300 g/L.

Preferably, the adding amount of the iron carbon filler in S2 is 100 g/L.

Preferably, in the S2, the pH value of the antibiotic wastewater is adjusted to 3.0-5.0.

Preferably, in the S2, the pH of the antibiotic wastewater is adjusted to 3.0.

Preferably, in the S2, the air input of the micro-nano bubble reactor is 10-60 mL/min.

Preferably, in the step S2, the air input of the micro-nano bubble reactor is 30 mL/min.

Preferably, in the S2, the reaction time is 1.5-2.5 h.

Preferably, in the S2, the reaction time is 2 h.

Preferably, the antibiotic wastewater is tetracycline hydrochloride wastewater.

The method for detecting and calculating the degradation rate in the tetracycline hydrochloride wastewater specifically comprises the following steps: samples were taken every 15 minutes and centrifuged in a centrifuge at 4900r/min for 5 minutes, and the supernatant was taken and placed in an ultraviolet spectrophotometer to measure its absorbance at a maximum absorption wavelength of 358 nm.

(A) degradation rate₀-A_t)/A₀ X 100% (formula 1)

In the formula 1, A₀Is the initial absorbance of the tetracycline hydrochloride waste water (TC) solution; a. the_tThe absorbance of the TC solution at the time t of the reaction.

The invention has the beneficial effects that:

1) according to the method for treating the antibiotic wastewater, the antibiotic wastewater is treated by combining micro-nano bubbles with iron-carbon micro-electrolysis, and through improvement of process conditions, the degradation rate of the antibiotic wastewater can reach more than 80% at most, the removal rate of Total Organic Carbon (TOC) can reach more than 48% at most, and compared with the degradation effects of single micro-nano bubbles and single iron-carbon micro-electrolysis, and conventional bubbles and iron-carbon micro-electrolysis on the antibiotic wastewater, the micro-nano bubbles have an obvious synergistic effect on the iron-carbon micro-electrolysis;

2) the method for treating the antibiotic wastewater has the advantages of simple operation, mild and easily-controlled conditions, safety, environmental protection and good repeatability, and has great industrial application value in the antibiotic wastewater treatment process.

Drawings

FIG. 1 is an X-ray diffraction (XRD) pattern of the iron-carbon filler of example 1 before and after wastewater treatment;

FIG. 2 is a Fourier transform infrared (FT-IR) spectrum of the iron carbon filler of example 1 before and after wastewater treatment;

FIG. 3 is a graph showing the pH and TOC changes at different time points during the treatment of the antibiotic wastewater in this example 1;

FIG. 4 is a graph of the degradation rate of tetracycline hydrochloride wastewater in different systems according to example 2;

FIG. 5 is a graph of the degradation rate of tetracycline hydrochloride wastewater by different reaction times in this example 3;

FIG. 6 is a graph showing the degradation rate of tetracycline hydrochloride wastewater by different Fe-C dosages in example 4;

FIG. 7 is a graph of the degradation rate of tetracycline hydrochloride wastewater in this example 5 at different initial pH values;

fig. 8 is a graph of degradation rates of tetracycline hydrochloride wastewater by different micro-nano bubble air input in this example 6.

Detailed Description

The present invention is further illustrated by the following specific examples so that those skilled in the art can better understand the present invention and can practice it, but the examples are not intended to limit the present invention.

Example 1

The antibiotic wastewater in the embodiment takes tetracycline hydrochloride wastewater as an example, and the specific treatment method comprises the following steps:

s1, soaking the iron-carbon filler in the solution for 0.5h, and then cleaning the iron-carbon filler with water;

s2, adding the cleaned iron-carbon filler into tetracycline hydrochloride wastewater with the concentration of 20mg/L, wherein the adding amount is 100g/L, then adjusting the pH value of the tetracycline hydrochloride wastewater to 3.0, simultaneously switching on the micro-nano bubble reactor, wherein the air inflow is 30mL/min, ventilating until the tetracycline hydrochloride wastewater is milky, and reacting for 2 hours.

XRD detection is carried out on the iron-carbon filler after tetracycline hydrochloride wastewater treatment and the iron-carbon filler before wastewater treatment in the embodiment, and the result is shown in FIG. 1.

By XRD, crystalline phase and crystal before and after micro-electrolysis reaction of iron-carbon fillerDegree detection and analysis are carried out, and compared with a standard PDF card, as can be seen from the analysis in fig. 1, obvious peaks exist near 20.86 degrees, 26.55 degrees, 44.67 degrees, 65.16 degrees and the like before reaction, and no obvious peak exists at other positions, wherein iron is mainly concentrated on a crystal face of 44.67 degrees (110) and a crystal face of 65.16 degrees (200), carbon is concentrated on a crystal face of 26.55 degrees (002), and the crystal face of 20.86 degrees (100) is SiO₂The iron-carbon filler (Fe-C) is illustrated to contain a large amount of elemental iron and carbon and a small amount of SiO before the reaction₂. After the reaction of the micro-nano bubble/iron-carbon filler (MB/Fe-C) system, the peaks at 20.86 degrees, 26.55 degrees, 35.55 degrees, 44.67 degrees and 50.14 degrees still exist, but the intensities are weakened, which indicates that iron and carbon are consumed in the micro-electrolysis reaction process under the acidic condition. However, stronger Fe was found in Fe-C after the reaction₃O₄、Fe₂O₃The peaks in (a) and (b), which correspond to 62.63 ° (440) and 35.64 ° (119), respectively, indicate that there is conversion of iron in the system to iron oxide.

FT-IR detection was performed on the iron-carbon filler after the tetracycline hydrochloride wastewater was treated in this example and the iron-carbon filler before the untreated wastewater, and the results are shown in FIG. 2.

The surface functional groups before and after the micro-electrolysis reaction of the iron-carbon filler are detected and analyzed by FT-IR, and the wavelength is 3200-3700cm as can be seen from FIG. 2^-1Belonging to the structure-OH or-NH₂In a tensile vibration of 1631cm^-11076cm, due to-OH bending vibration of adsorbed water molecules^-1The band at (A) demonstrates the presence of a Si-O-Si bond, which corresponds to stretching vibration of Si ═ O or C-N and C-O, 565cm^-1The band of (2) is due to stretching vibration of Fe-O. 3200-3700cm after the reaction of the MB/Fe-C system^-1，1631cm^-1，1076cm^-1，565cm^-1The band intensities of the iron and the carbon are weakened, which shows that the iron and the carbon are transferred to the iron-containing sludge through the reaction with TC through flocculation, coprecipitation, adsorption or inter-particle bridging and the like in the iron and carbon micro-electrolysis treatment process.

In the process of treating tetracycline hydrochloride wastewater in example 1, the pH and TOC of wastewater at different time periods were also measured, and the results are shown in fig. 3.

As can be seen from the analysis in FIG. 3, the pH value in the MB/Fe-C system gradually increased as the reaction proceeded, and then the rising rate decreased gradually and gradually to be maintained at about 6.5, because the ferrous ions were oxidized (4 Fe)²⁺+O₂+2H₂O→4Fe³⁺+4OH^-) The reaction generates hydroxyl free radical, and the degradation generates small molecular organic acid to ensure that the micro-electrolysis system still maintains a slightly acidic environment. The TOC content in the MB/Fe-C system is rapidly reduced along with the reaction, and the TOC removal rate is 47.89% after the reaction is carried out for 2 hours, which shows that the organic matters in the system are continuously converted and decomposed along with the reaction.

Example 2

In this example, the degradation effect of tetracycline hydrochloride wastewater under different systems was studied, and the content of tetracycline hydrochloride in the wastewater was sampled and detected every 15min, and the degradation rate of tetracycline hydrochloride wastewater was calculated by formula 1, and the detection calculation results are shown in fig. 4. Wherein, the system 1 is to directly adjust the pH value of the tetracycline hydrochloride wastewater with the concentration of 20mg/L to 3.0, then switch on a micro-nano bubble reactor, and ventilate until the solution is milky white, and react for 2 hours; the system 2 is that the iron-carbon filler is soaked in the solution for 0.5h, then is washed clean by water, then the washed iron-carbon filler is added into tetracycline hydrochloride wastewater with the concentration of 20mg/L, the adding amount is 100g/L, then the pH value of the antibiotic wastewater is adjusted to 3.0, and the reaction is carried out for 2 h; the system 3 is that the iron-carbon filler is soaked in the solution for 0.5h, then is washed clean by water, then is added into tetracycline hydrochloride wastewater with the concentration of 20mg/L, the adding amount is 100g/L, then the pH value of the tetracycline hydrochloride wastewater is adjusted to 3.0, a conventional bubble reactor is switched on, and the air is introduced until the solution is milky, and the reaction is carried out for 2 h; system 4 is the system described in example 1.

From the analysis in fig. 4, under the condition of the system 1, when the air inflow of the micro-nano bubbles (MB) is 30mL/min, the removal rate of tetracycline hydrochloride (TC) is 11.79%, the change is not obvious, which indicates that the removal effect of TC under the MB condition is weak; under the condition of the system 2, namely the removal rate of TC after the iron-carbon filler (Fe-C) is used alone for 2 hours of reaction is only 35.92%, and the MB and the Fe-C are difficult to degrade TC by the system 1 and the system 2; under the condition of the system 3, the removal rate of TC by the CB/Fe-C system is improved to a certain extent, and after 2h of conventional bubble aeration reaction, the degradation rate of TC by the CB/Fe-C system reaches 51.19 percent, which shows that the degradation of TC by Fe-C can be improved by Conventional Bubble (CB) aeration, and the conventional bubble aeration increases the contact reaction efficiency of Fe-C and solution; under the condition of the system 4, when the concentration of TC is 20mg/L, after 2h of reaction, the removal rate of the MB/Fe-C system to the TC reaches 80.84%, which is far higher than that of a single MB system and a single Fe-C and CB/Fe-C system under the same condition, and the result shows that the MB and Fe-C micro-electrolysis system has the optimal capacity of decomposing the TC.

Example 3

This example actually investigated the effect of different reaction times on the degradation effect of TC. In this example, under the process conditions of example 1, the total time is 150min, samples are taken every 15min, and TC in the treated wastewater is detected and the degradation rate is calculated, and the result is shown in fig. 5.

From the analysis in fig. 5, it is found that the removal rate of TC steadily increased with the increase of the reaction time, and reached 80.84% at 120min of the reaction, and then became stable. This is because [ H ] is generated in the solution with the increase of the reaction time]、·OH、Fe²⁺And Fe³⁺The amount of Fe is increased, which is not only beneficial to the oxidation-reduction reaction, but also can promote the Fe²⁺Better generates catalytic oxidation reaction with OH, increases the effect of removing pollutants, but generates a layer of compact oxidation film on the surface of the scrap iron after a certain time, generates passivation and hinders the reaction. Therefore, the optimal aeration reaction time for this experiment was 120 min.

Example 4

This example investigated the effect of different Fe-C additions on TC degradation. The results are shown in FIG. 6, which are the same as in example 1, except that the amounts of the iron-carbon filler added were changed to 50g, 150g, 200g and 300 g.

As can be seen from the analysis of FIG. 6, as the amount of Fe-C added increases, the TC removal rate tends to increase and then decrease. When the amount of Fe-C added was 50g, the TC removal rate was 76.36% after 2 hours of the reaction. When the amount of Fe-C added is increased to 100And when g is used, the TC removal rate can reach 80.84%. This is mainly due to the fact that [ H ] is generated by the reaction of the system with the increase of the amount of Fe-C added at a constant concentration]、Fe²⁺、Fe³⁺The OH content gradually increases, and the redox capacity gradually increases; when the addition amount of Fe-C is more than 100g/L, the removal rate of TC is reduced along with the increase of the addition amount of Fe-C, because the excessive Fe is in a supersaturated state, the excessive Fe not only increases the cost and causes the waste of samples, but also the excessive Fe is oxidized into Fe²⁺And Fe³⁺The phenomenon of yellowing is easy to appear in the effluent, Fe (OH)₂、Fe(OH)₃The flocs are increased, and the electrochemical reaction is not facilitated.

Example 5

This example investigates the effect of different initial pH values on TC degradation. The results are shown in FIG. 7, which are the same as example 1, except that the initial pH was changed to 1, 5 and 7.

From the analysis in fig. 7, it can be seen that pH changes in the wastewater at different time points have a greater effect on TC degradation. Wherein, when the pH value is 3, the TC removal rate is the highest and can reach 80.84%; when the pH value is 1, the TC removal rate is low, and the phenomenon is mainly caused because the strong acid condition inhibits Fe in the MB/Fe-C system²⁺And Fe³⁺The formation of flocs weakens the flocculation of iron salts and the generation of strong oxidizing OH, thereby reducing the TC removal effect. When the initial pH is more than 3, the TC removal rate is remarkably reduced with the increase of the pH, because the increase of the pH leads to the reduction of the potential difference in the MB/Fe-C system, the micro-electrolysis capability is weakened, and the generation of OH is inhibited, thereby reducing the removal rate. As can be seen from the above, the optimum initial pH was 3.

Example 6

This example investigated the effect of MB intake on TC degradation effect. The results are shown in FIG. 8, which are the same as example 1, except that the intake air amount of MB was changed to 10mL/min, 20mL/min, 40mL/min, 50mL/min and 60 mL/min.

As can be seen from the analysis in fig. 8, the MB intake air amount has an influence on the removal of TC. Under the condition that the concentration of TC is 20mg/L, the removal rate of the MB intake air to the TC is in a trend of increasing and then decreasing along with the increase of the MB intake air. Wherein, when the MB air input is increased from 10mL/min to 30mL/min, the degradation effect is gradually enhanced and reaches the best at 30mL/min, and the TC removal rate is 80.84%. And when the MB air inflow is increased from 30mL/min to 60mL/min, the degradation effect is reduced to 57%. The main reason for this phenomenon is that the generated micro-nano bubbles can increase the friction between the wastewater and the filler, reduce the hardening and blocking effects on the surface of the filler, accelerate the full contact between the organic matter and the filler, and promote the electrode reaction. When the MB air inflow is 30mL/min, the wastewater solution is in a white opaque state, after aeration is stopped, the white opaque state can be kept for 2-3 min due to the fact that the micro bubbles rise slowly, and more OH free radicals can be generated when the bubbles break, so that 30mL/min is the optimal air inflow for generating micro-nano bubbles.

In conclusion, according to the antibiotic wastewater treatment method, the antibiotic wastewater, especially the tetracycline hydrochloride wastewater, is treated by combining the micro-nano bubbles with the iron-carbon micro-electrolysis method, and compared with the single micro-nano bubbles, the single iron-carbon filler micro-electrolysis and the combination of the conventional bubbles and the iron-carbon filler micro-electrolysis, the degradation effect of the tetracycline hydrochloride wastewater is shown to have a remarkable synergistic effect on the iron-carbon filler micro-electrolysis. The results show that: when the reaction time is 120min, the addition amount of Fe-C is 100g/L, pH is 3, and the MB air input is 30mL/min, the best degradation effect of 20mg/L tetracycline hydrochloride reaches 80.84%, and the TOC removal rate is 47.89%. The invention has good application prospect for treating the antibiotic pharmaceutical wastewater.

The above-mentioned embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. The equivalent substitution or change made by the technical personnel in the technical field on the basis of the invention is all within the protection scope of the invention. The protection scope of the invention is subject to the claims.

Claims

1. The method for treating the antibiotic wastewater is characterized by comprising the following steps of:

s1, soaking the iron-carbon filler in tetracycline hydrochloride wastewater for 0.5-1 h, and then cleaning with water;

s2, adding the cleaned iron-carbon filler into tetracycline hydrochloride wastewater, adjusting the pH value of the tetracycline hydrochloride wastewater to be acidic, simultaneously switching on the micro-nano bubble reactor, observing that the solution is milky, and reacting for 1-2 hours.

2. The method for treating antibiotic wastewater according to claim 1, wherein the iron-carbon filler has a mass ratio of iron to carbon of 1: 1.

3. The method for treating antibiotic wastewater according to claim 1, wherein the amount of the iron-carbon filler added in S2 is 50-300 g/L.

4. The method for treating antibiotic wastewater in accordance with claim 3, wherein the amount of the iron-carbon filler added in S2 is 100 g/L.

5. The method for treating antibiotic wastewater according to claim 1, wherein in S2, the pH of antibiotic wastewater is adjusted to 3.0-7.0.

6. The method for treating antibiotic wastewater according to claim 1, wherein in the S2, the air input of the micro-nano bubble reactor is 10-60 mL/min.

7. The method for treating antibiotic wastewater according to claim 6, wherein in the S2, the air input of the micro-nano bubble reactor is 30 mL/min.

8. The method for treating antibiotic wastewater according to claim 1, wherein the reaction time in S2 is 1.5-2.5 h.

9. The method for treating antibiotic wastewater according to claim 1, wherein the antibiotic wastewater is tetracycline hydrochloride wastewater.