Effective Photocatalytic Reduction of Cr(VI) by Carbon Modified (CM)-n-TiO2 Nanoparticles under Solar Irradiation

Photocatalytic reduction of toxic Cr(VI) was successfully achieved using carbon modified titanium oxide (CM-n-TiO2) nanoparticles under natural sunlight illumination. Modification of titanium oxide by carbon significantly enhanced the photocatalytic reduction of Cr(VI) under natural sunlight irradiation. The effects of various experimental parameters such as catalyst dose, initial concentration of Cr(VI), and solution pH on the reduction rate of Cr(VI) were investigated. The highest reduction rate of Cr(VI) was obtained at the optimal conditions of pH 5 and 2.0 g·L?1 of CM-n-TiO2. Interestingly, in the presence of phenol, as a sacrificial electron donor, the rate of Cr(VI) reduction was nearly 1.7 times higher than in its absence. The solar photoreduction of Cr(VI) in aqueous solution using CM-n-TiO2 obeyed a pseudo-first order kinetics according to the Langmuir-Hinshelwood model.

Biomarkers and Ultra Structural Evaluation of Marine Pollution by Polycyclic Aromatic Hydrocarbons

The present study is endeavored to study the oxidative stress and antioxidant response as well as the ultrastructural change of both liver and muscle tissues of Siganus rivulatus collected from polluted region (El-Mex Bay) and control region (Marsa Matrouh) to identify the significance of biomarkers. The results revealed that, El-Mex Bay was polluted by different types of chemicals including hydrocarbons comparing with the reference area (Matrouh area). Where, the concentration range of total hydrocarbons in sediment samples collected from Matrouh coast was 409.24 - 521.26 ng/g, dry weight, where as this range in sediment samples collected from El-MexBay was 4159.77 - 4589.81 ng/g, dry weight. In this context, the induction of antioxidant systems in fish collected from polluted area in response to oxidative stress should be considered as a clear indication of the presence of pollution and environmental health degradation. Also, The increase in lipid peroxidation was a useful indicator of the pollution load in the present study. The results suggest that chemical pollution is capable of inducing morphological alteration in liver offish collected from polluted area. The present study indicated that ultra-structural changes serveas biomarker of stress in aquatic environment.

Growth Rate Assessment of Alcyonacean Sarcophyton glaucum from Northern Hurghada, Red Sea, Egypt

Eighteen specimens of the soft coral Sarcophyton glaucum have been collected and tagged to determine the growth rate using the weight variations technique and to investigate the reproductive season histologically. Six colonies were totally weighed and 12 fragments (produced from three colonies) were marked and weighed. Some samples showed sever shrinkage that lead to death. The maximum semiannual growth rate was recorded in summer (30.05 gm/6 m). The average monthly growth reached 3.95 gm/month. Many factors affect the growth rate such as water currents, turbidity, sedimentation, temperature and reproduction process. The studied species is a dioecious species (unisex), where the Autozooid polyps are the reproductive organs while siphonozooids are sterile. Female gonads were observed to develop at late July before male gonads which began at late September. Larvae releasing started at late January and the gonads are completely spawned in February. Fertilization occurs internally to form planulae larvae which librated completely in February. The oogenesis exhibited prolonged about 23 months, which gave rise to oocytes of different developmental stages in female colonies at any given time, and a spermatogenic cycle of only 10 - 12 months.