阅读说明：本技术 一种回收水体中铜离子的方法 (Method for recovering copper ions in water body ) 是由 陈水亮 傅文娜 徐晖 包雨澜 于 2021-08-09 设计创作，主要内容包括：本发明提供了一种回收水体中铜离子的方法,该方法包括以下步骤：将附着在载体上的微生物置于含有铜离子的水体中,或者将微生物分散于含有铜离子的水体中,或者将载体置于含有微生物和铜离子的水体中；使得所述水体中的铜离子被微生物吸附,并与所述微生物组织中或释放的有机磷酸基团或无机磷酸基团结合,形成有机磷酸铜或无机磷酸铜,并成核、结晶,并生长矿化形成花状结构的磷酸铜化合物。在本发明中,利用直接从自然环境中(如生活污水或活性污泥)富集生长的微生物,或直接以这些为接种源在含磷溶液中培养的微生物,吸附、矿化水体中的铜离子,形成花状磷酸盐,从而实现水体中铜离子的去除回收。(The invention provides a method for recovering copper ions in a water body, which comprises the following steps: placing the microorganisms attached to the carrier in a water body containing copper ions, or dispersing the microorganisms in the water body containing copper ions, or placing the carrier in the water body containing microorganisms and copper ions; so that the copper ions in the water body are adsorbed by the microorganisms and combined with organic phosphate groups or inorganic phosphate groups in or released by the microorganism tissues to form organic copper phosphate or inorganic copper phosphate, and the copper phosphate compound with a flower-like structure is formed through nucleation, crystallization and mineralization. In the invention, the copper ions in the water body are adsorbed and mineralized by utilizing microorganisms which are directly enriched and grown from natural environment (such as domestic sewage or activated sludge) or directly cultured in a phosphorus-containing solution by taking the microorganisms as an inoculation source to form flower-shaped phosphate, thereby realizing the removal and recovery of the copper ions in the water body.)

1. A method for recovering copper ions in a water body comprises the following steps:

placing the microorganisms attached to the carrier in a water body containing copper ions, or dispersing the microorganisms in the water body containing copper ions, or placing the carrier in the water body containing microorganisms and copper ions; so that the copper ions in the water body are adsorbed by the microorganisms and combined with organic phosphate groups or inorganic phosphate groups in or released by the microorganism tissues to form organic copper phosphate or inorganic copper phosphate, and the copper phosphate compound with a flower-like structure is formed through nucleation, crystallization and mineralization.

2. The method of claim 1, wherein: the method also comprises the step of collecting the organic copper phosphate or the inorganic copper phosphate after the growth and mineralization.

3. The method according to claim 1 or 2, characterized in that: the microorganism is obtained by directly enriching and growing from domestic sewage or activated sludge; or cultured in a solution containing phosphorus element by using domestic sewage or activated sludge as an inoculation source.

4. The method according to claim 1 or 2, characterized in that: the microorganism is a microorganism with a phosphorus content of > 3%.

5. The method of claim 4, wherein: the microorganism is phosphorus accumulating bacteria with phosphorus content of 6-8%.

6. The method according to claim 1 or 2, characterized in that: the organic phosphate group is an organic matter containing a phosphate group; the inorganic phosphate group is orthophosphate, hydrogen phosphate or dihydrogen phosphate.

7. The method of claim 6, wherein: the organic phosphate group is adenosine triphosphate, nucleic acid or phospholipid.

8. The method according to claim 1 or 2, characterized in that: the copper organophosphate is a copper phosphate compound formed by combining organic phosphate groups and copper ions; the inorganic copper phosphate is a copper phosphate compound formed by an inorganic phosphate group and copper ions.

9. The method according to claim 1 or 2, characterized in that: the concentration range of the copper ions in the water containing the copper ions is 1-200 mg/L.

10. The method of claim 9, wherein: the concentration range of the copper ions in the water containing the copper ions is 1-50 mg/L.

Technical Field

The invention relates to the technical field of sewage treatment, in particular to a method for recovering copper ions in a water body.

Background

Under natural conditions, microorganisms can secrete organic matters through metabolism, regulate the pH of the surrounding environment, change the concentration of mineral ions, finally induce ion mineralization and limit and regulate the process of crystal growth, namely microorganism mineralization. The mineralization of microorganisms has been widely used for the synthesis of nanomaterials, the removal/recovery of nitrogen and phosphorus, the recovery/removal of heavy metal ions in soil or water. The product of microbial mineralization comprises carbonate, phosphate, sulfate, oxalate, iron oxide and the like. For example, Pseudomonas stutzeri can be used to induce mineralized calcium carbonate precipitation [ Wang et al, European Journal of mineral, 2015,27(6):717 729 ] and to fix heavy metal ions during calcium carbonate precipitation; struvite is produced by using magnesium ions and ammonium ions mineralized by genera such as Proteus mirabilis [ Prywer et al, Crystal Growth & Design,2009,9(8): 3538-. Phosphate minerals account for about one fourth of biomineralized minerals, of which struvite (magnesium ammonium phosphate) is the most studied one.

Patent document CN 107352737 a discloses a biological metal recovery method. The method takes sludge in a wastewater treatment pool or sludge in the pool as an inoculation source of sulfate-reducing mixed bacteria, takes a multi-layer wire mesh filler as a carrier, and reduces and adsorbs metal ions (such as copper ions) in wastewater in a fixed bed reactor. The method mainly utilizes sulfate reducing mixed bacteria to reduce and adsorb heavy metal ions in the water body for removal, and recovers the metal through extrusion, drying and straw burning.

Patent document US005520811A discloses a metal enrichment method. The method utilizes enzyme catalysis to decompose phosphate radical formed by polyphosphate enriched in the polyphosphate bacteria body to react with metal ions to form insoluble phosphate to enrich and recover the metal ions. In the method, the time for the microorganism to react with the metal ions is relatively short (less than 24 hours), the interaction between the metal ions and the microorganism only stays in the adsorption reaction stage, the adsorption capacity of the metal ions is relatively low, and the recovery of the enriched metal ions is complex. In addition, the method only aims at specific microorganisms, namely phosphorus accumulating bacteria.

Research shows that the fermentation liquid of Rahnella LRP3 can mineralize copper ions in the solution to form a flower ball-shaped phosphorus-copper compound, and effectively reduce the concentration of the copper ions in the sewage [ 2020, 10.13327/j.jjlau.2020.5024 of Jilin university school newspaper. However, the bacteria need to obtain the phosphorus source by taking sodium phytate, the culture process of a specific strain is complex, the requirement on the biological environment is high, the culture cost is high, and the bacteria are difficult to be applied to material preparation and removal of heavy metal pollution of a water body.

Disclosure of Invention

The invention provides a method for recovering copper ions in a water body, aiming at solving the problem of copper ion pollution and improving the recycling efficiency of the copper ions.

The invention provides a method for recovering copper ions in a water body, which comprises the following steps:

placing the microorganisms attached to the carrier in a water body containing copper ions, or dispersing the microorganisms in the water body containing copper ions, or placing the carrier in the water body containing microorganisms and copper ions; so that the copper ions in the water body are adsorbed by the microorganisms and combined with organic phosphate groups or inorganic phosphate groups in or released by the microorganism tissues to form organic copper phosphate or inorganic copper phosphate, and the copper phosphate compound with a flower-like structure is formed through nucleation, crystallization and mineralization.

In some preferred embodiments, the method further comprises the step of collecting the nucleated growth mineralized organic or inorganic copper phosphate.

In some preferred embodiments, the microorganisms are directly obtained from domestic sewage or activated sludge enrichment growth; or cultured in a solution containing phosphorus element by using domestic sewage or activated sludge as an inoculation source. Preferably, the microorganism is a microorganism with a phosphorus content of > 3% (dry cell weight), such as a polyphosphate containing 6-8% phosphorus.

In some preferred embodiments, the organophosphate group is an organic containing phosphate group, such as adenosine triphosphate, nucleic acids, phospholipids; the inorganic phosphate group may be orthophosphate, hydrogen phosphate or dihydrogen phosphate.

In some preferred embodiments, the copper organophosphate is a copper phosphate compound formed by combining an organic phosphate group with copper ions; the inorganic copper phosphate is a copper phosphate compound formed by an inorganic phosphate group and copper ions.

In some preferred embodiments, the concentration of the copper ions in the water body containing the copper ions ranges from 1 mg/L to 200 mg/L; preferably 1-50 mg/L. The lower the copper ion concentration, the tendency of the copper phosphate to form flower-like structures; the higher the concentration, the less pronounced the flower-like structure.

In the invention, the copper ions in the water body are adsorbed and mineralized by utilizing microorganisms which are directly enriched and grown from natural environment (such as domestic sewage or activated sludge) or directly cultured in a phosphorus-containing solution by taking the microorganisms as an inoculation source to form flower-shaped phosphate, thereby realizing the removal and recovery of the copper ions in the water body. Phosphate and copper ions in the microorganisms form sediments to remove the copper ions in the water body, a biological film enriched on a carrier can be used for adsorbing and recovering the copper ions in the water body, the copper ions are mainly recovered in a flower-shaped copper phosphate form, and phosphorus is recovered in the process.

The invention utilizes the synergistic effect of microorganisms on copper ion adsorption and crystallization mineralization; the adsorption effect can reach saturation in a short time within a few hours; and the crystallization mineralization is that copper ions react with organic and inorganic phosphate radicals in microorganisms to generate precipitates of copper phosphate, copper carbonate compounds and the like, and the crystallization mineralization is carried out, so that the required time is longer. The removal capacity of copper ions can be greatly improved by the crystallization and mineralization of the copper ions by the microorganisms, and meanwhile, the recovery of crystallization and mineralization products is utilized.

Drawings

Fig. 1 shows Scanning Electron Microscope (SEM) morphology (a) and energy spectrometer (EDS) elemental analysis and elemental content (B) of flower-like copper phosphate formed by microbial mineralization on the surface of a carbon brush.

FIG. 2 shows SEM appearance of flower-like copper phosphate formed by mineralization of microorganisms on the surface of charcoal, wherein (A) corresponds to a copper ion concentration of 4mg L in water^-1(B) the concentration of copper ions in the corresponding water body is 8mg L^-1(C) the concentration of copper ions in the corresponding water body is 12mg L^-1(D) the concentration of copper ions in the corresponding water body is 4mg L^-1EDS elemental analysis of the flower-like copper phosphate obtained from the experimental group.

FIG. 3 shows the concentration profile of copper ions for 6 cycles, with the microbial membranes supported on charcoal placed in solutions of different initial copper ion concentrations.

FIG. 4 shows SEM morphology of flower-like copper phosphate formed by mineralized copper ions with biofilm dispersed in solution, where (A) corresponds to a copper ion concentration of 80mg L in water^-1(B) the concentration of copper ions in the corresponding water body is 120mg L^-1(C) the concentration of copper ions in the corresponding water body is 80mg L^-1EDS elemental analysis of the flower-like copper phosphate obtained from the experimental group.

Figure 5 shows SEM morphology of flower-like copper phosphate formed by potentiostatic screened microbial membrane mineralized copper ions.

FIG. 6 shows the copper ion concentration-time curve obtained from two parallel experiments of microbial membrane adsorption mineralization of copper ions, 1-adsorption phase, 2-nucleation mineralization phase; the inset is an enlarged view of the adsorption phase.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the present invention, the method for recovering copper ions in a water body may comprise any one of the following steps:

A. placing the carrier attached with the microorganisms in a water body containing copper ions, so that the copper ions in the water body are combined with organic phosphate groups or inorganic phosphate groups released in or from the microorganism tissues to form organic copper phosphate or inorganic copper phosphate and perform nucleation growth; wherein the microorganism is obtained by directly enriching and growing from domestic sewage or activated sludge; or the microorganism is obtained by culturing domestic sewage or activated sludge serving as an inoculation source in a solution containing phosphorus; the microorganism is attached to the surface of the carrier to form a microbial film; the organic copper phosphate or the inorganic copper phosphate nucleates and grows on a microbial film or a carrier;

B. dispersing the microbial film in a water body containing copper ions, so that the copper ions in the water body are combined with organic phosphate groups or inorganic phosphate groups released in or from the microbial tissue to form organic copper phosphate or inorganic copper phosphate, and nucleating and growing; wherein the microorganism is obtained by directly enriching and growing from domestic sewage or activated sludge; or the microorganism is obtained by culturing domestic sewage or activated sludge serving as an inoculation source in a solution containing phosphorus; the organic copper phosphate or the inorganic copper phosphate nucleates and grows on the microbial film;

C. placing a carrier in a water body containing microorganisms and copper ions, so that the copper ions in the water body are combined with organic phosphate groups or inorganic phosphate groups released in or from the tissues of the microorganisms to form organic copper phosphate or inorganic copper phosphate and nucleate and grow; wherein microorganisms in the water body naturally adhere to the carriers to form a microbial film; the organic copper phosphate or the inorganic copper phosphate nucleates and grows on the microbial film or the carrier.

Example 1:

culturing of microbial membranes and adsorption and mineralization of copper ions: 300mL of municipal sewage (from Nanchang Qingshan lake sewage plant) was used as the mother solution, to which 1.64g L was added^-1Sodium acetate with addition of CuCl₂·2H₂O, keeping the concentration of copper ions at 6mg L^-1. Carbon brush carriers (diameter 3cm, length 6 cm) were placed in the solution and cultured under anaerobic conditions, with the solution being changed every 48h for 10 cycles.

Morphological characterization and elemental analysis: and (3) taking out a microbial membrane sample, soaking the microbial membrane sample in 5 wt.% of glutaraldehyde, taking out the biological membrane after 24 hours, dehydrating the biological membrane in ethanol, and finally drying the biological membrane. The morphology was observed by SEM and the elemental composition of the flower-like material was analyzed by EDS.

An SEM (scanning electron microscope) morphology chart and an EDS (electronic data System) chart of flower-shaped copper phosphate formed on the surface of the carbon brush are shown in the attached figure 1. FIG. 1 shows that in domestic sewage, carbon brush carriers can enrich low-concentration copper ions in a solution while enriching growth microorganisms; the copper ions are enriched on the surface of the carbon brush carrier in a flower-shaped copper phosphate form, so that the carbon brush carrier is easy to recycle.

Example 2:

culturing a microbial membrane: 100mL of municipal sewage is used as a culture solution, and 1.64g L is added^-1Sodium acetate, charcoal carrier (charred at 800 deg.C, with dimensions of 3cm in length, 2cm in width and 2cm in height) is immersed in the solution, and the microbial film is automatically enriched and grown under anaerobic condition.

Adsorption and mineralization of copper ions: placing the microbial film in a container containing 1.64g L^-1Sodium acetate, concentration 4mg L^-1The solution was renewed every 48 hours in the copper ion solution and incubated for 10 cycles.

Morphological characterization and elemental analysis: the procedure is as in example 1. The SEM topography and EDS of the flower-like copper phosphate formed on the surface of charcoal are shown in figure 2.

Detection of copper ion concentration: sampling a water sample to monitor the change of the concentration of copper ions in the solution in each period, wherein the sampling intervals are 0h, 1h, 6h and 20h, 10mL of the solution is taken each time, the solution is filtered by a filter with the pore diameter of 0.2 mu m, the solution is placed in a cuvette, a color reagent is added step by step, and the concentration of the copper ions in the solution is measured by a spectrophotometer. The change of the copper ion concentration in the solution in 6 periods is tested, and the change curve of the copper ion concentration in 6 periods is shown in figure 3.

Example 3:

this example is substantially the same as example 2, except that the copper ion concentration of the solution in this example is 8mg L^-1。

Example 4:

this exampleSubstantially the same as in example 2, except that the copper ion concentration of the solution in this example was 12mg L^-1。

The change curve of the copper ion concentration of 6 periods in the attached FIG. 3 shows that the microbial film can convert 4mg L^-1、8mg L^-1And 12mg L^-1The copper ion with the lower concentration is reduced to less than 1mg L^-1And the method proves that the mineralization of the microbial film can be used for removing the low-concentration copper ions in the recovered water body. Fig. 2 shows that copper ions are enriched on the carrier in flower-like copper phosphate, and are easy to recycle.

Example 5:

culturing a microbial membrane: the same as in example 2.

Adsorption and mineralization of copper ions: scraping off microbial membrane on charcoal carrier, and respectively dispersing in 80mg L^-1、120mg L^-1The copper ion solution is shaken for reaction for 72 hours and then centrifuged to take out the biological membrane.

In this example, the biofilm was peeled off the carrier and dispersed in water. The microorganism film is suspended during the process of adsorbing and mineralizing copper ions and is not supported by a carrier.

Morphological characterization and elemental analysis: soaking the biological membrane in 5 wt.% of glutaraldehyde for 24h, centrifuging, dehydrating with ethanol, and naturally drying. The morphology was observed by SEM and the elemental composition of the flower-like material was analyzed by EDS. The SEM topography and EDS profile of the copper phosphate formed in the biofilm is shown in FIG. 4. The SEM topography showed that spherical copper phosphate grew in suspended biofilms, i.e. the growth of copper phosphate was independent of whether supported by a carrier or not. However, in contrast to the flower-like copper phosphate formed on the support (as in examples 1 and 4), the flower-like structure of the copper phosphate formed in the suspended biofilm was not evident, mixed with the biofilm, and difficult to recover. This indicates that the immobilization of the carrier on the biofilm is important for the growth of flower-like structure copper phosphate and is beneficial for later recovery.

Example 6:

culturing a microbial membrane: containing 1.64g L in 100mL^-1Inoculating domestic sewage in 50mM phosphoric acid buffer solution of sodium acetate, and respectively using stones with sizes of 2cm in length, 2cm in width and 0.4cm in thicknessThe ink plate carrier is a working electrode and a counter electrode, an Ag/AgCl electrode is used as a reference electrode, and a constant potential of +0.2V is applied; after 72h of culture, a layer of reddish-brown microbial film was enriched on the graphite plate carrier.

Adsorption and mineralization of copper ions: and (3) placing the microbial membrane in 20mL of water containing copper ions with the concentration of 20mg/L, and taking out the biological membrane after 72 hours.

Morphological characterization and elemental analysis: the procedure is as in example 1. The SEM topography of the mineralized copper phosphate is shown in figure 5. This example illustrates that an electroactive microbial film (mainly Geobacter) cultured by potentiostatic enrichment can also adsorb and mineralize copper ions in water to form flower-like copper phosphate, using domestic sewage as an inoculum.

Example 7:

culturing a microbial membrane: substantially the same as in example 6, except that the graphite plate carrier was replaced with a graphite brush having bristles of 2cm in height and 3cm in diameter.

Adsorption and mineralization of copper ions: the biological membrane is placed in 20mL with the concentration of 20mg L^-1In the copper ion solution of (2).

Detection of copper ion concentration: the concentration change of copper ions in the copper ion solution was monitored by the same method as in example 2, except that the sampling intervals were varied at intervals of 5min, 30min, 3h, 6h, 12 hours, and the sampling time span was 100 h. The change curve of the copper ion concentration with time is shown in figure 6.

FIG. 6 illustrates the copper ion removal from the microfilm is divided into two processes, adsorption (stage 1) and nucleation mineralization (stage 2). The microbial film firstly adsorbs copper ions in the solution and reaches balance in a short time (0-3 hours); then, the copper ions react with phosphate radicals decomposed in or on the microorganisms, nucleate in or on the microorganisms, and slowly mineralize to form flower-like structures.

Example 8:

culturing a microbial membrane: the same as in example 6.

Adsorption and mineralization of copper ions: 6 microbial membrane electrodes with equivalent mass of the microbial membranes enriched in parallel are respectively placed in 200mL of water body with the copper ion concentration of 20 mg/L. Taking out one microbial membrane electrode every 48 hours, washing with distilled water for 3 times, drying and weighing. The mass data for the different electrodes are shown in table 1.

Calculating the copper ion adsorption mineralization capacity of the microbial film:

capacity of adsorption and mineralization is delta m/m₀；

Wherein m is₀Represents the mass of the dry microorganism; Δ m represents the weight gain of the biofilm.

The results of this example show that the total capacity of the microbial film for the adsorption and mineralization of copper ions reaches 1.12g/g (g copper/g dry microbes), which is about 10 times the adsorption capacity (0.114 g/g).

TABLE 1 adsorption mineralization Capacity of biofilm on copper ions

The above embodiments are only for illustrating the invention and are not to be construed as limiting the invention, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention, therefore, all equivalent technical solutions also fall into the scope of the invention, and the scope of the invention should be defined by the claims.