Optimization of conditions for the preparation of activated carbons from olive-waste cakes

Estimation of surface area and pore volume of activated carbons by methylene blue and iodine numbers

“…Indeed, the methylene blue molecule has an area 15 of 2.08 nm 2 and can only enter in large micropores and mesopores. 5 The iodine molecule is relatively small with an area 15 of 0.4 nm 2 and can enter in the smaller micropores.…”

“…To test the accuracy of the method, we used experimental and literature data. The literature data were obtained from activated carbons produced from olive-waste cakes, 5 tree seed husks, 8 bituminous coal, wood, 9 Eucalyptus bark, 10 rubberwood sawdust, 11 waste newsprint, 12 sugarcane bagasse, 13,14 babassu, coconut shells, 14 sugarcane residues, 7 olive stones, 15 petroleum pitch, 16 shells and fruit pits, 17,18 fruit seeds 18 and knitted fabrics, 19 besides commercial activated carbon. 20 The experimental data were obtained using activated carbons produced in our laboratory from spent coffee grounds, 21 bean husks 22 and a commercial sample.…”

“…In the development of these materials it is very important to satisfy such physical properties, because they will directly influence the performance of the material in its application. 5 The surface areas of activated carbons are usually measured using the Brunauer-Emmett-Teller (BET) method, 6 which employs the nitrogen adsorption at different pressures at the temperature of liquid nitrogen (77 K). The surface area according to BET is then determined by the product of the cross-sectional area of the nitrogen molecule, of the Avogadro's number and of the specific monolayer capacity of nitrogen, which is obtained by an equation proposed by BET with further modifications.…”

“…In relation to methylene blue, the iodine molecule possesses inferior dimensions which make its penetration in micropores possible. 5 These characteristics confer such molecules the potential for using them as probes in the study of the physical structure of activated carbons. In spite of this, no detailed study has been found concerning the quantitative relationships between methylene blue and iodine numbers and the structural characteristics of the activated carbons.…”

Adsorption of mercury (II) from liquid solutions using modified activated carbons

“…Among the available technological alternatives for the removal of trace metals from water, adsorption has been considered an economically feasible one [2][3][4][5][6][7][8] . Activated carbons are universal adsorbents that can be obtained from a wide variety of raw materials including wastes of industrial activities [9][10][11][12][13] . Activated carbons have been found to be a very effective alternative for mercury removal from water [14][15][16][17][18][19][20][21] .…”