Amorphous titanium dioxide-based nanomaterial and its preparation method and method for extracting germanium from amorphous titanium dioxide-based nanomaterial

Abstract

The present invention relates to the technical field of preparation of composite materials and extraction of metal ions, and in particular to an amorphous titanium dioxide-based nanomaterial, a preparation method thereof, and a method for extracting germanium from the amorphous titanium dioxide-based nanomaterial. The present invention mixes tetrabutyl titanate and a solvent, then adds a NaOH solution to mix, and reacts. After the reaction is completed, the mixture is centrifuged, washed, dried, and ground to obtain an amorphous titanium dioxide-based nanomaterial. The nanomaterial is added to a germanium ion solution with adjusted pH, reacted, filtered, and collected to remove germanium. The nanomaterial is eluted to complete the extraction of germanium. The present invention prepares amorphous titanium dioxide by a one-step method under normal temperature conditions, and the specific surface area is 161.72 m 2 / g, its preparation is simple, the cycle is short and safe, the cost is greatly reduced, the acidity range of the germanium-containing solution can be treated (pH = 3 to 10), and it has good adsorption performance for germanium under both acidic and alkaline conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of composite materials and extraction of metal ions, in particular to an amorphous titanium dioxide-based nanomaterial and a preparation method thereof, and a method for extracting germanium from the amorphous titanium dioxide-based nanomaterial. Background Art

[0002] Currently, germanium (Ge) extraction methods include microbial leaching, ion exchange, liquid membrane, solvent extraction, tannin precipitation, chlorination distillation, and adsorption. Microbial leaching offers simple operation, high recovery, and low cost, with minimal impact on coal combustibility, minimal environmental impact, and low acid consumption. However, its adsorption mechanism requires further research, and biosorption resources are limited. Ion exchange offers high selectivity and environmental friendliness, addressing emulsification issues, but suffers from high cost, demanding operating conditions, long reaction times, and low resin loading. Liquid membrane offers rapid separation, low energy consumption, high efficiency, and strong selectivity, but the emulsion preparation and demulsification process is complex and difficult to control stability. Solvent extraction offers advantages such as rapid separation, strong selectivity, and high efficiency, but the extraction process is unstable, the extractant easily emulsifies, pollutes the environment, and is costly. Tannin-based germanium precipitation is widely used in industry, characterized by its mature technology, simple process, and high germanium precipitation efficiency. However, it consumes large amounts of tannin, cannot be recycled, and is costly. Chlorination distillation is widely used in industry. It features mature technology, simple equipment, low cost, and high-quality products, but its recovery rate is suboptimal. Among these methods, adsorption offers the most promising alternative for recovering germanium from zinc slag leachate due to its high efficiency, environmental friendliness, ease of operation, high selectivity, and low cost. Importantly, the solid adsorbent used can be easily separated from the solution, without adversely affecting the subsequent zinc electrochemical process. Therefore, adsorption is a promising alternative to the tannin process.

[0003] The Chinese patent with publication number CN113926429A discloses a hydroxyl-modified titanium dioxide composite material, its preparation method and application in the recovery of germanium; the technical solution adopted is: take a certain amount of butyl titanate and n-propanol in a beaker, mix them evenly, add the mixture to a certain concentration of tartaric acid, malic acid or succinic acid solution respectively, stir at 65°C for 2 hours, stir the obtained suspension for 12 hours, wash it to neutrality and dry it. Take the above intermediate product and add it to sodium hydroxide solution, stir it for 0.5 hours, wash it to neutrality, and obtain titanium dioxide composite materials with different amounts of hydroxyl groups. The surface of the hydroxyl-modified titanium dioxide composite material contains a large number of hydroxyl functional groups, which can selectively adsorb germanium from a mixed solution of Cu, Al, Zn, Si and Ge. It is not only low-cost and simple to prepare, but also stable and non-toxic.) However, the preparation process of this patent is relatively complicated, the preparation cycle is long, and the adsorption time is long (24 hours).

[0004] Chinese patent publication number CN113969356A discloses a method for separating zinc and germanium from zinc smelting slag using titanium dioxide. This invention involves acid leaching the zinc smelting slag, then adding titanium dioxide directly to the acid leaching solution for stirring and adsorption. The titanium dioxide adsorbs germanium from the acid leaching solution, separating the germanium from the acid leaching solution and achieving zinc and germanium separation. This simplifies the process for separating germanium and zinc from zinc smelting slag, reduces the difficulty of separating the two, reduces separation costs, and improves separation efficiency, resulting in a germanium content of over 9.16% in the resulting germanium concentrate. However, in this scheme, the adsorbent's adsorption temperature for germanium is 80-90°C, making the adsorption conditions relatively harsh. Furthermore, the adsorbent's adsorption performance for germanium is significantly affected by pH (adsorption conditions: germanium solution pH = 2-5).

[0005] Therefore, how to provide an amorphous titanium dioxide-based nanomaterial that is simple to prepare and has good adsorption properties for germanium under both acidic and alkaline conditions has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0006] The purpose of the present invention is to provide an amorphous titanium dioxide-based nanomaterial and a preparation method thereof, and a method for extracting germanium from the amorphous titanium dioxide-based nanomaterial, so as to solve the problems existing in the prior art.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The present invention provides a method for preparing an amorphous titanium dioxide-based nanomaterial, comprising the following preparation steps:

[0009] Tetrabutyl titanate and a solvent are mixed, and then a NaOH solution is added to the mixture for reaction. After the reaction is completed, the mixture is centrifuged, washed, dried, and ground to obtain an amorphous titanium dioxide-based nanomaterial.

[0010] Preferably, the solvent comprises ethanol, n-propanol or isopropanol;

[0011] The volume ratio of tetrabutyl titanate to the solvent is 1:4-9.

[0012] Preferably, the concentration of the NaOH solution is 0.1-1 mol / L; the volume ratio of the tetrabutyl titanate to the NaOH solution is 1:2-6.

[0013] Preferably, the reaction temperature is 25-100° C. and the reaction time is 2-24 h.

[0014] Preferably, the tetrabutyl titanate and isopropyl alcohol are mixed at 500-1000 r / min and stirred for 0.1-1 h.

[0015] Preferably, the NaOH solution is added and mixed at 500-1000 r / min for 0.1-1 h.

[0016] The present invention also provides the above-mentioned amorphous titanium dioxide-based nanomaterial.

[0017] The present invention also provides a method for extracting germanium from the above-mentioned amorphous titanium dioxide-based nanomaterial, comprising the following steps:

[0018] After adjusting the pH of the germanium ion solution, amorphous titanium dioxide-based nanomaterials are added, reacting at 280-320K for 5-600 minutes, collecting the amorphous titanium dioxide-based nanomaterials adsorbed with germanium by filtration, and eluting with an eluent to complete the extraction of germanium.

[0019] Preferably, the pH of the germanium ion solution is 3-10; the concentration of the germanium ion solution is 5-100 mg / L; and the usage ratio of the germanium ion solution to the amorphous titanium dioxide-based nanomaterial is 20 mL:5-30 mg.

[0020] Preferably, the eluent is a sodium hydroxide solution having a concentration of 0.3 to 0.8 mol / L; the ratio of the eluent to the amorphous titanium dioxide-based nanomaterial adsorbed with germanium is 15 to 30 mL: 15 mg; and the elution is performed at 280 to 320 K for 1 to 3 hours.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This scheme prepares amorphous titanium dioxide-based nanomaterials by a one-step method at room temperature with a specific surface area of 161.72m 2 / g, its preparation is simple, the cycle is short and it is safe. The reagents used in the present invention are low-priced, the treatment method is relatively simple, and the cost is greatly reduced. The acidity range of the germanium-containing solution that can be treated is wide (pH = 3 to 10), and it has good adsorption performance for germanium under both acidic and alkaline conditions, with an adsorption capacity of up to 134.8 mg / g. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a flow chart for preparing the amorphous titanium dioxide-based nanomaterial of the present invention;

[0024] Figure 2 Graph showing the adsorption amount and adsorption rate of germanium by the amorphous titanium dioxide-based nanomaterials of Examples 1.1 to 1.4 of the present invention and Comparative Example 1;

[0025] Figure 3 Graph showing the adsorption amount and adsorption rate of germanium by the amorphous titanium dioxide-based nanomaterials of Example 1.1, Examples 2.1 to 2.4 of the present invention and Comparative Example 2;

[0026] Figure 4 Graphs showing the adsorption amount and adsorption rate of germanium by the amorphous titanium dioxide-based nanomaterials of Examples 1.1 and 3.1 to 3.7 of the present invention;

[0027] Figure 5 Graphs showing the adsorption amount and adsorption rate of germanium by the amorphous titanium dioxide-based nanomaterials of Example 1.1, Examples 4.1 to 4.5, and Comparative Examples 3.1 to 3.3 of the present invention;

[0028] Figure 6 Graphs showing the adsorption amount and adsorption rate of germanium by the amorphous titanium dioxide-based nanomaterials of Example 1.1, Examples 5.1-5.2, and Comparative Examples 4.1-4.3 of the present invention;

[0029] Figure 7 Graphs showing the adsorption amount and adsorption rate of germanium by the amorphous titanium dioxide-based nanomaterials of Examples 1.1 and 6.1 to 6.5 of the present invention;

[0030] Figure 8 Graphs showing the adsorption amount and adsorption rate of germanium by the amorphous titanium dioxide-based nanomaterials of Example 1.1, Examples 7.1 to 7.8, and Comparative Examples 5.1 to 5.2 of the present invention;

[0031] Figure 9 Graphs showing the adsorption amount and adsorption rate of germanium by the amorphous titanium dioxide-based nanomaterials of Examples 1.1 and 8.1 to 8.5 of the present invention;

[0032] Figure 10 Graphs showing the adsorption amount and adsorption rate of germanium by the amorphous titanium dioxide-based nanomaterials of Examples 1.1 and 9.1 to 9.5 of the present invention;

[0033] Figure 11 Graphs showing the adsorption amount and adsorption rate of germanium by the amorphous titanium dioxide-based nanomaterials of Examples 1.1 and 10.1 to 10.10 of the present invention;

[0034] Figure 12 This is a cyclic regeneration diagram of the amorphous titanium dioxide-based nanomaterial adsorbing Ge(IV) according to the present invention;

[0035] Figure 13 The pseudo-first-order kinetic model of the adsorption of Ge(IV) by the amorphous titanium dioxide-based nanomaterial of the present invention is shown in FIG.

[0036] Figure 14 The pseudo-second-order kinetic model of the adsorption of Ge(IV) by the amorphous titanium dioxide-based nanomaterial of the present invention is shown in FIG.

[0037] Figure 15 This is a Langmuir isotherm fitting curve diagram of the adsorption of Ge(IV) by the amorphous titanium dioxide-based nanomaterial of the present invention;

[0038] Figure 16 This is a Freundlich isotherm fitting curve diagram of Ge(IV) adsorption on the amorphous titanium dioxide-based nanomaterial of the present invention;

[0039] Figure 17 This is an infrared spectrum of the amorphous titanium dioxide-based nanomaterial of the present invention before and after the adsorption of germanium;

[0040] Figure 18 This is the XPS total spectrum of the amorphous titanium dioxide-based nanomaterial before and after the adsorption of germanium;

[0041] Figure 19 This is the O1s fine spectrum of the amorphous titanium dioxide-based nanomaterial of the present invention;

[0042] Figure 20 This is the O1s fine spectrum of the amorphous titanium dioxide-based nanomaterial after adsorbing germanium. DETAILED DESCRIPTION

[0043] The present invention provides a method for preparing an amorphous titanium dioxide-based nanomaterial, comprising the following preparation steps:

[0044] Tetrabutyl titanate and a solvent are mixed, and then a NaOH solution is added to the mixture for reaction. After the reaction is completed, the mixture is centrifuged, washed, dried, and ground to obtain an amorphous titanium dioxide-based nanomaterial (Amo-TiO2-OH).

[0045] In the present invention, the solvent comprises ethanol, n-propanol or isopropanol, preferably n-propanol or isopropanol, more preferably isopropanol;

[0046] The volume ratio of tetrabutyl titanate to the solvent is 1:4-9, preferably 1:5-8, and more preferably 1:6-7.

[0047] In the present invention, the concentration of the NaOH solution is 0.1 to 1 mol / L, preferably 0.2 to 0.8 mol / L, more preferably 0.3 to 0.7 mol / L, and even more preferably 0.5 to 0.6 mol / L; the volume ratio of tetrabutyl titanate to the NaOH solution is 1:2 to 6, preferably 1:2.8 to 5.6, more preferably 1:3.5 to 5, and even more preferably 1:4 to 4.5.

[0048] In the present invention, the reaction temperature is 25-100° C., preferably 30-90° C., more preferably 40-80° C., and even more preferably 50-60° C., and the reaction time is 2-24 h, preferably 2 h.

[0049] In the present invention, the tetrabutyl titanate and isopropyl alcohol are mixed at 500-1000 r / min, preferably 600-900 r / min, more preferably 700-800 r / min, and stirred for 0.1-1 h, preferably 0.2-0.8 h, more preferably 0.4-0.6 h, and even more preferably 0.5 h.

[0050] In the present invention, the NaOH solution is added and mixed at 500-1000 r / min, preferably 600-900 r / min, more preferably 700-800 r / min, and stirred for 0.1-1 h, preferably 0.2-0.8 h, more preferably 0.4-0.6 h, and even more preferably 0.5 h.

[0051] The present invention also provides the above-mentioned amorphous titanium dioxide-based nanomaterial.

[0052] The present invention also provides a method for extracting germanium from the above-mentioned amorphous titanium dioxide-based nanomaterial, comprising the following steps:

[0053] After adjusting the pH of the germanium ion-containing solution, amorphous titanium dioxide-based nanomaterials are added, and the reaction is carried out at 280-320K, preferably 303K, for 5-600min, preferably 40-480min, more preferably 60-360min, and even more preferably 120-240min. The amorphous titanium dioxide-based nanomaterials adsorbed with germanium are collected by filtration and eluted with an eluent to complete the extraction of germanium.

[0054] In the present invention, the pH of the germanium ion solution is 3 to 10, preferably 4 to 9, more preferably 5 to 8, and even more preferably 6 to 7; the concentration of the germanium ion solution is 5 to 100 mg / L, preferably 10 to 75 mg / L, and even more preferably 30 to 50 mg / L; the amount ratio of the germanium ion solution to the amorphous titanium dioxide-based nanomaterial is 20 mL: 5 to 30 mg, preferably 20 mL: 10 to 25 mg, and even more preferably 20 mL: 15 to 20 mg.

[0055] In the present invention, the eluent is a sodium hydroxide solution, the concentration of the sodium hydroxide solution is 0.3-0.8 mol / L, preferably 0.4-0.7 mol / L, and more preferably 0.5 mol / L; the amount ratio of the eluent to the amorphous titanium dioxide-based nanomaterial adsorbed with germanium is 15-30 mL:15 mg, preferably 18-25 mL:15 mg, and more preferably 20 mL:15 mg; the elution is carried out at 280-320 K, preferably 303 K, for 1-3 h, preferably 2 h.

[0056] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0057] Example 1.1

[0058] 8 mL of tetrabutyl titanate and 55 mL of isopropyl alcohol were added to a beaker and stirred at 800 rpm for 0.5 h. 20 mL of 0.5 mol / L NaOH solution was then added and stirring continued for 0.5 h. The mixture was stirred at 40°C for another 2 h before centrifugation. The mixture was washed with deionized water and ethanol until neutral, dried in a vacuum oven at 40°C, and ground into a powder to obtain an amorphous titanium dioxide-based nanomaterial.

[0059] 15 mg of amorphous titanium dioxide-based nanomaterials were mixed with 20 mL of 50 mg / L Ge(IV) solution at pH = 3, and then shaken at 303 K for 600 min to complete the adsorption.

[0060] Example 1.2

[0061] The only difference from Example 1.1 is that the concentration of the NaOH solution is 0.1 mol / L.

[0062] Example 1.3

[0063] The only difference from Example 1.1 is that the concentration of the NaOH solution is 0.3 mol / L.

[0064] Example 1.4

[0065] The only difference from Example 1.1 is that the concentration of the NaOH solution is 0.7 mol / L.

[0066] Comparative Example 1

[0067] The only difference from Example 1.1 is that the concentration of the NaOH solution is 0 mol / L.

[0068] The adsorption properties of the amorphous titanium dioxide-based nanomaterials prepared in Examples 1.1 to 1.4 and Comparative Example 1 are as follows: Figure 2 As shown in the figure, with increasing NaOH concentration, the adsorption capacity and adsorption rate of germanium by Amo-TiO2-OH first increased and then slowly decreased. When the NaOH concentration was 0.5 mol / L, the prepared adsorbent had the best adsorption performance for germanium, with an adsorption capacity of 50.68 mg / g and an adsorption rate of 72.05%. Therefore, the concentration of the NaOH solution is an important factor affecting the preparation of the adsorbent.

[0069] Example 2.1

[0070] The only difference from Example 1.1 is that the reaction temperature is 25°C.

[0071] Example 2.2

[0072] The only difference from Example 1.1 is that the reaction temperature is 60°C.

[0073] Example 2.3

[0074] The only difference from Example 1.1 is that the reaction temperature is 80°C.

[0075] Example 2.4

[0076] The only difference from Example 1.1 is that the reaction temperature is 100°C.

[0077] Comparative Example 2

[0078] The only difference from Example 1.1 is that the reaction temperature is 4°C.

[0079] The adsorption properties of the amorphous titanium dioxide-based nanomaterials prepared in Example 1.1, Examples 2.1 to 2.4 and Comparative Example 2 are as follows: Figure 3 As shown by Figure 3 It can be seen that with the increase of temperature, the adsorption amount and adsorption rate of Amo-TiO2-OH for germanium both show a trend of first increasing and then gradually decreasing; when the temperature is 25℃, the prepared adsorbent has the best adsorption performance for germanium, with an adsorption amount of 59.33 mg / g and an adsorption rate of 84.36%.

[0080] Example 3.1

[0081] The only difference from Example 1.1 is that the amount of isopropyl alcohol used is 35 mL.

[0082] Example 3.2

[0083] The only difference from Example 1.1 is that the amount of isopropyl alcohol used is 40 mL.

[0084] Example 3.3

[0085] The only difference from Example 1.1 is that the amount of isopropyl alcohol used is 45 mL.

[0086] Example 3.4

[0087] The only difference from Example 1.1 is that the amount of isopropyl alcohol used is 50 mL.

[0088] Example 3.5

[0089] The only difference from Example 1.1 is that the amount of isopropyl alcohol used is 60 mL.

[0090] Example 3.6

[0091] The only difference from Example 1.1 is that the amount of isopropyl alcohol used is 65 mL.

[0092] Example 3.7

[0093] The only difference from Example 1.1 is that the amount of isopropyl alcohol used is 70 mL.

[0094] The adsorption properties of the amorphous titanium dioxide-based nanomaterials prepared in Example 1.1, Examples 3.1 to 3.7 and Comparative Example 2 are shown in FIG. Figure 4 As shown by Figure 4 It can be seen that with the increase in the amount of isopropyl alcohol used, the adsorption capacity and adsorption rate of Amo-TiO2-OH on germanium both first increased and then slightly decreased; when the amount of isopropyl alcohol used was 55mL, Amo-TiO2-OH had the best adsorption performance for germanium, with an adsorption capacity of 62.65mg / g and an adsorption rate of 86.86%. When the amount of isopropyl alcohol was increased from 35mL to 55mL, the adsorption capacity of Amo-TiO2-OH on germanium increased by 7.41mg / g and the adsorption rate increased by about 10%, indicating that the amount of isopropyl alcohol used has a certain influence on the adsorption performance of Amo-TiO2-OH on germanium. The present invention selected an appropriate amount of isopropyl alcohol of 55mL.

[0095] Example 4.1

[0096] The only difference from Example 1.1 is that the amount of sodium hydroxide used is 25 mL.

[0097] Example 4.2

[0098] The only difference from Example 1.1 is that the amount of sodium hydroxide used is 30 mL.

[0099] Example 4.3

[0100] The only difference from Example 1.1 is that the amount of sodium hydroxide used is 35 mL.

[0101] Example 4.4

[0102] The only difference from Example 1.1 is that the amount of sodium hydroxide used is 40 mL.

[0103] Example 4.5

[0104] The only difference from Example 1.1 is that the amount of sodium hydroxide used is 45 mL.

[0105] Comparative Example 3.1

[0106] The only difference from Example 1.1 is that the amount of sodium hydroxide used is 5 mL.

[0107] Comparative Example 3.2

[0108] The only difference from Example 1.1 is that the amount of sodium hydroxide used is 10 mL.

[0109] Comparative Example 3.3

[0110] The only difference from Example 1.1 is that the amount of sodium hydroxide used is 15 mL.

[0111] The adsorption properties of the amorphous titanium dioxide-based nanomaterials prepared in Example 1.1, Examples 4.1 to 4.5 and Comparative Examples 3.1 to 3.3 are as follows: Figure 5 As shown by Figure 5 As can be seen, as the amount of NaOH solution increases, the adsorption capacity and adsorption rate of germanium by Amo-TiO2-OH first increase and then slightly decrease. When the amount of NaOH solution is 20mL, Amo-TiO2-OH has the best adsorption performance for germanium, at 87.58%. When the amount of NaOH solution increases from 5mL to 20mL, the adsorption capacity of Amo-TiO2-OH for germanium increases by 18.11mg / g, and the adsorption rate increases by about 25%. The present invention selects a suitable amount of NaOH solution of 20mL.

[0112] Example 5.1

[0113] The only difference from Example 1.1 is that isopropanol is replaced by ethanol.

[0114] Example 5.2

[0115] The only difference from Example 1.1 is that isopropanol is replaced by n-propanol.

[0116] Comparative Example 4.1

[0117] The only difference from Example 1.1 is that isopropyl alcohol is replaced by ethylene glycol.

[0118] Comparative Example 4.2

[0119] The only difference from Example 1.1 is that isopropyl alcohol is replaced by propylene glycol.

[0120] Comparative Example 4.3

[0121] The only difference from Example 1.1 is that isopropanol is replaced by glycerol.

[0122] The adsorption properties of the amorphous titanium dioxide-based nanomaterials prepared in Example 1.1, Examples 5.1-5.2 and Comparative Examples 4.1-4.3 are as follows: Figure 6 As shown by Figure 6It can be seen that it is impossible to prepare samples using ethylene glycol, propylene glycol and glycerol as solvents. There is no significant difference in the adsorption properties of the samples prepared using ethanol, n-propanol and isopropanol as solvents. The adsorption properties of the samples prepared using isopropanol as solvent are relatively good, with the adsorption amount and adsorption rate of germanium being 63.17 mg / g and 87.59% respectively.

[0123] Example 6.1

[0124] The only difference from Example 1.1 is that the reaction time is 6 h.

[0125] Example 6.2

[0126] The only difference from Example 1.1 is that the reaction time is 10 h.

[0127] Example 6.3

[0128] The only difference from Example 1.1 is that the reaction time is 14 h.

[0129] Example 6.4

[0130] The only difference from Example 1.1 is that the reaction time is 18 h.

[0131] Example 6.5

[0132] The only difference from Example 1.1 is that the reaction time is 24 h.

[0133] The adsorption properties of the amorphous titanium dioxide-based nanomaterials prepared in Example 1.1 and Examples 6.1 to 6.5 are as follows: Figure 7 As shown by Figure 7 It can be seen that the reaction time has little effect on the adsorption performance of Amo-TiO2-OH for germanium. As the reaction time increases, the amount and adsorption rate of germanium adsorbed by Amo-TiO2-OH do not change much. When the reaction time is 2 to 24 hours, the amount of germanium adsorbed by Amo-TiO2-OH is approximately 61.5 mg / g, and the adsorption rate is approximately 85.6%. The present invention selects an appropriate reaction time of 2 hours.

[0134] Example 7.1

[0135] The only difference from Example 1.1 is that the amorphous titanium dioxide-based nanomaterial is mixed with the Ge(IV) solution at pH=4.

[0136] Example 7.2

[0137] The only difference from Example 1.1 is that the amorphous titanium dioxide-based nanomaterial is mixed with the Ge(IV) solution at pH=5.

[0138] Example 7.3

[0139] The only difference from Example 1.1 is that the amorphous titanium dioxide-based nanomaterial is mixed with the Ge(IV) solution at pH=6.

[0140] Example 7.4

[0141] The only difference from Example 1.1 is that the amorphous titanium dioxide-based nanomaterial is mixed with the Ge(IV) solution at pH=7.

[0142] Example 7.5

[0143] The only difference from Example 1.1 is that the amorphous titanium dioxide-based nanomaterial is mixed with the Ge(IV) solution at pH=8.

[0144] Example 7.6

[0145] The only difference from Example 1.1 is that the amorphous titanium dioxide-based nanomaterial is mixed with the Ge(IV) solution at pH=9.

[0146] Example 7.7

[0147] The only difference from Example 1.1 is that the amorphous titanium dioxide-based nanomaterial is mixed with the Ge(IV) solution at pH=10.

[0148] Example 7.8

[0149] The only difference from Example 1.1 is that the amorphous titanium dioxide-based nanomaterial is mixed with the Ge(IV) solution at pH=11.

[0150] Comparative Example 5.1

[0151] The only difference from Example 1.1 is that the amorphous titanium dioxide-based nanomaterial is mixed with the Ge(IV) solution at pH=1.

[0152] Comparative Example 5.2

[0153] The only difference from Example 1.1 is that the amorphous titanium dioxide-based nanomaterial is mixed with the Ge(IV) solution at pH=2.

[0154] The adsorption properties of the amorphous titanium dioxide-based nanomaterials prepared in Example 1.1, Examples 7.1 to 7.8 and Comparative Examples 5.1 to 5.2 are as follows: Figure 8 As shown by Figure 8It can be seen that pH is one of the important factors affecting the adsorption performance of adsorbents. Because germanium exists in different states at different pH values, the acidity of the solution has a significant impact on the adsorbent's ability to adsorb germanium. Within the pH range of 1 to 3, the adsorption rate of Ge(IV) by the adsorbent gradually increases with increasing pH. After pH 3, the adsorption rate remains almost unchanged. As the pH gradually increases, the influence of H+ on the adsorption process gradually decreases. Therefore, the present invention selects a pH of 3 for its implementation.

[0155] Example 8.1

[0156] The only difference from Example 1.1 is that the concentration of the Ge(IV) solution is 5 mg / L.

[0157] Example 8.2

[0158] The only difference from Example 1.1 is that the concentration of the Ge(IV) solution is 10 mg / L.

[0159] Example 8.3

[0160] The only difference from Example 1.1 is that the concentration of the Ge(IV) solution is 30 mg / L.

[0161] Example 8.4

[0162] The only difference from Example 1.1 is that the concentration of the Ge(IV) solution is 75 mg / L.

[0163] Example 8.5

[0164] The only difference from Example 1.1 is that the concentration of the Ge(IV) solution is 100 mg / L.

[0165] The adsorption properties of the amorphous titanium dioxide-based nanomaterials prepared in Example 1.1 and Examples 8.1 to 8.5 are as follows: Figure 9 As shown by Figure 9 It can be seen that with the increase of initial concentration, under the condition of a certain adsorbent dosage, the adsorption rate gradually decreases and the adsorption amount gradually increases.

[0166] Example 9.1

[0167] The only difference from Example 1.1 is that the amount of amorphous titanium dioxide-based nanomaterial used is 5 mg.

[0168] Example 9.2

[0169] The only difference from Example 1.1 is that the amount of amorphous titanium dioxide-based nanomaterial used is 10 mg.

[0170] Example 9.3

[0171] The only difference from Example 1.1 is that the amount of amorphous titanium dioxide-based nanomaterial used is 20 mg.

[0172] Example 9.4

[0173] The only difference from Example 1.1 is that the amount of amorphous titanium dioxide-based nanomaterial used is 25 mg.

[0174] Example 9.5

[0175] The only difference from Example 1.1 is that the amount of amorphous titanium dioxide-based nanomaterial used is 30 mg.

[0176] The adsorption properties of the amorphous titanium dioxide-based nanomaterials prepared in Examples 1.1 and 9.1 to 9.5 are as follows: Figure 10 As shown by Figure 10 As can be seen, the adsorption rate of germanium increases with increasing adsorbent Amo-TiO2-OH dosage. However, the adsorption capacity gradually decreases with increasing adsorbent dosage. When the adsorbent dosage increases from 5 mg to 30 mg, the adsorption rate significantly increases, while the adsorption capacity initially increases and then decreases slightly. Furthermore, when the dosage exceeds 15 mg, the trend of increasing adsorption rate weakens with further increases in dosage, and the adsorption capacity decreases more significantly.

[0177] Example 10.1

[0178] The only difference from Example 1.1 is that the adsorption time is 5 minutes.

[0179] Example 10.2

[0180] The only difference from Example 1.1 is that the adsorption time is 10 min.

[0181] Example 10.3

[0182] The only difference from Example 1.1 is that the adsorption time is 20 min.

[0183] Example 10.4

[0184] The only difference from Example 1.1 is that the adsorption time is 40 min.

[0185] Example 10.5

[0186] The only difference from Example 1.1 is that the adsorption time is 60 min.

[0187] Example 10.6

[0188] The only difference from Example 1.1 is that the adsorption time is 90 min.

[0189] Example 10.7

[0190] The only difference from Example 1.1 is that the adsorption time is 120 min.

[0191] Example 10.8

[0192] The only difference from Example 1.1 is that the adsorption time is 240 min.

[0193] Example 10.9

[0194] The only difference from Example 1.1 is that the adsorption time is 360 min.

[0195] Example 10.10

[0196] The only difference from Example 1.1 is that the adsorption time is 480 min.

[0197] The adsorption properties of the amorphous titanium dioxide-based nanomaterials prepared in Examples 1.1 and 9.1 to 9.5 are as follows: Figure 11 As shown by Figure 11 It can be seen that in the initial stage of adsorption, the Ge(IV) adsorption rate of the adsorbent Amo-TiO2-OH gradually increases with the increase of adsorption time; when the adsorption time is 480 min, the adsorption rate remains almost unchanged and reaches adsorption equilibrium.

[0198] Test Example 1

[0199] After each adsorption, the adsorbent was collected by filtration and then dried in a vacuum drying oven. Then, the dry saturated adsorbent was rinsed with 0.1 mol / L NaOH eluent and shaken at 303 K for 3 h. Five consecutive cycles of adsorption-desorption experiments were performed to evaluate the cyclic regeneration performance of amorphous titanium dioxide-based nanomaterials.

[0200] Figure 12 Figure 2 shows the cyclic performance of Ge(IV) adsorption on Amo-TiO2-OH. Using 0.1 mol / L NaOH as the eluent, the adsorption performance of Amo-TiO2-OH remained virtually unchanged after five adsorption-desorption cycles, demonstrating the adsorbent's excellent regeneration performance and its clear advantages in practical applications.

[0201] Test Example 2

[0202] The present invention adopts the most widely used pseudo-first-order kinetic model and pseudo-second-order kinetic model to perform fitting analysis on kinetic data, and applies the Langmuir and Freundlich isothermal adsorption models to perform fitting analysis on experimental data.

[0203] Depend on Figure 13 and Figure 14The kinetic parameters calculated by the pseudo-first-order and pseudo-second-order kinetic model are shown in Table 1. It can be seen from the data in the table that in the process of Amo-TiO2-OH adsorbing germanium, the R 2 The R of the second-order kinetic model is 0.82029. 2 The p-value of 0.99915 is 0.99915, which can well describe the adsorption process, indicating that both physical and chemical adsorption occur in the adsorption process. Compared with the pseudo-first-order kinetic model, the pseudo-second-order kinetic model has a better fitting result, and the adsorption amount calculated by the pseudo-second-order kinetic model is closer to the actual adsorption amount, which shows that chemical adsorption plays a major role in the Ge(IV) adsorption process.

[0204] Figure 15 and 16 The Langmuir and Freundlich isotherm fitting curves of Ge(IV) adsorption on Amo-TiO2-OH are shown in Table 1. The isotherm model parameters calculated from the fitting curves in the figure are shown in Table 1. It can be seen from the curves in the figure and the data in the table that both the Langmuir and Freundlich isotherm models can well describe the adsorption process at the three temperatures of 25°C, 35°C, and 45°C, indicating that the adsorption process of Ge(IV) is a process of the combined action of homogeneous and heterogeneous phases. The Langmuir isotherm model fitting effect of the adsorption process of Amo-TiO2-OH is better, indicating that the adsorption process is a monolayer adsorption. Moreover, it can be seen from the adsorption results that the reduction of the adsorption temperature is conducive to increasing the adsorption amount of Ge(IV).

[0205] Table 1 Isothermal fitting parameters of germanium adsorption on Amo-TiO2-OH

[0206]

[0207] Test Example 3

[0208] The present invention also tests the infrared spectra of Amo-TiO2-OH before and after the adsorption of germanium, the XPS total spectrum of Amo-TiO2-OH before and after the adsorption of germanium, the O1s fine spectrum of Amo-TiO2-OH, and the O1s fine spectrum of Amo-TiO2-OH after the adsorption of germanium.

[0209] The infrared spectra of Amo-TiO2-OH before and after adsorption of germanium are shown in the figure below. Figure 17 As shown in the figure, the absorption peaks of -OH and Ti-OH in the infrared spectrum after germanium adsorption are weakened accordingly, which indicates that the group that plays an adsorption role on germanium is likely to be -OH group. In order to further explore the adsorption mechanism of Amo-TiO2-OH on germanium, the XPS graphs of Amo-TiO2-OH before and after germanium adsorption were characterized. The results are shown in the figure. Figure 18As shown in the figure, the absorption peak of Ge 3d appears in the XPS spectrum of Amo-TiO2-OH after the adsorption of germanium, indicating that germanium reacts with the active sites on the surface of Amo-TiO2-OH. The XPS spectra of O1s before and after the adsorption of germanium on Amo-TiO2-OH are also analyzed. The results are shown in the figure. Figure 19 、 20 As shown in the figure. It can be seen that before the adsorption of germanium, the O1s spectrum has absorption peaks of Ti-OH (530.12eV) and Ti-O (530.78eV). After the adsorption of germanium, the O1s spectrum can be divided into absorption peaks of Ti-OH (529.55eV), Ti-O (530.59eV) and O-Ge (531.87eV). By comparison, it was found that the absorption peak of O-Ge appeared in the XPS spectrum of O1s after adsorption, and the peak area was 22.17%, indicating that germanium was adsorbed on the surface of Amo-TiO2-OH. Comparing the absorption peaks of Ti-OH before and after adsorption, it was found that the peak area of Ti-OH decreased from 50.26% to 28.57% after adsorption, and the binding energy moved from 530.12eV to 529.55eV, indicating that Ti-OH participated in the adsorption of germanium. At a pH of 3, germanium existed in the form of Ge(OH)4. This is because Ti-OH complexed with Ge(OH)4 to form an O-Ge bond, thereby increasing the density of O atoms and reducing the binding energy. Therefore, the adsorption of germanium by Amo-TiO2-OH is a chelation effect between Ti-OH and Ge(OH)4 on the adsorbent surface.

[0210] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing an amorphous titanium dioxide-based nanomaterial, characterized in that: The preparation method comprises the following steps: mixing tetrabutyl titanate and a solvent, adding a NaOH solution, mixing, reacting, centrifuging, washing, drying, and grinding after the reaction to obtain an amorphous titanium dioxide-based nanomaterial; wherein the volume ratio of the tetrabutyl titanate to the solvent is 1:4-9; The solvent comprises ethanol, n-propanol or isopropanol.

2. The method for preparing an amorphous titanium dioxide-based nanomaterial according to claim 1, characterized in that: The concentration of the NaOH solution is 0.1-1 mol / L; the volume ratio of the tetrabutyl titanate to the NaOH solution is 1:2-6.

3. The method for preparing an amorphous titanium dioxide-based nanomaterial according to any one of claims 1 to 2, characterized in that: The reaction temperature is 25-100° C. and the reaction time is 2-24 hours.

4. The method for preparing an amorphous titanium dioxide-based nanomaterial according to claim 3, characterized in that: The tetrabutyl titanate and isopropyl alcohol are mixed at 500-1000 r / min and stirred for 0.1-1 h.

5. The method for preparing an amorphous titanium dioxide-based nanomaterial according to claim 4, characterized in that: The NaOH solution is added and mixed at 500-1000 r / min for 0.1-1 h.

6. An amorphous titanium dioxide-based nanomaterial prepared by the preparation method according to claims 1 to 5.

7. A method for extracting germanium from amorphous titanium dioxide-based nanomaterials according to claim 6, characterized in that: The method comprises the following steps: adjusting the pH of a germanium ion-containing solution, adding amorphous titanium dioxide-based nanomaterials, reacting at 280-320K for 5-600min, collecting the amorphous titanium dioxide-based nanomaterials adsorbed with germanium by filtration, eluting with an eluent to complete germanium extraction, wherein the pH of the germanium ion-containing solution is 3-10; the eluent is a sodium hydroxide solution with a concentration of 0.3-0.8 mol / L; the usage ratio of the eluent to the amorphous titanium dioxide-based nanomaterials adsorbed with germanium is 15-30mL:15mg; and the elution is performed at 280-320K for 1-3h.

8. The method for extracting germanium from amorphous titanium dioxide-based nanomaterials according to claim 7, characterized in that: The concentration of the germanium ion solution is 5-100 mg / L; the usage ratio of the germanium ion solution to the amorphous titanium dioxide-based nanomaterial is 20 mL:5-30 mg.

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