The expanded perlite possesses excellent buoyancy ability, low density, and high
porosity (>90%). Therefore, the expanded perlite has all the popular properties of an
oil sorbent.
The fatal problem is that this mineral material is not hydrophobic for the
oilsorption process. Treating with polysilicons makes the expanded perlite hydrophobic and is appropriate for selective oilsorption. In oilsorption processes, the
expanded perlite spreads over the polluted water and sorbs the oil; finally, it is
removed from the water surface by pumping.
Roulia et al. (2003) used three sizes of expanded perlite as a carrier of emulsifiers.
They produced modified expanded perlite by adding expanded perlite to an emulsifier solution. The effect of grain size of the expanded perlite was investigated on the
heating oil and watersorption capacities. In all sizes, watersorption capacity of
expanded perlite was greater than its sorption for oil. Among Among 0-2.5 mm
(A), 0-4 mm (B) and 1-5 mm (C) particle size, group A had the greatest water and oil
uptakes.
Figure 12.35 shows the effects of different sizes of the expanded perlite, oil/water
ratio, and soaked-perlite on the sorption percentage. According to Fig. 12.35 a, d,
and e, the watersorption capacity of the expanded perlite is again greater than that of
its oilsorption capacity, about 1.8 times. In the case of b (Fig. 12.35 b), first, perlite
was added to water and after that oil was added, but still oilsorption was ~30%.
They suggested that oil and water may be sorbed at different sites and oilsorption
capacity of the expanded perlite did not exceed 45%. The hydrogen bonds of Si-OH
and Si-O groups with water were considered as a possible mechanism for
watersorption of the expanded perlite. On the other hand, mechanical adsorption
and van der Waals forces cause sorption of the oil molecules. Then, the expanded
perlite was modified by various emulsifiers. Table 12.11 presents the amount of
emulsion adsorbed for different perlite samples.
The spread of modified perlite over the spilled oil showed that the emulsifier
molecules dispersed the oil and perlite, simultaneously (in laboratory conditions).
The light perlite particles, which adsorbed more emulsion, moved on the surface and
spread quickly over it and acted as an adsorber of the emulsion formed. In the
experiments, the lowest oilsorption capacity was observed for the hydrophobic
perlite (with silicon). Therefore, the silicon and emulsifiers were not compatible.
The modified expanded perlite may be appropriate for calm and rough sea conditions
because of the quick sorption action and no agitation required.
Fly Ash
Many industries produced a lot of fly ash annually, which was released into the
atmosphere in the past. Nowadays, air pollution control laws prevent their release.
Therefore, fly ash is collected and used in many industries like the cement industry.
This low cost and ample waste is generally spherical in shape with size range of
0.5–300 μm. The main chemical compositions of fly ash are SiO 2 , Al 2 O 3 , Fe 2 O 3 ,
MgO, TiO 2 , and sometimes CaO. Recently, fly ash has attracted a lot of attention for
12 Remediation of Pollution by Oil Spills
443
porosity (>90%). Therefore, the expanded perlite has all the popular properties of an
oil sorbent.
The fatal problem is that this mineral material is not hydrophobic for the
oilsorption process. Treating with polysilicons makes the expanded perlite hydrophobic and is appropriate for selective oilsorption. In oilsorption processes, the
expanded perlite spreads over the polluted water and sorbs the oil; finally, it is
removed from the water surface by pumping.
Roulia et al. (2003) used three sizes of expanded perlite as a carrier of emulsifiers.
They produced modified expanded perlite by adding expanded perlite to an emulsifier solution. The effect of grain size of the expanded perlite was investigated on the
heating oil and watersorption capacities. In all sizes, watersorption capacity of
expanded perlite was greater than its sorption for oil. Among Among 0-2.5 mm
(A), 0-4 mm (B) and 1-5 mm (C) particle size, group A had the greatest water and oil
uptakes.
Figure 12.35 shows the effects of different sizes of the expanded perlite, oil/water
ratio, and soaked-perlite on the sorption percentage. According to Fig. 12.35 a, d,
and e, the watersorption capacity of the expanded perlite is again greater than that of
its oilsorption capacity, about 1.8 times. In the case of b (Fig. 12.35 b), first, perlite
was added to water and after that oil was added, but still oilsorption was ~30%.
They suggested that oil and water may be sorbed at different sites and oilsorption
capacity of the expanded perlite did not exceed 45%. The hydrogen bonds of Si-OH
and Si-O groups with water were considered as a possible mechanism for
watersorption of the expanded perlite. On the other hand, mechanical adsorption
and van der Waals forces cause sorption of the oil molecules. Then, the expanded
perlite was modified by various emulsifiers. Table 12.11 presents the amount of
emulsion adsorbed for different perlite samples.
The spread of modified perlite over the spilled oil showed that the emulsifier
molecules dispersed the oil and perlite, simultaneously (in laboratory conditions).
The light perlite particles, which adsorbed more emulsion, moved on the surface and
spread quickly over it and acted as an adsorber of the emulsion formed. In the
experiments, the lowest oilsorption capacity was observed for the hydrophobic
perlite (with silicon). Therefore, the silicon and emulsifiers were not compatible.
The modified expanded perlite may be appropriate for calm and rough sea conditions
because of the quick sorption action and no agitation required.
Fly Ash
Many industries produced a lot of fly ash annually, which was released into the
atmosphere in the past. Nowadays, air pollution control laws prevent their release.
Therefore, fly ash is collected and used in many industries like the cement industry.
This low cost and ample waste is generally spherical in shape with size range of
0.5–300 μm. The main chemical compositions of fly ash are SiO 2 , Al 2 O 3 , Fe 2 O 3 ,
MgO, TiO 2 , and sometimes CaO. Recently, fly ash has attracted a lot of attention for
12 Remediation of Pollution by Oil Spills
443