KR20140070727A

KR20140070727A - Adsorbent, Method for producing the adsorbent and Method for remediation of contaminated water using the same

Info

Publication number: KR20140070727A
Application number: KR1020120134328A
Authority: KR
Inventors: 조동완; 전철민; 김용제; 송호철; 전병훈
Original assignee: 한국지질자원연구원
Priority date: 2012-11-26
Filing date: 2012-11-26
Publication date: 2014-06-11

Abstract

The present invention is an adsorbent in which chitosan and magnetite are mixed and beadsed together to adsorb and remove copper and arsenic.
The adsorbent according to the present invention comprises a carrier including clay minerals having a negative charge on the surface thereof, chitosan linked to the carrier by a cross-linking agent, and a magnetite bonded to the carrier.

Description

[0001] The present invention relates to an adsorbent, a method for producing the same, and a method for recovering contaminated water using the adsorbent.

The present invention relates to an adsorbent for adsorbing and removing copper and arsenic from streams and groundwater contaminated with copper and arsenic, a method for producing adsorbent, and a method for recovering contaminated water using the same.

Copper requires an appropriate amount as an essential element of the human body, but a high concentration of copper ions is harmful to the human body by adversely affecting the liver, kidney, and nervous system.

Arsenic is known to cause fatal damage to lungs, skin, and liver during ingestion and induce various cancers. Arsenic is present in the form of trivalent in an oxidizing environment and pentavalent in a reducing environment, and is present in a state bound to metals and sulfur in a natural environment, and is observed at a high concentration mainly in a metal sulfide mineral rich region.

Industries are often contaminated with copper and arsenic simultaneously because arsenic is used as the main ingredient in the materials used to strengthen copper alloys.

Methods available to purify surface water and groundwater contaminated with inorganic contaminants include ion exchange, precipitation, adsorption, and membrane processes. The adsorption process is relatively more efficient and economical than other processes and has been widely used as an environmental purification method.

However, as described above, the development of an adsorbent for efficiently removing these pollutants from streams and groundwater in a region where copper and arsenic are simultaneously observed at a high concentration is insufficient.

In addition, it is possible to prevent the secondary pollution spread by reclaiming the adsorbent after the pollutant is removed by injecting the adsorbent into the polluted water such as ground water or river, but research on this is not actively carried out.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an adsorbent which can adsorb and remove copper and arsenic contained in polluted water and can be easily separated and recovered after adsorption, The purpose of the method is to provide.

In order to accomplish the above object, the adsorbent according to the present invention comprises a carrier including clay minerals having negative charge on the surface thereof, chitosan linked to the carrier by a cross-linking agent, and magnetite bonded to the carrier, .

As the carrier, zeolite-based clay minerals such as montmorillonite clay minerals such as bentonite and hollandite may be used.

In addition, the crosslinking agent includes a phosphate group, and is preferably TPP (Tripoly Phosphate).

In order to accomplish the above object, the present invention provides a method for producing an adsorbent, comprising: a carrier containing a clay mineral having a negative charge on its surface; and a magnetite mixed with a chitosan solution having a pH of 3 to 5, And forming a beaded adsorbent by dropping the mixed solution by a predetermined amount in a cross-linking agent solution for interconnecting the chitosan.

Hollandite is used as the carrier, TPP (tripolyphosphate) containing a phosphate group is used as the crosslinking agent, and the magnetite is preferably composed of nano-sized particles.

In the present invention, the chitosan is contained in an amount of 15 to 26% by weight, the carrier is contained in an amount of 15 to 26% by weight, and the magnetite is mixed in a ratio of 50 to 70% by weight based on the total weight of the chitosan, the carrier and the magnetite.

In order to achieve the above object, the present invention provides a method for recovering contaminated water, comprising: a carrier including clay minerals having a negative charge on a surface thereof; chitosan linked to the carrier by a crosslinking agent; And adsorbing copper and arsenic contained in the contaminated water to the adsorbent to remove the adsorbent.

In an embodiment of the present invention, the adsorbent can be separated and recovered by a magnet after the adsorption of copper and arsenic in the contaminated water is completed by utilizing the magnetite component of the adsorbent being bonded to the magnet.

The adsorbent according to the present invention adsorbs and removes copper ions in the contaminated water by the carrier having a surface negative charge and chitosan and adsorbs and removes the arsenic ions in the contaminated water by the magnetite captured by the carrier and chitosan .

Also, in the present invention, chitosan coated on a support using a crosslinking agent can be stably bonded to the support irrespective of changes in the surrounding pH environment, and the ion interaction of the phosphate group contained in the cross- Can be removed.

Since the adsorbent according to the present invention includes magnetite, it is advantageous that the adsorbent can be easily separated and recovered by using magnetism after the treatment for contaminated water is completed.

1 is a view for explaining the action of removing metal ions by chitosan.
2 is a schematic flow diagram of a method for producing an adsorbent according to the present invention.
Fig. 3 is a table showing the results of characteristic analysis for HE (hollandite) and CCM (adsorbent).
4 is a SEM photograph of the HE.
5 is a SEM photograph of the CCM.
6 is an EDS analysis graph of HE.
Figure 7 is an EDS analysis graph of the CCM.
8 and 9 are graphs showing the removal rates of copper and arsenic as a function of the weight ratio.
FIG. 10 is a graph showing adsorption rates under the conditions of initial concentrations of copper and pentavalent arsenic ions of 45.1 and 39.5 mg L-1, respectively.
11 is a graph showing the results of isothermal adsorption experiments of copper and pentavalent arsenic ions using CCM

Hereinafter, the adsorbent for simultaneous removal of copper and arsenic according to an embodiment of the present invention will be described in more detail.

The adsorbent according to the present invention is composed of a carrier, chitosan bonded to or coated on the carrier, and magnetite bonded to the carrier, and is formed in a beaded powder form.

The carrier is a body which acts as a body to which a chitosan and a magnetite to be described later are combined. In the present invention, a material having a negative charge on its surface is used so that the magnetite can be primarily bonded. Since the magnetite has a positive charge on its surface, the magnetite and the carrier can be primarily bonded when a material having magnetite and surface negative charge is used as the carrier. In addition, since metal ions such as copper have a positive charge mainly on the surface, a substance having a surface negative charge can act to remove heavy metal ions.

In addition, it is advantageous that the support has a small specific surface area (for example, nano size) as a porous substance. If the specific surface area is wide, not only the magnetite and chitosan can be bound to the carrier in a large amount, but also the metal ions as the pollutant source can be bound to a large extent, which is effective in removing the contamination source.

Clay minerals are used in the present invention as carriers having these requirements. Namely, montmorillonite-based clay minerals such as bentonite or zeolite-based clay minerals such as hollandite can be used. In this embodiment, hollandite is used as a support.

Hollandite is a mineral with a porous structure, a large surface area and an intrinsic crystal channel, and is suitable for providing a place where a magnetite and chitosan can be mixed and impregnated. It has the advantage of adsorbing positively charged metal ions Have. There is also the advantage that the metal ions are removed by the intraparticle diffusion action in the hole structure of the hole lanthanide.

On the other hand, in the present invention, chitosan, which is mainly used for mainly removing copper ions, is coated on the surface of a carrier and stabilized by a crosslinking agent.

Chitosan is an alkaline deacetylated material of chitin, which has high hydrophilicity and contains many hydroxyl and amino groups on its surface. Chitosan is an environmentally friendly material that is non-toxic, biodegradable, and has high applicability.

Chitosan can adsorb and remove copper ions in contaminated water by metal chelation. As shown in Fig. 1, the metal chelate is formed by bonding a nitrogen atom of an amine group (a form in which a proton is not added) and an oxygen atom of a hydroxyl group together to a metal ion.

As described above, chitosan has excellent applicability as an environment-friendly substance and has excellent adsorption ability of metal ions by metal chelation, but the state changes depending on the pH condition around the chitosan. That is, chitosan is dissolved in an acidic environment, but is solidified in an alkaline environment.

In the present invention, chitosan can be coated on the carrier by using the characteristics of being dissolved in a liquid state in an acidic environment. That is, when chitosan is formed into a liquid phase in an acidic solution and then the carrier is mixed with the chitosan solution, chitosan is coated on the surface of the carrier (including the inner surface of the porous structure).

However, if the environment of the contaminated water is acidic (mostly acidic conditions), the chitosan solution can be separated from the carrier and the structural instability must be solved.

For this purpose, in the present invention, a crosslinking agent is used so that chitosan is not destabilized by pH conditions but is bonded to a carrier to maintain a solid state. The crosslinking agent improves the binding stability by linking chitosan and chitosan to each other so that chitosan is entirely connected to the surface of the carrier. In this embodiment, a crosslinking agent containing a phosphate group (PO ₃ ^- , P ₂ O ₅ ^- ) is used. Specifically, tripolyphosphate (TPP), glutaraldehyde can be used. In this example, TPP was used as a crosslinking agent.

When a proton is added to the amine group (-NH ₂ ), which is a functional group of chitosan under the condition of weak acidity, to form -NH ₃ ⁺ , it binds to a phosphate group which is negatively charged in TPP. As the chitosan adjacent to each other is linked to the cross-linking agent, the chitosan and the cross-linking agent are combined with each other to form a composite state in which the chitosan is coated on the support. Accordingly, even when the contaminated water has an acidic condition, the chitosan can be maintained in a solid state on the carrier without being dissolved in the contaminated water.

Magnetite is for adsorbing and removing arsenic ions (especially pentavalent arsenic) in polluted water. Magnetite is known to be a substance capable of effectively adsorbing arsenic with zero valence iron.

In this embodiment, a nano-sized magnetite is bonded to a carrier to remove arsenic in contaminated water. The magnetite is primarily bonded to a surface negative charge carrier such as hollandite. In this state, chitosan and a crosslinking agent are coated on the surface of the hollandite. That is, it can be explained that the magnetite is captured by hollandite and chitosan-crosslinking agent.

Further, by using the magnetite as the adsorbent, there is an advantage that the adsorbent can be easily separated and recovered from the polluted water after the contamination source treatment by the adsorbent is finished. That is, since the magnetite is a ferromagnetic substance and has a strong bonding force with the magnet, there is an advantage that the adsorbent can be easily separated from the polluted water by using the magnet. This can provide a solution to the problem of secondary contamination by spreading the adsorbent itself along the polluted water after the adsorption removal of the pollutant source is completed.

As described above, the adsorbent according to the present invention can adsorb and remove metal ions by hollandite, adsorb and remove copper ions by chitosan, and adsorb and remove arsenic ions by magnetite. Further, after the adsorption and removal to the contaminant source are completed, the adsorbent can be easily recovered by using the magnet, thereby preventing the secondary contamination diffusion.

Hereinafter, a method for producing an adsorbent according to the present invention will be described in detail.

2 is a schematic flow diagram of a method for producing an adsorbent in accordance with an embodiment of the present invention.

Referring to FIG. 2, in an adsorbent manufacturing method according to an embodiment of the present invention, a carrier, chitosan, and magnetite are prepared. They are all prepared in the form of a solid powder. In this embodiment, a nano-sized hollandite was used as a carrier, and a magnetite and nano-sized fine particles were used.

Then, the chitosan is supplied to a weakly acidic solution having a pH of 3 to 5 to dissolve the chitosan to form a chitosan solution. A solution having a pH of less than 3 can dissolve the magnetite later, and when the pH exceeds 5, it is not easy to dissolve the chitosan, so the pH is preferably maintained at 3 to 5. However, the pH range may be extended as long as solubility of chitosan and elution of magnetite do not occur. In this embodiment, chitosan is dissolved using acetic acid.

After the chitosan solution is prepared as described above, hollandite and magnetite are supplied to the chitosan solution and mixed with stirring for a certain period of time (30 minutes in this embodiment). To stir the magnetite and holandite into the chitosan solution, ultrasonic waves are applied during stirring.

The total weight of hollandite, magnetite and chitosan is 100. In this embodiment, the magnetite is mixed in a ratio of 50 to 70 wt%, hollandite 15 to 26 wt%, and chitosan 15 to 26 wt%. The hollandite used as the support is small in weight but has a porous structure and has a large surface area, so that the magnetite and chitosan can be combined with each other.

Magnetite is mainly used for adsorbing arsenic. Experimental investigations have shown that the removal rate does not increase when the mixing ratio of magnetite is increased from 50 wt% to 70 wt%, while the arsenic removal rate is higher than 70 wt%. Also, in case of chitosan, it was also found that the removal rate of copper did not increase when the content of the chitosan exceeded 26 wt%. The removal rate of copper and arsenic is the highest at 1: 1: 2 mixture ratio (weight ratio) of hollandite: chitosan: magnetite.

As described above, hollandite and magnetite are mixed in a chitosan solution to prepare a mixed solution, and then a crosslinking agent solution for stabilizing chitosan is prepared. In this embodiment, TPP is used as a crosslinking agent. That is, after the TPP crosslinking agent is dissolved in a weakly acidic solution of about pH 4, the mixed solution is dropped into the crosslinking agent solution by a predetermined amount. Chitosan, which encapsulates the surface of the carrier, binds to the TPP crosslinking agent and is stabilized and solidified into a bead state.

The beaded adsorbent can be separated from the crosslinking agent solution by using a magnet or a known solid-liquid separator, washed with distilled water and dried to form an adsorbent.

Regarding the amount of the crosslinking agent bound to the adsorbent, in this embodiment, the amount of the crosslinking agent is not limited, and the chitosan can sufficiently bind to the crosslinking agent. Theoretically, the increase of the bond between the cross-linking agent and chitosan is very advantageous in terms of stabilization of the chitosan according to the ambient pH condition. However, since the amine group of the chitosan is consumed when the chitosan and the cross-linking agent are combined, It may be degraded.

Experimental investigations, however, showed that the copper removal rate of the adsorbent was improved even when the amount of crosslinking agent used was increased. This was confirmed as a result of the adsorption of the metal ion by the phosphate group of the crosslinking agent. Therefore, in this embodiment, rather than using a crosslinking agent in a predetermined amount to bind the mixed solution, the mixed solution is dropped into the crosslinking agent solution so that the chitosan and the crosslinking agent can be sufficiently bonded, thereby enhancing the binding stability of the chitosan.

The adsorbent produced in the above-described manner can be used for the contaminated water recovery treatment through various methods. That is, the adsorbent may be placed in a column or the like on the movement path of the polluted water, so that copper and arsenic may be adsorbed and removed when the polluted water passes through the adsorbent column. Alternatively, an adsorbent may be applied to the membrane to remove contaminants.

After the adsorption of the metal in the groundwater and the river water is completed by using the adsorbent, the adsorbent to which the metal is added can be easily recovered by using the magnet.

The Applicant has conducted experiments on the method of producing the adsorbent according to the present invention and the effect of the present invention. That is, in the experiment, a composite having magnetism was formed by bead formation using chitosan, nano magnetite, hollandite and TPP. The adsorption capacity of copper and pentavalent ions was evaluated by various experimental conditions such as adsorption rate, isothermal adsorption, thermodynamics, and underwater pH effect.

1. Experimental material

Chitosan, nanomagnetite (NMT), sodium tripolyphosphate (STPP), copper chloride, sodium arsenate, and acetic acid, which are approximately 75-85% deacetylated and Sigma-Aldrich Corporation and have viscosities of 190,000-310,000 g mol ^-1 acid (99%), sodium hydroxide, and hydrochloric acid were purchased and used. Heulandite (HE) was purchased from Donghae Chemical and used in 100 mesh sieve.

2. Preparation of chitosan / hollandite / Fe ₃ O ₄ complex

2 g of chitosan was dissolved in 100 mL of acetic acid (2%) to form a chitosan solution. STPP solution was prepared by injecting 13.3 g into 1 L of distilled water and adjusted to pH 4 with 1 N HCL. A predetermined amount of NMT and HE were injected into the chitosan solution and mixed with ultrasonic waves for 30 minutes. The mixtures were dropped into 100 ml of STPP solution in a 10 ml syringe and beaded through the interaction of amino groups of chitosan and phosphate groups of TPP.

The beaded composites were preserved in solution for 12 hours, washed several times with distilled water to remove residual TPP, and then dried in a 50 degree oven for 24 hours. The dried composite was ground and sieved on a 100 mesh screen. The adsorbent formed by the above procedure was named chitosan / hollandite / magnetite (CCM).

For the characterization of hallandite and CCM, the shape of mineral, zeta potential at pH 5 in water and BET surface area were measured by Sirion FE-SEM / EDS analyzer (Netherlands), Malvern Zetasizer nano zs (UK) and Micrometritics ASAP 2020 (USA). The magnetic properties of the two materials were also measured with a Bartington magnetic susceptibility meter (UK) with a 36 mm inner diameter and a volume of 10 cc.

3. Adsorption experiments

Copper and pentavalent arsenic adsorption experiments were carried out using 25 mL high density polyethylene vials. Standard solutions of copper and pentavalent arsenic were prepared by diluting 1,000 mg L ^-1 stock solution and adjusted to pH 5. Adsorption rate experiments were performed by injecting 0.1 g into vials containing 45.1 mg L ^-1 copper ions and 39.5 mg L ^-1 5 arsenic ions in 20 mL solutions. The vials were shaken at 23 rpm for 600 min at 150 rpm. The samples were filtered at 0.45 μm filter (Whatman, USA) at each set time and the concentrations of copper and pentavalent arsenic ions were measured. Adsorption isotherm experiments are copper and 5, the concentration range of the arsenic ions, respectively 16-656 and 17-336 mg L ^- ^1, giving a change in the other conditions was conducted in the same manner as adsorption test speed. All experiments were repeated twice, and the adsorption amounts of copper and pentavalent arsenic ions by CCM were calculated as follows.

q _e (mg g ^-1 ) = ( _Co - _Ce ) V / W

Where C ₀ and C _e are the initial and equilibrium concentrations of the adsorbed material, W is the adsorbent amount (g), and V is the volume (L) of the solution. Concentrations of copper and pentavalent arsenic ions were analyzed by ICP-OES (Ultima 2C, Horiba), and the pH in water was measured with a pH meter (Horiba, Ltd. Kyoto, Japan). The experimental results are as follows.

4.1. Adsorbent characterization

Table 1 in Figure 3 shows the results of characterization for HE and CCM. In the underwater Ph 5, HE and CCM showed 0.173 and -0.425 mV, respectively, indicating that the reforming process affected the charge on the HE surface. The change in surface charge is presumably due to the negative charge of the anionic TPP molecular sieve on the CCM surface. It is also possible that the added NMT contributed to the reduction of the change of the surface telephone by TPP because PZC was close to pH 8.

The BET results showed that the reforming process reduced the surface area from 22.1 to 5.1 m ² g ^- ¹ . It is believed that the crosslinked chitosan bound to the hydroxylated edge of HE and aggregated on the HE surface or blocked the HE pore to reduce the surface area. Furthermore, there is a possibility that the magnetite particles are fixed on the surface of the HE, thereby blocking the pores. However, magnetism that was not seen in the HE appeared through the modification. Susceptibility of the measured CCM is 3.0 × 10 ^-4 m ³ kg ^- and a number of times using the magnetic force in the similar value to ¹ in the normal magnetite susceptibility value ^{(1.0 × 10 -3 m 3 kg} -1 4.0 × 10 -4) It seems to be easy.

The surface properties of HE and CCM were observed with FE-SEM, and the micrographs of HE and CCM were shown in Figs. 4 and 5, respectively. The HE surface shows the shape of a typical montmorillonite mineral and is relatively clean (Fig. 4). On the other hand, in the case of CCM, nano-sized particles are seen covering the surface (FIG. 5).

The results of the EDS analysis show that HE contains 32 wt% of O, 31.7 wt% of Al, 13.3 wt% of Al and 11.8 wt% of C, (4.8 wt%), Fe (0.6 wt%), K (0.6 wt%), and Mg (0.4 wt%). However, the results of EDS analysis for CCM showed that the major components were Fe (30.6 wt%), C (23.4 wt%) and P (11 wt%). Changes in the constituents due to these modifications are attributed to TPP addition with phosphate groups, clay mineral surface coverage with magnetite-chitosan mixture, and magnetite impregnation on mineral surfaces.

4.2. Composition ratio for optimum adsorbent

FIGS. 8 and 9 show the results of the removal efficiency (%) and adsorption amount (mg g ^-1 ) of copper and pentavalent arsenic ions by CCM. The graph of Figure 8 is the initial concentration of each 109.4 Cu (II) mg L ^-1 and 10.3 As (V) mg L and HE chitosan weight ratio change from ^-1 removal efficiency according to (PA: fixed at 0.33: NMT = 1) and Fig. 9 is a graph of the initial concentration, respectively ^{118.2 Cu (II) mg L -1} and 10.6 as (V) NMT and HE weight change in mg L ^-1 removal of the (HE:: chitosan = 1 fixed at 1) efficiency to be.

The weight ratio of HE to NMT was fixed at 1: 0.33 and adsorbents were prepared by changing the weight of HE and chitosan.

Referring to the graph of FIG. 8, when the ratio of chitosan was increased to 4 in a state where the weight ratio of HE and NMT was fixed, the copper ion adsorption amount increased from 8.1 to 13 mg g ^-1 , Was not changed at about 0.03 mg g.

These results indicate that the increase of the weight ratio of chitosan is not effective for the adsorption of 5-valent arsenic ions but the adsorption rate of copper ions is increased. The presence of chitosan showed no effect on adsorption of arsenic on 5. This is because the amine function of chitosan is consumed by the ionic crosslinked TPP. Chitosan must have a cationic amine group in order to adsorb pentavalent arsenic, but most of the amine groups are consumed while the added TPP acts as a bridge of chitosan. In addition, it is presumed that TPP which is anion when 5 - arsenic adsorbed acts as a competitive ion on NMT surface.

Copper ion adsorption also occurs when only HE is applied, which can be explained by mass transfer between clay mineral surface and copper ion. Copper ions are adsorbed on the surface of the HE due to the phenomenon of sticking to the surface of the HE and the phenomenon of entering the HE crystal channel or pores. The increase in the amount of adsorption of copper ions with increasing chitosan ratio is due to the ability of the crosslinked chitosan on the surface of the HE to adsorb. As mentioned earlier, phosphate groups of TPP are present in the adsorbent while consuming the amine groups of chitosan. Therefore, it can be considered that the crosslinking phenomenon can consume copper ions capable of adsorbing amine groups and interfere with copper ion adsorption.

The opposite result, however, can be explained as a result of previous studies that the phosphate function can serve as a site for adsorption to cationic ions.

For the next experiment, the weight ratio of HE and chitosan was selected to be 1: 1, which is considered to be the most suitable, and fixed. The weight ratio of HE to chitosan was fixed at 1: 1, and an adsorbent was prepared by varying the weight ratio of HE and NMT (graph of FIG. 9). When only NMT was applied, the efficiency of 5 - arsenic removal was as high as 97%, but the removal efficiency of copper ion was as low as 7.8%. When the weight ratio of NMT was increased from 0.33 to 4, the 5-arsenic adsorption was enhanced because more NMT was added to the HE surface to provide a site for 5-arsenic adsorption.

However, considering the high arsenic adsorption rate in NMT alone process, the removal rate of 5 - arsenic adsorption was not significantly increased with increasing NMT weight ratio. This is presumed to be due to the repulsive force of TPP due to the negative repulsive force and that the surface charge of chitosan-TPP particles decreases when the weight ratio of TPP is increased. It was observed that the removal rate of 5-arsenic in the case of NMT weight ratio 2 (25.7%) was similar to that of 4 (25.8%) while the removal rate of copper ion adsorption was reduced by 8.6% in case of NMT weight ratio 4.

Overall results showed that the optimal adsorbent composition ratio of HE, chitosan, and NMT for copper and 5-arsenic ion adsorption was 1: 1: 2.

4.3. Adsorption rate and isothermal adsorption

FIG. 10 is a graph showing adsorption rates under the conditions of initial concentrations of copper and pentavalent arsenic ions of 45.1 and 39.5 mg L-1, respectively. Referring to the graph of FIG. 10, 86% of the initial copper ion concentration was rapidly removed by CCM in the initial 20 minutes, and the arsenic removal efficiency gradually increased over 120 minutes. The equilibrium state of the copper and the pentavalent arsenic ion adsorption removal reached 70 and 120 minutes, respectively. The difference in adsorption rate between copper and pentavalent arsenic ions is due to the different adsorption sites provided by CCM. In the case of copper ions, there are many places in CCM where clay ions can be adsorbed, such as clay minerals, surfaces, and functional groups of crosslinked chitosan. In general, the large surface area of numerous adsorption sites and clay minerals leads to fast adsorption processes. However, in the case of 5 - arsenic ions, the adsorption rate is slower than that of copper ion because it is adsorbed and removed by NMT only. Adsorption amounts of copper and pentavalent arsenic ions were 8.4 and 2.2 mg g ^- ¹ , respectively.

FIG. 11 is a graph showing the results of copper and pentavalent isothiocyanate adsorption experiments using CCM (initial concentrations of copper and pentavalent arsenic ions: 16-656 and 17-336 mg L ^-1 ; amount of adsorbent: 5 g L ^-1 ; initial pH in water = 5).

The graph of FIG. 11 shows that the adsorption amount increases with increasing initial concentration of copper and pentavalent arsenic ions, and maximum adsorption amounts were 17.2 and 5.9 mg g ^- ¹ , respectively.

From the above experimental results, it was confirmed that the adsorbent according to the present invention can remove both copper and arsenic, and in particular, adsorbents having a ratio of hollandite: chitosan: magnetite of about 1: 1: Ions can be most actively removed.

The ease of separation and recovery of the adsorbent by using the magnetic property of the magnetite can increase the usability of the adsorbent according to the present invention.

In addition, chitosan and cross-linking agent are excellent in moldability, so that it is possible to produce an adsorbent very economically and easily, thereby confirming the possibility of mass production of an adsorbent.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation and that those skilled in the art will recognize that various modifications and equivalent arrangements may be made therein. It will be possible. Accordingly, the true scope of protection of the present invention should be determined only by the appended claims.

Claims

A carrier comprising clay minerals having a negative charge on the surface;
Chitosan linked to the carrier by a crosslinking agent; And
And a magnetite bonded to the support.

The method according to claim 1,
Wherein the clay mineral is hollandite.

The method according to claim 1,
Wherein the cross-linking agent comprises a phosphate group.

The method of claim 3,
Wherein the crosslinking agent is TPP (Tripoly Phosphate).

The method according to claim 1,
Arsenic is adsorbed and removed by the magnetite,
Wherein the copper is adsorbed and removed by the chitosan.

A carrier containing clay minerals having a negative charge on the surface, and a magnetite to a chitosan solution having a pH of 3 to 5 in which the chitosan is dissolved, and mixing them to form a mixed solution; And
And forming a beaded adsorbent by dropping the mixed solution by a predetermined amount in a cross-linking agent solution for interconnecting the chitosan.

The method according to claim 6,
Wherein the support is hollandite.

The method according to claim 6,
Wherein the cross-linking agent comprises a phosphate group.

9. The method of claim 8,
Wherein the crosslinking agent is TPP (Tripoly Phosphate).

The method according to claim 6,
In the total weight of the chitosan, the carrier and the magnetite,
Wherein the chitosan is 15 to 26% by weight, the support is 15 to 26% by weight, and the magnetite is 50 to 70% by weight.

The method according to claim 6,
Wherein the magnetite is a nanomagnetite.

An adsorbent according to any one of claims 1 to 11,
Copper, and arsenic, and adsorbing copper and arsenic in the polluted water to the adsorbent to remove the polluted water.

13. The method of claim 12,
Using the fact that the magnetite component of the adsorbent is bonded to the magnet,
Wherein the adsorbent is separated and recovered by a magnet after adsorption of copper and arsenic in the polluted water is completed.