Inorganic material for removing harmful substance from wastewater and method of preparing the same, and method for wastewater treatment
10052623 ยท 2018-08-21
Assignee
Inventors
- Cheng-Kuo Tsai (Hsinchu, TW)
- Huan-Yi Hung (Hsinchu, TW)
- Pang-Hung Liu (Hsinchu, TW)
- Hsien-Hui Tai (Hsinchu, TW)
- Gaw-Hao Huang (Hsinchu, TW)
- Shu-Fang Hsu (Hsinchu, TW)
- Ren-Yang Horng (Hsinchu, TW)
Cpc classification
B01J39/14
PERFORMING OPERATIONS; TRANSPORTING
C02F2101/22
CHEMISTRY; METALLURGY
C03C2204/00
CHEMISTRY; METALLURGY
C02F2103/346
CHEMISTRY; METALLURGY
C03C11/00
CHEMISTRY; METALLURGY
C02F1/288
CHEMISTRY; METALLURGY
C02F2209/001
CHEMISTRY; METALLURGY
International classification
B01J39/14
PERFORMING OPERATIONS; TRANSPORTING
C02F1/52
CHEMISTRY; METALLURGY
Abstract
An inorganic material for removing a harmful substance from wastewater is provided. The inorganic material includes a plurality of porous silicate particles having a glass phase structure, wherein the plurality of porous silicate particles include silicon dioxide, aluminum oxide, barium oxide, cesium oxide, and boron oxide, and have a zeta potential of a negative value at pH of from 1 to 5, and wherein the average pore diameter of the porous silicate particles is in a range of from 3 to 50 nm. Moreover, a method for preparing an inorganic material for removing a harmful substance from wastewater and a method for wastewater treatment are further provided.
Claims
1. An inorganic material for removing a harmful substance from wastewater, comprising: A plurality of porous silicate particles having a glass phase structure, wherein the porous silicate particles comprise silicon dioxide, aluminum oxide, barium oxide, cesium oxide, and boron oxide, and wherein the porous silicate particles have an average pore diameter of from 3 nm to 50 nm, a specific surface area of from 65 m.sup.2/g to 500 m.sup.2/g, and have a zeta potential of a negative value at pH of from 1 to 5.
2. The inorganic material of claim 1, wherein pore diameters of at least 60% pore volume of the porous silicate particles are in a range of from 3 nm to 50 nm.
3. The inorganic material of claim 1, wherein the porous silicate particles have a specific weight of from 0.5 g/cm.sup.3 to 0.8 g/cm.sup.3.
4. The inorganic material of claim 1, wherein the silicon dioxide and the aluminum oxide in the component of the porous silicate particles are at a weight ratio of from 2 to 5.
5. The inorganic material of claim 1, further comprising an active metal adsorbed into the glass phase structure of the porous silicate particles.
6. The inorganic material of claim 5, wherein the active metal comprises at least one of sodium, potassium, calcium, and magnesium.
7. The inorganic material of claim 5, wherein the active metal is in an amount of from 3% to 21%, based on a weight of the inorganic material.
8. The inorganic material of claim 1, wherein the inorganic material has an adsorption capability of higher than 10 mg/g for a heavy metal.
9. The inorganic material of claim 8, wherein the heavy metal comprises at least one of a transitional metal and arsenic.
10. The inorganic material of claim 1, wherein the porous silicate particles have a crystal of the harmful substance crystallized thereon.
11. The inorganic material of claim 10, wherein the crystal of the harmful substance is at least one of an arsenic crystal, a boron crystal, a phosphor crystal and a fluorine crystal.
12. A method for preparing an inorganic material for removing a harmful substance from wastewater, comprising: Preparing a silicate powder comprising silicon dioxide, aluminum oxide, barium oxide, cesium oxide and boron oxide; and Reacting the silicate powder with a metal compound at a reaction temperature of from 800 C. to 1500 C. to form a plurality of porous silicate particles having a glass phase structure, wherein the porous silicate particles have an average pore diameter of from 3 nm to 50 nm, a specific surface area of from 65 m.sup.2/g to 500 m.sup.2/g, and a zeta potential of a negative value at pH of from 1 to 5, and wherein the silicate powder and the metal compound are at a weight ratio of from 1:1 to 1:20.
13. The method of claim 12, wherein the silicate powder is prepared from LCD panel glass as a raw material.
14. The method of claim 12, wherein a content of the boron oxide is higher than 5%, based on a weight of the silicate powder, and the content of the boron oxide is less than 5%, based on a weight of the porous silicate particles.
15. The method of claim 12, wherein the silicon dioxide and the aluminum oxide in the component of the silicate powder are at a weight ratio of from 2 to 5.
16. The method of claim 12, wherein the metal compound is at least one selected from the group consisting of potassium carbonate, sodium carbonate, calcium carbonate and magnesium carbonate.
17. A method for treating wastewater containing a harmful substance, comprising: Feeding the wastewater containing a harmful substance into a fluidized bed reactor containing a support for the harmful substance in the wastewater to be crystallized on the support and removed to obtain treated water, wherein the support comprises the inorganic material of claim 1; and Feeding the treated wastewater out from the fluidized bed reactor.
18. The method of claim 17, wherein the porous silicate particles have a particle diameter in a range of from 0.1 mm to 0.4 mm.
Description
BRIEF DESCRIPTIONS OF THE DRAWINGS
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DETAILED DESCRIPTIONS
(14) Unless specified in the context, the singular forms, a, an and the, used in the specification and the appended claims include the plural forms.
(15) In the present disclosure, the term glass phase refers to an amorphous semi-solid state. Further, since the structure of silicate with a glass phase structure is very complicated, the composition of silicate is expressed as an oxide of each metal, rather than a salt form. The term heavy metal includes transitional metals and metalloid element arsenic having biotoxicity.
(16) In the present disclosure, waste LCD panel glass is used as a raw material for preparing an inorganic material. The method for preparing the inorganic material includes the following steps. Firstly, silicate powder produced by using waste LCD panel glass as a raw material and a metal compound are prepared, wherein the silicate powder includes silicon dioxide, aluminum oxide, barium oxide, cesium oxide and boron oxide. Secondly, the silicate powder reacted with the metal compound at a reaction temperature of from 800 to 1500 C., so as to form a plurality of porous silicate particles having a glass phase, wherein the porous silicate particles each has a pore diameter of from 1 to 100 nm, and the porous silicate particles have an average pore diameter of from 3 to 50 nm.
(17) Specifically, the silicate powder can be prepared by pulverizing the waste LCD panel glass. The particle diameter of the silicate powder is not particularly limited, and it can be, for example, from micrometers to millimeters. The components of the silicate powder include silicon dioxide, aluminum oxide, boron oxide, barium oxide and cesium oxide, wherein the amount of barium oxide is higher than 5%, based on the weight of the silicate powder.
(18) In some embodiments, the waste LCD panel glass and common soda-lime glass can be used to prepare the silicate powder. Therefore, the components of the silicate powder can further include sodium oxide, magnesium oxide, and calcium oxide.
(19) In the present disclosure, a metal compound that is more active, e.g., an alkaline metal compound of group IIIA or an alkaline earth metal compound of group IIA, is mixed and melted with the silicate powder at a reaction temperature of from 800 to 1500 C. for a reaction to take place. Group IIIA metal ions, such as boron, can be removed by group IA or IIA metal ions, which are more active. Accordingly, the structure of the original silicon skeleton of silicate can be modified to create active sites for adsorbing highly reactive metal ions (e.g., group IA or IIA metal ions), and the highly reactive metal ions can have a replacement reaction with heavy metal ions in an acidic environment. Further, a large amount of nano-scale pores can be formed in the structure of silicate, and the nano-scale pores can adsorb more heavy metal ions than micro-scale pores.
(20) In some embodiments, the metal compound is selected from potassium carbonate, sodium carbonate or a combination of the above compounds. In other embodiments, the metal compound can further include at least one of calcium carbonate and magnesium carbonate. The metal compound is mixed and melted with the silicate powder at a weight less than that of the silicate powder. Specifically, the silicate powder and the metal compound are at a weight ratio of from, for example, 1:1 to 1:20, or for example, 1:1 to 1:10.
(21) The temperature for reacting the silicate powder and the metal compound is from, for example, 800 to 1500 C., or for example, 900 to 1300 C. The reaction time is no longer than 1 hour, for example, 5 to 30 minutes. After the reaction is completed, the silicate melt is cooled to room temperature, by an approach like natural cooling or rapid cooling, so as to form a plurality of porous silicate particles having a glass phase structure.
(22) Because the metal compound may be present in an excessive amount, an acidic solution (e.g., a mixed solution of nitric acid, hydrochloric acid and citric acid at concentrations of from 0.1 to 1M) can be used to dissolve residues of the metal compound and impurities. Then, solid-liquid separation is performed to obtain a solid. Afterwards, the solid is baked to dry at a temperature higher than 110 C., and thereby obtaining the porous silicate particles having a glass phase structure.
(23) The inorganic material of the present disclosure includes a plurality of porous silicate particles having a glass phase structure. The components of the porous silicate particles include silicon dioxide, aluminum oxide, barium oxide, cesium oxide and boron oxide, wherein the amount of boron oxide is not higher than 5%, based on the weight of the porous silicate particles.
(24) Specifically, the particle diameter of each of the porous silicate particles is not particularly limited, and it can be, for example, from micrometers to nanometers. In some examples, each of the porous silicate particles has a particle diameter of from 0.1 to 0.4 mm, for example, 0.2 to 0.3 mm.
(25) Moreover, the pore diameters, specific surface areas and specific density of the porous silicate particles are not particularly limited. The average pore diameter of the porous silicate particles is from 3 to 50 nm, for example, from 8 to 25 nm. The specific surface area of the porous silicate particles is from 65 to 500 m.sup.2/g, and the specific density of the porous silicate particles is from 0.5 to 0.8 g/cm.sup.3, for example, 0.61 g/cm.sup.3.
(26) In some embodiments, the inorganic material can further include an active metal, which is adsorbed at the active sites in the surface structures of the porous silicate particles. The active metal includes at least one of sodium, potassium, calcium, and magnesium. The amount of the active metal is from 3 to 21%, based on the weight of the inorganic material (i.e., the weight of the porous silicate particles and the active metal).
(27) Because the porous silicate particles of the inorganic material of the present disclosure have a large amount of asymmetrical charges, ion exchange sites (i.e., active sites), and pores with large specific surface areas at the same time, the heavy metals in wastewater can be chemically and physically adsorbed.
(28) The inorganic material of the present disclosure can be applied to the adsorption of a heavy metal from wastewater. As such, the inorganic material can be in an adsorbed state with an adsorbed heavy metal, a desorbed state removing an adsorbed heavy metal, or a regenerated state with a regenerated, highly active metal. Specifically, in an adsorbed state, the inorganic material can further include a heavy metal adsorbed onto the porous silicate particles, and the heavy metal includes at least one of a transitional metal and arsenic. The weight of heavy metal adsorbed onto each gram of the inorganic material can be higher than 10 mg.
(29) The method for wastewater treatment of the present disclosure includes a step of providing wastewater containing a heavy metal, wherein the pH of the wastewater is not greater than 5; and the heavy metal in the wastewater is adsorbed onto the plurality of porous silicate particles having a glass phase structure, wherein the porous silicate particles contain silicon oxide, aluminum oxide, barium oxide, cesium oxide and boron oxide, the pore diameter of each of the porous silicate particles is from 1 to 100 nm, and the average pore diameter of the porous silicate is from 3 to 50 nm.
(30) In the inorganic material of the present disclosure, the porous silicate particles can be recycled for reuse by desorption and regeneration. Accordingly, after the heavy metal is adsorbed onto the porous silicate particles, the method for wastewater treatment of the present disclosure can further include the following steps. The heavy metal adsorbed onto the porous silicate particles is desorbed by an acidic solution. Then, the porous silicate particles without the adsorbed heavy metal are regenerated by a basic solution. Afterwards, the regenerated porous silicate particles are subjected to an adsorption treatment, for example, re-adsorbing the heavy metal from the wastewater.
(31) Specifically, the desorption of the porous silicate particles with the adsorbed heavy metal can be achieved by using 4 to 5 wt % of a nitric acid solution to react at room temperature for 5 to 20 minutes, so as for H.sup.+ in the acidic solution to replace the heavy metal adsorbed onto the porous silicate particles. The regeneration of the desorbed porous silicate particles can be achieved by using a sodium hydroxide solution or a potassium hydroxide solution at a pH of from 6 to 10.5, so as for the sodium or potassium ions in the solution to replace H.sup.+ at the active sites of the porous silicate particles for the active sites to become an active metal with high reactivity again.
(32) The inorganic material of the present disclosure can also be applied to fluidized bed crystallization (FBC) as a support for a fluidized bed reactor, so as for a harmful substance (such as arsenic, boron, phosphor or fluorine) to form a crystal on the support, and thereby removing the harmful substance from wastewater.
(33) The method for wastewater treatment of the present disclosure also includes a step of feeding wastewater into a fluidized bed reactor containing a support, so as for the harmful substance in the wastewater to crystallize on the support for removal, wherein the support includes the inorganic material of the present disclosure.
(34) After wastewater is treated by the method for wastewater treatment of the present disclosure, the inorganic material of the present disclosure further includes the crystal of the harmful substance crystallized on the porous silicate particles. Specifically, the harmful substance can crystallize on the surfaces or within the pores of the porous silicate particles. In some embodiments, the crystal of the harmful substance is at least one of an arsenic crystal, a boron crystal, a phosphor crystal, and a fluorine crystal. As shown in
(35) In some embodiments, when the inorganic material of the present disclosure is used as a support in a fluidized bed reactor for treating wastewater, the average pore diameter of the porous silicate particles contained in the inorganic material is from 3 to 50 nm, the specific density of the porous silicate particles is from 0.5 to 0.7 g/cm.sup.3, the particle diameter of each of the porous silicate particles is from 0.1 mm to 0.4 mm, and the pH of the wastewater is controlled in the range of from 8.5 to 11.5.
(36) The following specific examples illustrate the detailed description of the present disclosure, so as to enable a person having ordinary skill in the art to conceive the other advantages and effects of the present disclosure from the disclosure of the present specification. The present disclosure can also be implemented or applied based on the other different examples. Each of the details in the present specification can also be modified or altered based on different aspects and applications, without departing from the spirit of the present disclosure.
Examples 1 to 11 Preparation of Inorganic Materials
(37) After waste LCD panel glass powder was dissolved in hydrofluoric acid (HF), an inductively coupled plasma-atomic emission spectroscopic (ICP/AES) analysis was performed on the composition and component ratios of the glass. The analytical results are listed in Table 1.
(38) TABLE-US-00001 TABLE 1 Silicon Aluminum Boron Calcium Magnesium Cesium dioxide oxide oxide oxide oxide oxide Polyvalent Component (SiO.sub.2) (Al.sub.2O.sub.3) (B.sub.2O.sub.3) (CaO) (MgO) (SrO) element Weight % 58.9 17.8 8.5 3.05 3.2 8.38 0.17
(39) Silicate powder was prepared by using the waste LCD panel glass. Different weight ratios were used to mix the silicate powder with a metal compound, and different temperatures were used for the silicate powder to form porous silicate particles by reacting with the metal compound, and thereby obtaining inorganic materials of the present disclosure. The compositions of the raw materials and the reaction temperatures in examples 1 to 11 are listed in Table 2.
(40) TABLE-US-00002 TABLE 2 Reaction Waste LCD temper- Inorganic panel glass Group IA Group IIA ature material powder (g) Compound Compound ( C.) Example 1 200 200 g sodium 20 g calcium 1500 carbonate carbonate Example 2 200 400 g sodium 20 g calcium 1500 carbonate carbonate Example 3 200 600 g sodium 0 1300 carbonate Example 4 200 800 g sodium 0 1300 carbonate Example 5 200 500 g sodium 0 1300 carbonate plus 500 g potassium carbonate Example 6 150 1200 g potassium 0 900 carbonate Example7 100 600 g sodium 0 900 carbonate plus 400 g potassium carbonate Example8 100 1500 g sodium 0 800 carbonate plus 500 g potassium carbonate Example 9 200 200 g sodium 10 g calcium 1500 carbonate carbonate Example 10 200 400 g sodium 10 g calcium 1500 carbonate carbonate Example 11 200 600 g sodium 10 g calcium 1300 carbonate carbonate
(41) SEM, TEM, and XRD were used to analyze the LCD panel glass powder and the inorganic materials in the examples.
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(44) A specific surface area analyzer was used to determine the specific surface area of each of the inorganic materials using a BET method (i.e., measuring using a nitrogen adsorption isothermal line at a relative pressure of from 0.058 to 0.202), determine the pore diameter distribution of the each of the inorganic materials (i.e., measuring using a nitrogen desorption branch) and the proportion of each pore diameter in an accumulated pore volume (i.e., measuring using a nitrogen desorption isothermal line) using a BJH method. The specific surface area (i.e., BET specific surface area), average pore diameter (i.e., BJH-desorbed average pore diameter (4V/A)) and the proportion of pore diameters of from 3 to 50 nm in the pore volumes (i.e., the proportion of BJH desorption pores each with a diameter of from 3 to 50 nm in the desorbed, accumulated pore volume) in examples 1, 3 and 5 to 8 are listed in Table 3.
(45) TABLE-US-00003 TABLE 3 Proportion of pore diameters of Specific Average pore from 3 to 50 nm surface area diameter in the pore volume (m.sup.2/g) (nm) (%) Unmodified waste 0.4 None None LCD panel glass powder Example 1 27.1 22.6 60.1 Example 3 159.2 13.62 78.5 Example 5 163.7 8.99 77.5 Example 6 65.2 19.41 61.0 Example 7 93.6 13.53 75.9 Example 8 118.9 13.21 73.2
(46) As shown in Table 3, the waste LCD panel glass powder did not contain pores, and the specific surface area of 0.4 m/g.sup.2. On the contrary, the inorganic materials of the present disclosure had nano-scaled pores, wherein at least 60% of the pore volumes consisted of pore diameters of from 3 to 50 nm, and the specific surface areas of the inorganic materials were from 65.2 to 163.7 m.sup.2/g. As compared with the specific surface area of waste LCD panel glass powder, the specific surface areas of the inorganic materials of the present disclosure increased by about 160 to 410 folds.
(47) After the inorganic material in example 3 was dissolved in HF, an ICP/AES analysis was performed on the composition and component ratios of the inorganic material. The analytical results are listed in Table 4.
(48) TABLE-US-00004 TABLE 4 Barium Sodium oxide oxide Component Al.sub.2O.sub.3 B.sub.2O.sub.3 (BaO) CaO MgO (Na.sub.2O) SrO SiO.sub.2 Weight 12.36 1.14 0.21 3.78 2.55 26.75 2.95 44.12 (%)
(49) As shown in
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(51) As shown in
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(53) As shown in
(54) In
(55) The following test examples illustrate the method by adsorbing a heavy metal ion by using the inorganic material of the present application and the efficiency thereof.
Test Example 1 Exchange Capability of Surface Charges of Inorganic Materials and Cations
(56) The inorganic materials in examples 2 and 3 and the unmodified waste LCD panel glass powder were selected for use. A zeta potential analyzer was used to determine the zeta potential of each of the inorganic materials at different pH conditions using electrophoretic light scattering (ELS), and zeta potential (mV) was plotted against pH (i.e., from pH 0 to 10) to calculate the isoelectric points (ZPC) of the inorganic materials and the unmodified waste LCD panel glass powder.
(57) As shown in
Test Example 2 Maximum Adsorption Capability of Inorganic Materials for a Single Metal Ion
(58) The adsorbability of a single metal ion by the inorganic material in example 3 was performed using 6 types of heavy metal ions, including copper, nickel, lead, zinc, cadmium and chromium. A Langmuir model in a monolayer adsorption mode was used to calculate the maximum adsorption capability (mg/g) per gram of the inorganic material to adsorb a single heavy metal ion. Test solutions each with a volume of 100 mL, and containing each of the heavy metal ions at concentrations of 5, 8, 10, 15, 20, 25, 40, 60 and 80 mg/L, respectively, were formulated. Regarding each of the test solutions, 0.1 g of the inorganic material was added, and the pH was adjusted to 3 to simulate electroplating wastewater and soil acid wash. An adsorbability test was conducted for 24 hours. A filter membrane was used to filter each of the test solutions, and an ICP/AES analysis was then directly performed to determine the amounts of the adsorbed heavy metal ions.
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(60) TABLE-US-00005 TABLE 5 Maximum Regression analysis adsorption Equilibrium parameter of Heavy capability q.sub.max constant K determination metal ion (mg/g) (L/g) R.sup.2 Cu 50.0 3.33 0.9981 Ni 31.9 13.6 0.9999 Cd 52.6 3.80 0.9996 Cr 21.7 9.2 0.9999 Zn 22.1 2.42 0.9989 Pb 50.2 7.11 0.9993
(61) As shown in Table 5, the inorganic material of the present disclosure in strong acid (pH=3) not only had the capability to adsorb heavy metal ions, but also showed maximum adsorption capability of 50.0 (mg/l) for Cu, 31.9 (mg/g) for Ni, 52.6 (mg/g) for Cd, 21.7 (mg/g) for Cr, 22.1 (mg/g) for Zn, and 50.2 (mg/g) for Pb.
Test Example 3 Adsorption of Arsenic-Containing Wastewater by Inorganic Materials
(62) An As-containing test solution with an initial concentration of 110 (mg/L) was formulated. 2 g of the inorganic materials of examples 3 and 6 were added to a fixed volume of 200 mL of the test solution, respectively. The mixtures were oscillated in a reciprocatory motion on an oscillator at 180 rpm for 60 minutes. A 0.45 filter membrane was used to filter each of the test solutions, and an ICP/AES analysis was directly performed to determine the amount of As after the adsorption. The test results of the adsorbability using the As-containing wastewater by the inorganic materials are listed in Table 6.
(63) TABLE-US-00006 TABLE 6 Initial As Concentration after concentration As adsorption Removal rate (mg/L) (mg/L) (%) Example 3 110 60.5 45.0 Example 6 110 16.7 84.8
(64) As shown in Table 6, the inorganic materials made by mixing and melting different mixing portions of the metal compound could effectively increase the removal rate of As from 45% to 84.8%.
Test Example 4 Maximum Adsorption Amount of Actual Wastewater by Inorganic Materials of the Present Disclosure
(65) An adsorption experiment was conducted on the inorganic materials of examples 3, 4 and 5 by using many types of heavy metals in the electroplating wastewater obtained from a plant, so as to determine whether the inorganic materials of the present disclosure had adsorption capability for electroplating wastewater having complicated components. 100 mL of acidic or basic electroplating wastewater containing heavy metal ions like Cr, Cu, Ni and Zn was added with 1 wt % (1 g) of the inorganic materials in examples 3-5, respectively, for an adsorption analysis. The test conditions were an oscillation intensity of 180 rpm, an adsorption time of 60 minutes, and an adsorption temperature of 25 C. After the adsorption test, an ICP-AES analysis was performed on the concentrations of the heavy metal ions in the electroplating wastewater. The maximum adsorption amounts and removal rates of the various types of heavy metal ions in the electroplating wastewater by using the inorganic materials are listed in Table 7.
(66) TABLE-US-00007 TABLE 7 Cr Cu Ni Zn Initial concentration (mg/L) 33.1 32.1 38.3 27 Example 3 Concentration after 0.22 0.16 17.7 0.25 adsorption (mg/L) Adsorbed amount 3.26 3.19 2.04 2.65 (mg/g) Total adsorbed 11.14 amount (mg/g) Removal rate (%) 99.9 99.9 53.82 99.9 Example 4 Concentration after 0.18 0.11 14.9 0.12 adsorption (mg/L) Adsorbed amount 3.20 3.11 2.27 2.61 (mg/g) Total adsorbed 11.19 amount (mg/g) Removal rate (%) 99.9 99.9 61.07 99.9 Example 5 Concentration after 0.17 0.08 13.66 0.08 adsorption (mg/L) Adsorbed amount 3.29 3.20 2.47 2.69 (mg/g) Total adsorbed 11.66 amount (mg/g) Removal rate (%) 99.9 99.9 64.36 99.9
(67) As shown in Table 7, the inorganic materials with different compositions all had adsorption capability for various types of heavy metal ions in the acidic or basic electroplating wastewater, and the maximum adsorption amount stably reached 11 mg/g or higher.
(68) The followings are test examples of the inorganic materials of the present disclosure in the treatment of various types of wastewater conformity to the EU (EPA) effluent standard for harmful substances in effluent.
Test Example 5 Treatment of Simulated Industrial Wastewater by Inorganic Materials
(69) Aqueous nitrate solutions containing As, Pb, Cd, Cr, Ni, Cu and Zn were formulated in a laboratory to simulate industrial wastewater containing various types of harmful substances. ICP-AES was used to determine the initial concentration of each of the harmful substances. 20 g of each of the inorganic materials in examples 1, 2, 9 and 10 were added to 200 g of the simulated industrial wastewater (the amount added was 10% w/w, as calculated from the weight percents of the inorganic materials based on the simulated industrial wastewater), respectively, and oscillated to adsorb. The treatment conditions were an oscillation intensity of 180 rpm, an adsorption time of 30 minutes, and an adsorption temperature of 25 C. The concentrations of the substances in the simulated industrial wastewater after adsorption are listed in Table 8.
(70) TABLE-US-00008 TABLE 8 Harmful substance As Cd Cr Cu Ni Pb Zn Effluent standard <0.5 <0.03 <2 <3 <1 <1 <5 (ppm) Initial concentration 109.1 116.8 114.4 114.8 115.3 110.9 110.7 (ppm) Example Concentra- 28.2 105.5 56.1 93.3 71.2 33.1 97.2 1 tion after adsorption (ppm) Removal 74.2 9.7 51.0 18.8 38.3 70.1 12.2 rate (%) Example Concentra- 36.4 106.4 67.0 95.3 71.3 49.8 98.9 2 tion after adsorption (ppm) Removal 66.7 8.9 41.4 17.0 38.1 55.1 10.6 rate (%) Example Concentra- 18.9 105.4 47.2 91.1 64.8 36.0 96.4 9 tion after adsorption (ppm) Removal 82.6 9.8 58.8 20.6 43.8 67.5 12.9 rate (%) Example Concentra- 16.7 95.3 44.0 82.8 56.2 40.3 86.0 10 tion after adsorption (ppm) Removal 84.7 18.4 61.6 27.9 51.3 63.7 22.3 rate (%)
(71) As shown in Table 8, the various types of the harmful substances could be adsorbed onto the inorganic materials from the simulated industrial wastewater. However, competitive adsorption was also observed, and the order of competitive adsorption of the harmful substances by the inorganic materials were As>Pb>Cr>Ni>Cn>Zn>Cd.
Test Example 6 Multiple Times of Treatments of Cyanogen-Based Industrial Wastewater Obtained from an Actual Plant by an Inorganic Material
(72) The initial pH of the cyanogen-based industrial wastewater was 2.37. Without adjusting the pH, 10 g of the inorganic material in example 3 was added to 200 g of the cyanogen-based industrial wastewater (the amount added was 5% w/w, as calculated from the weight percents of the inorganic material based on the cyanogen-based industrial wastewater) for multiple times of oscillation to adsorb. The treatment conditions were an oscillation intensity of 180 rpm, an adsorption time of 30 minutes, and an adsorption temperature of 25 C. After the treatment, an ICP-AES analysis was performed on the concentrations (ionic concentrations) of the harmful substances in the cyanogen-based industrial wastewater. The measured concentrations of the harmful substances are listed in Table 9.
(73) TABLE-US-00009 TABLE 9 Harmful substance Cr Cu Pb Zn Effluent <2 <3 <1 <5 standard (ppm) Initial 0.72 434 22.7 111 concentration (ppm) Concentration 0.01 61.7 0.20 103 after 1.sup.st adsorption (ppm) Removal rate 98.7 85.8 99.1 7.2 after 1.sup.st adsorption (%) Concentration <0.1 15.4 <0.1 39.2 after 2.sup.nd adsorption (ppm) Removal rate 75.0 61.9 after 2.sup.nd adsorption (%) Concentration <0.01 <0.1 <0.1 0.11 after 3.sup.rd adsorption (ppm) Removal rate 99.7 after 3.sup.rd adsorption (%)
(74) As shown in Table 9, before the first adsorption, the initial Cr concentration was already below the effluent standard. After the first adsorption, the Cr concentration reduced to an undetectable concentration of an apparatus. The Cu concentration reduced from 434 ppm to 61.7 ppm, the Pb concentration reduced from 22.7 ppm to 0.20 ppm (conforming the legal effluent standard of <1 ppm), and the Zn concentration reduced from 111 ppm to 103 ppm.
(75) After the second adsorption, the Cr concentration kept below the effluent standard, and the introduction of the inorganic material did not cause desorption of the harmful substance. The Cu concentration reduced from 61.7 ppm to 15.4 ppm, the Pb concentration further reduced from 0.20 ppm to less than 0.1 ppm, and the Zn concentration reduced from 103 ppm to 39.2 ppm.
(76) After the third adsorption, the introduction of the inorganic material did not cause desorption of the harmful substance. The Cu concentration reduced from 15.4 ppm to less than 0.1 ppm, and the Zn concentration reduced from 39.2 ppm to 0.11 ppm. Both of the substances have conformed to the legal effluent standard.
(77) Competitive adsorption was observed from the data shown in Table. 9, and the order of competitive adsorption in the industrial wastewater having this type of composition was Pb>Cr>Cu>Zn. During the first adsorption, the adsorption of Cu onto the inorganic material was higher than the adsorption of Zn onto the inorganic material. Therefore, the change in the Zn concentration during the first adsorption was not obvious. During the second adsorption, the adsorption of Zn onto the inorganic material significantly increased. During the third adsorption, the inorganic material mainly adsorbed Zn. After the third adsorption, the Zn concentration conformed to the legal effluent standard.
(78) Moreover, the pH of the cyanogen-based industrial wastewater measured after the first adsorption was 9.3, the pH of the cyanogen-based industrial wastewater measured after the second adsorption was 9.2, and the pH of the cyanogen-based industrial wastewater after the third adsorption was 9.1. In this test example, no additional treatment was performed to adjust the pH (i.e., the initial pH of about 3) of the cyanogen-based industrial wastewater before the adsorptions. The harmful substances in the treated cyanogen-based industrial wastewater conformed to the legal effluent standard, and the pH of the treated cyanogen-based industrial wastewater also approached the standard of neutral water (i.e., pH of from 6 to 9).
Test Example 7 Multiple Times of Treatments of Acidic Industrial Wastewater Obtained from an Actual Plant by an Inorganic Material
(79) The initial pH of acidic industrial wastewater was 3.45. Under a condition that the pH of the wastewater was not adjusted, 10 g of the inorganic material in example 11 was added to 200 g of the acidic industrial wastewater (i.e., the amount added was 5% w/w, as calculated from the weight percents of the inorganic material based on the industrial wastewater), and oscillation was performed in batches for adsorption. The treatment conditions were an oscillation intensity of 180 rpm, an adsorption time of 30 minutes, and an adsorption temperature of 25 C. After the treatment, an ICP-AES analysis was performed on the concentrations (ionic concentrations) of the harmful substances in the acidic industrial wastewater. The measured concentrations of the harmful substances are listed in Table 10.
(80) TABLE-US-00010 TABLE 10 Harmful substance Cr Cu Pb Zn Effluent <2 <3 <1 <5 standard (ppm) Initial 39.4 35.5 0.19 30.0 concentration (ppm) Concentration <0.1 1.90 0.14 <0.1 after the 1.sup.st adsorption (ppm) Removal rate 99.8 94.7 28.0 99.9 after the 1.sup.st adsorption (%) Concentration <0.1 1.17 <0.1 <0.1 after the 2.sup.nd adsorption (ppm) Removal rate 38.0 after the 2.sup.nd adsorption (%)
(81) As shown in Table 10, before the first adsorption, the initial Pb concentration was already below the effluent standard. During the first adsorption, the introduction of the inorganic material did not cause desorption of the harmful substances. After the first adsorption, the concentration of the harmful substance Cr reduced from 39.4 ppm to less than 0.1 ppm (which had conformed to the effluent standard), the Cu concentration reduced from 35.5 ppm to 1.90 ppm (which had conformed to the effluent standard), and the Zn concentration reduced from 30.0 ppm to less than 0.1 ppm (which had conformed to the effluent standard). It can be observed from the removal rates of various types of harmful substances listed in Table 10 that most of the harmful substances have been removed after the acidic industrial wastewater was subjected to the first adsorption, and the acidic industrial wastewater had reached the effluent standard after the first adsorption. Further, the measured pH of the industrial wastewater after the first adsorption was 6.1, and the measured pH of the industrial wastewater after the second adsorption was 6.7. Apparently, the pH of the treated acidic industrial wastewater also conformed to the standard of neutral water of effluent.
Test Example 8 Reliability Test on an Inorganic Material
(82) A test of 5 cycles of adsorption-regeneration-adsorption was performed on 3 g of an inorganic material saturated with the adsorbed heavy metals in the acidic industrial wastewater. For the inorganic material, the adsorption and desorption amounts were measured after every cycle, and the first adsorption amount was used as a basis to calculate the maintenance rate of adsorption capability of the inorganic material. As such, the reliability of the inorganic material was obtained.
(83) For desorption of the inorganic materials under an acidic condition, inorganic acids, such as citric acid, sulfuric acid, nitric acid, hydrochloric acid, can be used as desorbents. In this test example, nitric acid was formulated into a desorbent. The weight of the desorbed heavy metal per gram of the inorganic material was calculated, and the desorption amount of the inorganic material was calculated. Desorption conditions R1, R2 and R3 are listed in Table 11.
(84) The desorbed inorganic material was added to a regeneration tank filled with water (the desorbed inorganic material and water was at a weight ratio of 1:1). 1M of sodium hydroxide solution was added to the regeneration tank, until the solution in the tank become basic (i.e., pH of 9). As such, the regeneration of the inorganic material was completed.
(85) The regenerated inorganic material was subjected to adsorption-desorption again to measure the adsorption and desorption amounts of the inorganic material after each regeneration. The first adsorption amount of the inorganic material was used as a basis to calculate the maintenance rate of the adsorption capability of the inorganic material for the heavy metal after each adsorption and desorption, so as to conceive the reliability of the inorganic material being recycled for use. The results of the reliability test are listed in Table 12.
(86) TABLE-US-00011 TABLE 11 Nitric acid Desorption concentration Time condition (wt %) (mins) R1 4 5 R2 4 20 R3 5 20
(87) TABLE-US-00012 TABLE 12 Desorption Desorption Desorption Reliability test condition R1 condition R2 condition R3 First Adsorption 7.5 7.5 7.5 amount (mg/g) Desorption 3.0 5.4 3.0 amount (mg/g) Desorption rate (%) 34.9 62.8 35.3 Second Adsorption 6.1 6.5 6.4 amount (mg/g) Desorption 5.2 5.7 5.2 amount (mg/g) Desorption rate (%) 85.3 88.6 80.6 Maintenance 81.3 86.7 85.3 rate of adsorption capability (%) Third Adsorption 6.2 6.4 6.5 amount (mg/g) Desorption 3.9 4.5 4.2 amount (mg/g) Desorption rate (%) 58.4 64.8 59.2 Maintenance 82.7 85.3 86.7 rate of adsorption capability (%) Adsorption 6.6 7.1 6.5 amount (mg/g) Fourth Desorption 4.1 4.7 4.3 amount (mg/g) Desorption rate (%) 62.1 66.2 62.8 Maintenance 88.0 94.7 85.3 rate of adsorption capability (%) Fifth Adsorption 6.7 6.8 6.5 amount (mg/g) Desorption 4.3 4.5 4.2 amount (mg/g) Desorption rate (%) 64.2 66.1 60.8 Maintenance 89.3 90.7 86.7 rate of adsorption capability (%)
(88) As shown in Table 12, the inorganic material of the present disclosure could still maintain an adsorption efficiency of 80% or higher after multiple times of adsorption-desorption-regeneration. Hence, the inorganic material of the present disclosure could indeed be recycled for use many times.
(89) In summary of the test examples above, it can be observed from
(90) In the present disclosure, a metal compound reconfigures the composition and chemical structure of waste LCD panel glass, thereby obtaining an inorganic material including porous silicate particles having a glass phase structure. The porous silicate particles of the present disclosure can be used to treat the harmful substances in strongly acidic wastewater as an inorganic material. Not only that the treated strongly acidic wastewater can conform to an effluent standard, but also the inorganic material adsorbed with the harmful substances can be recycled for use via desorption and regeneration.
Test Example 9 Comparison of Conventional Silica Sand and the Inorganic Material in Example 3 (Hereinafter Referred to as MCL Material) in the Adsorption of Boron (B)-Containing Wastewater
(91) Boron-containing wastewater having an initial concentration of 200 (mg/L) was formulated for a wastewater treatment by fluidized bed crystallization. The wastewater and crystal precursor (i.e., barium chloride) were fed into the fluidized bed reactor 1 containing the support 2 via the pipeline 11, so as for the harmful substances to crystallize on the support 2. The harmful substances were then recycled, and fed out as treated wastewater via the pipeline 12.
(92) Conventional silica sand and the MCL material were used as the support 2, respectively, and assessment was performed under the same conditions: the wastewater feeding stream (15 mL/min), crystal precursor (barium chloride, concentration: 0.37 M), and pH (from 8.5 to 11.5). The filling level of the two types of support was fixed to 55 g. It was found that the height of conventional silica sand support bed was 11.8 cm. Since the height of the MCL material support bed caused the volume to expand due to low density, the height of the bed was 28.1 cm. It is also found that the flow rate required by the refluxing force by the conventional silica sand support was 240 ml/min, whereas the flow rate required by the refluxing force by the MCL material support was 40 mL/min Therefore, the refluxing force required by the MCL material support was of the conventional silica sand support, and the overall refluxing force reduced by 83%.
(93) As shown in Table 13, the density of the MCL material was low. The MCL material can effectively reduce the refluxing force of the fluidized bed reactor when being used as a support, such that the energy consumption and cost can be reduced. Further, the specific surface area of the MCL material was way higher than that of the conventional silica sand, such that a larger crystallizing surface can be provided, and thereby effective increasing the boron crystallization rate and boron removal rate.
(94) TABLE-US-00013 TABLE 13 Conventional silica sand MCL material Specific density (g/cm.sup.3) 2.66~2.67 0.57~0.65 Particle diameter (mm) 0.4~0.6 0.2~0.3 Specific surface area (m.sup.2/g) 2.06 174.6 Crystallizing surface (m.sup.2/m.sup.3) 7.71*10.sup.5~7.75*10.sup.5 2.68*10.sup.8~3.06*10.sup.8
(95) It can be observed that, during the treatment of wastewater with the two types of support, the conventional silica sand was filled with white precipitate after 1 day of reaction, and the interior of the MCL material was a transparent solution. It was also found that after 5 days of reaction, the feeding outlet on the conventional silica sand support was filled with white precipitate, whereas the feeding outlet was still a transparent solution. This can prove that the use of the MCL material in the fluidized bed reactor as a support could reduce the sludge formation from the boron-containing wastewater, and substantially reduce the cost of secondary sludge treatment.
(96) The boron removal rate and the boron crystallization rate for the wastewater subjected to the treatment of the two supports were measured. As shown in
(97)
(98)
(99) Accordingly, the SEM identification could also verify that the conventional silica sand support still had no crystals formed after 5 days of reaction, such that no crystallization rate was calculated. On the contrary, the MCL material support contained crystals grown for 5 days of reaction, and the crystals continued to grow on the surfaces of the existing crystals. As a result, the MCL material support had a high crystallization rate.
Test Example 10 Assessment on the Energy Consumption of the Refluxing Forces of a Conventional Silica Sand Support and an MCL Material Support
(100) Energy consumption required for operating a fluidized bed reactor of a 10M pump lift was estimated from the refluxing forces required for the actual operation of a conventional silica sand support and an MCL material support (i.e., the force required for controlling the rotational speed of the pump 4 in
(101) TABLE-US-00014 TABLE 14 Conventional silica MCL material sand support support Flowing amount (liter/min, LPM) 133 22.2 Pump lift (M) 10 10 Power (HP) 5 0.83 Electricity (KW) 3.73 0.62 Electricity per day (KW) 90 15 Electricity per month (KW) 2685.6 447.6 Electricity per year (KW) 32227.2 5371.2
(102) The above examples are merely for exemplification, and not intended to limit the present disclosure. A person skilled in the art can modify and alter the above examples without departing from the spirit and scope of the present disclosure. Accordingly, the scope of the present disclosure should be accorded to the appended claims of the present application.