A method for removing hexavalent chromium by using the interaction of microorganisms with copper ions

Abstract

The application provides a method for removing hexavalent chromium by using the interaction between microorganisms and copper ions, comprising the following steps: S1, providing microorganisms, wherein the microorganisms comprise Alcaligenes faecalis; S2, obtaining a treatment liquid with a combined system; the treatment liquid contains hexavalent chromium and divalent copper ions; wherein the initial concentration of the hexavalent chromium in the treatment liquid is 50-500 mg / L, and the initial concentration of the divalent copper ions in the treatment liquid is 10-100 mg / L; and S3, culturing the microorganisms in the treatment liquid to remove the hexavalent chromium in the treatment liquid. The application can quickly and efficiently remove the hexavalent chromium in water bodies.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water pollution treatment, and particularly relates to a method for removing hexavalent chromium by utilizing the interaction between microorganisms and copper ions. BACKGROUND

[0002] Chromium is the second largest heavy metal pollution source in industrial wastewater, and exists in the form of Cr(III) and Cr(VI) in the water environment, the toxicity of which is closely related to the valence state, and the toxicity of Cr(VI) is the strongest, about 100 times that of Cr(III). Cr(VI), as a highly soluble and highly mobile toxic substance, has teratogenicity, permeability, mutagenicity and persistence, and is listed as one of the eight chemical substances that threaten the health of organisms. Therefore, converting highly toxic Cr(VI) into Cr(III) with lower toxicity is considered to be the main idea for repairing Cr(VI) pollution.

[0003] Compared with traditional physical and chemical methods, microbial remediation technology has many advantages, such as high cost-effectiveness, easy to implement on a large scale, good environmental compatibility, etc., and has become a remediation method that attracts much attention. In natural water environment, one of the main detoxification mechanisms of microorganisms to survive under Cr(VI) exposure is to reduce toxic Cr(VI) to Cr(III) with relatively small toxicity, and to precipitate at near neutral pH.

[0004] At present, there are many microorganisms for removing Cr(VI), for example, P. phragmitetus D1 (CGMCC No. 1.6399) is involved in Multi-omics response of Pannonibacter phragmitetus BB to hexavalent chromium, which can be used to remove hexavalent chromium; however, through actual exploration, the removal rate of P. phragmitetus D1 bacteria to Cr(VI) is only 65.4% after reacting in a single Cr(VI) system for 72h.

[0005] In view of this, it is necessary to provide a method for removing hexavalent chromium by utilizing the interaction between microorganisms and copper ions, so as to solve or alleviate the technical defect that the removal rate of P. phragmitetus D1 bacteria to Cr(VI) is not high. SUMMARY

[0006] The main purpose of the present application is to provide a method for removing hexavalent chromium by utilizing the interaction between microorganisms and copper ions, which aims to solve the technical problem that the removal rate of P. phragmitetus D1 bacteria to Cr(VI) is not high.

[0007] To achieve the above object, the application provides a method for removing hexavalent chromium by using the interaction between microorganisms and copper ions, comprising the steps of:

[0008] S1, providing microorganisms, wherein the microorganisms comprise Alcaligenes plantonicus;

[0009] S2, obtaining a treatment liquid with a combined system; the treatment liquid contains hexavalent chromium and divalent copper ions;

[0010] wherein the initial concentration of the hexavalent chromium in the treatment liquid is 50-500 mg / L, and the initial concentration of the divalent copper ions in the treatment liquid is 10-100 mg / L;

[0011] S3, culturing the microorganisms in the treatment liquid to remove the hexavalent chromium in the treatment liquid.

[0012] Further, the source of the treatment liquid comprises any one of the following:

[0013] taking a first initial liquid containing the hexavalent chromium and the divalent copper ions, and taking the first initial liquid as the treatment liquid;

[0014] taking a second initial liquid containing the hexavalent chromium, and then adding the divalent copper ions to the second initial liquid to obtain the treatment liquid;

[0015] taking a third initial liquid containing the hexavalent chromium and the divalent copper ions, and then supplementing the divalent copper ions to the third initial liquid to obtain the treatment liquid.

[0016] Further, one or more of the first initial liquid, the second initial liquid, and the third initial liquid is hexavalent chromium-containing industrial wastewater.

[0017] Further, the treatment liquid has nutrients for the growth of the microorganisms.

[0018] Further, the nutrients comprise a carbon source, a nitrogen source, a phosphorus source, and trace elements.

[0019] Further, in the step S3, before the culturing of the microorganisms in the treatment liquid, the method further comprises:

[0020] obtaining a bacterial liquid containing the microorganisms grown to the logarithmic phase;

[0021] adding the microorganisms in the bacterial liquid to the treatment liquid, and the volume percentage of the bacterial liquid to the treatment liquid is not less than 5%.

[0022] Further, the OD 600 of the bacterial liquid is 1.0.

[0023] Further, the pH of the processing liquid is 9-10.

[0024] Further, the temperature of the culture is 25-45 DEG C, and the duration of the culture is no less than 12h.

[0025] Further, the plant P. phragmitetus D1 includes P. phragmitetus D1.

[0026] Compared with the prior art, the present application has at least the following advantages:

[0027] The present application provides a method for removing hexavalent chromium in water body by using the interaction of P. phragmitetus D1 bacteria and divalent copper ions, by obtaining P. phragmitetus D1 bacteria-Cu(II)-Cr(VI) combined treatment system, and culturing the combined treatment system, Cr(VI) can be basically completely removed in 20h, which provides a new idea for expanding the practical application of microbial Cr(VI) reduction; compared with the Cr(VI) system alone, the maximum removal rate of P. phragmitetus D1 bacteria to Cr(VI) is only 65.4% after 72h of reaction. Therefore, the method for removing Cr(VI) in water body by using Cu(II) to strengthen P. phragmitetus D1 bacteria provided by the present application fully utilizes the synergistic treatment effect of P. phragmitetus D1 bacteria and divalent copper ions on Cr(VI), and has high treatment rate and short treatment time for Cr(VI) in Cr(VI) containing wastewater. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained according to the structures shown in these drawings without creative labor.

[0029] Figure 1 Data effect diagram for the influence of Cr(VI) on the growth of P. phragmitetus D1 bacteria in Example 1 of the present application;

[0030] Figure 2 Data effect diagram for the influence of Cu(II) on the growth of P. phragmitetus D1 bacteria in Example 2 of the present application;

[0031] Figure 3Data effect diagram for the data of the influence of coexistence of Cu(II) and Cr(VI) on the growth of P.phragmitetus D1 bacteria in embodiment 3 of the present application;

[0032] Figure 4 Data effect diagram for the data of the Cr(VI) removal capacity of P.phragmitetus D1 bacteria in embodiment 4 of the present application;

[0033] Figure 5 Data effect diagram for the data of the Cr(VI) removal capacity of P.phragmitetus D1-Cu(II)-Cr(VI) combined treatment system (reaction solution) in embodiment 5 of the present application;

[0034] Figure 6 XPS diagram of the product after P.phragmitetus D1-Cu(II)-Cr(VI) combined treatment system (reaction solution) is cultured for 12h in embodiment 6 of the present application; wherein (a) is the XPS diagram of Cr, and (b) is the XPS diagram of Cu.

[0035] Figure 7 Microbial SEM diagram before and after P.phragmitetus D1-Cu(II)-Cr(VI) combined treatment system (reaction solution) is cultured in embodiment 7 of the present application; wherein (a) is the microbial SEM diagram after being cultured for 0h, and (b) is the microbial SEM diagram after being cultured for 24h.

[0036] The implementation, functional features and advantages of the present application will be further described with reference to the accompanying drawings. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the protection scope of the present application.

[0038] In addition, the technical solutions in each embodiment of the present application can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can realize the combination, and when the combination of technical solutions appears to be contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is also not within the protection scope claimed by the present application.

[0039] As a further explanation of the drawings in the specification, Figure 1 The concentration value in the formula (I) represents the concentration of Cr(VI), Figure 2The concentration value in the table represents the concentration of divalent copper ion Cu(II). In addition, P.phragmitetus D1 is referred to as D1 in the drawings; and in D1-Cu(II)-Cr(VI), Cu(II)-Cr(VI) and D1-Cr(VI), D1 represents that P.phragmitetus D1 provided in the corresponding examples is contained in the reaction solution, and the concentration value before Cu(II) and the concentration value before Cr(VI) represent the concentration of Cu(II) and Cr(VI) in the corresponding medium, respectively.

[0040] It should be understood that the chromium-polluted water body is a complex system, in which Cr(VI) usually coexists with other heavy metals, thereby affecting the life activities of microorganisms and changing the ability and efficiency of microorganisms to reduce Cr(VI).

[0041] Cu(II) is a common coexisting heavy metal in Cr(VI)-polluted sites (such as electroplating plants, tanneries, chemical manufacturing plants and metal processing sites), but it is not clear whether Cu(II) has a positive or negative effect on the biological reduction of Cr(VI); therefore, in order to improve the practicality of the microbial remediation technology in the application of Cr(VI) in wastewater environment, it is crucial to use the coexisting heavy metal divalent copper ion Cu(II) to strengthen the ability of microorganisms to reduce hexavalent chromium.

[0042] The present application provides a method for removing hexavalent chromium by using the interaction between microorganisms and copper ions, comprising the steps of:

[0043] S1, providing microorganisms, wherein the microorganisms comprise or are Pannonibacter phragmitetus; the Pannonibacter phragmitetus can comprise or be P.phragmitetus D1 (Pannonibacter phragmitetus D1); in the present application, the P.phragmitetus D1 is purchased from Beina Chuanglian Biotechnology Co., Ltd.

[0044] Specifically, in use, the P.phragmitetus D1 stored at-80℃ can be activated and cultured in 20 mL of culture solution for 12-18 h, and then 2 mL of the activated P.phragmitetus D1 bacteria can be inoculated into 100 mL of culture solution for expansion culture; the culture solution can be 25 g / L LB liquid medium (25 g of LB broth is dissolved in 1 L of pure water). In the subsequent examples of the present application, the culture medium used is LB medium.

[0045] S2, obtaining a treatment solution with a combined system; the treatment solution contains hexavalent chromium and divalent copper ions.

[0046] The pH of the treatment liquid can be 9-10; the treatment liquid can have nutrients for growth and metabolism of the microorganism, and the nutrients can include or be carbon source, nitrogen source, phosphorus source and trace elements.

[0047] The carbon source can include or be one or more of sodium lactate, lactic acid, glucose and yeast extract; the nitrogen source can include or be peptone; and the phosphorus source can include or be one or more of potassium dihydrogen phosphate and dipotassium hydrogen phosphate.

[0048] The initial concentration of the hexavalent chromium in the treatment liquid is 50-500 mg / L, and the initial concentration of the divalent copper ion in the treatment liquid is 10-100 mg / L. In subsequent embodiments of the present application, the divalent copper ion Cu(II) is specifically provided by CuSO4, that is, the Cu(II) in the present application is a divalent copper ion; and in subsequent embodiments of the present application, Cr(VI) is specifically provided by K2Cr2O7. It should be noted that since the divalent copper ion exists in the treatment liquid in ionic form, it is not equivalent to insoluble copper oxide and other divalent copper-containing substances.

[0049] The source of the treatment liquid includes or is any one of the following:

[0050] Taking a first initial liquid containing both the hexavalent chromium and the divalent copper ion as the treatment liquid;

[0051] Taking a second initial liquid containing the hexavalent chromium, and then adding the divalent copper ion to the second initial liquid to obtain the treatment liquid;

[0052] Taking a third initial liquid containing both the hexavalent chromium and the divalent copper ion, and then supplementing the divalent copper ion to the third initial liquid to obtain the treatment liquid.

[0053] One or more of the first initial liquid, the second initial liquid and the third initial liquid can be hexavalent chromium-containing industrial wastewater.

[0054] S3, culturing the microorganism in the treatment liquid to remove the hexavalent chromium in the treatment liquid.

[0055] The temperature of the culture can be 25-45℃, and specifically can be 30-40℃; the duration of the culture can be no less than 12 h, and specifically can be 12-72 h; and the culture can be carried out under oscillation, and the rotation speed of the oscillation can be 150 rpm.

[0056] Before the microorganism is cultured in the treatment liquid, a bacterial solution can be obtained, the bacterial solution can contain or only contain the microorganism P.phragmitetus D1 grown to the logarithmic phase, and the OD 600 = 1.0.

[0057] Then, the microorganism in the bacterial solution is added to the treatment liquid to obtain a D1 bacterial-Cu-Cr combined treatment system (reaction liquid), and the volume percentage of the bacterial solution to the treatment liquid can be not less than 5%, and specifically can be 10-100%.

[0058] It should be known that the purpose of the present application is to provide a method for strengthening P.phragmitetus D1 bacteria and Cr(IV) in a purified water body by using divalent copper ions Cu(II); by changing the copper ion and P.phragmitetus D1 bacterial system environment, the key physiological and ecological factors affecting chromium enrichment are determined, and then by controlling the key physiological and ecological factors, the synergistic effect of P.phragmitetus D1 bacteria and copper ions is fully exerted, thereby providing important theoretical reference and practical guidance for improving the microbial remediation efficiency of Cr(VI) contaminated water bodies.

[0059] In the present application, P.phragmitetus D1 bacteria have strong tolerance to Cr(VI) and Cu(II), and in a single Cr(VI) system, the maximum removal rate of P.phragmitetus D1 bacteria is only 65.4% after 72h of reaction, and the addition of Cu(II) greatly promotes the efficiency of P.phragmitetus D1 bacteria, and Cr(VI) can be completely removed in 20h at the fastest, which provides a new idea for expanding the practical application of P.phragmitetus D1 bacteria in treating Cr(VI).

[0060] The following are specific examples of the present invention:

[0061] Example 1

[0062] Effect of Cr(VI) on P.phragmitetus D1 bacterial growth:

[0063] Liquid culture media containing Cr(VI) with Cr(VI) concentrations of 0, 50, 100, 250, 500 and 1000ppm (mg / L) were obtained, and then the pH of the culture medium was adjusted to 9 by using 0.1M / L HCl solution and 1g / L NaOH solution.

[0064] The activated P. phragmitetus D1 culture solution (OD = 1.0) was added to the liquid medium with different Cr(VI) concentrations to obtain a plurality of reaction solutions; for each reaction solution, the volume ratio of the P. phragmitetus D1 culture solution to the liquid medium was 2%.

[0065] The reaction solution was placed in a constant temperature shaker at 30°C, 150 r·min -1 The constant temperature shaker was shaken and cultured, and 2 mL of the reaction solution was taken at different time points during the culture process to measure the OD by a spectrophotometer. 600 .

[0066] As shown in Figure 1 , when the Cr(VI) concentration was 50 ppm, the growth of P. phragmitetus D1 had almost no effect; as the Cr(VI) concentration gradually increased, the toxic effect on P. phragmitetus D1 gradually increased, and when the concentration was 1000 ppm, P. phragmitetus D1 could not grow.

[0067] Example 2

[0068] Effect of Cu(II) on the growth of P. phragmitetus D1:

[0069] The liquid medium containing Cu(II) with Cu(II) concentrations of 0, 10, 25, 50, and 100 ppm was obtained, and then the pH of each liquid medium was adjusted to 9 using 0.1 M / L HCl solution and 1 g / L NaOH solution.

[0070] The activated P. phragmitetus D1 culture solution (OD = 1.0) was added to the liquid medium with different Cu(II) concentrations to obtain a plurality of reaction solutions; for each reaction solution, the volume ratio of the P. phragmitetus D1 culture solution to the liquid medium was 2%.

[0071] The reaction solution was placed in a constant temperature shaker at 30°C, 150 r·min -1 The constant temperature shaker was shaken and cultured, and 2 mL of the reaction solution was taken at different time points during the culture process to measure the OD by a spectrophotometer. 600 .

[0072] As shown in Figure 2 , within the range of 100 ppm concentration, Cu(II) promoted the growth of P. phragmitetus D1; and as the Cu(II) concentration gradually increased, the promoting effect also gradually increased.

[0073] Example 3

[0074] Effect of Cu(II) and Cr(VI) coexistence on the growth of P. phragmitetus D1:

[0075] Test group:

[0076] Liquid medium of Cu(II)-Cr(VI) combined system with Cu(II) concentration of 10, 30, 50, 100 ppm was obtained respectively; in each Cu(II)-Cr(VI) combined system, the concentration of Cr(VI) was 50 ppm. Then, 0.1 M / L HCl solution and 1 g / L NaOH solution were used to adjust the pH of each liquid medium to 9.

[0077] Activated P. phragmitetus D1 culture solution (OD = 1.0) was added to the liquid medium of Cu(II)-Cr(VI) combined system with different Cu(II) concentrations above to obtain multiple reaction liquids; for each reaction liquid, the volume ratio of P. phragmitetus D1 culture solution to liquid medium was 2%.

[0078] The reaction liquids were placed in a constant temperature shaker for incubation at 30°C, 150 r·min -1 During the incubation, 2 ml of reaction liquid was taken at intervals to measure OD 600 .

[0079] Control group:

[0080] Compared with the test group, in the liquid medium of Cu(II)-Cr(VI) combined system, the combined system was 50 ppm Cu(II)-50 ppm Cr(VI), i.e. the concentration of Cu(II) was 50 ppm and the concentration of Cr(VI) was 50 ppm, and the pH of the medium was consistent with that of the test group; in the control group, P. phragmitetus D1 culture solution was not added to the liquid medium above.

[0081] The liquid medium of Cu(II)-Cr(VI) combined system was placed in a constant temperature shaker for incubation at 30°C, 150 r·min -1 During the incubation, 2 ml of reaction liquid was taken at intervals to measure OD 600 .

[0082] As shown in Figure 3 , under the condition of Cr(VI) concentration of 50 ppm, low concentration (10-100 ppm) coexisting Cu(II) had no inhibitory effect on the growth of P. phragmitetus D1; compared with the single Cr(VI) system, Cu(II) in the combined system had a promoting effect on the growth of P. phragmitetus D1.

[0083] Combined with Examples 1, 2, and 3, P. phragmitetus D1 exhibits strong tolerance to Cr(VI) and Cu(II) promotes its growth. These practical results indicate that P. phragmitetus D1 has the potential to adapt to certain complex industrial environments.

[0084] Example 4

[0085] The Cr(VI) removal capacity of P. phragmitetus D1:

[0086] Liquid culture media containing Cr(VI) with concentrations of 50, 100, 250, and 500 ppm were obtained, and the pH of the culture media was adjusted to 9 using 0.1 M / L HCl solution and 1 g / L NaOH solution.

[0087] Take the activated P. phragmitetus D1 culture medium (OD = 1.0) after 8 hours of activation, centrifuge the P. phragmitetus D1 culture medium (8000 rpm, 5 min), remove the supernatant and retain the precipitate (microorganism), and add the precipitate to each of the above liquid culture media to obtain multiple reaction solutions; wherein, for each reaction solution, the volume ratio of P. phragmitetus D1 culture medium (for ease of calculation, the actual added precipitate) to liquid culture medium is 10%.

[0088] The above reaction solutions were placed at 30°C and 150 rpm. -1 The mixture was cultured in a constant temperature shaker for 3 days. During the culture, 2 mL of the reaction solution was taken at different time intervals and centrifuged (8000 rpm, 5 min) to obtain the supernatant. The supernatant was filtered through a microporous membrane (pore size of 0.45 μm) and the Cr(VI) content was determined by ICP-OES.

[0089] like Figure 4 As shown, when the initial Cr(VI) concentration was 50 mg / L, only about 65.4% of Cr(VI) was removed by P. phragmitetus D1 after 72 hours; as the initial Cr(VI) concentration increased, the Cr(VI) removal efficiency of P. phragmitetus D1 decreased, and the maximum removal capacity of P. phragmitetus D1 for Cr(VI) was 34.6 mg.

[0090] Example 5

[0091] Cu(II) enhances the removal capacity of P. phragmitetus D1 bacteria for Cr(VI):

[0092] Test group:

[0093] Obtain liquid medium (treatment liquid) of Cu(II)-Cr(VI) combined system with Cu(II) concentration of 0, 10, 30, 50, 100 ppm respectively; in each Cu(II)-Cr(VI) combined system, the concentration of Cr(VI) is 50 ppm. Then adjust the pH of each liquid medium to 9 by using 0.1M / L HCl solution and 1g / L NaOH solution.

[0094] Take P. phragmitetus D1 bacterial culture solution (OD = 1.0) activated for 8h, centrifuge the P. phragmitetus D1 bacterial culture solution (8000rpm, 5min), and remove the supernatant to retain the precipitate (microorganism), add the precipitate to each of the above liquid media to obtain multiple reaction liquids; wherein for each reaction liquid, the volume ratio of P. phragmitetus D1 bacterial culture solution to liquid medium is 10%.

[0095] Place each of the above reaction liquids in a constant temperature shaker at 30℃, 150r·min -1 Shake and cultivate for 3d, and during the cultivation process, take 2mL reaction liquid at different time intervals, centrifuge (8000rpm, 5min) to obtain the supernatant, filter the supernatant with a microporous filter membrane (pore size is 0.45μm), and use ICP-OES to determine the Cr(VI) content.

[0096] Control group:

[0097] Compared with the test group, in the medium of Cu(II)-Cr(VI) combined system, the combined system is 50ppm Cu(II)-50ppm Cr(VI), i.e. the concentration of Cu(II) is 50ppm and the concentration of Cr(VI) is 50ppm, and the pH of the medium is consistent with that of the test group; in the control group, P. phragmitetus D1 bacterial culture solution is not added to the above medium.

[0098] Place the liquid medium of Cu(II)-Cr(VI) combined system in a constant temperature shaker at 30℃, 150r·min -1 Shake and cultivate for 3d, and during the cultivation process, take 2mL liquid medium at different time intervals, centrifuge (8000rpm, 5min) to obtain the supernatant, filter the supernatant with a microporous filter membrane (pore size is 0.45μm), and use ICP-OES to determine the Cr(VI) content.

[0099] As Figure 5As shown, in the coexistence system of Cr(VI) and Cu(II), 50mg / L Cr(VI) can be completely reduced by P. phragmitetus D1 within 26 hours.

[0100] However, in the system of Cr(VI) alone (only hexavalent chromium and P. phragmitetus D1 bacteria exist, and the concentration of divalent copper ions is 0), its efficiency is slow. Therefore, the addition of Cu(II) greatly improves the removal capacity of P. phragmitetus D1 bacteria on Cr(VI).

[0101] From Figure 5 It can be seen that when the concentration of Cu(II) increases from 10mg / L to 100mg / L, the concentration of Cu(II) is positively correlated with the Cr(VI) reduction rate of P. phragmitetus D1, and the complete removal time of Cr(VI) decreases from 26 hours to 20 hours.

[0102] Note: Figure 5 In the above-mentioned figure, the dotted line is the reaction solution of the test group corresponding to 100mg / L divalent copper ions, and when the triangular symbol in the dotted line is not easy to identify, the dotted line can be directly used to indicate 100mg / L (ppm) of divalent copper ions.

[0103] Combined Figures 1-4 analysis, the direct reduction of P. phragmitetus D1 on Cr(VI) is relatively slow, which may be due to the toxicity of Cr(VI) and thus affect the removal rate of Cr(VI); but the addition of Cu(II) promotes the growth of the strain, which reduces the toxic effect of Cr(VI) on the strain.

[0104] Example 6

[0105] Cu(II) enhances the process of P. phragmitetus D1 bacteria removing Cr(VI) to change the valence state of heavy metals:

[0106] In order to determine the chemical valence state change of Cr and Cu in the reaction process, the reaction solution after 12h culture of P. phragmitetus D1-50ppm Cu(II)-50ppm Cr(VI) system in Example 5 was taken, that is, the reaction solution (test group) containing P. phragmitetus D1 bacteria corresponding to the culture medium with Cu(II) concentration of 50ppm and Cr(VI) concentration of 50ppm was obtained.

[0107] The reaction solution was centrifuged (8000rpm, 5min) to remove the supernatant, and the precipitate was washed with sterile water several times and freeze-dried to obtain the product after combined treatment and analyzed by XPS.

[0108] As Figure 6 shown in the Cr spectrum, 564.1ev is Cr(III), indicating that the final reduction product of Cr(VI) is Cr(III); in the high-resolution Cu spectrum, 931.78eV is Cu(I) and Cu(0), and 932.6ev is Cu(II), indicating that during the reduction of Cr(VI), Cu is also reduced to produce Cu(I).

[0109] Example 7

[0110] Effect of Cu(II)-Cr(VI) combined treatment system on P.phragmitetus D1 cell:

[0111] In order to determine the effect of Cr and Cu on P.phragmitetus D1 bacteria during the combined treatment process, the reaction liquid after 0h and 24h of culture in the P.phragmitetus D1-50ppm Cu(II)-50ppm Cr(VI) system in Example 5 (test group) was taken.

[0112] The reaction liquid taken at two time points was centrifuged (8000rpm, 5min) to remove the supernatant to obtain P.phragmitetus D1 cell, which was fixed with glutaraldehyde (2.5%) and dehydrated with anhydrous ethanol gradient and freeze-dried, and the dry product was ground and analyzed by SEM using ion sputtering.

[0113] As Figure 7 shown, the cell shape before culture (0h) and after culture (24h) has no difference, indicating that the Cu(II)-Cr(VI) combined treatment process has no effect on P.phragmitetus D1 bacteria.

[0114] In the above technical solution of the present application, the above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation made under the technical concept of the present application, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A method for removing hexavalent chromium by using the interaction of microorganisms with copper ions, characterized in that, The method comprises the steps of: S1, providing microorganisms, wherein the microorganisms comprise P. phragmitetus; S2, obtaining a treatment liquid with a combined system, wherein the treatment liquid contains hexavalent chromium and divalent copper ions; wherein the initial concentration of the hexavalent chromium in the treatment liquid is 50-500 mg / L, and the initial concentration of the divalent copper ions in the treatment liquid is 10-100 mg / L; S3, culturing the microorganisms in the treatment liquid to remove the hexavalent chromium in the treatment liquid.

2. The method of removing hexavalent chromium of claim 1, wherein, The source of the treatment liquid comprises any one of the following: taking a first initial liquid containing the hexavalent chromium and the divalent copper ions as the treatment liquid; taking a second initial liquid containing the hexavalent chromium, and then adding the divalent copper ions to the second initial liquid to obtain the treatment liquid; taking a third initial liquid containing the hexavalent chromium and the divalent copper ions, and then supplementing the third initial liquid with the divalent copper ions to obtain the treatment liquid.

3. The method of removing hexavalent chromium of claim 2, wherein, One or more of the first initial liquid, the second initial liquid, and the third initial liquid is industrial wastewater containing hexavalent chromium.

4. The method of removing hexavalent chromium of claim 1, wherein, The treatment liquid has nutrients for the growth of the microorganisms.

5. The method of removing hexavalent chromium of claim 4, wherein, The nutrients comprise a carbon source, a nitrogen source, a phosphorus source, and trace elements.

6. The method of removing hexavalent chromium of claim 1, wherein, Before the step S3, the method further comprises the steps of: obtaining a bacterial liquid containing the microorganisms grown to the logarithmic phase; adding the microorganisms in the bacterial liquid to the treatment liquid, wherein the volume percentage of the bacterial liquid to the treatment liquid is not less than 5%.

7. The method of removing hexavalent chromium of claim 6, wherein, OD of the bacterial solution 600 = 1.

0.

8. The method of removing hexavalent chromium of claim 1, wherein, The pH of the treatment liquid is 9-10.

9. The method of removing hexavalent chromium of claim 1, wherein, The temperature of the culture is 25-45℃, and the duration of the culture is not less than 12 h.

10. The method of removing hexavalent chromium according to any one of claims 1-9, wherein, The P. phragmitetus comprises P. phragmitetus D1.

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