Method for resourceful treatment of steel pickling waste liquid by using bio-electrochemical system and application thereof

Abstract

The application discloses a method for resourceful treatment of steel pickling waste liquid by using a bioelectrochemical system and application, and the method comprises the following steps: adding anaerobic granular sludge and nutrient solution into an anode chamber of a bioelectrochemical device, and adjusting the pH of an anode liquid in the anode chamber to 6.5-8; adding the steel pickling waste liquid to be treated into a cathode chamber; the cathode chamber and the anode chamber are separated by using a cation exchange membrane; a resistor with a resistance of 900-1100 omega is used to connect the cathode and the anode, a plurality of reaction cycles are set, the voltage change is measured in the whole period from starting to ending of each cycle, the reaction cycle is ended when the voltage data drops to be static, the anode liquid is replaced, and the next reaction cycle is carried out; and the starting is successful when the voltage is higher than 0.6 V. The steel pickling waste liquid is used as the cathode liquid (starting liquid), and the steel pickling waste liquid itself has strong acidity, so that additional acid does not need to be added to maintain the acidic condition of the cathode liquid, a large amount of buffer salt added for neutralization of the acid is saved, the operation cost is lower, and the economy is higher.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of steel pickling wastewater treatment, and particularly relates to a method for resourceful treatment of steel pickling wastewater by using a bioelectrochemical system and application. BACKGROUND

[0002] The steel pickling wastewater needs high cost to be treated as hazardous waste. The steel pickling wastewater contains high concentrations of residual acid and iron salt, which is a resource that can be recycled. Therefore, it is also of great significance to explore how to resourcefully utilize the steel pickling wastewater.

[0003] The bioelectrochemical system is a new and low-carbon platform for wastewater treatment and energy production. In the biological anode, microorganisms can convert the chemical energy of organic matter in wastewater into electrical energy during metabolism. In the start-up stage of the two-chamber bioelectrochemical system, potassium ferricyanide is usually used as the electron acceptor at the cathode. It has high toxicity, which leads to high difficulty and danger in process operation, and easily causes secondary pollution. In addition, a large amount of buffer salt needs to be added in the bioelectrochemical system to inhibit the rise of pH at the cathode, which has high cost and easily causes reagent waste. Therefore, using the above-mentioned reagent as the start-up liquid does not conform to the current environmental protection concept of sustainable development. SUMMARY

[0004] In order to overcome the deficiencies of the prior art, the present application uses steel pickling wastewater instead of the commonly used ferricyanide as the cathode start-up liquid of the bioelectrochemical system, and uses the steel pickling wastewater to provide Fe(II) ions and hydrogen ions and other key ions for the start-up of the bioelectrochemical device. The present application retains the advantages of low carbon and high efficiency of the bioelectrochemical system while greatly reducing the dosage of buffer salt and other reagents required for starting the bioelectrochemical system, and effectively reducing the pollution caused by the cathode liquid. Subsequently, the steel pickling wastewater used as the start-up liquid is applied to the coagulation and Fenton-like treatment process in water treatment. The dye and carbamazepine in the wastewater are removed in an efficient and low-cost manner. The present application successfully turns the steel pickling wastewater into a valuable resource, and becomes a green raw material for the electricity production and water treatment of the bioelectrochemical system. Compared with the prior art, the present application is more economical, and the raw materials used are more green and environmentally friendly.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0006] The first aspect of the present application provides a method for resourceful treatment of steel pickling wastewater by using a bioelectrochemical system, comprising the following steps:

[0007] (1) adding anaerobic granular sludge and nutrient solution into the anode chamber of the bioelectrochemical device, adjusting the pH of the anode liquid in the anode chamber to 6.5-8, adding the steel pickling wastewater to be treated into the cathode chamber of the bioelectrochemical device, and separating the cathode chamber and the anode chamber by using a cation exchange membrane;

[0008] (2) connecting the cathode and the anode by using a resistor with a resistance of 900-1100Ω, setting multiple reaction cycles, measuring the voltage change in the whole period from the start to the end of each cycle, ending the reaction cycle when the voltage data is observed to drop to a standstill, replacing the anode liquid, and carrying out the next reaction cycle; the start is successful when there is a voltage higher than 0.6V in the electrode system, that is, the steel pickling wastewater treatment is completed.

[0009] In step (2) of the method for resourceful treatment of steel pickling wastewater by using a bioelectrochemical system according to the application, the voltage data dropping to a standstill means that the voltage data remains basically unchanged, that is, the amplitude of the voltage change is less than 10%.

[0010] The steel pickling wastewater itself has strong acidity, and it does not need to add extra acid and buffer salt when used as the cathode starting liquid, thereby saving a large amount of reagent cost. At the same time, after the bioelectrochemical treatment, the acidity of the steel pickling wastewater is reduced and the concentration of divalent iron is increased, which can become a reagent in other water treatment processes such as coagulation process and Fenton treatment. The value of the steel pickling wastewater is further improved, and the technical goal of sustainable operation is achieved. The application uses the steel pickling wastewater as the cathode starting liquid of the bioelectrochemical system, and explores a new route for resourceful utilization of the steel pickling wastewater. Compared with the prior art, the application further saves the technical cost and reduces the secondary pollution while retaining the advantages of low-carbon wastewater treatment and efficient power generation of the bioelectrochemical system. The steel pickling wastewater is converted from hazardous waste to starting liquid of the bioelectrochemical system and reagent in coagulation process and Fenton treatment, and the high cost of steel wastewater treatment is realized to profit by forming water treatment reagents.

[0011] Preferably, the nutrient solution comprises: (9-10) g / L anhydrous disodium hydrogen phosphate, (8.5-9.5) g / L potassium dihydrogen phosphate, (0.4-0.6) g / L ammonium chloride, and (1.2-1.8) g / L sodium acetate.

[0012] Preferably, the VSS / TSS of the anaerobic granular sludge is 0.8±0.1. The source of the anaerobic sludge is not particularly limited in the present application, and commercially available anaerobic granular sludge can be used. In some embodiments of the present application, the anaerobic granular sludge used is commercially available, and the brand is Zikun Environmental Protection. The particle size is uniform, the particle diameter is 0.5-2.5 mm, the settling velocity of the granular sludge is 50-150 m / h, the granularity is >70%, the VSS / TSS is 0.8±0.1, and the sludge has high strength and strong resistance to organic load.

[0013] Preferably, the volume ratio of the granular sludge to the nutrient solution is 1:(1-1.2).

[0014] Preferably, the components of the steel pickling wastewater include: (120-800) mg / L H + , (3000-70000) mg / L Fe 3 + , (2000-20000) mg / L Fe 2+ , (40000-207410) mg / L Cl - , (200-980) mg / L SO4 2 , (150-760) mg / L NO3 - , (3-16) mg / L Mn.

[0015] Preferably, the volume ratio of the anode solution to the cathode solution is 1:(0.7-1).

[0016] Preferably, the anode material of the bioelectrochemical device is a carbon brush, and the cathode is a carbon electrode prepared by sintering pure acetylene black-PTFE on a carbon felt substrate.

[0017] Preferably, in step (2), 3-5 reaction cycles are set, and each cycle has a time of 5-7 days.

[0018] The second aspect of the present application provides the use of the method for resource utilization of steel pickling wastewater by a bioelectrochemical system in the preparation of a coagulant.

[0019] In the use, the steel pickling wastewater treated by the method for resource utilization of steel pickling wastewater by a bioelectrochemical system is used as a coagulant for coagulation treatment of wastewater.

[0020] The third aspect of the present application provides the use of the method for resource utilization of steel pickling wastewater by a bioelectrochemical system in the Fenton-like treatment of wastewater.

[0021] The application uses the steel pickling wastewater treated by the method of resourceful treatment of steel pickling wastewater by bio-electrochemical system as a Fenton-like treatment agent for Fenton-like treatment of wastewater.

[0022] Compared with the prior art, the application has the following beneficial effects:

[0023] 1. The existing research on bio-electrochemical start-up usually consumes ferricyanide and buffer salt as reagents. The application uses steel pickling wastewater as a cathode liquid (start-up liquid), which has strong acidity and does not need to add additional acid to maintain the acidic conditions of the cathode liquid. At the same time, a large amount of buffer salt added for neutralization of acid is saved, so that the operation cost is lower and the economy is higher.

[0024] 2. Experimental research shows that, in the process of bio-electrochemical reaction, compared with FeCl3 (pH=1-1.6) with the same concentration of Fe(III), the steel pickling wastewater retains the advantage of quickly starting the electrochemical reaction, and exhibits better power generation effect. This is because the steel pickling wastewater has a high concentration of Fe(III) as an electron acceptor, generating more Fe(II) and more electric energy, so that the steel pickling wastewater as a cathode liquid further improves the power generation capacity of the bio-electrochemical system.

[0025] 3. After the steel pickling wastewater is subjected to bio-electrochemical reaction, a large amount of Fe(II) is generated, and Fe(II) is usually used as a material for sewage coagulation treatment. Experimental data show that, in coagulation treatment, compared with the acid pickling wastewater without bio-electrochemical treatment, the coagulation effect is better. The reason is that, in the bio-electrochemical reaction of the steel pickling wastewater, H + is consumed, and the alkalinity rises. When it is added to sewage that needs to be coagulated, it can ensure the addition of Fe(II) required for coagulation treatment, and will not have a great impact on the pH of the water body, so that the pH range of the water body is kept in the slightly alkaline range conducive to the hydrolysis of Fe(II) to generate Fe(OH)3. The untreated steel pickling wastewater has high acidity, and when it is introduced into the sewage for coagulation treatment, the pH will drop sharply, thereby greatly reducing the hydrolysis reaction speed of Fe(II).

[0026] 4. Fenton oxidation is a water treatment process commonly used for treatment of organic wastewater, and its principle is that H2O2 reacts with Fe 2+The hydroxyl radical OH· with strong oxidizing ability is generated in the presence. The steel pickling wastewater after the reaction of the bio-electrochemical system has both the conditions of acidity and rich Fe(II), and is an ideal raw material for Fenton reaction. The experimental data show that the removal rate of carbamazepine in the Fenton reaction of the organic wastewater containing carbamazepine treated by the steel pickling wastewater after the reaction of the bio-electrochemical system can reach 100%; and after the bio-electrochemical reaction, the pH value of the steel pickling wastewater added into the wastewater for treatment is also lower, and the reagent used for subsequent pH adjustment can be further saved, so the steel pickling wastewater after the bio-electrochemical reaction has good application effect in the Fenton reaction. Compared with divalent iron, the steel pickling wastewater after the bio-electrochemical treatment is rich in hydrogen ions and manganese ions and other metal ions, and the manganese ions and other metal ions can further promote the reaction rate. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a schematic diagram of the bio-electrochemical reaction system of the application;

[0028] Figure 2 It is the measured voltage change of different periods;

[0029] Figure 3 It is the measured voltage change of ferric chloride and steel pickling wastewater diluted by two times;

[0030] Figure 4 It is the pH value change of ferric chloride and steel pickling wastewater diluted by two times;

[0031] Figure 5 It is the measured voltage change of steel pickling wastewater with different dilution multiples;

[0032] Figure 6 It is the pH change of steel pickling wastewater with different dilution multiples;

[0033] Figure 7 It is the pH change value after the steel pickling wastewater with different dilution multiples is added in the coagulation process;

[0034] Figure 8 It is the coagulation and decolorization effect of steel pickling wastewater with different dilution multiples;

[0035] Figure 9 It is the Fenton-like treatment effect of steel pickling wastewater with different dilution multiples. DETAILED DESCRIPTION

[0036] The specific embodiments of the present application are further described below. It is to be understood that the description of these embodiments is intended to help understand the present application and is not intended to limit the present application. Furthermore, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0037] The experimental methods in the following examples are all conventional methods unless otherwise specified. The experimental materials used in the following examples are all commercially available unless otherwise specified.

[0038] The biological electrochemical reaction system shown in the accompanying drawings is used for treating steel pickling waste liquid, and the biological electrochemical device used in the embodiments of the present application is shown in the accompanying drawings. Figure 1 The biological electrochemical reaction system shown in the accompanying drawings is used for treating steel pickling waste liquid, and the biological electrochemical device used in the embodiments of the present application is shown in the accompanying drawings. Figure 1 The biological electrochemical reaction system shown in the accompanying drawings is used for treating steel pickling waste liquid, and the biological electrochemical device used in the embodiments of the present application is shown in the accompanying drawings. The anode of the biological electrochemical device used in the embodiments of the present application is a carbon brush, and the cathode is a carbon electrode prepared by using carbon felt as a substrate and sintering pure acetylene black-PTFE. A cation exchange membrane is used between the anode and the cathode, 100 ml of anaerobic granular sludge (purchased from Zikun Environmental Protection) is added to the anode chamber, and 110 ml of nutrient solution is added to culture the sludge, and the pH of the anode liquid is adjusted to 6.5-8; the components and concentrations of the nutrient solution are as follows: anhydrous disodium hydrogen phosphate 9.5 g / L, potassium dihydrogen phosphate 9.1 g / L, ammonium chloride 0.5 g / L, and sodium acetate 1.5 g / L. About 165 ml-185 ml of pickling waste liquid or ferric chloride solution with different dilution multiples is added to the cathode chamber, and the pickling waste liquid and the ferric chloride are adjusted to the same pH.

[0039] In the following examples, the steel pickling waste liquid to be treated is taken from Foshan Kelang Environmental Protection Technology Co., Ltd., and the main physicochemical properties are as follows: color yellow-brown, colority 1000-1220, H + 600-800 mg / L, total Fe 24000-90000 mg / L, Fe 2+ 10000-20000 mg / L, Fe 3+ 14000-70000 mg / L, Cl - 190000-207410 mg / L, SO4 2- 920-980 mg / L, NO3 - 730-760 mg / L, Mn 14-16 mg / L.

[0040] In the present application, the physicochemical properties of the steel pickling waste liquid to be reacted are as follows: color yellow-brown, colority 500-620, H + 300-400 mg / L, total Fe 12000-45000 mg / L, Fe 2+ 5000-10000 mg / L, Fe 3+ 7000-35000 mg / L, Cl -80000-103705 mg / L, SO4 2- 460-490 mg / L, NO3 - 360-380 mg / L, Mn 7-8 mg / L.

[0041] Example 1 explores the reaction mechanism and effect of steel pickling waste liquid in a bioelectrochemical reaction system

[0042] A 1000 Ω resistor was used to connect the cathode and anode, and four reaction cycles were set, each cycle being seven days. The voltage change was measured during the entire period from the start of each cycle to the end of the reaction, and it was observed that the voltage data was higher than 0.6 V, which indicated a successful start and entry into the running period. During the running period, 4 to 5 samples were taken to measure the pH change, and the anode liquid pH was maintained at 6.5-8. When the voltage data was observed to drop to a standstill, the reaction cycle was ended, and the anode liquid was replaced after one cycle for the next reaction cycle.

[0043] Diluted two times steel pickling waste liquid was used as the cathode liquid of the bioelectrochemical reaction system. The voltage changes of the four cycles are shown in Figure 2 From cycle 1 to cycle 4, the average voltage value gradually increased, which may be due to the fact that the microorganisms in the reactor gradually adapted to the reaction environment, and the biological activity gradually increased, resulting in a gradual increase in the power generation capacity. The data of cycle 4 was ideal and more consistent with the theoretical basis for the successful start of bioelectrochemistry (voltage > 0.6 V), so the data of this cycle was selected for comparison of other parameters.

[0044] The voltage data of the diluted two times steel pickling waste liquid group and the FeCl3 group in cycle 4 are shown in Figure 3 FeCl3 (Fe 3+ concentration was used as the cathode liquid for the comparison, as shown in the attached Figure 3 The data showed that the FeCl3 group quickly reached the required voltage for starting, while the steel pickling waste liquid group also reached the starting voltage after four hours. After starting, the voltage of both groups showed an increasing trend, but the peak voltage reached by the steel pickling waste liquid group was slightly higher than that of the FeCl3 group. The total time of the reaction period for both groups in this cycle was about 1000 min (voltage > 0.6 V). It can be seen that the steel pickling waste liquid and acidic FeCl3 have similar power generation effects. It is worth mentioning that the pH data of the two groups of solutions in this reaction cycle are shown in Figure 4As shown in the figure, the pH of the two groups of solutions only slightly increases, and the pH of the FeCl3 group is slightly higher than that of the steel pickling wastewater group as a whole. After the reaction, the iron content of the two groups was measured, and the concentration of divalent iron ions of the two groups was increased, and the concentration of trivalent iron ions was decreased. The above data all show that the steel pickling wastewater conforms to the theoretical reaction mechanism of generating Fe(II) by discharging Fe(III) as an electron acceptor, further proving that the steel pickling wastewater can be used as the cathode liquid of the bioelectrochemical system to generate electricity.

[0045] Example 2 explores the effect of the dilution multiple of steel pickling wastewater on the bioelectrochemical reaction

[0046] The experiment uses dilution two times and dilution five times of steel pickling wastewater to generate voltage, and the same cycle 4 selected in example 1 is selected for comparison, and the voltage data change trend of the two is as shown in Figure 5 The data show that the voltage change trend of the dilution five times group is roughly the same as that of the dilution two times group, but the overall data is significantly lower than that of the dilution two times group, and the starting voltage of 0.6V is not reached, because the increase of the dilution multiple reduces the content of Fe(III) in the steel pickling wastewater, resulting in a decrease in the electricity generation capacity.

[0047] The pH data of the two groups of solutions in this reaction cycle are as shown in Figure 6 Due to the increase of the dilution multiple, the pH of the dilution five times group is slightly higher than that of the dilution two times group, but the overall change trend is still similar. After the reaction, the iron content of the two groups was measured, and the iron content of the dilution five times group was lower than that of the dilution two times group, but the change trend of the concentration of divalent iron ions was increased and the concentration of trivalent iron ions was decreased. Compared with the dilution five times of steel pickling wastewater, the dilution two times of steel pickling wastewater has better electricity generation effect, and the pH value is more conducive to the reaction, and is more suitable as the cathode starting liquid of the bioelectrochemical system.

[0048] Example 3 explores the application effect of steel pickling wastewater after bioelectrochemical reaction in the coagulation process

[0049] After the steel pickling wastewater is subjected to the bioelectrochemical reaction, a large amount of Fe(II) is generated, and Fe(II) is usually used as a material for sewage coagulation treatment. The experiment uses dilution two times and five times of steel pickling wastewater before and after the reaction for coagulation treatment, and 50mL of deionized water and 0.5mL of 9g / L gentian violet solution are selected for the experiment as the coagulation treatment of printing and dyeing wastewater, and then 180uL of 3moL sodium hydroxide solution is added, and finally 0.5mL of dilution two times and five times of steel pickling wastewater before and after the reaction is added for coagulation treatment. The pH data are as shown in Figure 7 The decolorization rate (which can be regarded as the coagulation effect) in the coagulation process is as shown in Figure 8

[0050] ​From the experimental data, it can be seen that, whether the steel pickling wastewater is diluted by two times or five times, the decolorization rate in the coagulation process, i.e. the application effect, is greatly improved after the bioelectrochemical reaction. This may be because, after the bioelectrochemical reaction, a large amount of Fe(II) is generated, and a large amount of H + is consumed at the same time, resulting in an increase in the alkalinity of the solution. Compared with the pickling wastewater without bioelectrochemical reaction, the pickling wastewater after the reaction has a smaller influence on the pH when added to the sewage to be coagulated, and is more conducive to the hydrolysis of Fe(II), thereby better generating Fe(OH)3 to achieve a better coagulation treatment effect.

[0051] Example 4: Application effect of steel pickling wastewater in Fenton-like treatment process

[0052] Fenton oxidation is a commonly used process for treating organic wastewater, and the reaction requires an acidic condition and a large amount of Fe(II), and the steel pickling wastewater has both of these conditions. In order to explore the application effect of the steel pickling wastewater in Fenton treatment, the steel pickling wastewater with different dilution ratios before and after the reaction was used to treat dye wastewater containing carbamazepine (carbamazepine is one of the main pollutants in pharmaceutical wastewater). In the experiment, 50 ml of dye containing carbamazepine (0.09 mol / L gentian violet and 10 mg / L carbamazepine) was selected as the printing and dyeing wastewater to be treated by Fenton-like process, then hydrogen peroxide solution was added to make the hydrogen peroxide concentration in the solution be 25 mg / L, and finally 0.5 mL of the steel pickling wastewater diluted by two times and five times before and after the reaction was added for Fenton-like treatment. The experimental treatment data are shown in Table 2. Figure 9 As shown in the experimental data, the degradation rate of carbamazepine in each experimental group is 100%, which can be approximately regarded as the treatment effect. Therefore, it can be seen that the steel pickling wastewater has excellent effect in Fenton-like treatment and can become an excellent raw material for Fenton-like treatment. It is worth mentioning that, after the steel pickling wastewater is treated by the bioelectrochemical system, the decrease in pH when the wastewater is added to the Fenton-like treated wastewater is smaller than that of the steel pickling wastewater without bioelectrochemical treatment, and the reagent required for subsequent pH adjustment of Fenton reaction can be saved. Therefore, it can be concluded that, compared with the untreated steel pickling wastewater, the steel pickling wastewater after the bioelectrochemical reaction is more suitable for Fenton-like treatment.

[0053] The embodiments of the present application are described in detail above, but the present application is not limited to the described embodiments. For those skilled in the art, various changes, modifications, replacements and variations of the embodiments can be made without departing from the principles and spirits of the present application, and still fall within the protection scope of the present application.

Claims

1. An application of steel pickling wastewater treated using a bioelectrochemical system in the preparation of coagulants or in Fenton-like wastewater treatment, characterized in that, The method for resource-based treatment of steel pickling waste liquid using a bioelectrochemical system includes the following steps: (1) Add anaerobic granular sludge and nutrient solution to the anode chamber of the bioelectrochemical device and adjust the pH of the anolyte in the anode chamber to 6.5-8; add the steel pickling waste liquid to be treated to the cathode chamber of the bioelectrochemical device; the cathode chamber and the anode chamber are separated by a cation exchange membrane; (2) Use a 900-1100Ω resistor to connect the cathode and anode, set multiple reaction cycles, and measure the voltage change during the entire period from the start of each cycle to the end of the reaction. When the voltage data is observed to drop to a standstill, end the reaction cycle, replace the anode liquid, and proceed to the next reaction cycle. When the voltage data is observed to be higher than 0.6V, the start is successful, that is, the steel pickling waste liquid is treated.

2. The application of the steel pickling wastewater treated by the bioelectrochemical system according to claim 1 in the preparation of coagulants or Fenton-like wastewater treatment, characterized in that, The nutrient solution consists of: (9-10) g / L anhydrous disodium hydrogen phosphate, (8.5-9.5) g / L potassium dihydrogen phosphate, (0.4-0.6) g / L ammonium chloride, and (1.2-1.8) g / L sodium acetate.

3. The application of the steel pickling wastewater treated by the bioelectrochemical system according to claim 2 in the preparation of coagulants or Fenton-like wastewater treatment, characterized in that, The VSS / TSS of the anaerobic granular sludge is 0.8±0.1; the volume ratio of the granular sludge to the nutrient solution is 1:(1-1.2).

4. The application of the steel pickling wastewater treated by the bioelectrochemical system according to claim 1 in the preparation of coagulants or Fenton-like wastewater treatment, characterized in that, The composition of the steel pickling waste liquid includes: (120-800) mg / LH⁺ + (3000-70000) mg / L Fe 3+ (2000-20000) mg / L Fe 2+ (40000-207410) mg / L Cl - (200-980) mg / L SO4 2 (150-760) mg / L NO3 - (3-16) mg / L Mn.

5. The application of the steel pickling wastewater treated by the bioelectrochemical system according to claim 4 in the preparation of coagulants or Fenton-like wastewater treatment, characterized in that, The volume ratio of the anolyte to the catholyte is 1:(0.7-1).

6. The application of the steel pickling wastewater treated by the bioelectrochemical system according to claim 1 in the preparation of coagulants or Fenton-like wastewater treatment, characterized in that, The anode material of the bioelectrochemical device is a carbon brush; the cathode is a carbon electrode prepared by sintering pure acetylene black-PTFE with carbon felt as the substrate.

7. The application of the steel pickling wastewater treated by the bioelectrochemical system according to claim 1 in the preparation of coagulants or Fenton-like wastewater treatment, characterized in that, In step (2), 3-5 reaction cycles are set, with each cycle lasting 5-7 days.

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