Application of xylenol orange functionalized polyvinyl alcohol fiber as metal indicator
By solidifying dicresol orange on polyvinyl alcohol fibers, a cheap and easy-to-get solid metal indicator was prepared, which solved the problem of small molecule indicators being recyclable and polluted the environment, and achieved high efficiency for heavy metal ions in water , low-cost testing.
Patent Information
- Application Number
- CN202210042061.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-01-14
- Publication Date
- 2024-12-20
- Estimated Expiration
- 2042-01-14
AI Technical Summary
Existing small molecule metal indicators are not recyclable, pollute the environment and are costly. Existing real-time sewage monitoring equipment is complex, expensive and has a limited scope of application.
Dicerol orange is solidly loaded on polyvinyl alcohol fibers to prepare a cheap and easy-to-get solid metal indicator with a simple preparation process, which is used to detect heavy metal ions in water, with significant color discoloration and excellent cycling properties.
It realizes low-cost, fast and recycled heavy metal ion detection, and the fiber has excellent selectivity and cyclic properties for Zn2+, solving the problem of non-recyclable utilization and contamination of small molecule indicators.
Smart Images
Figure CN114674814B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of metal color change indication, and relates to a xylenol orange functionalized polyvinyl alcohol fiber base indicator and a preparation method thereof. Background Art
[0002] Color-changing fiber materials refer to fibers with a special structure that can change their color when exposed to external environmental stimuli such as changes in pH, light, temperature or pressure. Color-changing fiber is a type of smart fiber and has potential practical application value in special clothing, packaging, protection, monitoring, sensors, military shelters and other fields.
[0003] At present, people still rely mainly on large-scale instrument analysis for heavy metal detection. Although large-scale instrument analysis is more accurate, it requires sampling, storage, pretreatment and other processes in advance, which is cumbersome and prone to various errors. In addition, sewage is distributed over a wide range. If it is fully tested, the workload is huge and the cost is high. Existing equipment with real-time sewage monitoring function has a limited scope of application, complex equipment, high price and complex maintenance. Therefore, people are eager to prepare convenient, fast and low-cost real-time sewage testing materials to solve the above contradictions.
[0004] Xylenol orange (XO) is a common complex indicator, which shows red when complexed with metals such as zinc, bismuth, cadmium, cobalt, copper, iron, mercury, indium, lanthanides, nickel, lead, scandium, thorium, zirconium, thallium, uranium (VI), and vanadium. Although traditional small molecule indicators have advantages such as high sensitivity and significant color change, they cannot be separated from the solution, and for systems with high requirements, they will cause certain pollution to the solution after measurement. In addition, some metal indicators are expensive and the preparation process is complicated, and their disadvantage of being difficult to recycle increases the application cost of these small molecule indicators. In recent years, in order to reduce environmental pollution and the application cost of metal indicators, more and more scholars have used different methods to immobilize small molecule metal indicators on various carriers to achieve the recycling of indicators.
[0005] Polyvinyl alcohol fiber (PVA fiber for short) is a synthetic fiber made of high-quality polyvinyl alcohol (PVA) with high polymerization degree as raw material and processed by specific advanced technology. It has the advantages of high strength, high modulus, low elongation, wear resistance, acid and alkali resistance, and good weather resistance. In addition, polyvinyl alcohol fiber contains a large number of chemically active hydroxyl groups inside and on the surface. These hydroxyl groups can be converted into a variety of other functional groups through simple chemical methods, and these functional groups can be used as bridging bonds for immobilized small molecule metal indicators.
[0006] In view of this, the present invention is proposed. Summary of the invention
[0007] In order to solve the problems of existing small molecule metal indicators that cannot be recycled, pollute the environment, and have high costs, the present invention proposes an application of xylenol orange functionalized polyvinyl alcohol fiber as a metal indicator. The carrier of the metal indicator is cheap and easy to obtain, the preparation process is simple, the color change is significant, the cost is low, and the cycle performance is good. It is a new type of solid-supported metal ion color change indicator. In order to combine the advantages of xylenol orange and polyvinyl alcohol fiber, the present invention immobilizes xylenol orange on polyvinyl alcohol fiber and uses it to detect heavy metal ions in solution. The solid indicator has a simple preparation method, significant color change, and also shows excellent recycling performance, and has good industrial application value.
[0008] In order to solve the above technical problems, the present invention adopts the following technical solutions:
[0009] The invention provides application of xylenol orange functionalized polyvinyl alcohol fiber as a metal indicator.
[0010] Furthermore, the xylenol orange functionalized polyvinyl alcohol fiber is used as a metal indicator to detect heavy metal ions in water.
[0011] Furthermore, the heavy metal ion is Zn 2+ .
[0012] The method for preparing the xylenol orange functionalized polyvinyl alcohol fiber of the present invention comprises the following steps:
[0013] (1) Pretreatment of polyvinyl alcohol fiber: put the polyvinyl alcohol fiber into distilled water, reflux reaction under magnetic stirring, filter, wash with distilled water, and dry the washed fiber for later use;
[0014] (2) The pretreated polyvinyl alcohol fiber, tetrasodium dimethyl phenol orange and concentrated phosphoric acid are added to distilled water, refluxed for a certain period of time under magnetic stirring, and then filtered. The obtained fiber is washed with distilled water until the filtrate does not show color under ultraviolet light, and then dried to obtain the dimethyl phenol orange functionalized polyvinyl alcohol fiber PVAF-XO.
[0015] Furthermore, in step (1), 60 mL of distilled water is required based on 1 g of polyvinyl alcohol fiber.
[0016] Furthermore, the reflux reaction time in step (1) is 2-10 h.
[0017] Furthermore, the temperature of the distilled water used for washing in step (1) and step (2) is 55-75°C.
[0018] Furthermore, in step (2), based on 0.5 g of pretreated polyvinyl alcohol fiber, the amount of tetrasodium dimethyl cresol orange used is 0.5-1.5 g, the amount of concentrated phosphoric acid used is 0.5-1.5 mL, and 30 mL of distilled water is required.
[0019] Furthermore, in step (2), the reflux time under magnetic stirring is 4-8 h.
[0020] Furthermore, the drying temperature in step (1) is 50-100°C and the drying time is 8-18 h, and the drying temperature in step (2) is 50-100°C and the drying time is 8-18 h.
[0021] After adopting the above technical solution, the present invention achieves the following beneficial effects:
[0022] (1) The present invention is the first to prepare a solid xylenol orange indicator using commercial polyvinyl alcohol fiber as a carrier. The solid indicator carrier is cheap and easy to obtain, has a simple preparation process, significant color change, low cost, and good recycling performance. It effectively solves the problems of existing small molecule indicators that are non-recyclable, pollute the environment, and have high costs.
[0023] (2) The xylenol orange functionalized polyvinyl alcohol fiber (PVAF-XO) prepared by the present invention is used to detect heavy metal ions in water. PVAF-XO fiber has excellent ion selectivity and is only selective for Zn 2+ In response, the fibers change from yellow to purple ( Figure 2 ). In addition, PVAF-XO has excellent cycling performance. 2+ After 8 cycles of color change in the solution, the fiber can still detect Zn 2+ ( Figure 4 ). BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 This is the synthetic route of xylenol orange functionalized polyvinyl alcohol fiber PVAF-XO.
[0025] Figure 2 The color change of PVAF-XO to different metal ions.
[0026] Figure 3 For PVAF-XO at different concentrations of Zn 2+ Color changes in ionic solutions.
[0027] Figure 4 For PVAF-XO in 1 mol / L Zn 2+ Color change after 8 cycles in ionic solution. DETAILED DESCRIPTION
[0028] The present invention will be further described below in conjunction with specific embodiments. It should be understood that the following embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention, and those skilled in the art in this field can make some non-essential improvements and adjustments based on the content of the above invention.
[0029] Example 1
[0030] The preparation method of xylenol orange functionalized polyvinyl alcohol fiber PVAF-XO in this embodiment is as follows:
[0031] (1) Pretreatment of commercial polyvinyl alcohol fiber: 5.0 g of commercial polyvinyl alcohol fiber was placed in a 500 mL round-bottom flask containing 300 mL of distilled water. After reflux for 5 h under magnetic stirring, the fiber was filtered and rinsed with 200 mL of 65°C distilled water. After washing, the fiber was dried in a drying oven at 60°C for later use.
[0032] (2) Add 0.5 g of pretreated polyvinyl alcohol fiber into a 100 mL round-bottom flask, then add 1.0 g of tetrasodium xylenol orange, 1 mL of concentrated phosphoric acid and 30 mL of distilled water. After reflux for 5 h under magnetic stirring, filter and collect the filtrate for the preparation of the next batch of fibers. After the reaction, the fiber is washed with 65 °C distilled water until the filtrate does not show color under ultraviolet light. Finally, it is dried in a drying oven at 60 °C for 12 h to obtain xylenol orange functionalized polyvinyl alcohol fiber (PVAF-XO).
[0033] The xylenol orange functionalized polyvinyl alcohol fiber (PVAF-XO) was applied to Zn 2+ The detection was carried out according to the following scheme.
[0034] 0.05 g PVAF-XO was placed in 5 mL Zn 2+ In the ionic solution, the color change of the fiber was observed within 10 min.
[0035] The experimental results are as follows Figure 2-4 PVAF-XO has excellent ion selectivity, which is only for Zn 2+ Appears purple, for water and other metal ions such as Pb 2+ 、Co 2+ 、Ni 2+ Cr 3+ , Mn 2+ , Fe 3+ All show the original yellow color of PVAF-XO ( Figure 2 ).
[0036] PVAF-XO to Zn 2+ The detection limit is low. It can turn purple to zinc ion solutions above 0.05 mol / L. Moreover, PVAF-XO can still respond to 0.004 mol / L zinc ions, but due to the low zinc ion concentration, the surface of PVAF-XO is slightly red ( Figure 3 ).
[0037] like Figure 4 As shown, PVAF-XO in 1.0 mol / L Zn2+ The solution can be recycled at least 8 times. After 1-6 cycles, PVAF-XO turns purple; after 7-8 cycles, PVAF-XO turns purple-red.
[0038] It should be understood that the embodiments of the present invention are intended to be illustrative and not to limit the protection scope of the present invention in any form. Those skilled in the art may make improvements based on the above examples, and all these improvements belong to the protection scope of the appended claims of the present invention.
Claims
1. Application of xylenol orange functionalized polyvinyl alcohol fiber as a metal indicator, characterized in that: The xylenol orange functionalized polyvinyl alcohol fiber is used as a metal indicator to detect heavy metal ions in water; the heavy metal ions are Zn 2+ ; The preparation method of xylenol orange functionalized polyvinyl alcohol fiber comprises the following steps: (1) Pretreatment of polyvinyl alcohol fiber: put the polyvinyl alcohol fiber into distilled water, reflux reaction under magnetic stirring, filter, wash with distilled water, and dry the washed fiber for later use; (2) The pretreated polyvinyl alcohol fiber, tetrasodium dimethyl phenol orange and concentrated phosphoric acid are added to distilled water, refluxed for a certain period of time under magnetic stirring, and then filtered. The obtained fiber is washed with distilled water until the filtrate does not show color under ultraviolet light, and then dried to obtain the dimethyl phenol orange functionalized polyvinyl alcohol fiber PVAF-XO.
2. The use according to claim 1, characterized in that: In step (1), 60 mL of distilled water is required based on 1 g of polyvinyl alcohol fiber.
3. The use according to claim 1, characterized in that: The reflux reaction time in step (1) is 2-10 h.
4. The use according to claim 1, characterized in that: The temperature of the distilled water used for washing in step (1) and step (2) is 55-75°C.
5. The use according to claim 1, characterized in that: In step (2), based on 0.5 g of pretreated polyvinyl alcohol fiber, the amount of tetrasodium dimethyl cresol orange used is 0.5-1.5 g, the amount of concentrated phosphoric acid used is 0.5-1.5 mL, and 30 mL of distilled water is required.
6. The use according to claim 1, characterized in that: The reflux time under magnetic stirring in step (2) is 4-8 h.
7. The use according to claim 1, characterized in that: The drying temperature in step (1) is 50-100°C and the drying time is 8-18 h. The drying temperature in step (2) is 50-100°C and the drying time is 8-18 h.