Study on Acid and Alkali Resistance of Nonwoven Geotextile
Abstract: Polyester filament non-woven geotextile, polyester staple fiber non-woven filament nonwoven geotextile for sale, and polypropylene staple fiber non-woven geotextile were studied. The corrosion resistance of polyester filament non-woven geotextile under different pH (acid-base) conditions was investigated. Effect of time, corrosion resistance on non-woven geotextile, corrosion resistance of polyester filament and polyester staple fiber non-woven geotextile with different weight (per square meter), and polypropylene staple fiber and polyester staple fiber non-woven filament nonwoven geotextile manufacturers Comparison of corrosion resistance. The results show that polyester filament and polyester staple fiber non-woven geotextile have good tolerance in an acid-base environment with pH=2~10. In the environment of pH≥12, polyester filament non-woven high quality filament nonwoven geotextile has a short time. The tensile properties of the fracture are completely lost, and the polyester staple fiber non-woven filament nonwoven geotextile manufacturers have better tolerance than the polyester filament; the polypropylene staple fiber non-woven geotextile has good resistance in both strong acid and alkali environment. Receptive, and its performance in a strong acid environment is better than polyester staple fiber nonwoven filament nonwoven geotextile for sale.
Keywords: non-woven filament nonwoven geotextile manufacturers; acid and alkali resistance; polyester filament; polyester staple fiber
1. Introduction
Non-woven filament nonwoven geotextile manufacturers are made by fiber-laid and consolidated methods. The fibers have a three-dimensional structure with good elongation and mechanical properties. Different materials and processes can be used to design fabrics with wide structural characteristics and different properties. Due to its excellent performance, simple processing, and low cost, it has become the main direction of filament nonwoven geotextile manufacturers development in the world today, accounting for more than 60% of the filament nonwoven geotextile for sale market share. Non-woven high quality filament nonwoven geotextile is used in a variety of applications, and their application functions in engineering can be summarized as five types of reinforcement, protection, drainage, filtration, and isolation. Currently widely used in road and railway roadbed reinforcement, coastal and riverbank protection, soil erosion control, bridge piers, tunnels, caves, flood control, and disaster relief projects, as well as landfills, hazardous waste landfills, mine tailings reservoirs engineering.
The types of solid waste in different landfills vary, and the slag produced by various mines is also different so that the leachate produced by the landfill and tailings pond has different acid-base characteristics. For example, in the sanitary landfill, the degradation of organic matter often produces a large number of acidic substances, so that the leachate produced by it is acidic; the red mud tailings reservoir uses the strong alkali sodium hydroxide as the dissolution agent in the smelting process of alumina. The red mud and its liquid solution produced are strongly alkaline. In addition, the pH of the gold tailings is 10 to 12, and the pH of the phosphogypsum is 1.5 to 4.5. In engineering applications, different acid-base exposure environments often cause the physical and chemical properties of nonwoven filament nonwoven geotextile for sale to decrease to varying degrees, which adversely affects the quality of the entire project.
At present, people’s corrosion resistance to non-woven high quality filament nonwoven geotextile is only a general understanding, and it is impossible to provide accurate and sufficient data support for engineering design and material selection, thus affecting the actual effect of the project. Therefore, this paper has studied from the following four aspects: 1 non-woven filament nonwoven geotextile for sale corrosion resistance under different pH (acid-base) conditions; 2 non-woven filament nonwoven geotextile manufacturers corrosion resistance under different exposure time; 3 different weights of filament Corrosion resistance of short-fiber non-woven filament nonwoven geotextile manufacturers; 4 Corrosion resistance of different types of non-woven filament nonwoven geotextile for sale. Through this research, it can provide systematic and comprehensive data support for the corrosion resistance of nonwoven high quality filament nonwoven geotextile, and provide theoretical and technical support for the application selection of non-woven geotextiles in engineering.
2. Materials and methods
2.1 Materials
The non-woven high quality filament nonwoven geotextile used in this test are all qualified products of our company (Shandong Haoyang New Engineering Materials Co., Ltd.), including: 200g/m2 polyester filament, polyester staple fiber, polypropylene staple fiber; 400g/m2 Polyester filament, polyester staple fiber; 600g/m2 polyester filament, polyester staple fiber. PH meter (PHS-3C), electrothermal constant temperature water bath (XMTD-7000), sodium hydroxide (analytical grade), concentrated sulfuric acid (analytical grade). The tensile properties of this test are expressed by the breaking strength and the elongation at break (the breaking strength is the tensile strength during the tensile test under the specified conditions, and the maximum force recorded by the sample is the breaking strength. The elongation at break corresponds to Elongation at break strength).
2.2 Test methods
2.2.1 Effect of different pH on the properties of nonwoven geotextiles
1 Prepare solutions with pH 2, 4, 6, 8, 10, 12 to meet the immersion of non-woven filament nonwoven geotextile for sale and number them separately; 2 Take filament nonwoven geotextile manufacturers of the same specification (200g/m2, 20cm× 8cm), immerse two non-woven high quality filament nonwoven geotextile in each pH solution prepared in 1 (the average value of the results), seal the beaker with plastic wrap; 3 put the beaker into a constant temperature water bath at 60 ° C, shake it daily or The beaker was stirred once to make it sufficiently uniform; after 47 days, the sample was taken out and rinsed with water, and naturally dried at room temperature, and the tensile properties of each sample were measured.
2.2.2 Effect of time on the performance of nonwoven geotextile
1 Prepare a solution with a pH of 2 and 12 as in 2.2.1 above; 2) Take 10 pieces of polyester filament non-woven filament nonwoven geotextile for sale of the same specification (200g/m2, 20cm×8cm) in a solution with a pH of 2 and 14. Immerse in 12 pieces and seal with plastic wrap; 3 take-ups out two samples after 3, 5, 7, 10, 15, and 20d, rinse with water, dry naturally at room temperature, and measure tensile properties (average The value is used as the calculated value. During the process, observe the change in pH and correct it.
2.2.3 Analysis of acid and alkali resistance of polyester filament nonwoven fabric and polyester staple fiber nonwoven fabric with the different gram weight
1 Configure the solution with pH 2 and 14 as shown in 2.2.1, and set 6 test groups for each pH; 2 take 200 g/m2 of filament non-woven filament nonwoven geotextile for sale and add 2 sets of pH 2 and 12 respectively. In solution, 2 pieces of staple fiber non-woven high quality filament nonwoven geotextile of 200g/m2 were respectively added to a set of solutions with pH 2 and 12; 400 pieces of filament non-woven geotextiles of 400g/m2 were respectively added to a set of pH 2 and In the solution of 12; take 400g/m2 of staple fiber non-woven high quality filament nonwoven geotextile into a set of solutions with pH 2 and 12 respectively; take 600g/m2 of filament non-woven geotextile and add a set of pH to each 2 and 12 solutions; take 600g/m2 staple fiber non-woven geotextiles into a set of solutions with pH 2 and 12 respectively; 3 seal the beaker with plastic wrap, remove the sample after 7d, rinse with water after being cleaned and dried at a constant temperature, the tensile properties were measured (average value was taken as a calculated value).
2.2.4 Comparison of acid and alkali resistance of polyester staple fiber and polypropylene staple fiber nonwoven geotextile
1 Prepare a solution with a pH of 2 and 14, see 1 in 2.2.1, set a test group for each pH; 2 take 4 pieces of PP staple fiber non-woven filament nonwoven geotextile manufacturers (200g/m2, 20cm×8cm) of the same specification, Add 2 pieces of solution with pH 2 and 12 respectively; take 4 pieces of polyester staple fiber non-woven filament nonwoven geotextile for sale (200g/m2, 20cm×8cm) of the same specification, and add 2 pieces to the solution with pH 2 and 12 respectively; 3 Seal the beaker with plastic wrap. After 7 days, take out the sample, clean it with water, measure its tensile properties after drying at room temperature (take the average value as the calculated value).
3. Results and analysis
3.1 Influence of different pH on the properties of nonwoven geotextiles
Simulate the different acid-base environments of non-woven high quality filament nonwoven geotextile in nature by formulating solutions of different pH to explore the performance changes of non-woven geotextile under different acid and alkali conditions, and then to landfills with different acid and alkali environments. Provide guidance for the selection and application of non-woven geotextiles for hazardous waste landfills and mine tailings projects. In this test, the same batch of polyester filament non-woven filament nonwoven geotextile for sale (200g/m2, 20cm×8cm) of the same specification was immersed in different pH solutions for 7d, and the pH-fracture was drawn according to the measured breaking strength and elongation at break. Strength – elongation at break curve, as shown in Figure 1. It can be seen from Fig. 1 that after 7d immersion with different pH, the breaking strength and elongation at break are lower than the original values in the range of pH=2~10, but all maintain a high level, such as breaking strength. The original values of elongation at break are 9.76kN/m and 78.2%. At pH=6, the breaking strength and elongation at break are 8.09kN/m and 68.50%, respectively, which is 17.1% lower than the original data. 12.4%. It is indicated that in the range of pH=2～10, the short-time acid-base environment has little effect on the tensile properties of polyester non-woven high quality filament nonwoven geotextile. In addition, polyester non-woven geotextile retains large breaking strength and fracture at pH=2. Elongation, while at pH=12, polyester non-woven geotextile has been basically dissolved, and its tensile properties are completely lost, indicating that polyester non-woven geotextile has good acid resistance and certain alkali resistance, but strong alkali resistance. The ability is poor, so the application of polyester non-woven geotextile in strong alkali environment should be cautious.
Fig.1 Effect of different pH on tensile properties of nonwoven geotextile
3.2 Effect of time on corrosion resistance of nonwoven geotextile
In order to investigate the change of tensile properties of non-woven filament nonwoven geotextile for sale in strong acid and alkali environments with time, this test takes the same batch of polyester non-woven filament nonwoven geotextile manufacturers (200g/m2, 20cm×8cm) of the same specification at pH= 2 and the solution of pH=12 were immersed for 3, 5, 7, 10, 15, and 20d, respectively, and the curves of breaking strength and elongation at break were obtained as shown in Fig. 2. It can be seen from Fig. 2 that the breaking strength and elongation at break of polyester filament non-woven high quality filament nonwoven geotextile decrease with time under strong acid and alkali conditions, but in strong acid environment, breaking strength and fracture The rate of decline of elongation was slower, and it decreased by 2.1% and 9.56% after immersion for 5 days. After 20 days of immersion, the breaking strength and elongation at break decreased by 25.7% and 17.14%, respectively. However, in a strong alkali environment, polyester filament The breaking strength and elongation at break of non-woven geotextiles decreased rapidly with time. The breaking strength and elongation at break of immersion for 5d decreased by 86.4% and 41.8%, respectively. The polyester non-woven high quality filament nonwoven geotextile after 7d had completely lost. Stretch performance. It is further verified that the polyester filament non-woven geotextile is not resistant to strong alkali, but has good acid resistance and good strength and tensile properties in a long acid environment, while for a strong alkali environment, polyester Filament non-woven geotextiles lose their strength and tensile properties in a short period of time.
Fig. 2 Effect of time on acid and alkali resistance of non-woven geotextile
3.3 Analysis of acid and alkali resistance of polyester filament nonwoven fabric and polyester staple fiber nonwoven fabric with different weights
In this test, 200, 400, 600g/m2 polyester filament non-woven filament nonwoven geotextile for sale and polyester staple fiber non-woven filament nonwoven geotextile manufacturers were tested for strong acid and alkali impregnation for 7d, and non-woven high quality filament nonwoven geotextile for filament and staple fiber with different weights. The strength and tensile properties of the cloth in a strong acid and alkali environment were analyzed and discussed, as shown in Figures 3 and 4.
Figure 3 Between breaking strength and elongation at break and gram weight (per square meter)
Relationship (polyester filament)
Figure 4 Between breaking strength and elongation at break and gram weight (per square meter)
Relationship (polyester staple fiber)
Figure 3 is a graph showing the relationship between the grammage and the breaking strength and elongation at break after impregnation of polyester filament nonwoven geotextile for sale for 7 days. It can be seen from Figure 3 that in a strong acid environment (pH=2), 200, 400, 600g The breaking strength and elongation at break of the /m2 polyester filament non-woven filament nonwoven geotextile manufacturers are at a high level after impregnation, as shown in Table 1. The 200g/m2 sample has a slight increase in the breaking strength of the blank after immersion, which may be due to the difference between the immersed sample and the blank sample, and the elongation at break of the 400, 600 g/m2 sample increases. It indicates that the elongation at break and the breaking strength are not the same proportion and the same trend change. In the strong alkali environment (pH=12), the breaking strength and elongation at break of 200, 400, 600g/m2 polyester filament non-woven filament nonwoven geotextile manufacturers showed a significant decline after immersion, and the breaking strength decreased in the order of 100. %(200g/m2)>89.1%(600g/m2)>85.6%(400g/m2), the order of elongation at break is 100% (200g/m2)>35.6% (600g/m2)>33.2% (400g) /m2), as shown in Table 1. It is indicated that the polyester non-woven high quality filament nonwoven geotextile has poor tolerance in the strong alkali environment, and the increase of the gram weight does not increase the fracture strength and tensile properties of the fracture well, thereby avoiding bad selection and causing no The necessary economic loss.
Table 1 Percentage of breakage strength and elongation at break of polyester filaments
Figure 4 is a graph showing the relationship between the grammage and the breaking strength and elongation at break after impregnation of polyester staple fiber nonwoven filament nonwoven geotextile manufacturers for 7 days. It can be seen from Figure 4 that in a strong acid environment (pH=2), 200, 400, 600g /m2 polyester staple fiber non-woven filament nonwoven geotextile for sale is similar to polyester filament non-woven high quality filament nonwoven geotextile. The breaking strength and elongation at break are at a high level after immersion, as shown in Table 2. In the strong alkali environment (pH=12), the breaking strength and elongation at break of 200, 400, 600g/m2 polyester staple fiber non-woven high quality filament nonwoven geotextile also decreased after impregnation, and the breaking strength decreased in the order of 73.3%. 200g/m2)>62% (400g/m2)>52.1% (600g/m2), the order of elongation at break is 41.9% (600g/m2)>37.6% (200g/m2)>24% (400g/m2) ),As shown in table 2. It shows that the resistance of polyester staple fiber in strong alkali environment is not very good, but it is obviously improved compared with the polyester filament, and the increase of gram weight also makes the breaking strength increase, and the elongation law of elongation Does not depend on the change of weight.
Table 2 Percentage of fracture strength and elongation at break of polyester staple fiber
3.4 Comparison of acid and alkali resistance of polyester staple fiber and PP staple fiber nonwoven geotextile
This test compares the tensile properties of polyester staple fiber and PP staple fiber nonwoven filament nonwoven geotextile for sale in a strong acid and alkali environment. The results are shown in Fig. 5. In the strong acid environment (pH=2), the PP staple fiber and polyester staple fiber non-woven filament nonwoven geotextile manufacturers maintain good tensile properties after impregnation, and the elongation at break is at the same level, but the PP staple fiber non-woven filament nonwoven geotextile manufacturers The breaking strength is significantly higher than that of polyester staple fiber nonwoven geotextile. In a strongly alkaline environment (pH=12), after impregnation of PP staple fiber non-woven high quality filament nonwoven geotextile, the breaking strength and elongation at break are basically at the same level as the blank sample, and the strength of the fracture after the impregnation of the polyester staple fiber non-woven high quality filament nonwoven geotextile The elongation at break showed a significant decrease, especially the breaking strength decreased by 73.3%. It shows that PP staple fiber has excellent resistance to strong acid and alkali, and its tensile properties in the strong acid environment are better than those of polyester staple fiber.
Fig.5 Comparative analysis of acid and alkali resistance of PP staple fiber and polyester staple fiber
4. Conclusion
(1) Polyester filament and polyester staple fiber non-woven filament nonwoven geotextile for sale have good tolerance in an acid-base environment with pH=2-10.
(2) In the environment of pH≥12, the tensile strength of the polyester filament non-woven filament nonwoven geotextile manufacturers is completely lost in a short time, and the polyester staple fiber non-woven geotextile has better tolerance than the polyester filament.
(3) In the strong acid environment, the performance of polyester staple fiber and polyester filament non-woven high quality filament nonwoven geotextile increases with the increase of gram weight (per square meter); in the strong alkali environment, with the weight of each weight (per The increase of the resistance performance of the polyester filament non-woven geotextile is not obvious, and the tolerance of the polyester staple fiber non-woven geotextile is gradually increased.
(4) Polypropylene staple fiber non-woven filament nonwoven geotextile for sale has good tolerance in both strong acid and alkali environment, and its performance in a strong acid environment is better than polyester staple fiber nonwoven filament nonwoven geotextile manufacturers.
Therefore, for landfills and mine tailings ponds with different acid-base environments, different types and different types of non-woven filament nonwoven geotextile manufacturers can be selected according to the acid and alkali resistance for the anti-seepage engineering and the protective layer of the membrane and the protective layer. It is composed of a three-dimensional composite drainage net, bentonite waterproof blanket (GCL) and composite geomembrane. For example, when the pH of the acid-base environment is <10, polyester filament, polyester staple fiber or polypropylene nonwoven geotextile can be selected. When the pH is ≥12 when the acid-base environment is strong alkali, the short-term application can be selected as polyester. Fiber or polypropylene non-woven filament nonwoven geotextile for sale, when used for a long time should choose polypropylene non-woven high quality filament nonwoven geotextile.
Because the leachate composition of different landfills and mine tailings ponds is very complicated, the performance of non-woven filament nonwoven geotextile manufacturers is not only affected by the acid-base environment, but other components will also have a certain impact on the performance of non-woven filament nonwoven geotextile for sale. Further in-depth exploration to obtain more complete data and provide accurate guidance for the construction of the project.