Rice hull and bagasse were also compared with polypropylene nonwoven web.
The sorption capacity and oil recovery of these sorbents were investigated experimentally (Bayat et al. 2005). Light crude oil, gas oil No. 1, gas oil No. 2, and heavy
crude oil were used as pollutants. The effect of specific surface area was investigated
using two mesh sizes of rice hull and bagasse. In order to easy collect and remove
rice hull and bagasse, they were wrapped into a hydrophobic cloth. Whereas,
polypropylene nonwoven web was without cloth and floated on the simulated sea
water. One gram of sorbent was added to the system containing varying amounts of
pollutants (10, 20, and 30 g) and 400 ml of simulated seawater. Table 12.4 represents
the oil uptake capacity of different sorbents and their recovery yields.
The results revealed that each gram of polypropylene nonwoven can sorb 7–9 g of
different pollutants and has the best oilsorption capacity. Bagasse with mesh 18–45
sorbs oil greater than bagasse with mesh 14–18 and rice hull with mesh 10–14. But
these sorbents showed a better performance for heavy crude oil than other oils. The
important impact of the viscosity of oils on the sorption behavior was apparent. An
increase in the viscosity decreases the oilsorption capacity. On the other hand, low
viscous oil removed faster from sorbents. The results of recovery indicated that the
oil recovery was greater for 14–18 mesh bagasse than that for 18–45 mesh due to the
higher specific surface area. The recovery of heavy crude oil was greater than those
of other oils. Polypropylene nonwoven web had the lowest recovery efficiency for
light crude oil.
According to these results, all adsorbents have good performance in oil cleanup
from seawater and polypropylene nonwoven is the best one. But rice hull and
Table 12.4 Experimental results of oil uptake capacities (g/g sorbent) and recovery yields (%) for
different sorbents and pollutants. LCO: Light crude oil, GO1: gas oil No. 1, GO2: gas oil No. 2 and
HCO: heavy crude oil
Oil
pollutant
Sorbent
Bagasse Mesh
14–18
Bagasse Mesh
18–45
Polypropylene
nonwoven
a
Rice hull Mesh
10–14
Results
LCO
Oiluptake
3.38
5.55
8.26
3.80
Recovery
yield
100.00
93.13
87.70
94.60
GO1
Oiluptake
4.01
5.22
7.60
3.70
Recovery
yield
97.75
91.51
94.27
90.29
GO2
Oiluptake
4.07
5.39
8.46
3.81
Recovery
yield
94.23
94.53
94.54
92.99
HCO
Oiluptake
5.30
5.54
9.12
5.15
Recovery
yield
100.00
96.70
95.67
96.00
a Thickness: 5.59 mm, Denier: 12.56, and Mass per area: 593.3 g/m
2
Modified after Bayat et al. (2005)
414
M. Fatehi et al.
The sorption capacity and oil recovery of these sorbents were investigated experimentally (Bayat et al. 2005). Light crude oil, gas oil No. 1, gas oil No. 2, and heavy
crude oil were used as pollutants. The effect of specific surface area was investigated
using two mesh sizes of rice hull and bagasse. In order to easy collect and remove
rice hull and bagasse, they were wrapped into a hydrophobic cloth. Whereas,
polypropylene nonwoven web was without cloth and floated on the simulated sea
water. One gram of sorbent was added to the system containing varying amounts of
pollutants (10, 20, and 30 g) and 400 ml of simulated seawater. Table 12.4 represents
the oil uptake capacity of different sorbents and their recovery yields.
The results revealed that each gram of polypropylene nonwoven can sorb 7–9 g of
different pollutants and has the best oilsorption capacity. Bagasse with mesh 18–45
sorbs oil greater than bagasse with mesh 14–18 and rice hull with mesh 10–14. But
these sorbents showed a better performance for heavy crude oil than other oils. The
important impact of the viscosity of oils on the sorption behavior was apparent. An
increase in the viscosity decreases the oilsorption capacity. On the other hand, low
viscous oil removed faster from sorbents. The results of recovery indicated that the
oil recovery was greater for 14–18 mesh bagasse than that for 18–45 mesh due to the
higher specific surface area. The recovery of heavy crude oil was greater than those
of other oils. Polypropylene nonwoven web had the lowest recovery efficiency for
light crude oil.
According to these results, all adsorbents have good performance in oil cleanup
from seawater and polypropylene nonwoven is the best one. But rice hull and
Table 12.4 Experimental results of oil uptake capacities (g/g sorbent) and recovery yields (%) for
different sorbents and pollutants. LCO: Light crude oil, GO1: gas oil No. 1, GO2: gas oil No. 2 and
HCO: heavy crude oil
Oil
pollutant
Sorbent
Bagasse Mesh
14–18
Bagasse Mesh
18–45
Polypropylene
nonwoven
a
Rice hull Mesh
10–14
Results
LCO
Oiluptake
3.38
5.55
8.26
3.80
Recovery
yield
100.00
93.13
87.70
94.60
GO1
Oiluptake
4.01
5.22
7.60
3.70
Recovery
yield
97.75
91.51
94.27
90.29
GO2
Oiluptake
4.07
5.39
8.46
3.81
Recovery
yield
94.23
94.53
94.54
92.99
HCO
Oiluptake
5.30
5.54
9.12
5.15
Recovery
yield
100.00
96.70
95.67
96.00
a Thickness: 5.59 mm, Denier: 12.56, and Mass per area: 593.3 g/m
2
Modified after Bayat et al. (2005)
414
M. Fatehi et al.