CN114291943A - Process for treating production wastewater of benzohydroxamic acid by ozone iron-carbon micro-electrolysis - Google Patents

Abstract

The invention provides an ozone iron-carbon micro-electrolysis process for treating benzhydroxamic acid production wastewater, comprising the following steps: S01, introducing ozone into the benzhydroxamic acid production wastewater, and continuously performing ozone reaction; S02, adding hydrogen peroxide , the iron-carbon mixed reagent, stir evenly, and continue to carry out the iron-carbon micro-electrolysis reaction; S03, add calcium hydroxide solution to adjust the pH value, and then continue to aerate; S04, let stand and settle, so that the iron-carbon micro-electrolysis reaction is obtained. Iron and ferric hydroxide precipitate. The present invention completes high-efficiency wastewater treatment through ozone+iron-carbon micro-electrolysis reaction and optimal experimental data research.

Description

A kind of ozone iron carbon micro-electrolysis process for benzhydroxamic acid production wastewater

technical field

The invention relates to the field of water treatment technology, in particular to a technology for treating benzhydroxamic acid production wastewater by ozone iron-carbon micro-electrolysis.

Background technique

Water environment pollution brings great challenges to water treatment and poses a great threat to the safe water supply of cities. With the development and progress of the economy and society, the demand for mineral products in industrial production continues to expand, resulting in the vigorous development of the mining industry. Among them, benzhydroxamic acid is a commonly used mineral processing agent, which is a refractory organic matter.

Benzohydroxamic acid production wastewater is an organic wastewater with strong acidity, pungent odor and high COD content. If it is directly discharged into the natural environment, it will accumulate in water, soil and other environments, resulting in pollution of water and soil. After being ingested by organisms, it will accumulate in organisms and produce physiological toxicity. Therefore, it is of great significance to find a quick and effective method to treat benzhydroxamic acid production wastewater.

At present, there are few studies on the use of biochemical methods to treat hydroxamic acid, and less research on mineral processing industrial wastewater containing hydroxamic acid collectors. In the research of industrial wastewater treatment, there are physicochemical process, biochemical process, advanced treatment and advanced oxidation technology. However, in actual industrial production, the composition of mineral processing chemical wastewater is different, which greatly increases the difficulty of wastewater treatment. It is difficult to ensure complete removal of organic substances in water by a separate process.

It is not difficult to see that the prior art still has certain defects.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a process for treating benzhydroxamic acid production wastewater by ozone-iron-carbon micro-electrolysis, and complete efficient wastewater treatment through ozone+iron-carbon micro-electrolysis reaction and optimal experimental data research.

To achieve the above object, the present invention adopts the following technical solutions:

A process for treating benzhydroxamic acid production wastewater by ozone iron carbon micro-electrolysis, comprising the following steps:

S01, feed ozone into the benzohydroxamic acid production wastewater, and continue to carry out ozone reaction;

S02, add hydrogen peroxide, iron-carbon mixed reagent, stir evenly, and continue to carry out iron-carbon micro-electrolysis reaction;

S03, add calcium hydroxide solution to adjust PH value, and then continue to aerate;

S04, standing and settling, so that the ferrous hydroxide and ferric hydroxide obtained by the iron-carbon micro-electrolysis reaction are precipitated.

Further, in the step S01, the ozone reaction time is 60-120min.

Further, in the step S01, the dosage of ozone is as follows: every liter of benzhydroxamic acid production wastewater corresponds to 6g/h.

Further, in the step S02, the dosage of hydrogen peroxide is as follows: every liter of benzhydroxamic acid production wastewater corresponds to 12 ml of hydrogen peroxide.

Further, in the step S02, the ratio of iron to carbon is 1:3.

Further, in the step S02, the dosage of iron carbon is as follows: every liter of benzhydroxamic acid production wastewater corresponds to 160 g of iron carbon.

Further, in the step S02, the iron-carbon micro-electrolysis reaction time is 1h.

Further, in the step S03, calcium hydroxide solution is added to adjust the pH value to 7.

Further, in the step S03, the aeration time is 30-60min.

Further, in the step S04, the settling time is 4h.

The invention provides a process for treating benzhydroxamic acid production wastewater by ozone iron carbon micro-electrolysis, which has the following advantages:

Through the combined process of ozone + iron-carbon micro-electrolysis, the wastewater from benzhydroxamic acid production is efficiently treated, which is better than the single treatment process. All process data are tested by experiments, and the optimal parameters are obtained, and the COD removal rate is high.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

Fig. 1 is a kind of schematic process flow diagram of a kind of ozone iron carbon micro-electrolysis treatment process of benzhydroxamic acid production wastewater provided in the first embodiment of the present invention.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention and the accompanying drawings. It should be noted that the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Example 1

Please refer to Fig. 1, the embodiment of the present invention provides a kind of ozone iron carbon micro-electrolysis process for the treatment of benzhydroxamic acid production wastewater alone, and specifically comprises the following steps:

S01, feed ozone into the benzohydroxamic acid production wastewater, and continue to carry out ozone reaction;

S02, add hydrogen peroxide, iron-carbon mixed reagent, stir evenly, and continue to carry out iron-carbon micro-electrolysis reaction;

S03, add calcium hydroxide solution to adjust PH value, and then continue to aerate;

S04, standing and settling, so that the ferrous hydroxide and ferric hydroxide obtained by the iron-carbon micro-electrolysis reaction are precipitated.

The technological feature of the invention is that a combined treatment process of ozone first and iron-carbon micro-electrolysis is adopted. The process principle is:

Ozone advanced oxidation mechanism:

Ozone is a very strong oxidizing oxidant. Through its oxidizing property, it reacts directly, and in the middle of a higher pH solution, the contact oxidation reaction produces hydroxyl radicals, and the oxidation of hydroxyl radicals is utilized to degrade organic matter. The oxidizing property of ozone is stronger than that of chlorine. It can penetrate the cell membrane and inactivate the nucleic acid and protein inside the cell, thereby killing bacteria in the water and oxidizing and removing organic pollutants in the water.

Ozone can be used to treat various pollutants in water, especially biologically refractory organic pollutants, with its super oxidizing ability, and can achieve better treatment effects. Since only a small amount of hydroxyl radicals can be generated under the condition of O3 treatment alone, more hydroxyl radicals can be excited and generated only by coordinating with other physical catalysis or chemical methods. Among them, under the catalysis of ferrous ions and iron ions, ozone can be decomposed to generate more hydroxyl radicals. The principle is as follows:

O ₃ +OH ^- →.O ₂ +.HO ₂

O ₃ +.HO ₂ →2O ₂ +.OH

Fe ²⁺ +O ₃ →Fe ³⁺ +.O ₃ ^-

H ⁺ +.O ₃ ^- →O ₂ +.OH

Fe ²⁺ +O ₃ →FeO ²⁺ +O ₂

FeO ²⁺ +HO ₂ →Fe ³⁺ +.OH+OH ^-

Iron-carbon micro-electrolysis principle:

Iron-carbon micro-electrolysis can carry out redox reactions in wastewater. Under the action of ferrous ions and hydrogen atoms, refractory organic pollutants in wastewater are degraded; at the same time, ferrous ions and iron ions can form ferrous hydroxide and Ferric hydroxide precipitation plays a coagulation role, destabilizing the suspended solids and organic substances in the wastewater, and condensing them into flocs, and the organic substances are removed. The specific principles are as follows:

(1) Electrochemical action: The electrochemical reaction plays a major role in wastewater, and the electrode reaction formula is:

Anodic reaction under oxygen-free conditions:

Fe-2eFe→Fe ²⁺

Cathodic reaction under anaerobic conditions:

2H ⁺ +2e→H ₂

Anodic reaction under aerobic conditions:

Fe-2eFe→Fe ²⁺

Cathodic reaction under aerobic conditions:

O ₂ +4H ⁺ +4e→2H ₂ O (acidic conditions)

O ₂ +2H ₂ O+4e→4OH ^- (neutral or basic conditions)

It can be seen from the above reaction formula of iron-carbon electrode that under acidic aerobic conditions, the electrochemical corrosion of iron-carbon is the fastest, and the effect of wastewater treatment is the best.

(2) Reduction: After the electrode reaction, there are highly active atomic H and nascent ferrous ions in the solution, which can break and open the organic matter, thereby degrading the organic matter.

(3) Oxidation: in the process of electrochemical reaction, free radicals can be generated, thereby oxidizing and removing organic matter.

(4) Coagulation: the iron in the anode loses two electrons to form ferrous ions, which can be converted into ferrous hydroxide and ferric hydroxide precipitation under aerobic and alkaline conditions, which can adsorb organic matter and become flocs Settling down, the organic matter is removed, and the reaction process is:

Fe ²⁺ +2OH ^- =Fe(OH) ₂ ↓

4Fe ²⁺ +8OH ^- +O ₂ +2H ₂ O=4Fe(OH) ₂ ↓

The research shows that the treatment effect of ozone + iron-carbon micro-electrolysis combined process is better than that of iron-carbon micro-electrolysis + ozone combined process. This is because, if the iron-carbon micro-electrolysis reaction is performed first, after the iron-carbon micro-electrolysis, the easily degradable organic substances in the wastewater will be removed first. In the subsequent ozone reaction, although the iron ions after the iron-carbon micro-electrolysis reaction can catalyze ozone However, most of the remaining waste water is refractory organic matter, and there is no coagulation and precipitation effect of ferric hydroxide, resulting in a decrease in the ability of ozone to oxidize organic matter. Therefore, the ozone oxidation reaction is advanced.

Preferably, in the step S01, the ozone reaction time is 60-120 min. Studies have shown that the degradation rate of organic matter in benzhydroxamic acid wastewater is positively correlated with the reaction time of ozone. When the reaction time is less than 60min, the degradation rate of organic matter increases significantly with the increase of ozone reaction time; when the reaction time exceeds 60min, the degradation rate of organic matter rate growth has slowed. Considering the problem of treatment efficiency, the optimal reaction time of ozone reaction is 60min.

Preferably, in the step S01, the dosage of ozone is: 6 g/h per liter of benzhydroxamic acid production wastewater. Studies have shown that due to the increase of ozone dosage, macromolecular organic matter in benzhydroxamic acid production wastewater is rapidly, effectively and completely decomposed.

Preferably, in the step S02, the dosage of hydrogen peroxide is: 12 ml of hydrogen peroxide per liter of benzhydroxamic acid production wastewater. Studies have shown that when the dosage of hydrogen peroxide exceeds or falls below 12ml, the rate of organic matter degradation is greatly reduced. This is because after the iron-carbon micro-electrolysis, the ferrous ions in the water can act as catalysts, so that the hydrogen peroxide generates hydroxyl radicals, which improves the oxidation performance of the hydrogen peroxide and improves the treatment effect; but when the amount of hydrogen peroxide added is too much, the excess Hydrogen peroxide will decompose itself and react with hydroxyl radicals, thereby reducing the content of hydroxyl radicals and weakening the reaction of oxidizing organic matter.

Preferably, in the step S02, the ratio of iron to carbon is 1:3. Studies have shown that when there is more iron than carbon, the degradation rate of organic matter is reduced, iron-carbon microelectrolysis is prone to hardening and passivation during the reaction, and the COD degradation effect is not obvious. When there is more carbon than iron, and the ratio of iron to carbon is 1:3, the organic matter degradation rate is the fastest, and the COD removal rate is the highest.

Preferably, in the step S02, the dosage of iron carbon is: 160 g of iron carbon per liter of benzhydroxamic acid production wastewater. Studies have shown that when the iron-carbon content is too high, iron oxides will aggregate, reducing the contact area between activated carbon and iron, thus affecting the treatment effect.

Preferably, in the step S02, the iron-carbon micro-electrolysis reaction time is 1h. Studies have shown that when the reaction time of iron-carbon micro-electrolysis exceeds 1h, the degradation rate of organic matter in benzhydroxamic acid production wastewater drops sharply, and then increases and decreases, but the COD removal rate is far less than that when the reaction time of iron-carbon micro-electrolysis is 1h. . This is because in the early stage of the reaction, not enough electrons are obtained to reduce the waste water of benzhydroxamic acid production. When the reaction continues, the electrons in the water begin to satisfy the reduction reaction of the waste water of benzhydroxamic acid production. However, the longer the reaction time, the , the iron surface will be oxidized and passivated, thus affecting the reduction reaction.

Preferably, in the step S03, calcium hydroxide solution is added to adjust the pH value to 7. Studies have shown that when the pH value of the reaction between iron-carbon micro-electrolysis and benzhydroxamic acid production wastewater is acidic, the potential difference of the iron-carbon micro primary battery is large, and the redox potential is also increased, which is more conducive to the dissolution of iron and produces a large amount of of ferrous ions and reduced hydrogen, speeding up the reaction rate. When the pH value is 7, the iron-carbon micro-electrolysis fully exerts the coagulation effect of ferrous ions and iron ions, the degradation rate of organic matter is the fastest, and the removal rate of COD is the highest.

Preferably, in the step S03, the aeration time is 30-60 min. Studies have shown that when the aeration time is 30-60min, the degradation rate of organic matter is the highest, and the removal rate of COD is the highest, and they are basically the same. Considering the reaction efficiency, and the aerated bubbles will prevent the effective contact area between iron carbon and organic pollutants, the optimal aeration time is 30min.

Preferably, in the step S04, the settling time is 4h. Studies have shown that, due to the micro-electrolysis of benzhydroxamic acid production wastewater and iron-carbon, the production of ferrous ions and iron ions, which are hydrolyzed to form ferrous hydroxide and ferric hydroxide flocculation and precipitation, the net capture and roll sweep to remove organic matter require time. , so the optimal settlement time is 4h.

The invention provides a process for treating benzhydroxamic acid production wastewater by ozone iron-carbon micro-electrolysis, and the benzhydroxamic acid production wastewater is treated by an ozone + iron-carbon micro-electrolysis composite treatment process. And through the detailed research and analysis of each experimental data, the optimal process data is obtained to realize the efficient treatment of benzhydroxamic acid production wastewater.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the patent of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can also be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims (10)

1. an ozone iron carbon micro-electrolysis process for benzyl hydroxamic acid production wastewater, is characterized in that, comprises the following steps: S01, feed ozone into the benzohydroxamic acid production wastewater, and continue to carry out ozone reaction; S02, add hydrogen peroxide, iron-carbon mixed reagent, stir evenly, and continue to carry out iron-carbon micro-electrolysis reaction; S03, add calcium hydroxide solution to adjust PH value, and then continue to aerate; S04, standing and settling, so that the ferrous hydroxide and ferric hydroxide obtained by the iron-carbon micro-electrolysis reaction are precipitated. 2. The process for treating benzhydroxamic acid production wastewater by ozone iron carbon micro-electrolysis according to claim 1, characterized in that: in the step S01, the ozone reaction time is 60-120min. 3. ozone iron carbon micro-electrolysis process according to claim 2 is characterized in that: in described step S01, the dosage of ozone is: every liter of benzhydroxamic acid production wastewater Corresponds to 6g/h. 4. ozone iron carbon micro-electrolysis process according to claim 1 is characterized in that: in described step S02, the dosage of hydrogen peroxide is: every liter of benzhydroxamic acid The production wastewater corresponds to 12ml of hydrogen peroxide. 5. ozone iron carbon micro-electrolysis process according to claim 1 is characterized in that: in described step S02, iron carbon ratio is 1:3. 6. ozone iron carbon micro-electrolysis process according to claim 5 is characterized in that: in described step S02, the dosage of iron carbon is: every liter of benzhydroxamic acid produces The waste water corresponds to 160 g of iron carbon. 7. The process for treating benzhydroxamic acid production wastewater by ozone iron-carbon micro-electrolysis according to claim 4, 5 or 6, characterized in that: in the step S02, the iron-carbon micro-electrolysis reaction time is 1h. 8. ozone iron carbon micro-electrolysis process according to claim 1 is characterized in that: in described step S03, add calcium hydroxide solution and adjust pH value to 7. 9. The process for treating benzhydroxamic acid production wastewater by ozone iron carbon micro-electrolysis according to claim 8, characterized in that: in the step S03, the aeration time is 30-60min. 10. The process for treating benzhydroxamic acid production wastewater by ozone iron carbon micro-electrolysis according to claim 1, characterized in that: in the step S04, the settling time is 4h.

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