388
A. Donia et al.
(2,3-chloro biphenyl) at a concentration of 1 mg l
−1 within 5 h at 28 °C. Bioreductive precipitation of bipod using Shewanella oneidensis cells mixed with sediment
samples contaminated with a mixture of polychlorinated biphenyl congeners led
to dechlorination of both lightly and highly chlorinated polychlorinated biphenyl
congeners adsorbed to the contaminated sediment matrix within 48 h at 28 °C. Fifty
milligrams per liter of bioPd led to a catalytic effect that was comparable to what seen
with 500 mg l
−1 commercial Pd(0) powder. The high reactivity of 50 mg l
−1 bioPd
observed in the soil suspension was reflected in the reduction of the sum of seven
most toxic polychlorinated biphenyls to 27% of their initial concentration (Windt
et al. 2005).
3 Removal of Heavy Metals Ions
The huge quantity of wastewater produced by industries such as hydrometallurgy
and mining contains toxic heavy metal ions (Rüdelet al. 2015). Experiments for the
elimination of these pollutants have continued to be carried out for a long time as
these heavy metal ions are a serious threat to human health. However, while most of
these methods are expensive, others have harsh environmental side effects. There is
a rise in the number of researchers invigorated to find the ideal solution to remove
heavy metal ions from the environment by employing biological techniques (Ojoawo
et al. 2017; Vilardi et al. 2018; Vilela et al. 2018).
The toxicity of both chromium (VI) and vanadium (V) was reduced simultaneously using Shewanella loihica PV-4 as, due to vanadium ore smelting, they are
frequently present in wastewater together. Vanadium (V) and chromium (IV) bioreduction has been observed to be indirectly proportional as the bio-reduction of vanadium (V), when elevated, decreases the bio-reduction of chromium (VI). Twentyseven days after the experiment, the efficiency of removal was observed to be 71.3%
for vanadium (V) while 91.2% for chromium (VI) (Wang et al. 2017). Biosynthesized Pd nanoparticles were utilized to remove Cr
6+ from wastewater. Biologically
manufactured nanoscale Pd nanoparticles are expected to have better catalytic efficiency in comparison with chemically reduced Pd nanoparticles because of their
smaller sizes and better surface-to-volume ratios. However, unlike their chemical
counterparts, biosynthesized Pd nanoparticles had lower catalytic ability for Cr (VI)
reduction without ultrasonic treatment. It has been clarified by numerous studies
that achieving a high catalytic productivity and mild extract environment cannot be
achieved by the reductive method of Cr
6+ viabacterially produced Pd nanoparticles
(Ha et al. 2016).
In a study performed to assess the potential of nanoparticles from microalgae
to absorb zinc and lead from pharmaceutical effluent, the silver nanoparticles
of Nannochloropsis sp. and Chlorella vulgaris exhibited percentage reduction
of 70.35% and 74.62%, respectively, for zinc. Researchers also found that gold
nanoparticles of Nannochloropsis sp. and Chlorella vulgaris had percentage reduction of 60.32% and 66.83%, respectively, for zinc. The concentration of lead was
A. Donia et al.
(2,3-chloro biphenyl) at a concentration of 1 mg l
−1 within 5 h at 28 °C. Bioreductive precipitation of bipod using Shewanella oneidensis cells mixed with sediment
samples contaminated with a mixture of polychlorinated biphenyl congeners led
to dechlorination of both lightly and highly chlorinated polychlorinated biphenyl
congeners adsorbed to the contaminated sediment matrix within 48 h at 28 °C. Fifty
milligrams per liter of bioPd led to a catalytic effect that was comparable to what seen
with 500 mg l
−1 commercial Pd(0) powder. The high reactivity of 50 mg l
−1 bioPd
observed in the soil suspension was reflected in the reduction of the sum of seven
most toxic polychlorinated biphenyls to 27% of their initial concentration (Windt
et al. 2005).
3 Removal of Heavy Metals Ions
The huge quantity of wastewater produced by industries such as hydrometallurgy
and mining contains toxic heavy metal ions (Rüdelet al. 2015). Experiments for the
elimination of these pollutants have continued to be carried out for a long time as
these heavy metal ions are a serious threat to human health. However, while most of
these methods are expensive, others have harsh environmental side effects. There is
a rise in the number of researchers invigorated to find the ideal solution to remove
heavy metal ions from the environment by employing biological techniques (Ojoawo
et al. 2017; Vilardi et al. 2018; Vilela et al. 2018).
The toxicity of both chromium (VI) and vanadium (V) was reduced simultaneously using Shewanella loihica PV-4 as, due to vanadium ore smelting, they are
frequently present in wastewater together. Vanadium (V) and chromium (IV) bioreduction has been observed to be indirectly proportional as the bio-reduction of vanadium (V), when elevated, decreases the bio-reduction of chromium (VI). Twentyseven days after the experiment, the efficiency of removal was observed to be 71.3%
for vanadium (V) while 91.2% for chromium (VI) (Wang et al. 2017). Biosynthesized Pd nanoparticles were utilized to remove Cr
6+ from wastewater. Biologically
manufactured nanoscale Pd nanoparticles are expected to have better catalytic efficiency in comparison with chemically reduced Pd nanoparticles because of their
smaller sizes and better surface-to-volume ratios. However, unlike their chemical
counterparts, biosynthesized Pd nanoparticles had lower catalytic ability for Cr (VI)
reduction without ultrasonic treatment. It has been clarified by numerous studies
that achieving a high catalytic productivity and mild extract environment cannot be
achieved by the reductive method of Cr
6+ viabacterially produced Pd nanoparticles
(Ha et al. 2016).
In a study performed to assess the potential of nanoparticles from microalgae
to absorb zinc and lead from pharmaceutical effluent, the silver nanoparticles
of Nannochloropsis sp. and Chlorella vulgaris exhibited percentage reduction
of 70.35% and 74.62%, respectively, for zinc. Researchers also found that gold
nanoparticles of Nannochloropsis sp. and Chlorella vulgaris had percentage reduction of 60.32% and 66.83%, respectively, for zinc. The concentration of lead was