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1.
Takeshi Katsumi Hiroyuki Ishimori Atsushi Ogawa Satoshi Maruyama Ryoichi Fukagawa 《Soils and Foundations》2008,48(3):407-417
When geosynthetic clay liners (GCLs) are applied as bottom liners at waste containment facilities, they are naturally prehydrated by absorbing moisture in the underlying base layers. In order to evaluate the effects of cations contained in waste leachates, this study investigated the effects of the water content distribution of the GCLs prehydrated with actual soils on their hydraulic conductivities against CaCl2 solutions. The “prehydration tests”, which were conducted prior to the hydraulic conductivity tests, showed that the water content distribution of the prehydrated GCLs depends on the properties of the GCLs and the base layers. In particular, drastic differences between GCLs with powdered bentonite and GCLs with granular bentonite were observed in the prehydration water content and its distribution. Prehydrated GCLs with powdered bentonite had a higher water content and a more homogenous distribution than those with granular bentonite. The hydraulic conductivity tests showed that most of the prehydrated GCLs exhibit a low hydraulic conductivity of k?1.0×10-8 cm/s against CaCl2 solutions with 0.1-0.5 M. However, GCLs with granular bentonite may be difficult to homogeneously prehydrate and exhibit an unstable hydraulic conductivity, which varies from k=2.9×10-9 cm/s to k=1.5×10-6 cm/s. The homogeneity of the water content distribution has been considered an important factor to obtain a required barrier performance under prehydration conditions, which are naturally generated in actual sites. 相似文献
2.
《Geotextiles and Geomembranes》2021,49(5):1129-1138
Hydraulic conductivity of seven geosynthetic clay liners (GCLs) to synthetic coal combustion product (CCP) leachates were evaluated in this study. The leachates are chemically representative of typical and worst scenarios observed in CCP landfills. The ionic strength (I) of the synthetic CCP leachates ranged from 50 mM to 4676 mM (TCCP-50, LRMD-96, TFGDS-473, LR-2577, HI-3179 and HR-4676). One of the GCLs contained conventional sodium bentonite (Na–B) and the other six contained bentonite-polymer (B–P) mixture with polymer loadings ranging from 0.5% to 12.7%. Hydraulic conductivity tests were conducted at an effective confining stress of 20 kPa. The hydraulic conductivity of the Na–B GCLs were >1 × 10−10 m/s when permeated with all six CCP leachates, whereas the B–P GCLs with sufficient polymer loading maintained low hydraulic conductivity to synthetic CCP leachates. All the B–P GCLs showed low hydraulic conductivity (<1 × 10−10 m/s) to low ionic strength leachates (TCCP-50, I = 50 mM and LRMD-96, I = 96 mM). B–P GCLs with P > 5% showed low hydraulic conductivity (<1 × 10−10 m/s) up to HI-3179 leachates. These results suggest that B–P GCLs with sufficient polymer loading can be used to manage aggressive CCP leachates. 相似文献
3.
Geosynthetic clay liners (GCLs) are used in landfill liner applications due primarily to their low hydraulic conductivity to water. The low hydraulic conductivity of GCLs comes from the structure of the clay in the bentonite. However, the interaction between clay and aggressive liquids may alter the structure of the clay and, thus, result in an increase in the hydraulic conductivity of the GCL. This paper presents the results of a project aimed at evaluating the impact of a synthetic leachate on the structure of four different bentonites used in the manufacturing of GCLs. The preparation of bentonite dispersions increased the interaction between the bentonites and the various liquids. The hydraulic properties of the dispersions also were tested using filter press tests to obtain flow curves. Results of these tests were correlated with the cationic concentration, electrical conductivity and pH of the dispersions, swell indexes of the bentonite extracted from the GCLs, and permittivities of the intact GCLs determined in oedopermeameter tests. The results showed that one bentonite was more sensitive to the synthetic leachate than the other bentonites. For example, the permittivities of the more sensitive bentonite based on the oedopermeameter tests and filter press tests were respectively 2.11 × 10−8 s−1 and 5.6 × 10−8 s−1, whereas the permittivities for other bentonites, including a natural sodium bentonite and two sodium-activated calcium bentonites, were respectively 5.7 to 6.5 × 10−9 s−1 and 3.2 to 3.5 × 10−8 s−1. The filter press test served as a quick and easy-to-use test to compare the performance of the various bentonites in containing a given liquid. However, the oedopermeameter test or direct permeation test is preferable to filter press tests or fluid loss tests for evaluating the long-term impact of a liquid on a bentonite. 相似文献
4.
《Soils and Foundations》2007,47(1):79-96
To investigate systematically the effects of electrolytic solutions on the barrier performance of geosynthetic clay liners (GCLs), a long-term hydraulic conductivity test for 3 years at longest was conducted on a nonprehydrated GCL permeated with inorganic chemical solutions. The hydraulic conductivity test for waste leachates was also conducted. The results of the test show that the hydraulic conductivity of GCLs significantly correlates with the swelling capacity of bentonite contained in GCLs. GCLs have excellent barrier performance of k<1.0×10-8 cm/s when the free swell is larger than 15 mL/2 g-solid regardless of the type and concentration of the permeant solution. In addition, when the results of the hydraulic conductivity test with chemical inorganic solutions were compared to those with waste leachates, the hydraulic conductivity of GCL permeated with chemical solution was almost the same within the electric conductivity of 0-25 S/m as that permeated with waste leachate having similar electric conductivity. The hydraulic conductivity of GCLs to be used in landfill bottom liners can be estimated by the hydraulic conductivity values obtained from the experiment using chemical solutions having the similar electric conductivity values, if the chemical solution had the electric conductivity within=25 S/m. 相似文献
5.
《Geotextiles and Geomembranes》2023,51(5):93-103
Flow in an idealized geosynthetic clay liner (GCL) containing bentonite comprised of equisized and equispaced square granules was simulated using a hydrodynamic model to quantitatively evaluate the premise that the hydraulic conductivity of GCLs diminishes as the bentonite granules hydrate and swell into adjacent intergranular pores, creating smaller and tortuous intergranular flow paths. Predictions with the model indicate that hydraulic conductivity decreases as granules swell and intergranular pores become smaller, and that greater granule swelling during hydration is required to achieve low hydraulic conductivity when the bentonite is comprised of larger granules, or the bentonite density is lower (lower bentonite mass per unit area). Predictions made with the model indicate that intergranular pores become extremely small (<1 μm) as the hydraulic conductivity approaches 10−11 m/s. These outcomes are consistent with experimental data showing that GCLs are more permeable when hydrated and permeated with solutions that suppress swelling of the bentonite granules, and that the hydraulic conductivity of GCLs with bentonite having smaller intergranular pores (e.g., GCLs with smaller bentonite granules, more broadly graded particles, or higher bentonite density) is less sensitive to solutions that suppress swelling. 相似文献
6.
《Geotextiles and Geomembranes》2020,48(6):912-927
The hydraulic conductivity of geosynthetic clay liners (GCLs) permeated with deionized water (S0) and NH4+ solutions, with concentrations of 100 mg/L (S100) and 1000 mg/L (S1000), was examined under six dry-wet cycles. The internal properties of virgin, desiccated, and healed GCLs were analyzed and quantified using X-ray computed tomography images. The hydraulic conductivity of the GCLs permeated with S0 and S100 underwent a negligible change during the six dry-wet cycles, whereas that of S1000 increased by almost three orders of magnitude after two desiccations. Each desiccation, after permeating with S0 and S100, generated a completely different macro-crack pattern; however, generation of macro-cracks at the same locations from dry cycles 2 to 6 and an abundance of micro-cracks were typical for S1000. This implies the severe deterioration of bentonite due to multi-desiccations and chemical compatibility with S1000. Moreover, the swell index of bentonite exposed to S1000 was reduced by approximately half, after six dry-wet cycles. Despite the lower volume percentage of macro-cracks for S1000 compared to S0 and S100, the swelling capacity of this bentonite was insufficient to fully heal these cracks. Hence, the swelling properties of bentonite dominate crack volume with regard to determining the hydraulic conductivity of GCLs. 相似文献
7.
8.
《Soils and Foundations》2022,62(6):101235
Polymer-enhanced bentonites for geoenvironmental containment barriers, such as bentonite-polyacrylic-acid composite (BPC), generally have low hydraulic conductivity (e.g., k < 10?10 m/s) even when exposed to aggressive waste solutions. However, understanding of diffusion and membrane behavior properties of enhanced bentonites and associated impacts on coupled contaminant transport through the barrier remains limited. In this study, hydraulic conductivity (k), effective diffusion coefficients (D*), and membrane efficiencies (ω) were measured for BPC with 3.2 % polymer content (by mass; referred to as BPC-3.2). Tests were performed with potassium chloride (KCl) solutions ranging from dilute (2.5 mM) to aggressive (400 mM) concentrations. As concentration increased, D* increased by a factor of three, ω decreased by two orders of magnitude, and k remained relatively low (1.2 × 10?11 to 2.9 × 10?11 m/s). The experimental results were paired with an existing coupled solute transport model to evaluate the significance of membrane behavior and diffusion on predicted total solute flux through a geosynthetic clay liner (GCL) and a GCL overlying an attenuation layer. The predicted mass flux was diffusion dominated, with the diffusive flux greater than the advective flux by one to two orders of magnitude. Membrane behavior reduced predicted total solute flux through the GCL by 5.8 to 61 %. The results demonstrate the role of coupled solute transport in the long-term performance of bentonite barriers, and advance understanding of contaminant transport in BPC. 相似文献
9.
《Geotextiles and Geomembranes》2022,50(4):590-606
This paper explores the influence of polymer enhancement on water uptake and retention by geosynthetic clay liners (GCLs) across a wide suction range (up to 106 kPa), including the low suction regime (0.1–10 kPa) typically omitted in past studies. The suction measurement methods used enabled elucidation of water uptake and retention behaviour through the framework of GCL pore structures and their corresponding suction regimes. Polymer enhanced GCLs (PE-GCLs) have high maximum water uptake, and both the water entry and air expulsion values tend to be high. Due to high swelling, the onset of geotextile confinement for PE-GCLs was observed at high suctions. The impact of polymer becomes more apparent when the bentonite achieves a pseudo-two-layer interlayer hydration state at a suction of about 40 MPa (RH = 75%). The hydration mechanism for the polymer fraction in bentonite is unique to the specific polymer type, polymer dosage, and manufacturing process. The water retention behaviour at the low suction range is caused by the in-filling of geotextile pores, bentonite swelling and extrusion, and polymer water adsorption. Insights from this study can form the basis for developing a more suitable bimodal generalised model for fitting the water retention curves of GCLs. 相似文献
10.
Effect of wet-dry cycles on standard & polymer-amended GCLs in covers subjected to flow over the GCL
《Geotextiles and Geomembranes》2021,49(5):1165-1175
The performance of five different GCLs (two GCLs with standard sodium bentonite and three GCLs with polymer enhanced bentonite) subjected to three different climatic modes of wet-dry cycles simulating conditions to which a GCL might expose in cover systems over a prolonged time is reported. The wetting cycles lasted for 8 h, while the drying cycles varied between 16 h, seven days, and 14 days. It is shown that after around a year of accelerated aging, the hydraulic conductivity of the aged GCLs increased notably when permeated with tap water at an applied effective stress of 15 kPa for a range of heads (0.07, 0.14, 0.21, 0.49, and 1.2 m). The combined effects of the number and the duration of the wet-dry cycles, the GCL's mass per unit area, the carrier geotextile, the size and the number of the needle punch bundles, and the thermal treatment to bond the needle-punch bundles to the carrier geotextile are discussed. The poor hydraulic performance of the polymer-amended/modified bentonite GCLs is discussed. 相似文献
11.
A study was conducted to investigate (1) physicochemical factors that influence polymer elution from GCLs containing a blend of bentonite and linear (water-soluble) polymer (LPB GCLs) and (2) the mechanism that controls the chemical compatibility of LPB GCLs when polymer elutes. A series of hydraulic conductivity (k), free swell and viscosity tests were performed on a commercial LPB GCL using DI water, varying concentrations of NaCl and CaCl?. Comparable tests were also performed on a conventional bentonite (CB) GCL containing the same untreated bentonite and the same physical properties as the LPB GCL. The LPB GCL showed improved swelling and hydraulic performance compared to the CB GCL when permeated with salt solutions. Total organic carbon analysis of the effluents showed that polymer eluted from the LPB GCL regardless of the permeant solution. However, the rate at which polymer eluted increased as the concentration and valence of the dominant cation increased. The rate at which polymer eluted also increased with hydraulic gradient. The mass of polymer retained inside the GCL matrix did not correlate with the k of the LPB GCL. Free swell tests coupled with chemical analysis suggest that, the improved chemical compatibility of the LPB GCL was due to the ability of the polymer to scavenge cations from the solution which allows the bentonite to undergo adequate swelling during the initial hydration period. Analogous to water-prehydrated CB GCLs, the dispersed structure of the bentonite fabric and increased adsorbed water molecules attained during initial swelling controls the k of the LPB GCL when polymer elutes. 相似文献
12.
《Geotextiles and Geomembranes》2020,48(6):950-961
In composite liners made of geomembrane (GMB)-geosynthetics clay liners (GCLs), maintaining bentonite in the GCL in a suitably hydrated state is critical for their performance. Hydration of GCL from subsoil, following industry best practice, is time consuming and conditional on suitable water chemistry in subsoil. In addition, under thermal gradients, dehydration occurs, with moisture migrating downwards to the subsoil, leading to the development of cracks in the bentonite and hence loss of performance.Two novel ideas are proposed in this paper, namely hydration of GCLs by artificial irrigation and hydraulic separation of the liner system from the underlying subsoil. Three new composite liner designs allowing for actively irrigating a geosynthetic clay liner (GCL) through a geocomposite layer were investigated. In two of the three designs, the hydraulic connection between the GCL and the subsoil was broken by placing an additional GMB between them. The new designs were tested in column experiments under 20 kPa overburden pressure and temperatures of up to 78 °C applied to the top of the liner. The performances of the new designs were compared to that of a standard GCL-GMB design where GCL was allowed to hydrate from a well-graded sandy subsoil. Three scenarios for the staging of hydration and thermal load application were investigated.Under active hydration of the composite liners, it took less than 14 days for the GCLs to reach a gravimetric water content ω of 110–130%, compared to 49 days taken to reach ω~95% under hydration from the subsoil. GCLs in the new designs in which the hydraulic connection with the subsoil was broken, remained well-hydrated (ω>100%) after 14 days of heating and no cracks appeared in the bentonite. On the other hand, the GCL in the conventional design experienced severe desiccation under the same conditions. The new designs hence offer a viable solution to the problem of slow hydration and/or thermal desiccation of GCLs. 相似文献
13.
《Geotextiles and Geomembranes》2021,49(6):1451-1469
A laboratory investigation was conducted on two different conventional GCLs (one with fine granular and another one with powdered bentonite) to explore the effect of prehydration and permeant fluid; GCL desiccation on the interface transmissivity, θ, between the interfaces of a 1.5 mm-thick high-density polyethylene (HDPE) geomembrane (GMB) and a GCL. The study also aimed to assess the self-healing capacity of desiccated GCLs for three different permeant solutions under a range of applied stresses (10–150 kPa). It was found that at stresses less than 70 kPa, θ was dominated by variability in the initial contact condition between the GMB-GCL interfaces. The effect of other factors was largely masked by the contact variability. At 100–150 kPa, the effects of initial variability were largely eliminated, but there was no notable effect of other factors on θ in the absence of desiccation. GCL desiccation increased θ by up to three orders of magnitude than an intact specimen at 10–100 kPa. Even at 150 kPa, desiccated specimens had a θ ≤ 8.0 × 10−9 m2/s for all specimens tested. The chemical composition of the permeant solutions, crack width, and nature of bentonite could play an important role in healing the cracks of desiccated GCLs. 相似文献
14.
GCLs containing powdered Na-bentonite treated with different dosages of a proprietary additive intended to reduce the impacts of chemical interactions were permeated with three solutions: a hyperalkaline solution (1 M NaOH and 1.3 mM CsCl) having similar pH to aluminum refining leachate, a 1.3 mM CsCl solution (no NaOH), and DI water. For a given permeant solution, the hydraulic conductivity of both GCLs was similar. Thus, the higher additive dosage had no measureable impact on hydraulic conductivity. Hydraulic conductivity of both GCLs decreased by a factor of approximately 1.5–1.8 during permeation with CsCl in response to osmotic swelling induced by the low ionic strength of the CsCl solution entering the pore space. In contrast, permeation with the NaOH–CsCl solution caused the hydraulic conductivity of both GCLs to increase modestly (<50 times the hydraulic conductivity to DI water), and then level out (or decrease slightly) as a result of reduced osmotic swelling in the interlayer combined with dissolution of the mineral. For the tests conducted with CsCl solution, nearly all of the Cs was adsorbed by the bentonite. In contrast, Cs broke through readily when the NaOH–CsCl solution was used as the permeant solution. Permeation with the NaOH–CsCl solution also increased the sodicity of the bentonite by replacing bound K, Ca, and Mg on the mineral surface. 相似文献
15.
《Geotextiles and Geomembranes》2019,47(6):740-754
The effects of the silt aggregation, compaction density, and water content of the subgrade on the hydration of five different geosynthetic clay liner (GCL) products is reported based on a series of laboratory column experiments conducted over a six-year period. GCLs meeting typical specifications in terms of minimum hydraulic conductivity and swell index are hydrated to equilibrium from the same subgrade soil with sufficient cations to cause cation exchange during hydration. It is then shown that the GCL bentonite granularity and GCL structure can have a significant (~four orders of magnitude) effect on hydraulic conductivity under the same test conditions (from 8 × 10−12 m/s for one GCL to 6 × 10−8 m/s for another GCL product). The effect of subgrade water content on the hydraulic performance of GCLs are not self-evident and quite dependent on the bentonite granularity, GCL structure, and permeant. Varying the subgrade water content from 5 to 16% and allowing the GCL to hydrate to equilibrium before permeation led to up to 5-fold difference in hydraulic conductivity when permeated with tap water and up to 60-fold difference when the same product is permeated with synthetic municipal solid waste leachate. When permeated with synthetic leachate, increasing stress from 70 kPa to 150 kPa led to a slight (average 37%; maximum 2.7-fold) decrease in hydraulic conductivity due to a decrease in bulk void ratio. It is shown that hydraulic conductivity is lower for GCLs with a scrim-reinforced geotextile, and/or with finer bentonite. It is shown that selecting a GCL based on the initial hydraulic conductivity and swell index in a manufacturers product sheet provides no assurance of good performance in field applications and it is recommended that designers pay more attention to selection of a GCL and preparation of the subgrade for important projects. 相似文献
16.
Chuang Yu Yu Yang Ze-xiang Wu Ji-fang Jiang Rao-ping Liao Yong-feng Deng 《Geotextiles and Geomembranes》2021,49(2):413-419
Geosynthetic clay liners (GCLs), which have a very low permeability to water and a considerably high self-healing capacity, are widely used in liner systems of landfills. In this study, a series of experimental tests were carried out under complex conditions on typical commercial GCLs from China. In particular, the effects of pH values and lead ions (Pb2+) were tested in addition to other factors. The swelling properties of natural bentonite encapsulated between geotextile components in the GCLs were tested first. The swelling capacity was reduced rapidly at pH values < 3 and concentrations of Pb2+ >40 mM. Permeability tests on GCLs with different concentrations of lead ions were then performed by using the self-developed multi-link flexible wall permeameter, and data showed that increases in lead ion concentrations greatly improved the permeability. Finally, self-healing capacity tests were conducted on needle-punched GCLs under different levels of damage. Results showed that the GCLs have a good self-healing capacity with small diameter damage holes (2 mm, close to three times the original aperture), but with a damage aperture larger than 15% of the sample area, the self-healing capacity could not prevent leakage; hence, in certain situations it will be necessary to repair the damage to meet the anti-seepage requirement. 相似文献
17.
Angelica Naka Giancarlo Flores Toru Inui Hirofumi Sakanakura Takeshi Katsumi 《Soils and Foundations》2019,59(5):1128-1147
The hydraulic and chemical compatibility of a geosynthetic clay liner (GCL), containing powdered Na-bentonite, was evaluated against artificial acid rock drainage (ARD) in terms of the swell index, hydraulic conductivity and heavy metal retention. Six artificial ARDs with an approximate pH of 3 and different metal concentrations (electrical conductivity, EC, ranging between 75 and 1000 mS/m; ionic strength ranging between 8 and 400 mM) were used in the experiments. The results of free swelling tests showed that high metal concentrations (EC higher than 70 mS/m) negatively impact the swell volume by lowering it. The hydraulic conductivity of the GCL permeated with distilled water was 1.2 × 10?11 m/s, falling in the range of 7.9 × 10?12 to 1.1 × 10?10 m/s when prehydrated with distilled water and permeated with ARDs. The ion exchange and metal precipitation appeared to be the main mechanisms controlling the metal attenuation on the bentonite. The ion exchange mechanism starts with the release of Na from the bentonite and the sorption of the bi- and tri-metals present in the ARDs onto the bentonite. After the depletion of Na, the ion exchange reaction proceeds with the desorption of Ca and Mg from the bentonite and the sorption of cations present in the ARDs onto the bentonite layers. The depletion of Na from the bentonite and the subsequent release of Ca and Mg correlate to the sudden drop in pH and a gradual increase or equilibration of the hydraulic conductivity. It is possible to say that, after this point, hydraulic and chemical equilibrium is reached. From the overall results, the tested GCL showed acceptably low hydraulic conductivity and the potential to attenuate heavy metals present in ARDs. 相似文献
18.
Combined passive treatment technologies have been used to treat acidic rock drainage (ARD), the well-known acute and costly environmental problem facing the mining industry. It is shown that geosynthetic clay liners (GCLs) were able to attenuate metals from lime treated ARD water, and maintain a neutral pH and low hydraulic conductivity (less than 4.0 × 10−11 m/s) after 16 pore volumes of permeation; this implies their usefulness as a potentially significant component in combined passive treatment systems. Presented are laboratory breakthrough data for Cu, Cd, Ni, Mn, and Zn from the permeation of GCLs with 16 pore volumes of ARD, treated ARD (TARD), and a landfill leachate. Metal retention occurred in all solutions, but was greatest for the TARD, producing removal efficiencies of greater than 80%. 相似文献
19.
Hydraulic conductivity of geosynthetic clay liners to tailings impoundment solutions 总被引:1,自引:0,他引:1
The results of a comprehensive testing program conducted to evaluate the hydraulic conductivity (k) of two geosynthetic clay liners (GCLs) considered as a liner component for a tailings impoundment at a proposed zinc and copper mine are reported. The two GCLs were permeated with a relatively low ionic-strength ground water (GW) from the mine site and two electrolyte solutions, a process water (PW) and a simulated leachate (SL), with chemical compositions consistent with those expected during operation of the impoundment. A total of 22 flexible-wall tests were performed to determine the effects of prehydration with the GW, type of GCL, type of permeant liquid, and duration of the back-pressure stage of the test. The k values for both GCLs permeated with the GW were 1.7 × 10−9 cm/s, which is within the range 1–3 × 10−9 cm/s typically reported for GCLs permeated with low ionic-strength liquids, such as deionized water. However, the mean values of k based on permeation of duplicate specimens of both types of GCL with either PW or SL relative to the values of k based on permeation with GW, or k/kw, ranged from a factor of 200 (2.3 orders of magnitude) to a factor of 7600 (3.9 orders of magnitude). Thus, both tailings impoundment solutions had significant adverse impacts on the hydraulic performance of both GCLs. Given the overall range of k/kw values, factors such as prehydration, type of GCL, type of permeant liquid, and duration of back pressure, were relatively insignificant. The results of this study serve to emphasize the need to perform hydraulic conductivity testing using site specific materials. 相似文献
20.
《Soils and Foundations》2014,54(3):329-344
The performance of landfill liners can be enhanced if they exhibit a semipermeable membrane behavior, which restricts the migration of contaminants. Consequently, enhancing the membrane property of clays used for liners is becoming increasingly important. As bentonite has already proven to be an excellent additive for improving the membrane behavior of clay, the hydraulic conductivities and membrane behaviors of a locally available clay, known as Fukakusa clay, amended with different amounts of dry bentonite (5%, 10%, 15%, and 20%) were herein evaluated. The chemico-osmotic efficiency coefficient, ω, was obtained under different concentration differences of KCl solution (0.5, 1, 5, 10, and 50 mM) for specimens in rigid-wall cells. The test results show that the ω of unamended clay is very low and can be ignored unless amended with bentonite, and that hydraulic conductivity k is suitably low (1.58×10−9 m/s). Additionally, ω decreased as the KCl concentration increased, which is consistent with the theory that increasing concentration causes progressively greater shrinkage of the diffuse-double layers of the clay particles. Furthermore, the mechanisms that influence the membrane behavior are discussed from the viewpoints of the diffuse-double layer and the interparticle pore size with the assistance of SEM. 相似文献