No abstract

The exploitation of different plant materials for the biosynthesis of nanoparticles is considered a green technology because it does not involve any harmful chemicals. In this study, iron oxide nanoparticles (Fe 3 O 4 -NPs) were synthesized using a completely green biosynthetic method by reduction of ferric chloride solution using brown seaweed water extracts. The two seaweeds Padina pavonica (Linnaeus) Thivy and Sargassum acinarium (Linnaeus) Setchell 1933 were used in this study. The algae extract was used as a reductant of FeCl 3 resulting in the phytosynthesis of Fe 3 O 4 -NPs. The phytogenic Fe 3 O 4 -NPs were characterized by surface plasmon band observed close to 402 nm and 415 nm; the obtained Fe 3 O 4 -NPs are in the particle sizes ranged from 10 to 19.5 nm and 21.6 to 27.4 nm for P. pavonica and S. acinarium, respectively. The strong signals of iron were reported in their corresponding EDX spectra. FTIR analyses revealed that sulphated polysaccharides are the main biomolecules in the algae extracts that do dual function of reducing the FeCl 3 and stabilizing the phytogenic Fe 3 O 4 -NPs. The biosynthesized Fe 3 O 4 -NPs were entrapped in calcium alginates beads and used in Pb adsorption experiments. The biosynthesized Fe 3 O 4 -NPs alginate beads via P. pavonica (Linnaeus) Thivy had high capacity for bioremoval of Pb (91%) while that of S. acinarium (Linnaeus) Setchell 1933 had a capacity of (78%) after 75 min. The values of the process parameters for the maximum Pb removal efficiency by Fe 3 O 4 -NPs alginate beads synthesized via P. pavonica (Linnaeus) Thivy were also estimated.Citation: El-Kassas Hala Y, Aly-Eldeen Mohamed A, Gharib Samiha M. 2016. Green synthesis of iron oxide (Fe 3 O 4 ) nanoparticles using two selected brown seaweeds: Characterization and application for lead bioremediation. Acta Oceanologica Sinica,

This study aims to investigate the abundance, community, and structure of phytoplankton, physicochemical parameters, and some eutrophication state indices, to estimate the water quality of eight selected beaches along the Alexandria Coast, in the southeast of the Mediterranean Sea. The samples were collected monthly from 2019 to 2020. Nutrient values ranged from 1.54 to 33.21 µM for nitrate, 0.01 to 1.98 µM for nitrite, 0.12 to 9.45 µM for ammonia, 0.01 to 1.54 µM for phosphate, and 0.67 to 29.53 µM for silicate. Phytoplankton biomass was characterized by chlorophyll-a concentration, which fluctuated between 0.12 and 12.31 µg L−1. The annual phytoplankton average was 63.85 ± 17.83 × 103 cells L−1. Phytoplankton was highly diversified (228 taxa), and the most diversified group was diatoms (136 taxa), followed by a remarkably low number of Dinophyta (36 taxa). Diatoms reached maximum abundance in December. Meanwhile, a dense bloom of microalga Chlorella marina occurred in June on some beaches. High temperature, high dissolved inorganic nitrogen, and less-saline waters have supported green algal proliferation. The Shannon–Wiener diversity index (H’) showed that there was a qualitative seasonal difference in the composition of the phytoplankton community. Waters of beaches 1–3 were classified as between clean and moderately polluted; and beaches 4–8 varied between moderately and heavily polluted. The study revealed that human activities might have triggered the algal bloom and may be responsible for alterations in the Alexandria coast ecosystem.

No abstract

No abstract