Microcystin-LR Adsorption by Activated Carbon

Adsorption of microcystins by carbon nanotubes

“…Lahti and Hiisvirta (1989) indicated that the concentrations of MCs hardly changed when small doses of powdered ACs were added, but Donati et al (1994) reported that the removal of MCs was a direct proportionality of ACs mesopore volume. Furthermore the decrease of pH was found to cause the increase in the adsorption of MCs by ACs (Pendleton et al, 2001), which is in accordance with the properties that the solubility of MC-LR in water was decrease with the increase of pH (De Maagd et al, 1999). In order to keep the stable pH, the phosphate buffer (pH 7.0) solution was adopted as reaction solution in the experiment.…”

“…Although the adsorption ability of MCs by wood-based powdered ACs was slightly higher than those of clays tested (Fig. 3), which was also lower than those of some reports (Donati et al, 1994;Mohamed et al, 1999;Pendleton et al, 2001). In order to keep the same condition, the adsorbents were all directly used without treatment prior to our experiment, which might cause the differences in the absorbed amounts of MCs.…”

“…When the adsorption of MCs was studied, the pore size in absorbent must be considered in order to fit for the molecular dimensions of MCs. The size of mesopore from 2 to 50 nm on the surface of wood-based ACs was responsible for the higher adsorption amount of MCs than those by the coconut-based ACs containing micropore below 2 nm only (Pendleton et al, 2001). According to this viewpoint, the outside diameters from 2 to 10 nm of CNTs might be just suitable for this requirement of longest length of 1.9 nm in the dimension of molecular MC-LR, so the adsorption amounts of both MC-RR and LR by CNTs with outside diameters from 2 to 10 nm were much high than those by CNTs with bigger outside diameters.…”

“…Pendleton et al (2001) found that the wood-based activated carbons (ACs) that contain both micropores and mesopores adsorbed more MC-LR than the coconut-based ACs that contain micropores only, however surface and solution chemistry played minor roles in the adsorption process. Donati et al (1994) also investigated the adsorption by several different powdered ACs and suggested that the removal of MC-LR was directly proportional to the mesopore volume (diameters between 2 and 50 nm) of adsorbents.…”

Specifications of the Quality of Granulated Activated Charcoal Used in Water Systems Treatment in Hemodialysis Centers in Brazil

“…The used ACs in the water treatment station of the Hemodialysis Center A have presented BET area (S BET ) between 764.9 m 2 /g e 1,017.4 m 2 /g, whereas the ones used in the Hemodialysis Center B have presented S BET between 632.8 m 2 /g and 789.5 m 2 /g ( A first observation of these results would imply in the choice of charcoals of any of the two centers, however, according to Quinlivan et al (2005), the BET area (SBET) is a poor indicator of the adsorption capacity of activated charcoals, hence, the sampled charcoals quality cannot be assessed only by their BET (SBET) area data, so, other effectiveness parameters must be taken into consideration in order to choose a charcoal for a determined aim. Thus, beyond that parameter, the secondary micropores and mesopores volumetric fractions must also be considered in the choice of an activated charcoal for the use in water treatment, as these pores are significantly important in the adsorption of organic micropollutants like the microcystins by the activated charcoals according to Donati et al (1994) and Pendleton et al (2001). According to Donati et al (1994), there is no correlation between the adsorption capacity of activated charcoals by microcystins and the BET area, the micropores volume and the number of Iodine.…”