TY - JOUR
AU - Jiang,, Fatang
AB - Abstract This study presents the preparation and measurement of a novel environmentally friendly konjac glucomannan (KGM)-based composite aerogels enhanced with wheat straw (WS) via a sol–gel and freeze-drying progress. With the addition of WS, the porosity of aerogels could be increased from 50 to 88.13%, the filtration resistance of aerogels could be reduced from 500 to 205 Pa, and the filtration efficiency could be improved to 90.38%. The addition of WS also enhances the mechanical properties of composite aerogels with compression modulus of 2000.66 Pa, compressive strength of 501.56 Pa and elasticity of 0.603. The results demonstrate the high potential of KGM-based composite aerogels enhanced with WS for applications in air filtering. 1 INTRODUCTION In recent years, air pollution has raised considerable attention with fast industrial development and urbanization. According to the Bulletin of China Environmental Status [1], the heavy smog caused by fine particles (PM2.5) has blanketed more than 17 provinces in China in 2013. In 2015, the air quality exceeded the ambient air quality standard in 78.4% of the total cities in China. In 2016, PM2.5 was the primary pollutant for 80.3% of the total pollution days. Particulate matter (PM) is a complex system composed of extremely small particles and liquid droplets [2, 3]. PM is categorized based on the particle sizes, such as PM2.5 (particle sizes <2.5 μm), PM10 (particle sizes <10.0 μm), etc. PM2.5 can readily penetrate the human bronchi and lungs [4], aggravating the air pollution and have a great harm to the ecological environment [5] and human health [6–10]. At present, the most effective way to solve the existing air quality problem is air filtration. Activated carbon fiber [11], nanofiber [12] and photocatalytic materials [13] have been used as air purification materials in conventional heating, ventilating and air conditioning systems (HVAC). In Jae Hong Park’s research [11], the overall particle removal efficiencies of the filter for all submicron particles were ~27% with no ionizers. Tang et al. [12] found that filtration efficiency of polydisperse NaCl particles at diameter of 50, 80, 100, 200, 300 and 500 nm is ~90%, especially at the diameter of 300 nm, the filtration efficiency is ~94%. At the diameter of 500 nm, the filtration efficiency is ~99%. Cuce and Riffat [14] pointed that the energy can be efficiently saved by using filtration materials in HVAC instead of traditional one. Aerogel is a synthetic porous ultralight material with extremely low density, large surface area and high mechanical strength. Aerogels are widely used as adsorption materials [15], catalysis [16], thermal and acoustic insulation [17]. Due to the high specific surface area, 3D network structure, low density and high porosity, aerogels are considered as efficient air purification materials to adsorb PM [18, 19], toxic gases [20] such as SO2, H2S, CO and NO, as well as volatile organic pollutants such as BTEX (benzene, toluene [21] and ethylbenzene), xylene, formaldehyde, methanol, acetone, cyclohexane, etc. Currently, classical aerogels are usually prepared from inorganic (silica) [22] or organic (petrochemical-based) materials [17]. However, silica aerogels are fragile and could generate hydrophobic dusts which could bring damage to human’s skin, eyes and lung [23]. The petrochemical-based aerogels are produced by non-sustainable chemical processes that involve toxic components [24]. In addition, classical aerogels are difficult to degrade in nature and can cause harm to the environment. Bio-aerogels are a new generation of aerogels that are bio-composite, green and environmentally friendly. Most of them are based on polysaccharides like cellulose [25], starch [26], chitosan [27], alginate [28] and pectin [29], and have been intensively studied in the past decade. Polysaccharide and protein source are rich in renewable resources, with the potential to transform various industrial processes from petroleum dependent into biotechnology [30]. Thus bio-aerogels have attracted more and more interest and developed to replace the classical one owing to its features of abundance, biodegradability, regeneration and sustainability. In addition, polysaccharides have in common the ability to form gels either by themselves in the presence of water or with other cross-linking agents, or mixed polysaccharides [31], hence, to be dried to obtain aerogels of various shapes and sizes with high porosity and specific surface area, as well as achieving remarkable air purifying properties. Nevertheless, the mechanical properties of bio-aerogels need to be improved and the adsorption of PM2.5 could be further explored. Wheat straw (WS) is one of the world largest agricultural byproducts. However, open-field burning of WS is a common way to eliminate residues after harvesting, by which large amounts of PMs and gaseous pollutants are released, leading to the serious environmental pollution [32]. Interestingly enough, the microstructure of WS is porous due to the dense fibrous cells in stalk, providing the potential to be used as filtering material. In this study, some samples of composite aerogels based on konjac glucomnnan (KGM), gelatin, starch and WS were prepared via a combination of sol–gel and freeze-drying method. The influence of the WS on the morphology, microstructure, mechanical properties, thermal stability and filtration performance of KGM-based aerogels were studied, with the goal of improving the filtration efficiency and reduce the filtration resistance, as well as reusing agricultural waste and turning it into advanced filter material. Our work could provide new development ideas for the application of polysaccharide-based aerogels as air purified materials. 2 MATERIALS AND METHODS 2.1 Materials KGM and WS were supplied by Licheng Biological Technology Co., Ltd (Wuhan, China). Potato starch was purchased from Wuhan Lin He Ji Food Co., Ltd (Wuhan, China). Gelatin was purchased from Sinopharm Chemical Reagent Co., Ltd (Shanghai, China). 2.2 Methods The preparation of KGM-based aerogels was presented in a patent for invention by Licheng Biological Technology in China [33]. Details of the work were shown as follows. 2.2.1 Preparation of KGM/gelatin/starch composite aerogels KGM/gelatin/starch (K/G/S) aerogels were prepared mainly following the method described in the previous work [34]. Potato starch (0–4.0%, w/v) and gelatin (1–3%, w/v) were accurately weighted and mixed first. Then KGM (0–1.5%, w/v) were added and mixed gradually for 1 h at 90°C to form a homogenous sols. Subsequently the sols were injected into a cylindrical 12-well cell culture cluster (22.1 mm, 3.8 cm2) putting into the 4°C refrigerator for aging molding for 2 h and then immediately frozen in a ultra-low temperature refrigerator (DW-FL262, Rowsen, China) at −15°C for 10 h. The frozen samples were freeze-dried in a freeze dryer (Modulyod-230, Thermo Electron Corporation, USA) at −55°C in a vacuum of 1 Pa. The aerogels were formed and obtained after complete ice sublimation in ~24 h. The formulas of samples are shown in Table 1. Table 1. Formulas of aerogels. Sample KGM (%, w/v) Gelatin (%, w/v) Starch (%, w/v) K0.5 0.5 0 0 K1 1 0 0 K1.5 1.5 0 0 K1G1 1 1 0 K1G2 1 2 0 K1G3 1 3 0 K1G2S2 1 2 2 K1G2S3 1 2 3 K1G2S4 1 2 4 Sample KGM (%, w/v) Gelatin (%, w/v) Starch (%, w/v) K0.5 0.5 0 0 K1 1 0 0 K1.5 1.5 0 0 K1G1 1 1 0 K1G2 1 2 0 K1G3 1 3 0 K1G2S2 1 2 2 K1G2S3 1 2 3 K1G2S4 1 2 4 Open in new tab Table 1. Formulas of aerogels. Sample KGM (%, w/v) Gelatin (%, w/v) Starch (%, w/v) K0.5 0.5 0 0 K1 1 0 0 K1.5 1.5 0 0 K1G1 1 1 0 K1G2 1 2 0 K1G3 1 3 0 K1G2S2 1 2 2 K1G2S3 1 2 3 K1G2S4 1 2 4 Sample KGM (%, w/v) Gelatin (%, w/v) Starch (%, w/v) K0.5 0.5 0 0 K1 1 0 0 K1.5 1.5 0 0 K1G1 1 1 0 K1G2 1 2 0 K1G3 1 3 0 K1G2S2 1 2 2 K1G2S3 1 2 3 K1G2S4 1 2 4 Open in new tab 2.2.2 Preparation of KGM/gelatin/starch/wheatstraw aerogels KGM/gelatin/starch/wheatstraw (K/G/S/WS) aerogels were prepared by the same method as in Section 2.2.1, the only different is that the WS was dried and pulverized into powders with a diameter of 0.095 mm, and was added into the mixed sol at the same time with KGM. According to Section 2.2.1, the optimized formula of the ratio of KGM to gelatin to starch was determined, and the content of WS varied from 0 to 3%. 2.2.3 Characterization of aerogels Mechanical properties. The mechanical properties of prepared aerogels were determined by using a TMS-PRO texture analyzer before test, samples were equilibrated for 48 h at 25°C and 50% relative humidity. The samples’ diameter was 20 mm, the thickness was ~10 mm, the probe compression rate was 60 mm/min, and compression ratio was 30%. The compressive strength and elasticity were obtained by secondary compression. The samples were subjected to a single compression with strain as abscissa and the stress as ordinate. The compressive modulus of the aerogels was calculated by the slope of the initial linear portion of the stress–strain curve [35]. Differential scanning calorimetry analysis. The aerogel samples were analyzed by using a Netzsch DSC-204-F1 differential scanning calorimeter (DSC). Firstly, the samples were dried to constant weight, and then a few milligrams of samples were accurately weighed into an aluminum crucible and with the same empty crucible as a reference. The temperature was raised from 25 to 400°C at a heating rate of 10°C/min, and the change of the heat flow with temperature was measured during the temperature rise. The entire test procedure was carried out under dry N2. Thermogravimetric analysis. The thermal stability of aerogels was studied by Netzsch TG 209 thermogravimetric (TG) analyzer. The temperature was raised at a rate of 10°C/min under a nitrogen flow rate of 20 mL/min, and the temperature was varied from 30 to 600°C. Scanning electron microscopy observations. The microstructure of aerogels was observed via scanning electron microscopy (SEM) (JSM6390LV, JEOL, Japan) at magnification of ×50 and ×500. The samples were cut into 5 × 1.5 mm2 circular pieces using a sharp razor blade. The cut surface of samples were coated with gold particles (Bio-Rad type SC 502, JEOL Ltd, Japan) by sputtering for 60 s, allowing surface visualization using an accelerated voltage of 30 kV. Density determination. The mass of aerogel samples was measured with the analytical balance. The density of aerogels was calculated as follows: ρ=mv Porosity determination. The porosity of aerogels was measured by the drainage method [36] as shown in Figure 1, and each test was repeated five times. N-hexane was used as the test liquid. Aerogels were immersed in n-hexane (V1) for until no bubble spilled out of the sample. The volume after aerogel immersing in n-hexane was V2, and the remaining n-hexane volume with aerogels removed was V3. The porosity was determined by the following formula: ε(%)=(V1−V3)/(V2−V3)×100% Figure 1. Open in new tabDownload slide Porosity determination of aerogels by the drainage method. Figure 1. Open in new tabDownload slide Porosity determination of aerogels by the drainage method. Filtration performance test of aerogels. The filtration efficiency and the filtration resistance of aerogels were determined by LZC-H comprehensive performance test bed (Figure 2). Sodium chloride with a median diameter of 0.26 μm and a test flow rate of 32 L/min was adopted. The samples were cut into wafers with a diameter of 15 cm and a thickness of 3 mm and placed in the fixture. Figure 2. Open in new tabDownload slide LZC-H comprehensive performance test bed of filtration materials. Figure 2. Open in new tabDownload slide LZC-H comprehensive performance test bed of filtration materials. Filtration efficiency (η) refers to the percentage of particles trapped by the sample filter under certain test conditions, and it was calculated by measuring the number of particles upstream and downstream by the counter. The formula is as follows: η=Mu−MdMu×100% where Mu is the number of upstream particles and Md is the number of downstream particles. The filter resistance (ΔP) refers to the total pressure difference between the upstream and downstream pressure of the measured sample. The pressure values are measured by the pressure gauges of upstream and downstream of the test pipe. The formula is as follows: ΔP=P2−P1 where P1 is the pressure in the pipe before filtration, Pa; P2 is the pressure in the pipe after filtration, Pa. 3 RESULTS AND DISCUSSION 3.1 Photo and SEM images of aerogels with/without WS 3.1.1 K/G/S-aerogels Macroscopic pictures of KGM/gelatin composite aerogels are shown in Figure 3. When KGM content is low, the overall appearance of aerogels was uniform. With the increase of KGM content, the layering appeared with the outer layer translucent and the middle opaque white (KGM 1%, gelatin 3% and KGM 1.5%, gelatin of 1–3%), which might be that phase separation of the gel process appeared. Figure 3. Open in new tabDownload slide Digital photograph of KGM/gelatin composite aerogels. Figure 3. Open in new tabDownload slide Digital photograph of KGM/gelatin composite aerogels. 3.1.2 Aerogels without WS Photo and SEM images of K/G/S aerogels without WS are shown in Figure 4. K stands for KGM, G stands for gelatin, S stands for starch and numbers represent the mass percentages of solution (water). Without addition of WS, K/G/S aerogels were white, with smooth and even surface. The SEM images showed cellular networks like microstructure of K/G/S aerogels, which were complete, homogeneous and three-dimensional, with the smooth pore walls. At larger magnification scale, the pores were observed to be close pores as shown in Figure 4. Figure 4. Open in new tabDownload slide Photo (a) and SEM images (b) at 50 times; (c) at 500 times of aerogels without wheat straw. Figure 4. Open in new tabDownload slide Photo (a) and SEM images (b) at 50 times; (c) at 500 times of aerogels without wheat straw. 3.1.3 Schematic of aerogel formation In order to better understand the distribution of the internal structure of aerogels, a schematic is shown in Figure 5. The results showed that aerogels exhibited 3D porous network structure. Thermal motion of the water molecules was limited with the decrease of temperature, resulting in the formation of more hydrogen bonds. Water molecules began to aggregate due to hydrogen bonds, forming some regular hexagonal clusters. Then ice crystals began to be formed. During freezing process, the solute molecules were pushed into the interstices of ice crystals, triggering intermolecular self-assembly. After ice crystals sublimation, the solute in the system was left and maintained its morphology during the freezing process, thus forming porous structure [37], as shown in Figure 5. Figure 5. Open in new tabDownload slide Schematic of aerogel formation. Figure 5. Open in new tabDownload slide Schematic of aerogel formation. 3.1.4 Aerogels with WS Figure 5 shows the microstructure of KGM-based aerogels with WS content from 0 to 3%. The letter WS stands for WS, others as Section 3.1.1. Figure 6a–c shows smooth and even surfaces of the KGM-based aerogels with WS, as well as the good formability and mechanical properties. The SEM images (Figure 6d–f) showed the microstructure of KGM-based aerogels with WS, and all the samples presented uniform pores with average pore size around 200 μm. WS was composed of fibrous tissue which is composed of multiple layers of fibroblasts, cell lumens, which had middle cavity of fibrous cells linked together to form a subtle honeycomb structure. Due to the special cavity structure of WS, the aerogels exhibited more microporous structures, and the pores are connected with each other with WS as the ‘bridge’, as shown in Figure 6g–i. This experimental phenomenon became more pronounced with the increase of WS content. Figure 6. Open in new tabDownload slide Photo (a–c) and SEM images (d–f at 50 times; g–i at 500 times) of aerogels with wheat straw. Figure 6. Open in new tabDownload slide Photo (a–c) and SEM images (d–f at 50 times; g–i at 500 times) of aerogels with wheat straw. According to the results shown in Figure 6, the microstructures of the KGM-based aerogels with different contents of WS were assumed and showed in Figure 7. The fibrous tissue of WS has a cavity structure, which links between pores in aerogel, increasing the permeability of aerogels. As the content of WS increased, the connections between pores also increased, as shown in Figure 7a–c, respectively, represent the microstructure of KGM-based aerogels with lower content, middle content and higher content of WS. Figure 7. Open in new tabDownload slide The assumed microstructure of KGM-based aerogels with lower content (a), middle content (b) and higher content (c) of wheat straw. Figure 7. Open in new tabDownload slide The assumed microstructure of KGM-based aerogels with lower content (a), middle content (b) and higher content (c) of wheat straw. 3.2 Mechanical properties of aerogels with/without WS As shown in Figure 8 and Table 2, the addition of WS had a great influence on the mechanical properties of the aerogels. At the beginning, the compressive modulus of aerogels increased with the addition of WS. With the WS content of 2%, the compressive modulus of aerogels reached the maximum value of 2000.66 kPa, which is 1.79 times of the compressive modulus of aerogels without WS (Table 2). WS can be embedded into the pore walls to make aerogels more porous, and can also play a role of mechanical support. However, if the adding amount of WS was too much, it will be deposited to the lower layer of materials. After moisture balance, the compressive strength of aerogels decreased significantly and the elasticity increased. Table 2. The compression modulus of aerogels balanced with different wheat straw content. Sample Compression modulus (kPa) K1G2S4-WS0 1117.80 ± 7.349d K1G2S4-WS1 1902.54 ± 17.46b K1G2S4-WS2 2000.66 ± 20.57a K1G2S4-WS3 1707.15 ± 10.908c Sample Compression modulus (kPa) K1G2S4-WS0 1117.80 ± 7.349d K1G2S4-WS1 1902.54 ± 17.46b K1G2S4-WS2 2000.66 ± 20.57a K1G2S4-WS3 1707.15 ± 10.908c Open in new tab Table 2. The compression modulus of aerogels balanced with different wheat straw content. Sample Compression modulus (kPa) K1G2S4-WS0 1117.80 ± 7.349d K1G2S4-WS1 1902.54 ± 17.46b K1G2S4-WS2 2000.66 ± 20.57a K1G2S4-WS3 1707.15 ± 10.908c Sample Compression modulus (kPa) K1G2S4-WS0 1117.80 ± 7.349d K1G2S4-WS1 1902.54 ± 17.46b K1G2S4-WS2 2000.66 ± 20.57a K1G2S4-WS3 1707.15 ± 10.908c Open in new tab Figure 8. Open in new tabDownload slide The stress–strain curve, compressive strength and elasticity of aerogels balanced with different wheat straw content. (a) Stress–strain curve; (b) partially enlarged of stress–strain curve for the strain range of 2–7%; (c) compressive strength of aerogels before and after the balance; and (d) elasticity of aerogels before and after the balance. Figure 8. Open in new tabDownload slide The stress–strain curve, compressive strength and elasticity of aerogels balanced with different wheat straw content. (a) Stress–strain curve; (b) partially enlarged of stress–strain curve for the strain range of 2–7%; (c) compressive strength of aerogels before and after the balance; and (d) elasticity of aerogels before and after the balance. 3.3 Thermal stability of aerogels with/without WS With the increase of temperature, heat flow changed as shown in Figure 9. Endothermic peak and exothermic peak appeared at around 100 and ~312.5°C, respectively. The endothermic peak at 100°C was due to the evaporation of water in aerogels. The exothermic peak at 312°C was due to the pyrolysis of polysaccharides and protein molecules in aerogel. No changes of peaks were observed after the addition of WS, indicating that the addition of straw had no effect on thermal stability of aerogels. The relationship between weight, weight loss rate of aerogels and the temperature is shown in Figure 10. As obtained from TG and DTG curves, the first stage weight loss of ~10% was due to the evaporation of free water and bound water in aerogels, which is independent of the thermal stability of samples. The second stage of heat loss is the pyrolysis of polysaccharide and protein. After the addition of WS, the maximum weight loss rate of the corresponding temperature remained, that is consistent with the DSC results. In addition, as the increase of WS content, the weight loss rate decreased, indicating that the addition of WS could improve the thermal stability of the composite aerogels. Figure 9. Open in new tabDownload slide DSC curves of composite aerogels balanced with different wheat straw content. Figure 9. Open in new tabDownload slide DSC curves of composite aerogels balanced with different wheat straw content. Figure 10. Open in new tabDownload slide TG curve (a) and DTG curve (b) of K/G/S aerogels balanced with different wheat straw content. Figure 10. Open in new tabDownload slide TG curve (a) and DTG curve (b) of K/G/S aerogels balanced with different wheat straw content. 3.4 Density and porosity determinations The density and the porosity of aerogels with various WS content are shown in Table 3. Along with the WS content increased, the density of aerogels increased from 0.0789 to 0.1098 g/cm3, which is caused by the total solid content. The porosity of aerogels increased as the content of WS increased from 0 to 2% (P < 0.05). While the WS content continued to increase, porosity of aerogels kept constant (P > 0.05). The WS can embed into the pore walls instead of the interstitial and internal cavity of aerogels, which can increase the internal air gap. This is consistent with the results of scanning electron microscopy. Table 3. Density and porosity of aerogels with/without wheat straw. Sample Density (g/cm3) Porosity (%) K1G2S4-WS0 0.0789 ± 0.0004d 57.05 ± 3.475d K1G2S4-WS1 0.0908 ± 0.0008c 74.52 ± 2.088c K1G2S4-WS2 0.0981 ± 0.0034b 88.13 ± 2.262a K1G2S4-WS3 0.1098 ± 0.0036a 87.45 ± 0.650ab Sample Density (g/cm3) Porosity (%) K1G2S4-WS0 0.0789 ± 0.0004d 57.05 ± 3.475d K1G2S4-WS1 0.0908 ± 0.0008c 74.52 ± 2.088c K1G2S4-WS2 0.0981 ± 0.0034b 88.13 ± 2.262a K1G2S4-WS3 0.1098 ± 0.0036a 87.45 ± 0.650ab Open in new tab Table 3. Density and porosity of aerogels with/without wheat straw. Sample Density (g/cm3) Porosity (%) K1G2S4-WS0 0.0789 ± 0.0004d 57.05 ± 3.475d K1G2S4-WS1 0.0908 ± 0.0008c 74.52 ± 2.088c K1G2S4-WS2 0.0981 ± 0.0034b 88.13 ± 2.262a K1G2S4-WS3 0.1098 ± 0.0036a 87.45 ± 0.650ab Sample Density (g/cm3) Porosity (%) K1G2S4-WS0 0.0789 ± 0.0004d 57.05 ± 3.475d K1G2S4-WS1 0.0908 ± 0.0008c 74.52 ± 2.088c K1G2S4-WS2 0.0981 ± 0.0034b 88.13 ± 2.262a K1G2S4-WS3 0.1098 ± 0.0036a 87.45 ± 0.650ab Open in new tab 3.5 Filtration performance of aerogels with/without WS Figure 11 shows that WS had a significant effect on the filtration efficiency and filtration resistance of aerogels. As the WS was evenly dispersed inside aerogels and embedded onto the pore wall due to the hollow structure of straw, the aerogels with WS showed smaller pore size after freeze drying than that of aerogels without WS. The addition of WS may change the closed cell structures of aerogels to make pores and cavities communicate with each other, resulting in the emergence of more space, and an increase of air flow channel. The filtration efficiency of aerogels increased slowly until the amount of WS was up to 2% (sample K1G2S4-WS2, with a filtration efficiency of 90.38%), which is similar to the aerogels without WS (sample K1G2S4-WS0, with a filtration efficiency of 97.32%). When the air containing with fine PM passes through aerogels, fine PM could be passed from the cavity in the middle of straw and voids caused by WS, making the filtration resistance significantly reduced. Zhang [38] has developed high-efficiency polyimide-nanofiber air filters with the filtration efficiency of more than 99.5%. Compared with the polyimide-nanofiber, our environmentally friendly KGM-based aerogels have similar properties. Figure 11. Open in new tabDownload slide Filtration efficiency of aerogels with/without wheat straw content for various particle sizes (a); filtration efficiency and filtration resistance of aerogels for particle matters of 0.3 μm and beyond (b). Figure 11. Open in new tabDownload slide Filtration efficiency of aerogels with/without wheat straw content for various particle sizes (a); filtration efficiency and filtration resistance of aerogels for particle matters of 0.3 μm and beyond (b). 4 CONCLUSION In this study, WS has been added to KGM/Gelatin/Starch composite aerogels to improve the filtration performance, mechanical properties and thermal stability, as the microstructure of aerogels can be changed by addition of WS. WS, which is always burned to release a large amount of pollutants including PM2.5, has been converted into a filtering material to reduce PM2.5 in this work. The SEM observations showed that the WS has a unique cavity structure, which could form microporous channels after embedded into the pore walls, resulting in the increasing porosity of the aerogels. The texture analysis, DSC analysis and TG analysis indicated that the addition of WS could significantly increase the mechanical properties and thermal stability of aerogels. The filtration performance results presented that the addition of WS has a significantly reduction of filtration resistance and air intake load of aerogels. Therefore, the addition of WS in the aerogels preparation might be a promising way to improve the mechanical properties and filtration performance of aerogels, as well as turn agricultural waste into advance filter material to fight against the air pollution. ACKNOWLEDGEMENTS This work was financially supported by the Technology support program of Hubei science and Technology Department (No. 2016ACA164). REFERENCES 1 Lu J , Cao X . 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TI - Microstructure and filtration performance of konjac glucomannan-based aerogels strengthened by wheat straw
JF - International Journal of Low-Carbon Technologies
DO - 10.1093/ijlct/ctx021
DA - 2019-08-31
UR - https://www.deepdyve.com/lp/oxford-university-press/microstructure-and-filtration-performance-of-konjac-glucomannan-based-TUJrO0xZid
SP - 335
EP - 75
VL - 14
IS - 3
DP - DeepDyve
ER -