Method of treatment of polluted soil using Saccharina japonica derived micro-sized biochar

Abstract

The present invention relates to a method for treating contaminated soil using kelp-based microbiochar, wherein the kelp-based microbiochar is prepared by activating peroxymonosulfate using kelp-based microbiochar as a catalyst, and wherein the kelp-based microbiochar comprises the steps of: washing and drying kelp (S1); mixing HTFS (Hydroxyl Terminated Functional Silicone) with the dried kelp and adding ammonia water to grind the dried kelp (S2); pyrolyzing the ground kelp (S3); and adding 0.01 to 0.5 parts by weight of lignin sulfonic acid and 0.01 to 0.5 parts by weight of sodium gluconate to 100 parts by weight of the pyrolyzed kelp, and grinding the pyrolyzed kelp using zirconium beads (S4).

Description

Technology Field

[0001] The present invention relates to a method for advanced oxidation treatment of soil contaminated with recalcitrant trace contaminants of the antibiotic class, such as ciprofloxacin, and more specifically, to a method for purifying contaminated soil by oxidizing trace contaminants of the antibiotic class through the catalytic action of peroxymonosulfate and kelp-based micro biochar. Background Technology

[0003] Antibiotics, known as representative trace pollutants, are not removed by conventional sewage treatment processes, resulting in high persistence and accumulation in the ecosystem, which is known to have adverse effects.

[0004] Ciprofloxacin exhibits antibacterial effects by inhibiting DNA synthesis and is one of the representative residual antibiotics used for acute bacterial sinusitis, acute exacerbations of chronic bronchitis, and simple urinary tract infections.

[0005] Ciprofloxacin has a solubility in water of 30,000 ppm and a log Kow value of 0.28, which indicates hydrophobicity, so it has a large bioaccumulation factor and, as an antibiotic, it has the characteristic of not being easily biodegraded by microorganisms.

[0006] Treatment methods mainly used to purify soil contaminated with organic pollutants, including these antibiotics, include air sparging, bioremediation, biodegradation, phytoremediation, reductive dechlorination, and advanced oxidation.

[0007] Technologies for treating organic pollutants in soil include methods using microorganisms or plants (Korean Patent Registration No. 10-39754), Fenton oxidation (Korean Patent Registration No. 10-1809888), permanganate and persulfate oxidation (Korean Patent Application No. 10-2014-0180542), organic acid soil washing process (Korean Patent Registration No. 10-1717126), nanobubble and inorganic acid multi-stage washing process (Korean Patent Registration No. 10-1768006), and steam extraction (Korean Patent Registration No. 10-41828). However, most of these technologies involve injection methods and injection devices. As with existing methods, the oxidizing agent injected into the ground to treat pollutants reacts with and is consumed not only by the pollutants but also by organic matter in the soil, which increases the amount of oxidizing agent used and can increase the overall purification cost.

[0008] During soil oxidation treatment, the persistence of the oxidizing agent within the soil acts as a major factor. Since the contact time with pollutants increases with duration, there is a need for technology capable of efficiently treating soil contaminated with organic pollutants over the long term. Prior art literature

[0010] Republic of Korea Patent Registration No. 10-39754, etc. The problem to be solved

[0011] The objective of the present invention is to utilize kelp-based microbiota as an activation catalyst in treating soil contaminated with pharmaceutical trace contaminants, such as ciprofloxacin, using advanced oxidation technology. As kelp is a type of seaweed, a large amount is discarded during the commercialization process due to its poor marketability.

[0012] The aim is to provide a method for effectively treating trace pollutants, such as ciprofloxacin, in the soil by activating an oxidizing agent using eco-friendly biochar produced through a pyrolysis process to recycle discarded kelp.

[0013] In addition, another objective of the present invention is that rapid oxidation treatment is possible in that it is a fine carbon catalyst that maximizes the activation efficiency of an oxidizing agent by using fine biochar, which is obtained by grinding difficult-to-decompose trace contaminants such as pharmaceuticals with an oxidizing agent through ball milling. means of solving the problem

[0015] The present invention for achieving the above objective is characterized by using kelp-based micro biochar, produced by ball milling kelp-based biochar produced by pyrolyzing discarded kelp in oxidation using peroxymonosulfate (PMS) for the efficient oxidation treatment of ciprofloxacin, a contaminant in the soil, as an activator.

[0016] The present invention will be described in more detail below.

[0017] The method for treating contaminated soil using kelp-based micro biochar according to the present invention (hereinafter referred to as the “treatment method of the present invention”) is characterized by treating contaminants through the activation of peroxymonosulfate using kelp-based micro biochar as a catalyst, wherein the kelp-based micro biochar is prepared by comprising the steps of: washing and drying kelp (S1); mixing HTFS (Hydroxyl Terminated Functional Silicone) with the dried kelp and adding ammonia water to grind the dried kelp (S2); thermally decomposing the ground kelp (S3); and adding 0.01 to 0.5 parts by weight of lignin sulfonic acid and 0.01 to 0.5 parts by weight of sodium gluconate to 100 parts by weight of the thermally decomposed kelp, and grinding the thermally decomposed kelp using zirconium beads (S4).

[0018] As an example, hydroxyl radicals ( ˙ OH), sulfate radical (SO4 -˙ ), singlet oxygen ( 1 It is characterized by generating O2.

[0019] As an example, it is characterized by including the step (S10) of forming a permeable reactive wall by injecting kelp-based biochar around a source of contamination and the step (S20) of injecting peroxymonosulfate into the source of contamination.

[0020] As an example, the above peroxymonosulfate is characterized as being potassium peroxymonosulfate.

[0021] As an example, the above pollutant is characterized by including one or more of organic pollutants and ciprofloxacin.

[0022] As one example, the organic pollutant is characterized by comprising at least one of phenol, bisphenol A, nitrophenol, dichlorophenol, trichlorophenol, benzene, toluene, ethylbenzene, xylene, TCE, PCE, total petroleum hydrocarbons (TPH), and polycyclic aromatic hydrocarbons (PAHs).

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[0029] The method of the present invention has the advantage of using a kelp-based micro biochar catalyst for treating trace contaminants such as ciprofloxacin in soil, using peroxymonosulfate to increase oxidation efficiency, and using a carbon catalyst manufactured by recycling discarded kelp.

[0030] In addition, as a ball-milled kelp-based micro biochar catalyst, the increased specific surface area of ​​the biochar carbon catalyst doubles the activation efficiency of peroxymonosulfate, which has the advantage of enabling faster removal of trace pollutants than conventional carbon catalysts. Brief explanation of the drawing

[0032] Figure 1 is a photograph showing a method for manufacturing kelp-based micro biochar, and Figure 2 is a graph showing the oxidation removal efficiency of kelp-based microbichar at different pyrolysis temperatures (500, 600, 700, 800℃) when treated with ciprofloxacin by kelp-based microbichar catalyst and peroxymonosulfate, and Figure 3 is a graph showing the results of removal efficiency according to concentration of peroxymonosulfate (left) and kelp-based microbichar catalyst (right) during ciprofloxacin oxidation treatment by kelp-based microbichar catalyst and peroxymonosulfate. Figure 4 is a graph showing the removal efficiency according to pH during ciprofloxacin oxidation treatment by a kelp-based micro biochar catalyst and peroxymonosulfate, and Figure 5 is a graph showing the effects of anions and humic acid on ciprofloxacin oxidation treatment by kelp-based micro biochar catalyst and peroxymonosulfate, and Figure 6 is a graph showing the ESR analysis results for kelp-based micro biochar catalysts and peroxymonosulfate, and Figure 7 is a photograph showing the results of a phytotoxicity assessment in soil treated with ciprofloxacin oxidation by a kelp-based microbichar catalyst and peroxymonosulfate, and Figure 8 is a photograph showing the results of the floating stability test of kelp-based micro biochar particles after 1 hour, 3 hours, and 24 hours. Specific details for implementing the invention

[0033] The structure and effects of the present invention are to be explained more specifically through the following examples; however, these examples are merely exemplary descriptions of the present invention, and the scope of the present invention is not limited to these examples.

[0034] The method of the present invention is characterized by treating soil contaminated with antibiotics such as ciprofloxacin through the activation of peroxymonosulfate using kelp-based micro biochar as a catalyst.

[0035] The method of the present invention is characterized by comprising the step of forming a permeable reactive wall by injecting kelp-based biochar around a source of contamination (S10) and the step of injecting peroxymonosulfate into the source of contamination (S20).

[0036] The method of the present invention is for purifying contaminated soil using kelp-based biochar as an activator and peroxymonosulfate as an oxidizing agent, by inserting a well around a source of contamination contaminated with organic pollutants and ciprofloxacin, injecting kelp-based biochar using a single or dual packer in the form of a permeable reactive wall, and then injecting peroxymonosulfate to purify the contaminants in the contaminated soil.

[0037] The above-mentioned peroxymonosulfate chemically oxidizes organic pollutants and ciprofloxacin in contaminated soil. That is, the above-mentioned peroxymonosulfate oxidizes pollutants by absorbing moisture in contaminated soil and releasing persulfate ions.

[0038] The above persulfate ions are powerful oxidizing agents that have excellent reactivity with organic pollutants and ciprofloxacin and have a high redox potential, so organic pollutants and ciprofloxacin in contaminated soil can be treated continuously and efficiently, and the treatment method is simple and treatment costs can be reduced.

[0039] At this time, the release of persulfate ions may be slow-release. Slow-release means that it is released gradually over a long period of time, and may be synonymous with sustained-release, etc.

[0040] That is, the above peroxymonosulfate is a hydroxyl radical ( ˙ OH), sulfate radical (SO4 -˙ ), singlet oxygen( 1 It generates O2 and enables the rapid removal of organic pollutants and trace pollutants such as ciprofloxacin.

[0041] Here, the organic pollutant may include at least one of phenol, bisphenol A, nitrophenol, dichlorophenol, trichlorophenol, benzene, toluene, ethylbenzene, xylene, TCE, PCE, total petroleum hydrocarbons (TPH), and polycyclic aromatic hydrocarbons (PAHs).

[0042] The above peroxymonosulfate refers to potassium peroxymonosulfate (Oxone). Peroxymonosulfate can be used as an oxidizing agent with strong oxidizing power, with a redox potential of +1.81V in the standard electrode potential in the half-reaction that produces hydrogen sulfate. It has the advantages of high solubility in water and ease of application over a wide pH range.

[0043] In conventional Fenton or persulfate oxidation, zero-valent iron (Fe(0)), divalent iron (Fe(II)), or iron sulfide (FeS, FeS2) are used as activators to generate radicals and induce chemical oxidation, but in the present invention, kelp-based biochar is used as a catalyst or activator without the use of zero-valent iron or divalent iron to induce environmentally friendly oxidation.

[0044] The above kelp-based biochar is characterized by being manufactured by including the steps of washing and drying kelp as shown in FIG. 1 (S1); grinding the dried kelp (S2); pyrolyzing the ground kelp (S3); and grinding the pyrolyzed kelp using zirconium beads (S4).

[0045] First, there is a step (S1) of washing and drying the kelp, and then a step (S2) of grinding the dried kelp.

[0046] In the above S2 step, an example is presented in which HTFS (Hydroxyl Terminated Functional silicone) is mixed with dried kelp and ground.

[0047] As particles become finer during grinding, aggregation between particles occurs, which can act as a factor that inhibits the functional expression of the kelp-based biochar mentioned above. Accordingly, the present invention provides an example in which HTFS (Hydroxyl Terminated Functional Silicone) is included during grinding.

[0048] The above HTFS is a reactive silicon that improves physical properties and, in particular, controls particle aggregation by applying low surface energy to the particles produced during grinding, thereby increasing the efficiency of particle refinement.

[0049] In addition, an example is presented in which ammonia water is added to prevent aggregation between fine particles and improve the degree of dispersion so that the crushing impact energy is effectively transferred. In particular, by adding ammonia water, an appropriate pH is maintained when injected into contaminated waste, thereby enabling control of soil acidification.

[0050] Next, there is a step (S3) of pyrolyzing the crushed kelp, for example, by pyrolyzing (heat treating) the crushed kelp using a Tubuler furnace at 600 to 900°C.

[0051] Finally, there is a step (S4) of crushing the pyrolyzed kelp using zirconium beads. Through this step (S4), the pyrolyzed kelp is crushed into fine particles, and as it has a large specific surface area, its reactivity is doubled.

[0052] In this step (S4), it is appropriate to perform grinding under particularly alkaline conditions (pH 10 or higher) and high temperature (60℃ or higher).

[0053] Meanwhile, the present step (S4) is characterized by including a step of adding lignin sulfonic acid to the pyrolyzed kelp and grinding it using zirconium beads. The pyrolyzed kelp is ground using zirconium beads while the lignin sulfonic acid is added.

[0054] The method involves adding lignin sulfonic acid, which is obtained as a byproduct during pulp production in paper mills, to the biochar particles to form an electric double layer on the particle surface, thereby generating electrostatic repulsion between the particles. In other words, it generates electrostatic repulsion between finely ground biochar particles to control adsorption between particles.

[0055] Preferably, it is appropriate to mix 0.01 to 0.5 parts by weight of lignin sulfonic acid with respect to 100 parts by weight of pyrolyzed kelp.

[0056] In addition, in this step (S4), an example is presented in which sodium gluconate is further added to improve the buoyancy stability of the biochar particles.

[0057] The above sodium gluconate contains atoms such as N, O, and S, so it is designed to easily bind to the surface of metal particles by means of lone pair electrons of the atoms, thereby covering the surface and removing metal adsorbed on the biochar during processes such as zirconium grinding, which is intended to improve the buoyancy stability of the biochar.

[0058] In other words, it is intended to enhance reaction sustainability by controlling the phenomenon where biochar precipitates prematurely due to the adsorption of metals, etc.

[0059] Preferably, it is appropriate to mix 0.01 to 0.5 parts by weight of sodium gluconate with 100 parts by weight of pyrolyzed kelp.

[0061] The following embodiments of the present invention will be explained by experiment.

[0063] Preparation Example: Preparation of a kelp-based micro biochar catalyst

[0064] First, wash and dry the kelp, then add 3g of dried kelp, 0.1g of HTFS, and 0.05mL of ammonia water together and grind slowly with a mortar for 30 minutes. Dry the mixture at 60℃ for 6 hours.

[0065] The dried mixture is pyrolyzed at 800°C for 1 hour, and the pyrolyzed kelp and zirconium beads are mixed and ground.

[0066] Here, 0.01 parts by weight of lignin sulfonic acid is added to 100 parts by weight of kelp, and zirconium beads are mixed and ground. The ground mixture is filtered through a 600 μm sieve to separate the zirconium beads and kelp-based micro biochar, thereby producing a biochar catalyst (KBC).

[0067] In addition, the biochar catalyst (KBC) is prepared in the same manner as the above KBC, provided that 0.01 parts by weight of lignin sulfonic acid and 0.01 parts by weight of sodium gluconate are further added to 100 parts by weight of kelp. BM Manufactured ).

[0068] In the following experiments, the experiments were conducted using KBC, and in the floating stability experiment shown in Fig. 8, KBC and KBC BM The experiment was conducted using .

[0070] Experimental Example: Kelp-based microbiocher carbon catalyst, oxidation treatment efficiency of pollutants using peroxymonosulfate, etc.

[0071] Figure 2 shows the results of oxidation efficiency according to the thermal decomposition temperature (500, 600, 700, 800℃) of kelp-based micro biochar when ciprofloxacin oxidation treatment is performed by kelp-based micro biochar catalyst and peroxymonosulfate.

[0072] It was confirmed that the removal efficiency of oxidation increases as the temperature increases. Accordingly, 800℃, which shows high removal efficiency in oxidation, was selected to conduct the experiment.

[0073] Figure 3 shows the results of the removal efficiency of peroxymonosulfate (left) and kelp-based microbichar catalyst (right) at different concentrations when ciprofloxacin is oxidized by kelp-based microbichar catalyst and peroxymonosulfate.

[0074] Peroxymonosulfate showed low efficiency at a concentration of 0.5 mM, but the removal efficiency increased as the concentration was increased to 1.0 mM, 2.0 mM, and 3.0 mM. It was confirmed that the removal efficiency of the kelp-based micro biochar catalyst increased as the concentration was increased from 0.5 mg / g to 2.0 mg / g.

[0075] Since there was no significant difference in removal efficiency between 1.0 mM, 2.0 mM, and 3.0 mM of peroxymonosulfate, the experiment was conducted with 1.0 mM set as the concentration of peroxymonosulfate.

[0076] The kelp-based micro biochar catalyst showed sufficient removal efficiency at 1.5 mg / g, so the experiment was conducted by setting the catalyst concentration to 1.5 mg / g.

[0077] Figure 4 shows the results regarding the effect of pH (3.0, 5.0, 6.3, 7.0, 9.0, 11.0) on ciprofloxacin oxidation treatment by kelp-based micro biochar catalyst and peroxymonosulfate. It was confirmed that the highest removal rate was observed at pH 6.3, which is the pH in natural conditions.

[0078] Figure 5 shows the anion (Cl) upon ciprofloxacin oxidation treatment by a kelp-based microbichar catalyst and peroxymonosulfate. - , HCO3 - , HPO4 2- , SO4 2- , NO3 - These are the results regarding the effects of ) and humic acid. All anions and humic acid did not affect the oxidation treatment of ciprofloxacin by kelp-based microbiota catalyst and peroxymonosulfate.

[0079] Figure 6 shows the results of an ESR experiment to investigate radicals generated by peroxymonosulfate using a kelp-based microbichar catalyst as an activator. Through this experiment, a 1:2:1:2:1:2:1 signal indicating DMPO-X as the activator and oxidizer, and a 1:1:1 singlet oxygen ( 1 The O2) signal was detected. Through this, 1 It was confirmed that a non-radical reaction of O2 occurred.

[0080] Figure 7 shows the results of phytotoxicity in soil treated with ciprofloxacin oxidation by a kelp-based microbichar catalyst and peroxymonosulfate.

[0081] It was found that some seeds in ciprofloxacin-contaminated soil failed to germinate, and the growth of the germinated seeds was lower compared to non-contaminated soil.

[0082] Seeds in oxidized ciprofloxacin-contaminated soil showed growth similar to that in non-contaminated soil, and produced a greater number of roots.

[0083] Figure 8 shows kelp-based microbiota particles (KBC and KBCBM These are the results of the floating stability test for ) after 1 hour, 3 hours, and 24 hours.

[0084] While it can be observed that KBC precipitates after 24 hours, KBC BM It was confirmed that it still maintains a floating state.

[0085] This is KBC BM In the case of KBC, it is determined that this is due to the increased buoyancy stability resulting from the removal of metals attached to the particles as a result of the additional addition of sodium gluconate salt during manufacturing, as seen above. That is, KBC BM In this case, the persistence of the reaction can be increased.

[0087] From the foregoing, those skilled in the art will understand that various changes and modifications are possible within the scope of the present invention without departing from its technical capabilities. Accordingly, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be determined by the claims.

Claims

Claim 1 A method for treating contaminated soil using kelp-based microbiochar, wherein the kelp-based microbiochar is prepared by activating peroxymonosulfate using kelp-based microbiochar as a catalyst, and wherein the kelp-based microbiochar comprises the steps of: washing and drying kelp (S1); mixing HTFS (Hydroxyl Terminated Functional Silicone) with the dried kelp and adding ammonia water to grind the dried kelp (S2); pyrolyzing the ground kelp (S3); and adding 0.01 to 0.5 parts by weight of lignin sulfonic acid and 0.01 to 0.5 parts by weight of sodium gluconate to 100 parts by weight of the pyrolyzed kelp, and grinding the pyrolyzed kelp using zirconium beads (S4). Claim 2 In claim 1, hydroxyl radicals ( ˙ OH), sulfate radical (SO4 -˙ ), singlet oxygen ( 1 A method for treating contaminated soil using kelp-based micro biochar characterized by generating O2. Claim 3 A method for treating contaminated soil using kelp-based micro biochar according to claim 1, characterized by including the step of forming a permeable reactive wall by injecting kelp-based biochar around a source of contamination (S10) and the step of injecting peroxymonosulfate into the source of contamination (S20). Claim 4 A method for treating contaminated soil using kelp-based micro biochar, characterized in that, in claim 1, the peroxymonosulfate is potassium peroxymonosulfate. Claim 5 A method for treating contaminated soil using kelp-based micro biochar, characterized in that, in claim 1, the contaminant comprises one or more of organic contaminants and ciprofloxacin. Claim 6 A method for treating contaminated soil using kelp-based microbiochar according to claim 5, characterized in that the organic pollutant comprises at least one of phenol, bisphenol A, nitrophenol, dichlorophenol, trichlorophenol, benzene, toluene, ethylbenzene, xylene, TCE, PCE, total petroleum hydrocarbons (TPH), and polycyclic aromatic hydrocarbons (PAHs). Claim 7 delete Claim 8 delete Claim 9 delete Claim 10 delete Claim 11 delete

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