Cation exchange capacity particle size

The cation-exchange capacity of the copper ferrocyanide gel used was found to be about 2.60 meq/g and its anion-exchange capacity about 0.21 meq/g. In all cases of various doses of gel used and types of anionic surfactants being removed, the tests indicated that a batch contact time of about 12 hours was sufficient for achieving maximum removals. Trials with various fractions of particle size demonstrated that both uptake and desorption (important in material regeneration) were most convenient and maximized on 170-200 BSS mesh size particles. Also, the adsorption of anionic surfactants was found to be maximum at pH 4 and decreased with an increase in pH. 

Zeolite surface chemistry resembles that of smectite clays. In contrast to clays, however, natural zeolites can occur as millimeter- or greater-sized particles and are free of shrink-swell behavior. As a result, zeolites exhibit superior hydraulic characteristics and are suitable for use in filtration systems (Breck 1974) and as permeable barriers to dissolved chemical migration. Internal and external surface areas up to 800 m2 g have been measured. Total cation exchange capacities in natural zeolites vary from 250 to 3000 meq kg 1 (Ming and Mumpton 1989). External cation exchange capacities have been determined for a few natural zeolites and typically range from 10 to 50 percent of the total cation exchange capacity (Bowman et al. 1995). 

Malcom, R. L., and Kennedy, V. C. (1970). Variation of cation exchange capacity and rate with particle size in stream sediment. J. Water Pollut. Control Fed. 42, 153-160. 

A wide variety of soils and sludge have now been treated. Soil characteristics that can impact the SET chemistry include the general soil type, which is treated (loam, sand, silt, and clay), the presence of humic material, the pH value, the soil s cation exchange capacity, its particle size, the amount of water present, and the iron content. Processes have been engineered to accommodate this wide range of variables [7,8,34]. Some soils can be treated... 

Bentonite rocks have many uses in the chemical and oil industries and also in agriculture and environmental protection. The usefulness of bentonite for each of these applications is based on its interfacial properties. These properties are determined by geological origin, chemical and mineral composition (especially montmorillonite content), and particle size distribution, and they include the specific surface area (internal and external), cation-exchange capacity (CEC), acid-base properties of the edge sites, viscosity, swelling, water permeability, adsorption of different substances, and migration rate of soluble substances in bentonite clay. 

Particle Size Distribution, Specific Surface Area (S), Cation-Exchange Capacity (CEC), Swelling in Water, and the Relative Amount of the Adsorbed 137Cs+ ion (x)... 

Table 1.1 Variations in the cation exchange capacity of kaoli-nite with particle size (from C. G. Harmon and F. Fraulini, J. Am. Ceram. Soc., 1940, 23, 252)...

At the local scale (i.e., for a given climate) several other factors modulate the distribution of SOC across the landscape. Of primary importance at this scale is soil texture (Parton et ai, 1987), a variable that is closely linked to other parameters such as bedrock type, nutrient status (cation exchange capacity), water holding capacity, illuviation and bioturbation rates, root penetration resistance, and the availability of oxygen to support aerobic microbial respiration. It is convenient that these variables tend to be coupled in such a way that soil texture becomes a useful prox) for all of them, with SOC levels generally increasing with decreasing particle size of the soil substrate. 

For particle-size analysis, the fine earth was treated with 3 M HjOj and sonicated (15 min, 15 kHz) coarse, medium and fine sand were retrieved by sieving at 0.25, 0.10 and 0.05 mm, respectively silt was separated from clay by sedimentation after dispersion in 0.01 M NaOH. The pHjj g was measured potentio-metrically (solid/liquid ratio of 1 2.5). Organic C and total N were measured on acidified samples using a Carlo Erba NA1500 analyser. Available P was determined according to Olsen et al. (1954). Effective cation exchange capacity (ECEC) was determined by summation of the cations displaced with 0.2 M BaCl2 and analyzed by atomic absorption with a Perkin-Elmer llOOB spectrophotometer. 

The sediments, homogenized to obtain representative subsamples, were subjected to measurement of physical and chemical properties, including particle size distribution, water content, pH, buffer and cation exchange capacity (CEC), electrical conductivity, elemental and mineralogical composition (assessed by X-ray... 

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