TWI545088B - Application of Long - acting Persulfate Remedged Ingredients in Polluted Water - Google Patents

Description

Method for preparing long-acting persulfate remediation tablet in contaminated water

The present invention relates to a method for preparing a long-acting persulfate remediation tablet for use in contaminated water, and more particularly to a method for preparing a tablet by mixing persulfate with cellulose and applying pressure by applying pressure. By.

The groundwater is polluted by petroleum hydrocarbons such as gasoline, which is an increasingly common and serious problem. The main sources of oil pollution include oil spills in underground oil storage tanks, oil pipe rupture, and leakage of ground oil, due to gas stations and The pipeline equipment of large oil storage tanks is mostly placed under the surface layer. With the old equipment, earthquake, poor construction or other human factors, the leakage opportunity increases. There are more than 2 million oil storage tanks in the United States, estimated to be 35. % oil storage tanks may be leaking oil (Bedient et al., 1999). At present, domestic oil pollution cases are gradually increasing, and soil and groundwater pollution problems have become an important issue at home and abroad.

Conventional treatment/remediation of contaminated groundwater technologies, such as pump and treat (R&T), is the most widely used technique for contaminated sites, but traditional methods often take a long time and the cost of long-term remediation is also It may increase, and the current remediation of contaminated sites, based on cost and related considerations, mostly takes the form of in-site remediation (US EPA, 2004).

In situ chemical oxidation (ISCO) is a method for remediation of target pollutants by injecting an oxidant into a contaminated area. Under ideal conditions, the pollutants will be completely oxidized into carbon dioxide, water and other harmless substances (ITRC, 2005). Common oxidant species include hydrogen peroxide (H ₂ O ₂ ) [Fenton's reagent], permanganate, persulfate, and ozone, while using persulfate as an oxidant. It is a relatively new in-situ chemical treatment program (ITRC, 2005). Persulfate is a strong oxidant. It can generate sulfate radicals (SO ₄ ^- ‧) by heat or metal (such as ferrous iron). Degradation of pollutants (Shiying et al., 2008; Chen et al., 2009).

At present, the conventional chemical oxidation method for groundwater remediation is as shown in Annex I, and it is published in the public notice No. 200927672 published on July 1, 1998. An oxidizing agent to degrade a contaminant and a oxidizing agent composition thereof, comprising: providing a oxidizing agent composition, the oxidizing agent composition being a mixture of a persulfate and a curing agent, the oxidizing agent composition And a plurality of micropores; and the oxidant composition is placed in a contaminated medium containing water, wherein the water in the contaminated medium containing water enters the oxidant composition through the micropores of the oxidant composition The persulfate is soluble in water and is slowly released from the micropores into a contaminated medium containing water.

The other is as shown in Annex II, which is published in the Patent Publication No. 583145 of April 11, 1993, "A kind of artificial oxygen-releasing compound with sustained release of oxygen". Its composition and combination ratio are (weight ratio): calcium peroxide (CaO2): sand: peat: cement: water = 1.126: 0.2: 0.183: 1:1.744, specific gravity 1.9g / cm3, of which calcium peroxide is used as a release oxidizing substance, The contact of calcium oxide with water will produce the following reaction: 2CaO 2+2H 2 O→2Ca(OH)2+O 2 Therefore, when the contaminated groundwater flows through the rectification wall filled with the artificial oxygen-releasing composition, the contaminants react with the calcium peroxide in the artificial oxygen-releasing composition to release the oxygen to In groundwater, the aerobic biodegradation reaction of organic matter is accelerated, and cement is used to coagulate other components to make a block-like artificial oxygen-releasing composition. The cement is used to avoid complete contact between calcium peroxide and water, causing rapid reaction and consumption of calcium peroxide. Peat is used to adjust the pH of the artificial oxygen-releasing composition and can be used to increase the water permeability of the artificial oxygen-releasing composition. The sand is also used to adjust the water permeability and oxygen release rate of the artificial oxygen-releasing composition.

However, as described above, the two conventional methods still have the following problems in practical applications: the above patents or methods only use persulfate or cement and persulfate to form an oxidant substance to remove contaminants in water. However, the effect of persulfate to remove contaminants under unactivated needs to be strengthened. In addition, the above patents or methods are intended to accelerate the removal of contaminants, requiring additional heating or addition of a transition metal (such as ferrous iron) to catalyze persulfate, in addition to causing In addition to the increase in remediation costs, the oxidation of divalent iron into ferric iron will cause blockage and reduce the permeability of the aquifer.

In addition, in recent years, the sustained-release oxidant substance has been attracting attention, and a specific adhesive substance is coated with an oxidizing agent such as persulfate. When the water passes through the semi-permeable substance, the internal oxidizing agent is dissolved, and the oxidizing agent release time is prolonged. Achieve long-term remediation effect. In the past, studies on the bonding of paraffin and cement have been conducted. In the study of cement as a binder, it is pointed out that when persulfate is mixed with cement, it will produce an appearance phenomenon, and the persulfate will be released in a short time, but part of it. The persulfate will be retained in the cement due to its coagulability, and the release effect will be unstable. Another study using paraffin as a binder, although persulfate release The effect of the discharge is stable compared to the cement type, but the initial release is also faster, and the paraffin needs to be heated to maintain 60 ° C during the production process. When persulfate encounters high temperature (>40 °C), it will thermally decompose and rapidly decompose. Therefore, the persulfate will be consumed in a large amount during the production process, so that the release effect of the finished product is affected to some extent. In addition, after the above two types of products are used, cement and paraffin will remain in the water body, and must be manually removed from the contaminated area and subjected to subsequent waste disposal, which will inevitably increase the cost of remediation.

Therefore, how to develop a persulfate-based combined remediation system, which has both long-acting oxidative and activating properties, and can improve the removal efficiency of contaminants, which is desired by the inventors to improve problem lies in.

Therefore, the present inventors have invented the present invention in view of the fact that the idea of creation and creation has been designed with many years of experience, and has been explored and tested by various parties, and has been repeatedly modified and improved.

The invention relates to a method for preparing a long-acting persulfate remediation tablet in a contaminated water, which mainly mixes persulfate with cellulose in proportion, and applies persulfate to cellulose through external pressure application. The mixture is made into a tablet, in which the persulfate is an oxidizing agent, the cellulose is a coating agent, and the ruthenium is coated with various components by cellulose, so that it is not easily released into the water body quickly, so as to facilitate persulfate. Maintain long-term release ability, in which persulfate is a relatively Long-acting oxidants, which do not tend to react with organic matter in the soil, also make the amount of agent required for persulfate application lower than other oxidants. Therefore, the use of persulfate oxidation can effectively remove pollution. In addition, the cost of remediation of the contaminated site can be reduced, and the stability of the persulfate in the present invention, combined with the persulfate chemical oxidation method and the existing passive rectification wall technology, can develop a combination of oxidation and integration. The remediation system, which is used to treat groundwater contaminated by oil, and because of the specific viscosity of cellulose, it will be dissolved in the water body, so that the area of contact between the coated material and the water body is reduced, so that it is packaged. The covering is not easy to dissolve in water. If the principle of rectifying the wall can be applied, the persulfate is mixed with cellulose to make a long-acting oxidizing agent refining tablet. The ingot is added to the rectification wall, which not only provides long-term remediation. The effect, and because of the self-decomposing nature of the cellulose, will reduce the treatment of the ingot after the groundwater; thereby, it can constitute the water for use in the contaminated water. Long-acting drug ingot persulfate remediation method were made.

(1) The method for producing a long-acting persulfate remediation tablet in a contaminated water of the invention, increasing the maintenance time of the oxidant in the reaction zone, and improving the overall ability to rectify pollutants.

(2) The method for producing the long-acting persulfate remediation tablet in the contaminated water of the invention, the cellulose has self-decomposing ability to avoid secondary pollution.

(3) The method for producing a long-acting persulfate remediation tablet in a contaminated water according to the present invention, wherein the persulfate can exist under the surface for a long time.

(4) The method for producing a long-acting persulfate remediation tablet for use in contaminated water of the present invention The law provides an appropriate formula for oxidizing agents and cellulose depending on the site conditions and the need for remediation.

(5) The method for producing the long-acting persulfate refining tablet in the contaminated water of the invention, the system has the functions of oxidation and activation, and can effectively remove the contaminants and maintain the persulfate.

Part of the invention:

(10) ‧‧‧Ingots

(11)‧‧‧Persulfate

(12)‧‧‧Cellulose

(13) ‧‧‧Mixture

(20)‧‧‧Mold

The first figure is a production flow chart of the present invention.

Second Figure: is a block flow diagram of the present invention.

In order to enable your review committee to have a better understanding and understanding of the purpose, features and effects of the present invention, please refer to the following [simplified description of the drawings] as follows: First, please see the first picture, The invention provides a method for preparing a long-acting persulfate remediation tablet for use in contaminated water, which mainly mixes persulfate (11) with cellulose (12) in proportion and transmits external pressure (5,000- With the application of 15,000 kg F/cm ² ), a mixture (13) of persulfate (11) and cellulose (12) is prepared into a tablet (10) in which persulfate (11) As an oxidant, cellulose (12) is a coating agent, and the ruthenium is coated with various components by cellulose (12), so that it is not easily released into the water body quickly, so as to facilitate the long-term release ability of the persulfate (11). Among them, persulfate (11) is a relatively long-acting oxidant, and its characteristic of not reacting with organic matter in the soil also makes the amount of the agent required for persulfate (11) application lower than other oxidants. Therefore, in addition to the effective removal of contaminants, the persulfate oxidation method can also reduce The cost of remediation of the contaminated site, and the use of the persulfate (11) stability, combined with the persulfate chemical oxidation method and the existing passive remediation wall technology, will be able to develop a remediation system that combines oxidation and integration. , 俾 is used to treat groundwater contaminated by oil, and because cellulose (12) has a specific viscosity, it will be dissolved in the water body, so that the area of contact between the coated material and the water body is reduced, so that it is packaged. The covering is not easily dissolved in water. If the principle of rectifying the wall can be applied, the persulfate (11) and the cellulose (12) are mixed to prepare a long-acting oxidizing agent (10), which is added by the ingot (10). In the remediation wall, not only can it provide long-term remediation effect, but also because cellulose (12) has self-decomposing properties, it will reduce the treatment of the ingot (10) after groundwater.

The invention provides a method for preparing a long-acting persulfate remediation tablet for use in a contaminated water, wherein the persulfate (11) and the cellulose (12) are scaled and required to be uniformly mixed. The mixture (13) of the persulfate (11) and the cellulose (12) is poured into a mold (20) of 10 cm*10 cm, and a specific pressure is applied by a hydraulic tableting machine to rectify the invention. The ingot (10) can be made (please view it as shown in the first and second figures).

The present invention provides a process for producing a long-acting persulfate remediation tablet for use in contaminated water, wherein the cellulose (12) is a hydroxypropyl methylcellulose.

The present invention provides a process for producing a long-acting persulfate remediation tablet in a contaminated water, wherein ferrous iron and citric acid are further added to the mixture (13).

According to the above invention, in recent years, the sustained-release oxidant substance has been attracting attention, and a specific adhesive substance is coated with an oxidizing agent such as persulfate to reduce the release time of the oxidizing agent and to achieve a long-term remediation effect. Cement is a study of adhesive materials; In the study of cement as a binder, it is pointed out that when persulfate is mixed with cement, it will produce an appearance phenomenon, so that the persulfate will be released in a short time, but some of the persulfate will be retained due to the solidification of the cement. Among them, the release effect is unstable, and the study of paraffin as a binder, although the persulfate release effect is more stable than cement, but the paraffin needs to be heated during the production process and must be maintained at 60 ° C, persulfate When the oxidant encounters high temperature (>40 °C), the activation phenomenon will occur, and the release effect will be affected to some extent. The above two studies need to manually take out the slow release oxidant substance from the contaminated area, which will increase the cost of remediation. The purpose of the design of the present invention is to mix the persulfate (11) with the cellulose (12), and to make the ingot (10) by applying pressure, and to slow down the persulfate by the viscosity of the cellulose (12) ( 11) The release in groundwater allows persulfate (11) to maintain a long-term remediation effect. The use of cellulose (12) can be self-decomposing, and the cost of remediation can be reduced. The method removes the sustained release oxidant substance from the contaminated area, and when the invention is rectified, it may also add divalent iron to accelerate the release of the persulfate (11) in the case of local pollution.

The invention provides a method for preparing a long-acting persulfate remediation tablet for use in contaminated water, which is prepared by mixing persulfate (11) with cellulose (12) and applying the applied pressure to the ingot (10). The cellulose (12) reacts with water to produce viscosity, which is beneficial to the long-term dissolution release of persulfate (11). Table 1 shows the ratio of different compositions of persulfate (11) and cellulose (12). Batch experiments, the daily persulfate (11) release results obtained for each experimental group are shown in Table 2, Table 3, and Table 4, indicating different tableting pressures, persulfate (11) dose, and hydroxypropyl The ratio of methylcellulose (12) as the influencing factor, the optimal ratio of oxidant release tablets (10) can maintain a stable release of about 10 Days, showing that the long-acting oxidizing agent remediation tablet (10) has the effect of allowing the oxidizing agent to maintain a long-term release effect. From the above results, the remediation system developed by the present invention is oxidative, not only for the methyl tertiary butyl ether. The site of pollution provides long-term remediation ability. Due to the characteristics of hydroxypropyl methylcellulose (12), persulfate (11) is also stably released for 10 days, reducing the cost of remediation. Synthetic long-acting oxidative remediation drugs Ingot (10) also has a long-term release effect and can be applied to the remediation of groundwater oil pollution.

The above-mentioned method for preparing a long-acting persulfate remediation tablet for use in contaminated water has the following advantages: (1) increasing the maintenance time of the oxidant in the reaction zone while improving the overall ability to rectify contaminants; (2) fiber Prime (12) has self-decomposing ability to avoid secondary pollution; (3) Persulfate (11) can exist under the surface for a long time; (4) It can provide appropriate formula of oxidant and cellulose (12) according to the site conditions and the time of remediation; (5) The system has oxidation at the same time. The function of activation can effectively remove contaminants and maintain the duration of persulfate (11).

The above is only a preferred embodiment of the present invention, and the scope of the present invention is not limited thereto; that is, the equal variation and modification of the scope of the patent application of the present invention should still belong to the present creation. Within the scope of the patent.

(10) ‧‧‧Ingots

(11)‧‧‧Persulfate

(12)‧‧‧Cellulose

(13) ‧‧‧Mixture

(20)‧‧‧Mold

Claims (5)

The invention relates to a method for preparing a long-acting persulfate remediation tablet for use in contaminated water, which mainly comprises mixing persulfate with cellulose in a ratio of 0.1 to 0.5, and passing through an external 5,000-15,000 kgF/cm ² The application of pressure, the mixture of persulfate and cellulose is made into a tablet, in which the persulfate is an oxidizing agent, the cellulose is a coating agent, and the ruthenium is coated with various components by cellulose, making it difficult to apply. It is quickly released into the water body to facilitate the long-term release of persulfate. The tablet also has characteristics such as oxidation and green remediation, which can accelerate the removal of pollutants and reduce the cost of remediation. The method for preparing a long-acting persulfate remediation tablet for use in a contaminated water according to claim 1, wherein the persulfate and the cellulose are in a ratio required for weighing, and after mixing, the The mixture of persulfate and cellulose is poured into a mold, and a specific pressure is applied by a hydraulic tableting machine, so that the rectifying tablet of the present invention can be produced. A method for producing a long-acting persulfate remediation tablet for use in a contaminated water according to claim 1 or claim 2, wherein the cellulose is a hydroxypropyl methylcellulose. A method for producing a long-acting persulfate remediation tablet in a contaminated water according to claim 1 or claim 2, wherein ferrous iron and citric acid are further added to the mixture. A method for producing a long-acting persulfate remediation tablet in a contaminated water according to claim 2, wherein the mixture of persulfate and cellulose is poured into a mold of 10 cm * 10 cm.