Strengthening of carbon sorbents by the introduction of mineral additives
E.S. Ushakova, L.V. Solovyova, A.G. Ushakov
Section: Ecologization of industry
The existing methods of strengthening carbon sorbents are considered, the method of introducing mineral additives
is analyzed in detail. The research was carried out on carbon sorbents made on the basis of carbon-containing waste: sawdust and excess active sludge of biological treatment facilities. Mineral additives were added to the sorbent at the mixture
preparation stage, after which the mixture was granulated. Preparing granules were dried and pyrolyzed at 600–650 о
Hot sorbent were cooled to 200 о
C by inert gas (CO2
) and air to room temperature. The introduction of mineral additives
in an amount of 4% by weight of the mixture, had a significant influence on the properties of sorbents: a 2-fold increase
in the ash content and the density of the sorbents, because of increasing content of mineral impurities (calcium oxide,
silica, alumina, iron and magnesium oxides), which have the relative dense lattice structure. Сompressive strength rose
from 0.40 to 1.02 kg per granule due to the content of tricalcium silicate (for cement) and kaolinite (for clay) increasing.
The moisture sorption decreased from 2.1 to 0.54 g/g for sorbent with cement and to 0.03 g/g for clay.
The introduction of cement and clay in the sorbent composition in an amount of 4% by weight of the mixture greatly
increases their strength, which can solve the problem of their destruction during water treatment, the collection of oilproducts and transportation, reduces the moisture sorption. It is necessary for collecting oil-products from water surface.
But at the same time, the oil capacity of the sorbent decreases to 2.1 g/g for sorbent with cement and to 1.55 g/g for
clay. The further research will be aimed at studying ways to increase the sorption capacity of hardened sorbents (modification with organic functional groups; demineralization with acid treatment and so on).