KR100443642B1 - Sawdust-based adsorbents and method to prepare the same - Google Patents

Abstract

The present invention relates to a sawdust-adsorbent for wastewater treatment, and more particularly, to a sawdust-adsorbent prepared by introducing a nitrogen-containing cationic adsorption functional group after crosslinking the sawdust with a crosslinking functional group-containing compound or a thermosetting resin. Compared with the adsorbents used, the adsorption rate and the amount of adsorption for contaminants contained in the water are very large, and the wastewater treatment process can be greatly improved, and after being used, it can be easily regenerated to reduce the economic burden on waste treatment. An environmentally friendly sawdust-adsorbent.

Description

Sawdust-Adsorbent for Wastewater Treatment and Manufacturing Method Thereof {Sawdust-based adsorbents and method to prepare the same}

The present invention relates to a sawdust-adsorbent for wastewater treatment, and more particularly, to a sawdust-adsorbent prepared by introducing a nitrogen-containing cationic adsorption functional group after crosslinking the sawdust with a crosslinking functional group-containing compound or a thermosetting resin. Compared with the adsorbents used, the adsorption rate and the amount of adsorption for contaminants contained in the water are very large, and the wastewater treatment process can be greatly improved, and after being used, it can be easily regenerated to reduce the economic burden on waste treatment. An environmentally friendly sawdust-adsorbent.

Dye wastewater, which is represented as waste water, is a non-degradable waste water which is inevitably discharged after a dyeing process, and its components are generally very complicated and include a large amount of auxiliaries and detergents in addition to dyes and mordants. In addition, the daily variation of the water quality is large depending on the operating conditions of the dyeing process. Contaminants in dye wastewater are generally poorly degradable, and in particular, dyes in wastewater have many toxic and inhibitory effects on microorganisms.

As wastewater treatment methods, various treatment methods such as basic treatment processes such as chemical, physical and biological treatment methods and final advanced treatment have been applied, but an effective wastewater treatment system has not been established yet.

Among them, a chemical treatment method is a method using a chemical unit process, and a representative method is an oxidation treatment process which lowers the concentration of pollutant in waste water by chemically decomposing contaminants using an oxidant. As chemicals, oxidants such as hydrogen peroxide solution are mainly used. Recently, ozone (Ozone, O ₃ ), etc. are newly spotlighted, but they sometimes generate toxic by-products after treatment, and substances generated after decomposition are present in waste water. Therefore, the chemical oxygen demand (COD) itself has a disadvantage that does not significantly lower.

As a biological treatment method, there is a method of treating wastewater using microorganisms in an aeration tank, which requires a lot of installation space for the facility, a long processing time and various conditions for maintaining the activity of microorganisms. There is a disadvantage in that they must satisfy the fluctuation of the processing capacity according to the season. In addition, the chemical treatment method or biological treatment method using the oxidation method has a problem that the color removal after treatment is not complete.

On the other hand, activated carbon adsorption is widely used as a physical treatment method (US Pat. No. 5,792,336), but there is a problem of regeneration and disposal of used activated carbon.

Therefore, in consideration of the recent trend of removing the chromaticity of industrial wastewater as a social problem, it is required to completely solve the problems of the conventional wastewater treatment method by developing a new adsorbent for physical treatment. .

Accordingly, the present inventors have tried to develop a new wastewater treatment adsorbent with excellent adsorption performance for contaminants contained in the wastewater. As a result, the use of sawdust, which is known to have adsorption capacity, as a raw material and the introduction of nitrogen-containing cationic adsorption functional groups after crosslinking, increases the adsorption rate and adsorption amount of dyes in wastewater, especially dyes in contaminants. The present invention was completed by recognizing that the selective removal ability of the components is excellent and the color improving effect is remarkable.

Accordingly, an object of the present invention is to provide an adsorbent for wastewater treatment, which is used in a wastewater treatment process and has excellent chromaticity improvement effect, and is easily regenerated and can be used semi-permanently.

In the present invention, sawdust is used as a raw material, and crosslinking is formed between sawdust particles with a crosslinking degree of 1 to 50%, and a wastewater treatment sawdust having a nitrogen-containing cationic adsorption functional group bonded at a content of 0.2 to 2.0 mmol / g. It is characterized by the adsorbent.

Referring to the present invention in more detail as follows.

The sawdust used as the raw material of the present invention can be easily obtained from the periphery, and it is preferable to use 50-5000 μm particles or fibrous forms. Sawdust can be applied as an adsorbent on its own, but usually does not interact with anionic dyes. Looking at the chemical structure of cellulose, the basic structure of sawdust, a hydroxyl group that can interact with these dyes Although there is (1 ° -OH of C-6), it does not act as strong as it can adsorb dyes present in water. This fact can be confirmed that the adsorption capacity for specific contaminants such as dye components when the sawdust is not subjected to a separate chemical treatment is relatively low.

On the contrary, in the present invention, the nitrogen-containing cationic adsorption functional group was introduced into the sawdust to improve the adsorption capacity for specific contaminants. The nitrogen-containing cationic adsorption functional group introduced into the adsorbent of the present invention exhibits strong adsorption capacity by the action of the aforementioned anionic dyes and electrostatic attraction. Comprehensive analysis of this fact suggests that electrostatic attraction plays a critical role in the adsorption and removal of dyes in dye wastewater. Therefore, it is important to chemically treat rice and introduce nitrogen-containing cationic adsorption functional groups.

Therefore, the present invention is characterized by the technical configuration of introducing a nitrogen-containing cationic adsorption functional group to sawdust to improve the adsorption capacity for specific contaminants, and the sawdust introduced with the adsorption functional group is easily dissolved in water. In order to prevent and facilitate the introduction of the adsorption functional group and improve the mechanical properties, crosslinking with a suitable crosslinkable material prior to the introduction of the adsorption functional group is another technical feature.

Hereinafter, the method for preparing the sawdust-adsorbent for wastewater treatment according to the present invention will be described in detail.

The method for producing a sawdust-adsorbent for wastewater treatment according to the present invention includes crosslinking the sawdust with a crosslinking functional group-containing compound or a thermosetting resin, and introducing a nitrogen-containing cationic adsorption functional group into the crosslinked sawdust.

In the process of crosslinking sawdust, a crosslinking functional group-containing compound or a thermosetting resin is used as the crosslinking agent. That is, sawdust is heat-treated at a temperature range of 20 to 120 ° C. in the presence of an alkali catalyst such as NaOH, KOH, Na ₂ CO ₃ , K ₂ CO ₃ together with a cross-linking functional group-containing compound, or sawdust together with a thermosetting resin. It crosslinks by heat-processing at 60-150 degreeC temperature range.

As a crosslinking functional group containing compound, the compound containing two or more functional groups, such as an epoxide group, an isocyanate group, an isothiocyanate group, an acyl halo group, a halo group, and an anhydride group, can be used. As a compound which has an epoxide group, epichlorohydrin, glycerol diglycidyl ether, polyethylene diglycidyl ether, etc. can be used, for example. As a compound which has an isocyanate group, aliphatic diisocyanate compounds, such as hexamethylene diisocyanate, aromatic diisocyanate compounds, such as toluene 2, 4- diisocyanate, etc. can be used, for example. As the compound having an isothiocyanate group, for example, aliphatic diisothiocyanate compounds such as hexamethylene diisothiocyanate, aromatic diisothiocyanate compounds such as toluene 2,4-diisothiocyanate and the like can be used. have. Examples of the compound having an acyl halo group include acyl halo compounds such as phosgen and triphosgen, aliphatic acyl halo compounds such as adipoyl chloride, aromatic acyl halo compounds such as terephthaloyl chloride, and the like. Can be used. As the compound having a halogen group, for example, aliphatic dihalogen compounds such as 1,4-dichlorobutane, aromatic dihalogen compounds such as α, α'-dichloro-p-xylene, and the like can be used. As a compound which has an anhydride group, aromatic dianhydride compounds, such as 1,2,4,5-benzene tetracarboxylic dianhydride, etc. can be used, for example. Moreover, urea resin, melamine resin, etc. can be used as a thermosetting resin. Preferably, crosslinking reaction with a compound having an epoxide functional group which can be easily obtained at the most economical price or crosslinking molding with urea resin is preferable.

In the crosslinking reaction, the crosslinking degree is preferably about 1 to 50%. If the crosslinking degree is less than 1%, the dissolution of sawdust into which the adsorption functional group is introduced cannot be completely prevented, and the mechanical strength of the adsorbent is low. It cannot be applied. In addition, if the crosslinking degree exceeds 50%, the space between the basic skeleton of the sawdust component is not sufficiently secured, and the mass transfer of the reactants is not smooth. Therefore, the adsorption functional group introduction rate is lowered. Even when this mass transfer problem occurs, the adsorption capacity is reduced.

Next, the adsorption functional group is introduced into the crosslinked sawdust to prepare a sawdust-adsorbent for wastewater treatment. In the present invention, since the nitrogen-containing compound is used to introduce the adsorption functional group, the nitrogen-containing compound may include aliphatic and aromatic secondary amines, tertiary amines, and quaternary ammonium. As the compound for the adsorption functional group introduction, a quaternary alkylammonium compound substituted with a hydroxy group or an epoxide group is preferable, and in particular, it is particularly preferable to use glycidyltrimethylammonium chloride or 3-chloro-2-hydroxypropyltrimethylammonium chloride. Do. Since the dye present in the dye wastewater is usually dissolved in water with an anionic functional group, the cationic adsorption functional group introduced into the adsorbent of the present invention exhibits an adsorptive capacity by the action of these anionic dyes and electrostatic attraction. Therefore, it can be seen that the adsorption capacity increases as the introduction amount of the cationic reactor increases. However, the amount of functional groups introduced over a certain level does not show any increase in adsorption capacity, since the space for dye adsorption on the surface of the adsorbent is saturated. Therefore, the amount of adsorption functional groups introduced into the crosslinked sawdust is also very important, and the range of 0.2 to 2.0 mmol / g is preferable. In fact, when the amount of nitrogen-containing cationic adsorption functional groups introduced is less than 0.2 mmol / g, there is a problem that the adsorption capacity for dyes present in the waste water is significantly lowered.

The sawdust-adsorbent for wastewater treatment obtained in the above-described manufacturing process has a granular or fibrous form of 0.01 to 5 mm, and is used in actual dye wastewater treatment processes to efficiently adsorb and remove pollutants in wastewater in a short time. Can be.

Meanwhile, the sawdust-adsorbent for wastewater treatment according to the present invention is easily regenerated through a simple regeneration process after being used in the wastewater treatment process, which is also an excellent quality of the sawdust-adsorbent of the present invention. That is, the sawdust-adsorbent used in the water treatment is dipped in an aqueous solution of a salt such as NaCl, an aqueous solution of an inorganic acid such as HCl, an aqueous solution of a base such as NaOH, an aqueous solution of an organic acid such as acetic acid, or an aqueous solution of an organic amine such as guanidine, and then washed at room temperature for a predetermined time. Reproduction can be sufficiently performed by a simple treatment process. It is effective to use the aqueous solution used for the said regeneration process in 0.1-10 N concentration range.

Although this invention is demonstrated in detail based on an Example, this invention is not limited to an Example.

Example 1.

100 g of sawdust (50-4000 μm particles) and 25 g of NaOH were added to a reactor, 500 mL of distilled water was added thereto, and 24 mL of epichlorohydrin was added thereto, followed by crosslinking by heating to 60 ° C. 120 mL of glycidyltrimethylammonium chloride (GTMAC) was added to the cross-linked sawdust and the reaction was continued to prepare a cationic sawdust-adsorbent. After the reaction was filtered, washed with distilled water and methanol and dried.

Example 2.

100 g of sawdust (particle form of 50-4000 μm) and 25 g of NaOH were added to a reactor, 500 mL of distilled water was added thereto, and 50 mL of glycerol diglycidyl ether was added thereto, followed by heating to 60 ° C. for crosslinking. 120 mL of glycidyltrimethylammonium chloride (GTMAC) was added to the cross-linked sawdust and the reaction was continued to prepare a cationic sawdust-adsorbent. After the reaction was filtered, washed with distilled water and methanol and dried.

Example 3.

100 g of sawdust (50 to 4000 μm in particle form) and 25 g of NaOH were added to a reactor, 500 mL of distilled water was added thereto, and 90 g of polyethylene glycol diglycidyl ether was added thereto, followed by crosslinking by heating to 60 ° C. 120 mL of glycidyltrimethylammonium chloride (GTMAC) was added to the cross-linked sawdust and the reaction was continued to prepare a cationic sawdust-adsorbent. After the reaction was filtered, washed with distilled water and methanol and dried.

Example 4.

100 g of sawdust (50-4000 μm particles) and 25 g of NaOH were added to a reactor, 500 mL of distilled water was added thereto, and 24 mL of epichlorohydrin was added thereto, followed by crosslinking by heating to 60 ° C. 200 mL of 3-chloro-2-hydroxypropyltrimethylammonium chloride was added to the crosslinked sawdust and the reaction was continued to prepare a cationic sawdust-adsorbent. After the reaction was filtered, washed with distilled water and methanol and dried.

Example 5.

100 g of sawdust (fiber of 50 to 1000 μm) and 25 g of NaOH were added to a reactor, 500 mL of distilled water was added thereto, and 24 mL of epichlorohydrin was added thereto, followed by crosslinking by heating to 60 ° C. 120 mL of glycidyltrimethylammonium chloride (GTMAC) was added to the cross-linked sawdust and the reaction was continued to prepare a cationic sawdust-adsorbent. After the reaction was filtered, washed with distilled water and methanol and dried.

Example 6.

100 g of sawdust (fiber of 50-1000 μm) and 25 g of NaOH were placed in a reactor, 500 mL of distilled water was added thereto, and 50 g of urea resin was added thereto, followed by heating to 60 ° C. for crosslinking. 120 mL of glycidyltrimethylammonium chloride (GTMAC) was added to the cross-linked sawdust and the reaction was continued to prepare a cationic sawdust-adsorbent. After the reaction was filtered, washed with distilled water and methanol and dried.

Test Example 1 Dye Adsorption Capacity Experiment

250 mg of sawdust-adsorbents prepared in Examples 1 to 6 were each taken and placed in a reactor. Congo Red dye, Reactive Black 5 dye, Reactive Orange 16 dye, Reactive Red 4 dye, Reactive Yellow 2 dye, Reactive Red 2 dye, Reactive Blue 19 dye or Reactive Blue 4 dye 500 mL of solution was added to each reactor and after 2 hours the absorbance of the dye solution was measured with a UV / VIS spectrophotometer. The results are shown in Table 1 below.

Comparative Examples include Samchully Carbotech Co., Ltd. palm-based activated carbon (Comparative Example 1), Samchully Carbotec Coal Coal Activated Carbon (Comparative Example 2), US Calgon's Activated Carbon F-300 (Comparative Example 3), US Calgon's Activated Carbon F -400 (Comparative Example 4), Rom & Haas, Germany Anion Exchange Resin Amberlite IRA-900 (Comparative Example 5), Rom & Haas, Germany Anion Exchange Resin Amberlite IRA-67 (Comparative Example 6), Germany Rom & Haas Absorbance was measured in the same manner as above using 4 anion exchange resin Duolite A-7 (Comparative Example 7), and the results are shown in Table 1 below.

division Dye adsorption rate (% after 2 hours) Congo Red Dye Reactive Black 5 Dye Reactive Orange 16 Dye Reactive Red 4 Dye Reactive Yellow 2 Dye Reactive Red 2 Dye Reactive Blue 19 Reactive Blue 4 Dye Example 1 57.6 70.4 76.7 70.5 89.7 63.9 87.3 96.4 Example 2 64.3 60.8 - - - - - - Example 3 52.3 75.1 - - - - - - Example 4 50.7 82.3 85.8 65.7 79.2 87.2 89.1 92.4 Example 5 53.2 69.3 - - - - - - Example 6 55.4 80.7 - - - - - - Comparative Example 1 3.6 4.5 - - - - - - Comparative Example 2 3.4 8.0 - - - - - - Comparative Example 3 6.2 12.4 - - - - - - Comparative Example 4 13.1 20.4 44.8 18.9 27.4 37.6 50.7 38.3 Comparative Example 5 1.9 13.2 - - - - - - Comparative Example 6 3.1 25.9 - - - - - - Comparative Example 7 5.0 6.4 - - - - - - Comparative Example 1: Samchully Cobotech Co., Ltd. Palm-based activated carbon (60-100 mesh, 150-250 μm) Comparative Example 2: Samchully Co., Ltd. Cobo-based activated carbon (60-100 mesh, 150-250 μm) Comparative Example 3: Calgon, USA Activated Carbon F-300 (60-100 mesh, 150-250 μm) Comparative Example 4 Calgon, USA Activated Carbon F-400 (60-100 mesh, 150-250 μm) Comparative Example 5 Anion Exchange Resin Amberlite, Rohm & Haas, Germany IRA-900 (1.0 eq / L) Comparative Example 6: Rohm & Haas, Germany Anion Exchange Resin Amberlite IRA-67 (1.6 eq / L, Acrylic) Comparative Example 7: Rohm & Haas, Germany Anion Exchange Resin Duolite A-7 ( 2.1 eq / L, Phenolic)

As shown in Table 1, the sawdust-adsorbent into which the nitrogen-containing cationic adsorption functional groups of Examples 1 to 6 according to the present invention are introduced is a conventional inorganic inorganic adsorbent (Comparative Examples 1 to 4) or ion exchange. It was confirmed that the dye removal efficiency was superior to the resins (Comparative Examples 5 to 7).

Test Example 2: Regeneration Experiment of Adsorbent

125 mg of the cationic sawdust-adsorbent of Example 1, which adsorbs the Reactive Black 5 dye in Test Example 1, was placed in a reactor and then deposited in 250 mL of the following regeneration solution. The absorbance of the regenerated solution after 2 hours was measured by a UV / VIS spectrophotometer to confirm the dissolution rate of the adsorbed dye into the regenerated solution.

Regeneration solution Dissolution rate 1N NaCl aqueous solution 34.3% 1N HCl aqueous solution 13.0% 1N NaOH aqueous solution 15.0% 1N acetic acid aqueous solution 25.0% 1M Guanidine Aqueous Solution 78.0%

As can be seen from the results of Table 2, the sawdust-adsorbent to which the dye is adsorbed is an aqueous solution of a salt such as NaCl, an aqueous solution of an inorganic acid such as HCl, an aqueous solution of a base such as NaOH, an aqueous solution of an organic acid such as acetic acid, or an organic amine solution such as guanidine. Was used as a regeneration solution, it was confirmed that the adsorbent can be reused when washed by dipping in the regeneration solution.

As described above, the sawdust-adsorbent incorporating the nitrogen-containing cationic adsorption functional group according to the present invention has a very high adsorption rate and adsorption amount compared to the adsorbent of the conventional dyes, and can greatly improve the wastewater treatment process. It is easy to recycle and less burden on the disposal of waste, which is not only environmentally friendly but also economically advantageous.

Claims (8)

Sawdust is used as a raw material, and the sawdust particles form crosslinks with 1 to 50% crosslinking, and nitrogen-containing cationic adsorption functional groups are combined at 0.2 to 2.0 mmol / g. -absorbent. The sawdust-adsorbent for wastewater treatment according to claim 1, wherein the nitrogen-containing cationic adsorption functional group is a quaternary alkylammonium salt compound substituted with a hydroxy group or an epoxide group. The sawdust-adsorbent for wastewater treatment according to claim 1, wherein the adsorbent is a granular or fibrous or crosslinked granule having a size of 0.01 to 5 mm. The sawdust-adsorbent for wastewater treatment according to claim 1, wherein the adsorbent is regenerated by washing and washing in aqueous NaCl solution, HCl solution, NaOH solution, acetic acid solution or guanidine solution. Crosslinking the sawdust with a crosslinking functional group-containing compound or a thermosetting resin with a degree of crosslinking of 1 to 50%, and introducing a nitrogen-containing cationic adsorption functional group into the crosslinked sawdust in an amount of 0.2 to 2.0 mmol / g. Method for producing a sawdust-adsorbent for wastewater treatment, characterized in that. The aliphatic or aliphatic compound according to claim 5, wherein the crosslinking functional group-containing compound contains two crosslinking functional groups selected from an epoxide group, an isocyanate group, an isothiocyanate group, an acylhalo group, a halogen group and an anhydride group. Method for producing a sawdust-adsorbent for wastewater treatment, characterized in that. 6. The method for producing a sawdust-adsorbent for wastewater treatment according to claim 5, wherein the thermosetting resin is selected from urea resin and melamine resin. 6. The sawdust-adsorbent for wastewater treatment according to claim 5, wherein the compound used for introducing the nitrogen-containing cationic adsorption functional group is glycidyltrimethylammonium chloride or 3-chloro-2-hydroxypropyltrimethylammonium chloride. Manufacturing method.