TW436335B - An effective treatment method for washing the soil contaminated by heavy metals - Google Patents

Abstract

This invention discloses an effective treatment method for washing the soil contaminated by heavy metals. Under the optimum operating conditions, the contaminated soil is leached by mixing with washing solutions which are prepared from phosphoric species and other additives. Experimental results show that the method is very effective for soil decontamination, and the residual concentration of heavy metals in soil can be as low as the environmental background after decontamination. In addition, the washing agents used for the decontamination can be reused with the same decontamination efficiency after electrolytic treatment. The soil after decontamination can be used for agriculture purpose again.

Description

43633S V. Description of the invention (1) The invention relates to a method for treating heavy metal contaminated soil and a method for recovering cleaning agents. β used m / first L: dyeing? The main ί can be divided into two major categories, the first type is organic pollution, the upper one is inorganic metal pollution, including heavy metal pollution and radioactive element pollution, of which the first: category related The production of heavy metal contaminated soil is mainly related to the self-association of heavy heavy metals including cadmium, copper, zinc, nickel, lead, and waste water. 'Project: The area of soil contaminated with cadmium existing in Taiwan is quite large, such as Zhongyuan, Guanyin, and Hemei districts in Changhua, Taoyuan, affected the vast agricultural land fallow and crop yields. According to the environmental protection regulations, before any π-contaminated soil can be used for other purposes, the pollutants in the soil must be removed to meet the control standards. Therefore, the development of a kind of energy-efficient solution to this heavy metal contaminated soil is quite equivalent. It is urgently needed, and in order for the contaminated soil to be used again effectively, soil decontamination must be carried out to reduce the content of heavy metals in the soil to below the environmental background value and the value regulated by environmental laws and regulations. Methods currently known to be used to treat contaminated soil include soil washing, electrokinetic treatment, vitrification, biological treatment, and plant absorption ( Vegetative absorption), solidification and incineration. Comparing soil cleaning and electrodynamic treatment, the biggest difference between the two is that the former uses various added chemical reagents to immerse or extract the heavy metals in the soil, while the latter mainly separates heavy metals from soil_ by the action of an external electric field ' Collected by the action of the electric field on the cathode. Due to electric power handling

436335 V. Description of the invention (2) It involves the influence of three factors, electrophoresis, electro-osmosis and electrolysis, which makes the migration speed of heavy metal elements in the soil slow. The cleaning method has become an effective method for such contaminated soils. In the past many literatures have reported that the use of soil cleaning methods to treat the pollution of steel, -mercury, lead, etc. has a certain degree of effect, but also has different treatment effects with different cleaning agent formulations and the characteristics of the soil itself, such as sand Contamination in the soil is relatively easy to remove. Conversely, the cleaning effect of clay is often greatly reduced. Therefore, how to develop a cleaning agent that is effective and suitable for various heavy metal elements and soil characteristics is the current focus of efforts of all parties. Soil cleaning method is a kind of decontamination method that combines physical and chemical to achieve the purpose of pollutant removal and waste reduction. The principle of soil cleaning mainly uses various reagents added to mix thoroughly with the contaminated soil, and then replaces the contaminated soil in the soil. Desorption or ion exchange and other reactions to achieve the effect of decontamination. There are quite a few factors that affect the soil cleaning effect, including (1) the type of Tianjin detergent, (2) the concentration of cleaning agent, (3) the cleaning method, (4) the cleaning time, (5) the pH value, (^) the cleaning temperature And (7) the effects of other external reagents and conditions, etc., commonly used beta lotions can be divided into three categories: (丨) acids, alkalis and general chemical reagents, such as Ma 'acid nitric acid, acetic acid, hydrogen peroxide, gasified iron, Gasification is about ... etc., (2) chelating agents, such as EDTA, ammonium oxalate and citrate (Cltrate), (3) surfactants, such as cleaning agents, SDS, CTAB, etc. In general, the effect of soil decontamination is not only related to the cleaning agent used, and it is also related to the characteristics of the soil, operating conditions, and the type of pollution elements. The inorganic pollution elements generally existing in the soil can be ion exchanged, chemically

4 3 633 5 V. Description of the invention (3) Combined with soil by physical adsorption, precipitation, substitution and agglomeration. The combination of different methods will make the cleaning effect different. In addition, different types of metals also have different cleaning effects. For example, the pollution between polymetals and soil scum is only on the surface of the soil. Such pollution is easier to remove, but the heavy metal pollution from soil scum in the environment is due to the waste water. It is caused by heavy metals deposited in the soil for a long time, and it is usually very tightly combined with the soil, and even enters the crystal layer of the soil, so it is difficult to remove. Although the literature (S. V. Kruglov; Radiochemistry,

Vol. 36, No. 6, 1 994) reveals that 6M hydrochloric acid and 7M nitric acid can improve the cleaning effect of some active elements in soils when boiling, and this soil cleaning method cannot really solve the polluted soil existing in the environment. The problem is because (1) it is not applicable to polluted soil with high concentration, because its maximum decontamination rate is only about 89%, and about 10% of the pollution exists in the soil. In the case of high concentration pollutants, after cleaning The concentration of pollutants remaining in the soil will still be higher than the standard regulated by environmental protection regulations; (2) HC1 and HN03 contain ci and ions, which will cause difficulties in wastewater treatment; Longer-not soil. Although the current literature shows that pickling has a better effect on the method of contaminated soil, the extension of the pseudo-cutting machine " silver (removal of π is less than its general grade) is still limited by the characteristics of the soil, the type of metal and The combination of π miscellaneous gold can be combined with deficient soil 壌 and other factors' make the decontamination efficiency of the lotion n ° Mo Tong can not meet the requirements of environmental protection regulations. The method of decontamination of heavy metal soil with acid detergent, For example U.S. special # *

436335 V. Description of the invention (4) 5,466,426 (1995), 5,505,925 (1996), 5,660,806 (1997), etc. 'The use of a cleaning solution containing 5% HOAC + 2,5% NH40AC on sand and clay (clay) The lead pollution on) was cleaned at the ratio of 250 ml / 50g miso detergent. When the extraction time reached 66 hours, the decontamination rate for lead contaminated sand was 94%, and for lead contaminated clay The division rate is only 19 ~ 21%. In this method, acetic acid (h0AC) is mainly used as the main component of the cleaning agent, and other substances are added as the cleaning agent. Such cleaning agents include

There are 5% HOAC, 5% HOAC + 5% HC1, 10% HOAC + 5% NH4 OAC 5% HOAC + 2.5% NaOAC, and 5% HOAC + 2.5% NH40AC. With the exception of the above cleaning agents, except for 5% H0AC + 2. 5% NH40AC, the decontamination effect of the other cleaning agents is not satisfactory. However, although 5% H0AC + 2. 5% NH40AC cleaning agent can be used to remove sand from the soil 94 % Of lead pollution, but can only remove 19 ~ 2 1% of lead pollution in clay. This is because the form of lead pollution in sand is mainly attached to the surface of the soil by adsorption, so it is easier to clean, otherwise Because the lead on the clay is coated in the inner layer of the clay, it is not easy to handle. The occurrence of general contaminated soil moth usually comes from long-term formation, and the characteristics of soil moth are by no means purely sandy soil types. For example, the soil quality of general agricultural land is usually not sandy soil. The pollution effect will be greatly reduced, and there are difficulties in practical application. Another commonly used soil decontamination method uses the principle of increasing the probability of adsorption of contaminating elements due to the large surface area of fine particles in the soil. Using screening methods, various soil particles of different particle sizes are first screened, and then Separate and clean soils containing more cadmium-contaminated metals, such as the United States

436335 V. Description of the invention (5) Li 5 ’342, 449 (1 994) This kind of combination of physics and paleontology is used to treat contaminated soil. This method first uses the physical size of the particles, Gan Shifang to open different light soil particles, among which soils with different particle sizes are moderately polluting elements, and then use organic acid cleaning agents to increase the pollution process. The soil part is cleaned and decontaminated. The cleaning agent used in this patent contains a combination of organic acids, mineral acids, and a few oxidants (such as HA, 〇3, etc.), mainly carboxylic acids (mono-, di :, and tri_) substituted with mono, di, and ginseng (mono-, di :, and tri_). carboxylic acids) as the main ingredients, of which mono-carboxylic acid contains sarnic acid, lactic acid, formic acid and benzoic acid, di-carboxylic acid contains oxalic acid, succinic acid and glutaric acid, and tri-carboxylic acid contains citric acid. Although there are so many reagents, the cleaning agent composed of H20 + 1% acetic acid + 1% (w / v) Naci + 1% (w / v) NH4N03 is the best. After cleaning for 12 hours,

Cu and Pb have a good cleaning effect, with an average efficiency of ~ 93%, but for its heavy metals such as Cd and Ni, the effect is not good. This method first uses the screening method to produce soils with different particle sizes, thereby reducing high pollution. (Small particle size) The soil is separated from the low-pollution C soil area, and then treated for the high-contamination soil moth 'theoretically feasible', but in fact due to the differences in soil properties and types of pollution elements, etc. There is no certain regularity, so it does n’t make much sense to subdivide different particle sizes. Also, in order to screen different soils with different particle sizes, a small amount may be feasible in the laboratory scale. 'Large-scale application equipment is not easy to design. Factory-type equipment is not easy. In addition, although the use of acetic acid as a cleaning agent in this method has a good cleaning effect on Zn, Cu, and Pb, the actual metal concentration in the soil still exceeds environmental protection regulations and the cleaning effect on other metal elements is not obvious. The cleaning time should be 12 hours.

Page 10 43633 6 V. The description of the invention (6) is too long for the application effect. In addition to using acids as cleaning agents, there are also alkalis used as cleaning agents. For example, U.S. Patent No. 5,516,968 (1996) is used for the decontamination of contaminated soils produced by the mixed waste of mercury and gaseous or radioactive elements. Mainly, use alkaline anhydrous ammonia as a cleaning agent. In this method, liquid ammonia solution and mercury-contaminated soil are mixed with each other in the reactor to form an ammoniacal liquid-mercury sludge. , And then use heating and bubble agitation to separate from the sludge and combine with liquid ammonia, and have a high mercury content of 7 fine-grained soil dispersions. After standing, take out this upper liquid-solid phase soil dispersion to take out the ammonia solution. Recycling is performed by evaporation, and the remaining fine-grained soil is stored or awaited for further processing, thereby reducing waste. However, this method still has the same problem as U.S. Patent No. 5,342,449 (1 994) = the difference between soil properties and soil quality is not that most of the pollutants are stored in granular soil, so it is not applicable to all For example, the liquid-solid: J must be further solidified during the process, and it needs to be left to stand overnight to make the upper part of the soil: the second soil soil fractions precipitate out. It is quite time-consuming, and it is only applicable to soil. The above patent is similar to the other one—U.S. Patents for soil staining use the cleaning and separation equipment invented by the invention to contaminate the soil, and then add the contaminated soil and water to form a slurry and heat it to a boiling state. -The mud is brought out, and the bubbles contained in the soil will be contaminated by centrifugation. The soil will be separated from the cleaning thorns after passing 4. Before this law

Page 11 43633 b V. Description of the invention (7) Item = Most of the pollutants are present in the fine-grained soil 'so they are still in contact with U.S. Patents 5,342'44 9 (1994) and 5,516, 968 (1996) The same problem, that is, there are still some pollutants in the larger particles, must be cleaned, and the use of electric field heating for a long time to generate air bubbles to remove clutter and dyes in the soil is also quite energy-consuming. 19. The present invention improves the above disadvantages, and provides a new and unique formulation of detergent and cleaning and decontamination method for contaminated soil. In addition to the soil decontamination rate greater than 99%, it remains after cleaning. The metal concentration in the soil is also in compliance with environmental protection regulations, and a cleaning agent recovery place is also provided. The cleaning process can be recycled, and the cleaning effect can still be maintained at 99%. In addition to avoiding the generation of a large amount of waste water, the cost of cleaning chemicals can also be saved. In addition to the method mentioned in the present invention, in addition to being able to be treated at a temperature lower than Foten and the effect of decontamination is higher than 99%, the experimental results show that the concentration of heavy metals remaining in the soil is exemplified by cadmium contaminated soil It can be reduced to about 0.2ρριη or lower, which meets the second-level environmental background value requirements of the EPA ’s provisional soil heavy metal standards and classifications in Taiwan (below 0.39ppm); in addition, the cleaning agent after cleaning can also be performed through recycling equipment. Cleaning agent recovery '. When the recovered reagent is reused in the cleaning of contaminated soil, its decontamination rate remains at 99-6. In this way, not only the cleaning agent can be reused repeatedly to reduce the amount of waste water and reduce the cost of operation, but also the soil after decontamination by this method can be used for agriculture after planting tests. In addition, the fast processing speed is also the invention Another feature of the method is that one batch of contaminated soil can be cleaned approximately every 3 hours on average. The scope of application of the present invention includes the treatment of all heavy metal contaminated soil /

Page 12 4 3 6336 V. Description of the invention (8) ~~~ The main principle of cleaning and decontamination is to use the characteristics of the cleaning agent with phosphoric acid as the main agent and the surface of the soil or the metal ions adsorbed on the soil and form bonds. The chemical reaction allows the metal ions to be washed out of the soil, and at the same time, the added metal ions are prevented from being adsorbed in the soil again by the addition of certain chemical additives. Because soil ingredients are mixed with many organic substances, such as humic acid and fulvic acid, these organic substances are usually surrounded on the surface of soil particles, and many pollution elements are associated with this kind of soil. Organic matter forms a bond, so if you want to remove the pollution source, you need to destroy the bond between these elements and organic matter. However, some contaminated metals will enter the interstitial layer of the soil particles after interacting with the soil for a long time. If you want to remove it, It takes a lot of effort in the selection and operation of the cleaning agent ^, the cleaning agent developed in the present invention is based on phosphoric acid as the main structure 'mixture' Because phosphoric acid has a strong oxidizing capacity, All substances can produce oxidation, in order to achieve the full effect of decontamination efficiency (in compliance with ^ regulations) 'a small amount of additives have the effect of strengthening cleaning. According to the test results, it is shown that the cleaning agent developed by this researcher uses the cleaning agent formulated in this study to treat the contaminated soil caused by general heavy metal elements such as cadmium, nickel, lead, 2 ..., through the cleaning agent of the present invention. f 'Removal effect can reach 99%, the content of heavy metals remaining in the soil has already met: the third level of environmental background value ㈣ temporarily set by the Environmental Protection Agency, taking cadmium as an example, the cadmium content in 壌 dyed soil 壌 is 73. 2ppm, the content of pickaxes in the residual soil after washing with this reagent is 0'37PPm, and the decontamination rate is as high as 99 5%. Others such as copper, lead, zinc, chromium, and nickel are also within the third-level standard.

4 3 633b V. Description of the invention (9) The decontamination effect of soil contaminated by heavy metals is quite excellent. In the course of this study, it was also found that if an appropriate h-agent was added to the cleaning agent, it would strengthen the cleaning of heavy metals in the soil. According to the experimental results, it is shown that adding various kinds of gaseous, sulfide and nitrate to the phosphoric acid formula cleaning solution is very helpful for the soil decontamination effect. Among them, the effect of nitrate and sulfide is the best. The removal efficiency of metal ions in the soil is increased by 5-10%. The main factors that affect the soil decontamination efficiency include cleaning agent formula ’additives and cleaning conditions, such as cleaning temperature, soil / cleaning agent ratio, concentration, etc. In this study, it was shown that the higher the concentration of the cleaning agent in the cleaning system, the faster the reaction rate, but in order to save operating costs, the concentration of the cleaning agent should not be too high, and the soil (g) / cleaning agent (mI) should be 1/3 ~ 1/4 case mix. Add a small amount of sulfide to the cleaning agent, and control the operating temperature above: preferably 70 ~ 80. . If the temperature is ‘above the boiling point, heat energy is wasted. If the temperature is too low, the reaction time is too long. Start cleaning. The reaction time is 2 ° ^ 3 hours.’ For the contaminated metal elements in the soil = 99%. ~ The best efficiency can be achieved. In addition, in the cleaning program, in order to consider various properties, cleaning effects and the use of cleaning agents and 2 suction program and reverse intersecting and cleaning operation program, the former two one out-one person can achieve complete For the purpose of cleaning, this person's cleaning procedure is to carry out the continuous cleaning of the ancient combat / π 冼 cleaning procedure for the descending operation process and the reverse flow. Second "and‘ make the entire soil cleaning operation procedure as shown in Figure 丨. :: Ί and reverse crossing, P will use the cleaning solution to contaminate the soil B first Page 14 α36335

436335 V. Description of the invention (11) Difficult, usually a cleaning agent containing between 0.1 to 0.7 kg per kg of solution is suitable. As for the optimal concentration of the additive, it contains 0.001 ~ 〇. Per kg of solution;! Kg is appropriate. * The following inventors will use experimental examples to illustrate the soil cleaning method, process and cleaning agent preparation of the present invention, and use soils that are actually polluted by heavy metals such as cadmium, copper, lead, zinc, chromium, nickel ... Utilize the effect of the cleaning agent and cleaning decontamination procedure of the present invention. To indicate the practicability of the present invention, 'Experiments with actual heavy metal pollution in Changhua and Taoyuan areas will be used for various experiments.' The heavy metal content in the soil after decontamination will be based on the level 3 environmental background value temporarily set by the Environmental Protection Agency as an example. The environmental background concentration of the third stage is 0.05 ppm to 0.39 ppm. The detailed steps and results are explained below. These experiments are only a part of the embodiments of the present invention, and do not represent the full range of use of the present invention, and therefore cannot be > limits to the use range of the present invention. Example 1: Take a certain amount of soil that is actually polluted by cadmium from the Tao · Park. Firstly, remove large stones, branches and other debris through preliminary screening, and use a grinder to break and mix the hard soil first. The soil is dried to remove the water contained on the soil surface, so that the weight of the reaction soil can be accurately known, and then this flooded soil is screened to 'remove small stones and debris larger than 36 mesh'. Concentration of heavy metal ions was used as the feed for the test soil. For the preparation of phosphoric acid formula cleaning agent, take general industrial phosphoric acid, add water and a small amount of inorganic acid to make it fully mixed, then add sulfate to stir at room temperature

436335 V. Description of the invention (12) Mix well, so that the prepared solution contains P04 = / H20 / S04 = at a ratio of 6/38/1 (mol). The prepared solution is stored for future use. 1 000 parts by weight of the soil sample prepared above was mixed with 3800 parts by volume of phosphoric acid mixed cleaning agent, and the ratio of the weight (g) / cleaning agent volume (m 1) of the soil preparation was set to 1/4. Stir in the reaction tank evenly, and heat the reaction tank to 80 t while heating: Wash at this temperature for 3 hours. In order to prevent the loss of cleaning liquid during the process, a condensation device must be installed. The filtration separates the soil from the cleaning agent, and the used cleaning agent starts electrolytic recovery. The operating voltage is 9 V, the current density is 0.23 A / cm2, and the operation time is 72 hours. The soil part is washed and filtered to filter the soil. After drying at 32 ° C, samples were taken to analyze the concentration of heavy metals in the soil and the decontamination efficiency. The cleaning results are shown in Table 1. This is the effect of one-time cleaning of contaminated soil, showing that the concentration of heavy metals in the soil, taking cadmium as an example, has decreased from 73_ 2ppm to less than 0.3 ppm. The average decontamination of heavy metals in soil is 99.5%, which is in line with the EPA ’s provisional soil The third level environmental background value standard for the content of cadmium metal: 0.05 ~ 0.39ppm. Example Two: Take the actual heavy metal contaminated soil (including cadmium, copper, lead, zinc, chromium, chromium, ..., etc.), and use the treatment method of Example 1 to prepare the soil for cleaning. The method is the same as in Example 1, and the same method as in Example 1 is used for soil cleaning, except that the soil used in this example contains other heavy metals in addition to cadmium pollution. The results are shown in Table 2 · " After cleaning, the cadmium was reduced from 4.17ppm to 0.25ppm. The copper was reduced from 61.5ppm to 6.93ppm, the error was reduced from 26.1ppm to 866ppm, the zinc was reduced from 42.4ppm to 23ppm, and the nickel was reduced from 34.8ppm.

4363 3 b V. Description of the invention (13) 2,38ppm ′ The concentration after treatment is within the third-level environmental background standard set by the Environmental Protection Agency. Example 3: r Take the actual heavy metal contaminated soil, and carry it out as in the method of Example 1. The experiment is different in that the soil used in this example comes from the heavy metal contaminated soil in the Changhua area. The cleaning results are shown in Table 3. . Cadmium was reduced from 2.98ppm to 0.2pρ, copper was reduced from 10.7ppm to 3.i8ppm, lead was reduced from 23.8ppm to 8.79ppm 'zinc was reduced from I9.6ppm to 4.27ppm, and chromium was reduced from 2.34ρρπ to 0. 89ppm, nickel decreased from 5.28ppm to 1.59ppm, and the concentration after treatment was within the environmental background standard set by the Environmental Protection Agency. Example 4: Take the soil contaminated with cadmium 'Use the method of Example 1 to prepare soil treatment and cleaning agent, and perform the soil' decontamination work 'according to the steps of Example 1 and the example-the difference lies in the pollution The soil cleaning time is variable, so as to observe the difference in the effect obtained in different cleaning times. Five batches of experiments were performed for this purpose. The reaction time was 1, 2, 3, 4, 5, and hours. The concentration of minerals in the soil is shown in Table 4. As the reaction time increases, * * gradually decreases. When the reaction time is 22, the residue / Λ 二 concentration is dangling, and the remaining cadmium in the soil With. f0.38ppm has reached the third level of the environmental background value set by the Environmental Protection Agency. If the reaction time is further increased, the tin content in the soil can be further reduced. Example 5 · Use as in Example 1 Method According to the steps of Example 1, soils containing cadmium contaminated with different concentrations were taken, soil pretreatment and cleaning agent preparation were performed, and

43 63 3 5 V. Description of the invention (14) The soil decontamination work differs from the first embodiment in that the contaminated soil of the feed is different in fertility. In this embodiment, five batches of experiments were performed, and the content of brocade in each batch of soil The order is 73_2ppm, 65.6ppm, 11.8ppm, 4.17ρριο and 2.96ppm. The analysis of the cadmium content in the soil after treatment is shown in Table 5. The cadmium contaminated soil with unfortunate concentrations remained in the soil after cleaning and decontamination. The cadmium content in this range is between 0.25 to 0.38 ppm, which is less than the third level of environmental background value set by the Environmental Protection Agency. Example 6: The same method as in Example 1 was used to prepare a cleaning agent and the same method was used to clean the actual heavy metal contaminated soil. This used cleaning agent was used as the raw material required for the electrolytic recovery of the cleaning agent in this example. This used cleaning agent was placed in an anode electrolytic cell, and a 〇 · 1Ν H2S04 solution was used as the catholyte 'using platinum titanium mesh and stainless steel as the anode and the cathode material' plus 10V voltage and current 28. 7Α for electrolysis The results after 23 hours of reaction are shown in Table 6. 'The removal efficiency of Pb, Cr · is about 70 ~ 80%, and cd,

The removal effect of Ni, Zn and Cu is 92 ~ 99%. Embodiment 7: Take soils containing actual pollution such as cadmium, copper, zinc, chromium, and nickel, use the same method as in Example 1 to perform soil pretreatment, and perform soil decontamination according to the steps of Example 1. One difference is that the cleaning agent used in this embodiment is a cleaning agent that is processed after being used and then processed through a recovery program, and the purpose is to prove that the cleaning agent of the present invention can be reused for cleaning the soil after being recovered by electrolysis. Here, the cleaning agent is recovered by using an electrolytic cell in an electrolytic manner at an operating voltage of 3V to 10V and a current density of 236335 A / cm2. 436335 V. Description of the invention (15) The heavy metals and organic matter in the cleaning agent are electrolyzed Remove. The cleaning agent recovered and processed by this method is stored as the cleaning agent required for this experiment. As in Example 1, the weight of the contaminated soil (g) and the volume (m 1) of the cleaning agent after the above treatment are mixed at a ratio of 1/4. Perform cleaning and other steps in the cleaning tank, and then analyze the remaining content of heavy metals in the soil and the decontamination efficiency. The results are shown in Table 7. 'The heavy metals remaining in the soil are less than the third-level standard β chart of the environmental background value set by the Environmental Protection Agency. The brief description of the first figure shows the flow chart of the reverse and cleaning operation of the processing method of the present invention. Explanation of symbols: Α cleaning agent Β contaminated soil C, C, first cleaning D second cleaning A ,, A "used cleaning agent, B1 soil after the first cleaning M clean soil 壌 E regeneration treatment tank

436335 Five 'invention description (16) Table 1. Decontamination efficiency of cadmium-contaminated soil. Decontamination efficiency of raw soil. Cadmium concentration (ppm). Soil cadmium concentration (ppm) after decontamination. 73.2 0.30 99.5% 65.6 0.38 99.4% 11.8 0.38 96.8%' 4.2 0.25 94.0% 3.0 0.37 87.5% 1.0 0.20 79.3% 0.3 < 0.1 > 70.6% Taiwan's soil heavy metal content standards and grades in the table for the classification of cadmium metal in the third grade standard value: 0.05 ~ 0.39ppm uni Page 21 43 633 5 V. Explanation of the invention (17) Table 2. Results of decontamination of soil contaminated by heavy metals Contamination of elemental original soil metal content (ppm) in Zhongfu District, Taojin, Jinmei concentration after soil cleaning (ppm) Decontamination rate third-level standard Cd 4.2 0.25 94.0 % 0'05 to 0.39 Cu 61.5 6.93 88.7% 12 to 20 Pb 26.1 8.66 66.8% 1 to 15 Zn 42.4 23.00 45.8% 11 to 25 Ni 34.8 2.38 93.2% 2 to 10

HI Page 22 436335 V. Description of the invention (18) Table 3. Results of decontamination of heavy metal contaminated soil Elemental soil metal concentration (ppm) Metal concentration after soil cleaning (ppm) Decontamination rate third level standard Cd 3.3 0.21 93.9% 0.05 to 0.39 Cu 4.6 3.17 31.1% 12 to 20 and Pb 40.6 13.00 67.9% 1 to 15 US Zn 11.7 3.96 66.2% 11 to 25 Zone Cr 15.0 0.89 94.1% 〇h to 10 Ni 1.9 1.58 16.8% 2 to 10 mill No. Page 23, 4363i V. Description of the invention (19) C-4-1 m K) -ω tJi | Time (Hr) S Solid (g) / Liquid (ml) 3.49 3.49 3.49 3.49 3.49 Local money concentration (ppm) 0.61 0.51 0.38 0.37 0.25 j cadmium concentration in soil after cleaning (ppm) > 4 'bismuth port iifelr gallium (Zhong S 瘅 left)

Page 24 43 63 V. Description of the invention (20) C-6-4 C-6-3 C-6-5 I C-6-2 C-6-1 OJ U) U > Time (Hr) mrnt 5: 5 1-i 1-k solid (g), liquid radon 2.96 4.17 11.81 65.62 73.21 Original recorded soil concentration (ppm) 0.37 0.25 0.38 0.38 0.37 | Soil cadmium concentration (ppm) after cleaning; 87.5% 94.0% 96.8% 99.4% 99.5 Decontamination rate

Page 25 436335 V. Description of the invention (21) Table 6. Electrolytic recovery results of used cleaning agent (operating voltage: 10V, current: 28.7A, time: 23 hum) Elemental conditions Pb Cd Cu Zn Cr Ni Before treatment (ppm ) 22 3 227 174 25 87 After treatment (ppm) 5 0.2 3 6 7 3 Removal rate (%) 78 93 99 97 72 96 ·. »Page 26 43 63 3 S V. Description of the invention (22) Table 7. The recovered cleaning agent is reused for the cleaning effect of contaminated soil. Changhua and the beautiful soil element. Raw metal concentration (ppm). Metal concentration (ppm) after soil cleaning. Decontamination rate Cd 3.9 0.1 97.4% Cu 467 15 96.8% Zn 355 3.8 98.9 % Cr 77 9.5 87.8% Ni 170 2.2 98.7%

1HHI Page 27

Claims (1)

43633s, Shen Jing's patent scope 1 * ~ ™ ·. Ten stable gold soils are used for quantification and rinsing treatment. 2. If you apply for the special ingredient 1 β, EB. If you apply for the special scale 鳆 concentration 4, please refer to the special The use of cold-stained soil passes to the total organic carbon of the anion. • If you apply for the first and third. If you apply for electrolysis; • If you apply for a special volume, the oxidation will be achieved by 3V-10V solution. The cleansing agents to be treated as described in item 7 are exposed to the anode tank under the operating range of 0.6 A / cm2, and treated with electro-polluted soil as the main agent; 2 heavy metal contaminated soil compounds "Every spoon" can be added with inorganic acid and a method for removing heavy metal components, and the method of adding the agent: the method described in item 1 of the range of benefits, each, fi <10,000, where the heavy metal contaminated soil I contains Cadmium, copper, zinc, nickel, lead, chromium and other periodic elements of the periodic table, VIB, boron B and IVA and other metal elements. The method described in item 1, the range of the main agent of the cleaning agent is For Zhao Ji ratio, it is less than 50%. The method described in item 1 of Li Yi ε, in which the clear The temperature at which the cleaning agent starts to be mixed after boiling is below the boiling point (A) The electrolytic and oxidative destruction methods of the cleaning agent used for decontamination of heavy metal contaminated soil will be placed in the anode tank and the green metal will be allowed to pass through the action of the electric field Ion-exchange membrane electrode, at the same time, the content of the anode cleaning agent is reduced by the application of voltage, and the green cleaning agent is recycled for reuse. The component of the cleaning agent described in item 5 or the one defined in 4 The composition is the same. The cleaning agent recovery system described in Item 5 of the beneficial range. Current density 0.2