JP2010193882A - Cultivation member for heavy metal hyperaccumulator plant and method of recovering heavy metal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cultivation member for heavy metal hyperaccumulator plant and a method of recovering a heavy metal, little in load of planting and collecting a heavy metal hyperaccumulation plant, wherein the planted plants can grow well. <P>SOLUTION: The method of recovering a heavy metal includes putting a heavy metal hyperaccumulator plant 5 and a cultivation soil 3 in a cultivation vessel 2 having a water-permeable side surface, and planting the heavy metal hyperaccumulator plant by putting the cultivation vessel 2 in a medium containing heavy metals so as to absorb the heavy metals into the heavy metal hyperaccumulator plant. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a technique for recovering heavy metal by cultivating a heavy metal super-accumulated plant in a medium containing heavy metal and allowing the plant to absorb heavy metal.

Conventional methods for purifying media contaminated with heavy metals include, for example, excavating the entire contaminated soil and treating it in a controlled disposal site, solidifying with cement, insolubilizing with chemicals, or soil washing. Mainstream. However, these treatment methods are effective for high-concentration contaminated areas, but they are not efficient for low-concentration contaminated areas because they require a large amount of energy input and enormous costs.

As another purification method, phytoremediation technology using the ability of plants to absorb and accumulate heavy metals has been studied. Phytoremediation is greatly affected by environmental factors, that is, plant growth is easily influenced by the climate, and it takes a long time for purification, so there are problems such as low immediate effect, but it is low cost and requires little labor However, it is attracting attention because it is an environmentally harmonious technology.

For example, Patent Document 1 describes a purification method using a fern plant Pteris genus. Patent Document 2 describes a purification method using plants of the genus Cyperaceae Eleocharis such as pine bay (Eleocharis acicularis).

JP 2002-540943 A International Publication No. 2007/091382 Pamphlet

In the inventions described in Patent Document 1 and Patent Document 2, plant seedlings to be cultivated are directly planted on the ground or riverbed of a place to be purified. And the plant after growing up is performed by cutting or pulling out from the ground or the like. However, this has a lot of effort. In particular, the purification method described in Patent Document 2 is effective in a watery environment such as a river or a swamp, but planting in these places is a great work.

Moreover, after planting directly, it was found that some plants do not grow well and die. In particular, the environment of the mine site is rich in clay, and it has been found that it is difficult to grow heavy metal superaccumulating plants such as pine trees.

An object of the present invention is to provide a heavy metal super-accumulated plant cultivating member and a heavy metal recovery method that are less burdensome for planting and collecting heavy metal super-accumulated plants and that allow the planted plants to grow well. .

In order to solve the above problems, a heavy metal super-accumulated plant cultivation member according to the present invention is a member for cultivating a heavy metal super-accumulated plant in a medium containing heavy metal, and has a water-permeable side surface. And the soil for cultivation put in the cultivation container. In addition to this, a connecting member for connecting a plurality of containers may be provided.

In the heavy metal recovery method according to the present invention, a heavy metal super-accumulated plant and soil for cultivation are placed in a cultivation container having a water-permeable side surface, and the heavy metal super-accumulated plant is planted by installing the cultivation container in a medium containing heavy metal, It is characterized by absorbing heavy metals in heavy metal super-accumulated plants. Furthermore, you may connect a some container with a connection member. As a plant to be cultivated, for example, a plant of the genus Cyperaceae Eleocharis can be used, and in particular, a plant of the genus Cyperaceae is preferably pine (Eleocharis acicularis).

The heavy metal super-accumulated plant cultivation member and the heavy metal recovery method according to the present invention have an effect that the heavy metal hyper-accumulated plant to be cultivated can be easily planted and collected after cultivation. Moreover, even after planting, the plant is less likely to wither and has the effect of growing well. In particular, heavy metals can be accumulated at a higher concentration by using soil for cultivation containing a soluble silicon compound.

It is a perspective view which shows a heavy metal super accumulation plant cultivation member. It is a conceptual diagram which shows the heavy metal collection | recovery method using a heavy metal super accumulation plant cultivation member. It is a graph which shows the heavy metal density | concentration in the pineapple in a direct cultivation method. Heavy metal concentration in pine trees in the cultivation method using heavy metal super-accumulated plant cultivation parts It is a graph which shows the arsenic density | concentration contained in the green leaf of the pineapple in greenhouse cultivation. It is a graph which shows the arsenic density | concentration contained in the dead leaf of a pineapple in greenhouse cultivation. It is a graph which shows a degree. It is a graph which shows the arsenic density | concentration contained in the root of a pineapple in greenhouse cultivation. It is a graph which shows the change of the density | concentration of lead Pb in the liquid for cultivation.

EMBODIMENT OF THE INVENTION The form for implementing this invention is demonstrated based on drawing. FIG. 1 is a perspective view showing a heavy metal super-integrated plant cultivation member, and FIG. 2 is a conceptual diagram showing a heavy metal recovery method using the heavy metal super-integrated plant cultivation member.

The heavy metal super-integrated plant cultivation member 1 includes a cultivation container 2 and a cultivation soil 3 placed in the cultivation container. The side surface of the cultivation container 2 is water permeable. Here, moisture permeability means that the cultivation soil 3 can be held and water can sufficiently enter and exit. For example, pottery plant pots, plastic pot planters, etc., which have a large number of holes on their sides, pots molded from peat moss called Jiffy Pot (registered trademark), etc. can be used.

In this cultivation container 2, soil 3 suitable for cultivation of the target heavy metal super-integrated plant is placed. For example, it is good to put sand or soil containing a lot of sand for pine cones.

Although the cultivation container 2 may be used alone, a plurality of the cultivation containers 2 may be further connected by the connecting member 4. For example, a wire mesh cage 4 that can accommodate a large number of cultivation containers 2 may be used as a connecting member, and the cultivation containers 2 on which the cultivation soil 3 is placed may be arranged in this cage. In addition to this, irregularities that can be engaged with each other outside the side surface of the cultivation container 2 may be provided to form a connecting member, or may be connected using a binding band or the like.

You may plant the seedling 5 of the heavy metal super accumulation plant which should be cultivated in the cultivation container 2 previously. Here, the heavy metal super-accumulated plant refers to a plant that can accumulate and accumulate heavy metals in the environment above the standard of each element. Cyperaceae Eleocharis plants are suitable in watery environments such as rivers, lakes, ponds, and swamps. For example, there are mulberry grouse, white crocodile, pine mackerel, pine bay, harii, and misumi.

Table 1 shows the maximum accumulated concentration of useful metals in pine trees. The results of measurements at three mines in Japan are shown. It is understood that it effectively absorbs harmful heavy metals such as copper, arsenic and lead, and is effective for water environment purification. Silver, gallium, zirconium, and the like are rare metals having a high use value, and can be reused as resources by collecting them. New mine development requires a great deal of cost and labor, and there are concerns about mine damage, but phytoremining, which recovers metals by growing heavy metal super-accumulated plants, can be carried out at low cost and without pollution.

Next, the heavy metal recovery method will be described. A plant is selected according to the place where the plant is cultivated and the purpose of cultivation (for example, the type of heavy metal to be collected, etc.), and the cultivation container 2 and the cultivation soil 3 are also selected. The cultivation container 2 and the cultivation soil 3 may be transported separately, and the cultivation soil 3 may be put in the cultivation container 2 locally. However, the cultivation container 3 and the cultivation soil 3 previously placed in the cultivation container 2 may be carried locally. Furthermore, plant seedlings and seeds may be added.

In an environment with a lot of water, it is only necessary to place the heavy metal super-accumulated plant cultivation member on the bottom of the water. Moreover, you may make it cover the lower part of the cultivation container 2 with soil. In addition to arranging the cultivation containers 2 one by one, as shown in FIG. 2, a plurality of cultivation containers 2 can be connected efficiently by a connecting member such as a wire mesh basket. In particular, in a place where the flow is strong, the cultivation container 2 can be prevented from flowing by connecting and installing the plurality of cultivation containers 2. For example, in the case of pine trees, it is preferable to plant around spring.

In an environment with little water, the cultivation container 2 may be installed so that all or part of the cultivation container 2 is buried in the ground.

Even when a grown plant is collected, the cultivation container 2 can be easily collected. For example, the recovered plant may be dried and then incinerated if it contains harmful metals to manage the ash. In addition, useful metals may be extracted and recovered from this plant and used as resources. Further, the durable cultivation container may be reused for the next cultivation.

A first embodiment of the present invention will be described. The heavy metal super-accumulated plant cultivation member and heavy metal recovery method of the present invention were applied to a pond at a resting mine remnant deposit site in Ehime Prefecture, and pine bai was transplanted for cultivation. The cultivation container used was a commercially available Jiffy Pot (registered trademark) having a diameter of 8 cm, which was filled with sand and planted with pine cones. By placing this cultivation container on the bottom of the pond, pine trees were transplanted.

Planted in May 2008 and cut in August.

On the other hand, as a 1st comparative example, the pineapple was planted directly to sediments, without using a heavy metal super accumulation plant cultivation member in the same place. Planted on July 28, 2006 and cut on November 22 of the same year.

In the first comparative example, which is direct planting, most of the pine trees have died about four months after planting. On the other hand, in the first example, the planted pine trees grew steadily without causing death even though the environment was rich in heavy metals. In comparison with the first comparative example, the biomass of pine bye in this example is significantly increased.

FIG. 3 is a graph showing the concentration of heavy metals in pine trees in the first comparative example, and FIG. 4 is a graph showing the concentration of heavy metals in pine trees in the first example. It can be confirmed that each heavy metal was accumulated at high concentration in Matsubai. In addition, it can be confirmed that the amount of absorbed zinc is remarkably improved in the first embodiment.

A second embodiment of the present invention will be described. The heavy metal super-accumulated plant cultivation member and heavy metal recovery method of the present invention were applied to a river in an abandoned mine remnant deposit site in Okayama Prefecture, and pine bai was transplanted for cultivation. The cultivation container and cultivation soil used are the same as those in the first embodiment. In addition, as a second comparative example, pine cones were directly planted in the bottom in the same place. Planting was carried out from September 3rd to 4th, 2008.

In the second comparative example, 80% of the planted pine trees died. On the other hand, in the second example, the pine tree grew healthy without causing death, and after two months, the pine tree biomass increased more than twice.

A third embodiment of the present invention will be described. It is an example which collect | recovers heavy metals using the heavy metal super accumulation plant cultivation member which has the soil for cultivation containing a soluble silicon compound. First, an example in which heavy metal super-integrated plant cultivation members are used in a river flowing through Jozankei hot spring town in Sapporo, Hokkaido will be described.

It has been reported that arsenic contamination caused by hot spring spring water has become a problem in tap water sources in Sapporo (Sakai et al., 2002). According to this report, arsenic is adsorbed to the sediment and flows out to the downstream. Therefore, when samples of water and bottom chambers were collected and analyzed at multiple locations in Jozankei hot spring town, high concentrations of arsenic were detected in all samples.

Heavy metal recovery using heavy metal super-accumulated plant cultivation materials was carried out at a slightly downstream location in a river flowing through Jozankei hot spring town on the Kaido Sapporo city. As a plant to be cultivated, Matsubai is used. Cultivation soil is put in a cultivation pot having a diameter of 9 cm and a height of 8 cm, and about 15 g of pine birch is planted. Here, in one group, only sand was added as soil for cultivation. In another group, sand and silicon fertilizer (Fuji Silysia Chemical Co., Ltd., 80.0 silica gel fertilizer (energy), guaranteed component amount: soluble silicic acid 80.0%) were each 50 wt. % Of each mixture was added. In addition, a plastic container having a length of 53.5 cm, a width of 37 cm and a height of 30 and having a large number of holes on the side surface is used. Each culture container was fixed with 15 culture pots arranged in 3 × 5.

A plastic container was installed at the bottom of the river so that all but the tip of the pine tree was soaked in water and cultivated for about three months from July to October. There was no difference in growth between the sand-only group and the group added with silicon fertilizer as soil for cultivation.

After cultivation, pineapple was collected, and the concentration of heavy metals in pineapple was measured by ICP-MS PIXE. The results are shown in Table 2. Here, the unit is mg / kg-DW.

As described above, in the case of As, Mn, and Fe, it can be confirmed that more heavy metals can be accumulated by adding silicon fertilizer to the cultivated soil and cultivating pine bai.

Next, the results of greenhouse cultivation of pine trees using the riverbed sediment collected at the place where the above cultivation was performed will be described. Using a plastic basket for cultivation, transplant about 100 g of pine by each. Use pure water as water. River sediment used as cultivation soil contains 274 mg / kg arsenic. In addition to the example of cultivating only the riverbed sediment, the same cultivation was performed on the soil for cultivation with silicon fertilizer added at 0.1%, 1%, and 10% by weight. It is cultivated for about 2 months from September to November. The concentration of arsenic in Matsubai was measured by ICP-MS PIXE.

FIG. 5 shows the arsenic concentration contained in green leaves, FIG. 6 shows the arsenic concentration contained in dead leaves, and FIG. 7 shows the arsenic concentration contained in roots. The vertical axis represents the arsenic concentration, and the unit is mg / kg. From this, it can be seen that the concentration of arsenic in pine trees increases by adding silicon fertilizer.

As mentioned above, it turned out that the heavy metal accumulation | concentration density | concentration of heavy metal superaccumulation plants, such as a pine cone, increases by adding silicon fertilizer to the soil for cultivation. This is due to the soluble silicon compound contained in the silicon fertilizer. The water culture of pine trees performed to confirm this will be described.

Copper standard solution, Zinc standard solution, Cadmium standard solution, Mercury standard solution, Lead standard solution, Gallium standard solution, Thallium standard An aqueous solution containing each heavy metal of Cu, Zn, Cd, Hg, Pb, Ga, Ag, In, and Tl at a concentration of 500 μg / L was prepared using a liquid (Thallium standard solution). And besides using this aqueous solution as a cultivation solution as it is, cultivation by adjusting the Si concentration to 0.5 mg / l, 1 mg / l, 4 mg / l by adding a silicon standard solution to the aqueous solution. A working solution was also made. Matsubai is cultivated for 21 days with these four types of cultivation liquids. During this period, the heavy metal concentration in the cultivation liquid was measured by ICP-MS. Moreover, the heavy metal density | concentration in a pineapple was measured by ICP-MS and PIXE after cultivation.

FIG. 8 is a graph showing changes in the concentration of lead Pb in the cultivation liquid. In all the cultivation liquids, the concentration of Pb decreases with time, and it is confirmed that pine trees absorb and accumulate Pb. And it can confirm that the reduction | decrease of Pb in cultivation liquid is quick, so that there are many silicon contents in cultivation liquid. It was confirmed that the concentrations of Cu, Zn, Cd, and Ga were greatly decreased in the cultivation liquid to which silicon was added. In particular, the effect was remarkable with a 4 mg / l silicon-containing cultivation solution.

Moreover, when the heavy metal density | concentration in a pineapple was measured, it was confirmed that the pineapple cultivated with the silicon-containing cultivation liquid has accumulated Pb at a higher concentration. Many other heavy metals also tended to be accumulated at higher concentrations in the pine trees grown in the silicon-containing cultivation solution.

According to the present invention, it is possible to easily plant and collect a heavy metal super-accumulated plant, to grow it healthy without causing the plant to die, and it can be widely applied to the environment of heavy metal from a medium. The present invention makes it possible to recover heavy metals from an aqueous medium and the like, and can be applied to environmental purification (phytoremediation), recovery of rare metals and precious metals from aqueous media containing useful heavy metals (phytomining), and the like. it can. In particular, fight mining can be utilized as a resource development for useful heavy metals that is low in cost and sustainable compared to conventional mine development.

1. 1. Heavy metal super-integrated plant cultivation member 2. Cultivation container Cultivation soil 4. Connecting member

Claims (10)

A member for cultivating a heavy metal super-accumulated plant in a medium containing a heavy metal, comprising a cultivation container having a water-permeable side surface and a cultivation soil placed in the cultivation container. The heavy metal super-integrated plant cultivation member according to claim 1, further comprising a connection member for connecting a plurality of containers. The heavy metal super-accumulated plant cultivation member according to claim 1 or 2 having a soil for cultivation containing a soluble silicon compound. The heavy metal super accumulation plant cultivation member according to claim 3 which has soil for cultivation containing silicon fertilizer. A heavy metal super-accumulated plant and soil for cultivation are placed in a cultivation container having a water-permeable side, and the heavy metal super-accumulated plant is planted by installing the cultivation container in a medium containing heavy metal, and the heavy metal is absorbed into the heavy metal hyper-accumulated plant. And a heavy metal recovery method. The heavy metal recovery method according to claim 5, wherein a plurality of containers are connected by a connecting member and installed in a medium containing heavy metal. The heavy metal recovery method according to claim 5 or 6, wherein the plant to be cultivated is a plant of the genus Cyperaceae Eleocharis. The heavy metal recovery method according to claim 7, wherein the plant of the genus Haryiaceae that is cultivated is pine bay (Eleocharis acicularis). The heavy metal recovery method according to claim 7 or 8, wherein soil for cultivation containing a soluble silicon compound is used. The heavy metal recovery method according to claim 9, wherein soil for cultivation containing silicon fertilizer is used.

Images