Titanium dioxide loaded trithiocyanuric acid modified loofah sponge as well as preparation method and application thereof

Abstract

The invention discloses titanium dioxide loaded trithiocyanuric acid modified loofah sponge and a preparation method and application thereof.The preparation method comprises the steps that loofah sponge is soaked in a sodium hydroxide aqueous solution and reacts for 8-24 h at the normal temperature, and alkali-treated loofah sponge is obtained; reacting the alkali-treated loofah sponge with an ethanol water solution of tetraethyl titanate at 20-100 DEG C for 12-48 hours to obtain a titanium dioxide-loaded loofah sponge; and reacting the titanium dioxide filament-loaded melon sponge, chloroacetyl chloride and an N, N-dimethylformamide solution of trithiocyanuric acid at 20-80 DEG C for 8-24 hours in sequence, taking out and drying to obtain the titanium dioxide-loaded trithiocyanuric acid modified loofah sponge. According to the preparation method of the titanium dioxide loaded trithiocyanuric acid modified loofah sponge, an organic framework does not need to be chemically synthesized; the titanium dioxide loaded trithiocyanuric acid modified loofah sponge obtained by the invention not only has excellent dye adsorption and degradation functions, but also has excellent adsorption and reduction capability on noble metal ions.

Description

Technical Field

[0001] This invention belongs to the field of modified natural polymer preparation technology, specifically relating to a titanium dioxide-supported trithiocyanate modified loofah sponge, its preparation method and application. Background Technology

[0002] Due to its easily modifiable surface and unique channel structure, loofah sponge has become an ideal adsorbent for wastewater treatment, capable of adsorbing oils, dyes, and heavy metal ions.

[0003] Loofah sponge-based modified materials are biomass modified materials prepared by chemical cross-linking or physical coating, and have the characteristics of large specific surface area and many active sites of loofah sponge-type materials.

[0004] However, natural loofah sponges have limited adsorption capacity for pollutants and lack redox capabilities, making them unable to deeply degrade dyes. Furthermore, the recycling of precious metal ions has not been considered.

[0005] Therefore, there is an urgent need in this field for a loofah-based modified material that can degrade organic dyes and recover precious metal ions. Summary of the Invention

[0006] The purpose of this section is to outline some aspects of the embodiments of the present invention and to briefly describe some preferred embodiments.

[0007] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0008] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing titanium dioxide-supported trithiocyanate modified loofah sponge.

[0009] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing titanium dioxide-supported trithiocyanate modified loofah sponge, comprising,

[0010] Loofah sponge was soaked in sodium hydroxide aqueous solution and reacted at room temperature for 8–24 hours to obtain alkali-treated loofah sponge.

[0011] Alkali-treated loofah sponge was reacted with an ethanol-water solution of tetraethyl titanate at 20–100°C for 12–48 h to obtain titanium dioxide-loaded loofah sponge.

[0012] Titanium dioxide-loaded loofah sponge was reacted with chloroacetyl chloride at 20–80°C for 8–24 h, and then reacted with trithiocyanate at 20–80°C for 8–24 h. After drying, titanium dioxide-loaded trithiocyanate-modified loofah sponge was obtained.

[0013] The concentration of chloroacetyl chloride is 7–15 g / L, and the concentration of trithiocyanate is 2–6 g / L.

[0014] In a preferred embodiment of the preparation method described in this invention, the concentration of the sodium hydroxide aqueous solution is 1–10 wt%.

[0015] In a preferred embodiment of the preparation method described in this invention, the alcohol-to-water ratio of the tetraethyl titanate aqueous solution is 1:1.

[0016] In a preferred embodiment of the preparation method described in this invention, the mass ratio of the loofah sponge supported by the titanium dioxide wire to chloroacetyl chloride is 1:0.5 to 1:2, and the mass ratio of the loofah sponge supported by the titanium dioxide wire to trithiocyanate is 1:0.5 to 1:2.

[0017] In a preferred embodiment of the preparation method described in this invention, the mass ratio of the loofah sponge supported on the titanium dioxide wire to chloroacetyl chloride is 1:2.

[0018] In a preferred embodiment of the preparation method described in this invention, the mass ratio of the loofah sponge supported on the titanium dioxide wire to the trithiocyanate is 1:1.

[0019] Another objective of this invention is to overcome the shortcomings of the prior art and provide a method for preparing titanium dioxide-supported trithiocyanate-modified loofah sponge.

[0020] Another objective of this invention is to overcome the shortcomings of the prior art and provide an application of titanium dioxide-supported trithiocyanate-modified loofah sponge in the adsorption and degradation of organic dye molecules in water and the adsorption and reduction of noble metal ions in water.

[0021] In a preferred embodiment of the application described in this invention, the pH of the adsorption and degradation of dyes and the adsorption and reduction of noble metal ions is 2 to 10, and the removal rate of dyes and noble metal ions can reach more than 95%.

[0022] Another objective of this invention is to overcome the shortcomings of the prior art and provide an application of titanium dioxide-supported trithiocyanate-modified loofah sponge in antibacterial applications.

[0023] Beneficial effects of this invention:

[0024] (1) The method for preparing titanium dioxide-supported trithiocyanate modified loofah sponge of the present invention does not require chemical synthesis of organic framework, but can be obtained by simply treating natural loofah sponge with alkali.

[0025] (2) The titanium dioxide-supported trithiocyanate-modified loofah obtained in this invention not only has excellent dye adsorption and degradation function, but also has excellent adsorption and reduction capacity for noble metal ions. The removal rate of dyes and noble metal ions can reach more than 95% in 6 hours. The sulfur atoms in trithiocyanate form strong chemical bonds (S-Ti bonds) with the surface of titanium dioxide, which significantly improves the loading stability of TiO2 and prevents the active components from falling off or becoming inactive during photocatalysis. The introduction of sulfur can regulate the band structure of TiO2, form intermediate energy levels, and promote the separation of photogenerated electron-hole pairs, thereby greatly improving the photocatalytic efficiency. The modification of trithiocyanate expands the light absorption range of TiO2 from the ultraviolet region to the visible light region, realizing a full-spectrum response, which makes it have excellent pollutant treatment performance under ultraviolet light and sunlight.

[0026] (3) The titanium dioxide-loaded trithiocyanate-modified loofah obtained in this invention has an antibacterial effect after adsorbing and reducing noble metal ions. The inhibition rate against Escherichia coli is over 98%, and the inhibition rate against Staphylococcus aureus is 100%. The in-situ generated nano-silver / gold particles kill bacteria through multiple pathways such as destroying cell membranes, inhibiting respiratory chains, and degrading intracellular DNA. In addition, the natural pore structure of the loofah enables the uniform dispersion of noble metal nanoparticles.

[0027] (4) The titanium dioxide-supported trithiocyanate modified loofah prepared in this invention still maintains high activity after multiple cycles. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0029] Figure 1 This is a SEM image of the titanium oxide-supported trithiocyanate-modified loofah sponge prepared in Example 1 of the present invention.

[0030] Figure 2 This is an elemental scan of the titanium oxide-supported trithiocyanate-modified loofah sponge prepared in Example 1 of the present invention. Detailed Implementation

[0031] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification. The raw materials used in the present invention are all common market products.

[0032] Example 1

[0033] (1) Soak 1g of loofah sponge in a 5wt% sodium hydroxide aqueous solution and react at room temperature for 8 hours to obtain alkali-treated loofah sponge;

[0034] (2) Then, the alkali-treated loofah sponge was directly reacted with an ethanol aqueous solution containing 1g tetraethyl titanate (concentration 0.01g / mL) at 100℃ for 24 hours to obtain titanium dioxide loofah sponge, wherein the alcohol-water ratio of the tetraethyl titanate ethanol aqueous solution was 1:1.

[0035] (3) The obtained titanium dioxide loofah sponge was reacted with 100 mL of N,N-dimethylformamide solution containing 3 g of chloroacetyl chloride and 2 g of trithiocyanate at 90 °C for 18 hours. After drying, the titanium dioxide-loaded trithiocyanate modified loofah sponge was obtained.

[0036] Example 2

[0037] (1) Soak 1g of loofah sponge in a 5wt% sodium hydroxide aqueous solution and react at room temperature for 18 hours to obtain alkali-treated loofah sponge;

[0038] (2) Then, the alkali-treated loofah sponge was reacted directly with an ethanol aqueous solution containing 1g tetraethyl titanate (concentration 0.01g / mL) at 80℃ for 18 hours to obtain titanium dioxide loofah sponge, wherein the alcohol-water ratio of the tetraethyl titanate ethanol aqueous solution was 1:1.

[0039] (3) The obtained titanium dioxide loofah sponge was then reacted with 100 mL of N,N-dimethylformamide solution containing 2 g of chloroacetyl chloride and 1 g of trithiocyanate at 70 °C for 18 hours. After drying, the titanium dioxide-loaded trithiocyanate modified loofah sponge was obtained.

[0040] Example 3

[0041] (1) Soak 1g of loofah sponge in a 5wt% sodium hydroxide aqueous solution and react at room temperature for 12 hours to obtain alkali-treated loofah sponge;

[0042] (2) Then, the alkali-treated loofah sponge was reacted directly with an ethanol aqueous solution containing 1g tetraethyl titanate (concentration 0.01g / mL) at 80℃ for 12 hours to obtain titanium dioxide loofah sponge, wherein the alcohol-water ratio of the tetraethyl titanate ethanol aqueous solution was 1:1.

[0043] (3) The obtained titanium dioxide loofah sponge was then reacted with 100 mL of N,N-dimethylformamide solution containing 1 g of chloroacetyl chloride and 0.6 g of trithiocyanate at 50 °C for 12 hours. After drying, the titanium dioxide-loaded trithiocyanate modified loofah sponge was obtained.

[0044] Example 4

[0045] (1) Soak 1g of loofah sponge in a 5wt% sodium hydroxide aqueous solution and react at room temperature for 12 hours to obtain alkali-treated loofah sponge;

[0046] (2) Then, the alkali-treated loofah sponge was reacted directly with an ethanol aqueous solution containing 1g tetraethyl titanate (concentration 0.01g / mL) at 80℃ for 12 hours to obtain titanium dioxide loofah sponge, wherein the alcohol-water ratio of the tetraethyl titanate ethanol aqueous solution was 1:1.

[0047] (3) The obtained titanium dioxide loofah sponge was then reacted with 100 mL of N,N-dimethylformamide solution containing 0.6 g chloroacetyl chloride and 0.6 g trithiocyanate at 40 °C for 8 hours. After drying, the titanium dioxide-loaded trithiocyanate modified loofah sponge was obtained.

[0048] Comparative Example 1

[0049] (1) Soak 1g of loofah sponge in a 5wt% sodium hydroxide aqueous solution and react at room temperature for 8 hours to obtain alkali-treated loofah sponge;

[0050] (2) Then, the alkali-treated loofah sponge was directly reacted with an ethanol aqueous solution containing 1g tetraethyl titanate (concentration 0.01g / mL) at 100℃ for 24 hours to obtain titanium dioxide loofah sponge, wherein the alcohol-water ratio of the tetraethyl titanate ethanol aqueous solution was 1:1.

[0051] (3) The obtained titanium dioxide loofah sponge was reacted with 100 mL of N,N-dimethylformamide solution containing 2 g of trithiocyanate at 90 °C for 18 hours. After drying, the titanium dioxide-loaded trithiocyanate modified loofah sponge was obtained.

[0052] Comparative Example 2

[0053] (1) Soak 1g of loofah sponge in a 5wt% sodium hydroxide aqueous solution and react at room temperature for 8 hours to obtain alkali-treated loofah sponge;

[0054] (2) Then, the alkali-treated loofah sponge was directly reacted with an ethanol aqueous solution containing 1g tetraethyl titanate (concentration 0.01g / mL) at 100℃ for 24 hours to obtain titanium dioxide loofah sponge, wherein the alcohol-water ratio of the tetraethyl titanate ethanol aqueous solution was 1:1.

[0055] (3) The obtained titanium dioxide loofah sponge was reacted with 100 mL of N,N-dimethylformamide solution containing 3 g of chloroacetyl chloride at 90 °C for 18 hours. After drying, the titanium dioxide-supported modified loofah sponge was obtained.

[0056] Comparative Example 3

[0057] (1) Soak 1g of loofah sponge in a 5wt% sodium hydroxide aqueous solution and react at room temperature for 8 hours to obtain alkali-treated loofah sponge;

[0058] (2) Then, the alkali-treated loofah sponge was directly reacted with an ethanol aqueous solution containing 1g tetraethyl titanate (concentration 0.01g / mL) at 100℃ for 24 hours to obtain titanium dioxide loofah sponge, wherein the alcohol-water ratio of the tetraethyl titanate ethanol aqueous solution was 1:1.

[0059] After removal and drying, the titanium dioxide-supported modified loofah sponge is obtained.

[0060] Example 5

[0061] (1) Structural characterization of titanium dioxide-supported trithiocyanate-modified loofah sponge:

[0062] The structure of the titanium dioxide-supported trithiocyanate-modified loofah sponge prepared in Example 1 was characterized by scanning electron microscopy and EDS, and compared with unmodified natural loofah sponge. Results are shown below. Figure 1 and Figure 2 .

[0063] (2) Adsorption and degradation performance of titanium dioxide-supported trithiocyanate-modified loofah sponge for dyes:

[0064] Weigh 0.05 g of the modified loofah sponge prepared in the examples and comparative examples and put it into 25 mL of malachite green aqueous solution with a concentration of 300 mg / L. At the same time, adjust the pH to between 2 and 10, and then irradiate it with ultraviolet light at 50°C and let it stand for 6 hours.

[0065] Then, the solution was taken and the malachite green content in the solution was detected by ultraviolet spectrophotometry; the control sample was unmodified natural loofah sponge, and the results are shown in Table 1;

[0066] The method for determining the malachite green content is as follows: the absorbance of malachite green aqueous solutions of different concentrations at 618 nm is measured by ultraviolet spectrophotometer, and a standard curve of concentration versus absorbance is plotted; the absorbance of malachite green aqueous solution at 618 nm before and after purification is measured to obtain the malachite green concentration and removal rate.

[0067] (3) Adsorption and reduction performance of titanium dioxide-supported trithiocyanate-modified loofah sponge for noble metal ions:

[0068] 0.05 g of the modified loofah sponge prepared in the examples and comparative examples were weighed and placed in 25 mL of silver nitrate solution with a concentration of 100 mg / L and tetrachloroauric acid solution with a concentration of 1000 mg / L, respectively. The pH was adjusted to between 2 and 8. Then, the mixture was irradiated with ultraviolet light at 50 °C and left to stand for 6 hours to obtain titanium dioxide-loaded trithiocyanate modified loofah sponge coated with nano-silver and nano-gold. The control sample was unmodified natural loofah sponge. The results are shown in Table 2.

[0069] The methods for determining the removal rates of silver nitrate and tetrachloroauric acid are as follows: the absorbance of aqueous solutions of silver nitrate and tetrachloroauric acid at different concentrations is measured by flame atomic absorption spectrophotometer, a standard curve of concentration versus absorbance is plotted, and the absorbance of aqueous solutions of silver nitrate and tetrachloroauric acid before and after purification is measured to obtain the concentration and removal rate of silver nitrate and tetrachloroauric acid.

[0070] (4) Cyclic performance of titanium dioxide-supported trithiocyanate-modified loofah sponge:

[0071] 0.05 g of titanium dioxide-loaded trithiocyanate-modified loofah sponge (after removing dyes and precious metal ions from steps (2) and (3)) was weighed out, and the contaminants were eluted with a mixed aqueous solution of 1 wt% hydrochloric acid and 22 μg / L thiourea. The mixture was then reused, and the operation was repeated. The control example was unmodified natural loofah sponge. The results are shown in Table 3.

[0072] (5) Antibacterial properties of titanium dioxide-supported trithiocyanate-modified loofah sponge after adsorption of noble metal ions:

[0073] Weigh 0.01 g of the titanium dioxide-supported trithiocyanate-modified loofah sponge coated with nano-silver and nano-gold obtained in (3) and 10 mL of OD 600 The bacterial suspension with a concentration of 0.01 was mixed in a sterile test tube and incubated with shaking at 37°C for 2 hours.

[0074] 50 μL of the cultured bacterial solution was spread parallel to three groups of solid culture medium plates (10 g / L tryptone, 10 g / L sodium chloride, 5 g / L yeast extract, 15 g / L agar, pH adjusted to 7.2-7.4, sterilized at 121℃ and 0.1 MPa for 15 min. After sterilization, the medium was cooled to about 50℃ and poured into bacterial culture dishes, then allowed to cool and solidify). The plates were incubated at 37℃ for 24 h, and colony counts were recorded. The control was unmodified natural loofah sponge. The results are shown in Table 4. The inhibition rate (%) was calculated as (colony count in the control group - colony count in the experimental group) / colony count in the control group × 100%.

[0075] Table 1

[0076]

[0077] Table 2

[0078]

[0079] Table 3

[0080]

[0081] Table 4

[0082]

[0083] from Figure 1 It can be seen that the surface of the titanium dioxide-supported trithiocyanate modified loofah is covered with a nano-titanium dioxide layer, which provides redox active sites for photocatalytic degradation of dyes and photocatalytic reduction of noble metal ions.

[0084] from Figure 2 It can be seen that, compared with natural loofah sponge, the surface of the titanium dioxide-loaded trithiocyanate-modified loofah sponge contains more sulfur and titanium elements, which improves the adsorption capacity of the loofah sponge.

[0085] Table 1 shows that, compared to the control example, the titanium dioxide-supported trithiocyanate-modified loofah exhibits an extremely high removal rate of malachite green. In particular, Example 1 shows a removal rate of malachite green that is more than three times that of the control example.

[0086] Table 2 shows that, compared with the control example, the removal rates of silver nitrate and tetrachloroauric acid by titanium dioxide-supported trithiocyanate-modified loofah were significantly improved. In Example 1, the removal rates of silver nitrate and tetrachloroauric acid by titanium dioxide-supported trithiocyanate-modified loofah after 6 hours were both above 99%, which is nearly 10 times that of the control example.

[0087] Table 3 shows that, compared to the control, the inhibition rate of trithiocyanate-modified loofah loaded with titanium dioxide coated with silver and gold nanoparticles significantly improved against *Escherichia coli* and *Staphylococcus aureus*. In Example 1, the inhibition rate of trithiocyanate-modified loofah loaded with titanium dioxide coated with silver nanoparticles against *Escherichia coli* and *Staphylococcus aureus* reached over 98%, and the inhibition rate of trithiocyanate-modified loofah loaded with titanium dioxide coated with gold nanoparticles against *Escherichia coli* and *Staphylococcus aureus* reached over 99%, which was much higher than that of the control.

[0088] The results above show that, compared to natural loofah sponge, the titanium dioxide-supported trithiocyanate-modified loofah sponge exhibits significantly improved adsorption and degradation capabilities for malachite green and adsorption and reduction capabilities for noble metal ions. More importantly, the titanium dioxide-supported trithiocyanate-modified loofah sponge prepared in this invention retains over 95% of its activity after five cycles of use.

[0089] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the present invention.

Claims

1. A method for preparing titanium dioxide-supported trithiocyanate-modified loofah sponge, characterized in that: include, Loofah sponge was soaked in sodium hydroxide aqueous solution and reacted at room temperature for 8–24 hours to obtain alkali-treated loofah sponge. Alkali-treated loofah sponge was reacted with an ethanol-water solution of tetraethyl titanate at 20–100°C for 12–48 h to obtain titanium dioxide-loaded loofah sponge. Titanium dioxide-loaded loofah sponge was reacted with chloroacetyl chloride at 20–80°C for 8–24 h, and then reacted with trithiocyanate at 20–80°C for 8–24 h. After drying, titanium dioxide-loaded trithiocyanate-modified loofah sponge was obtained. The concentration of chloroacetyl chloride is 7–15 g / L, and the concentration of trithiocyanate is 2–6 g / L.

2. The preparation method according to claim 1, characterized in that: The concentration of the sodium hydroxide aqueous solution is 1–10 wt%.

3. The preparation method according to claim 1 or 2, characterized in that: The ethanol-water solution of the tetraethyl titanate has an alcohol-to-water ratio of 1:1 and a solution concentration of 0.01 g / mL.

4. The preparation method according to claim 3, characterized in that: The mass ratio of the loofah sponge and chloroacetyl chloride loaded on the titanium dioxide filament is 1:0.5 to 1:2, and the mass ratio of the loofah sponge and trithiocyanate loaded on the titanium dioxide filament is 1:0.5 to 1:

2.

5. The preparation method according to claim 4, characterized in that: The mass ratio of the loofah sponge supported on the titanium dioxide wire to chloroacetyl chloride is 1:

2.

6. The preparation method according to claim 5, characterized in that: The mass ratio of the loofah sponge loaded with titanium dioxide wire to trithiocyanate is 1:

1.

7. Titanium dioxide-supported trithiocyanate-modified loofah sponge prepared by any of the preparation methods described in claims 1 to 6.

8. The application of the titanium dioxide-supported trithiocyanate-modified loofah sponge according to claim 7 in the adsorption and degradation of organic dye molecules in water and the adsorption and reduction of noble metal ions in water.

9. The application as described in claim 8, characterized in that: The pH range for adsorbing and degrading dyes and adsorbing and reducing noble metal ions is 2-10, and the removal rate of dyes and noble metal ions can reach more than 95%.

10. The application of titanium dioxide-supported trithiocyanate-modified loofah sponge as described in claim 7 in antibacterial applications.

Images