Search published articles


Showing 2 results for Savari
Response of Metallothionein biomarker in oyster Crassostrea sp. to the mercury and cadmium gradient
A. Azimi, A. Safahieh, A. Dadollahi Sohrab, H. Zolgharnein, A. Savari, B. Saffar,
Volume 7, Issue 3 (5-2014)
Abstract

Background and Objective: Present study aimed to investigate response of metallothionein (MT) in oyster Crassostrea sp. to the experimental concentrations of Hg and Cd in order to assess the possibility of MT usage as a biomarker of Hg and Cd contamination in this mollusk. Materials and Methods: Oysters were collected from docks of Imam Khomeini Port. After seven days acclimation period in laboratory, they were exposed with Hg at concentrations of 15 and 75 µg.L-1 and Cd at concentrations of 15 and 150 µg.L-1 for 14 days. MT levels were measured through spectrophotometric method after extraction and precipitation. After preparation and acid digestion, the concentration of heavy metals was quantified by atomic absorption. Results: The amounts of MT in oysters exposed with Hg and Cd were significantly increased compared with control samples (P<0.05). The highest value of MT biosynthesis in oysters exposed with concentrations of Hg and Cd were 137.2±7.6 and 312.4±17.9 µg.g-1 w.w respectively. Exposing the oysters with Cd induced biosynthesis of MT more than three times compared with control samples. Among Hg and Cd, there was only significant correlation between biosynthesis of MT and Cd bioaccumulation in oysters (P<0.01). Conclusion: MT protein in oyster Crassostrea sp. can be considered as a suitable biomarker of Cd contamination in body and environment. Hence, it could be used for assessing and monitoring ecosystems.


Synthesis of chitosan-zirconium magnetic nanofibers and its application for arsenic adsorption from wastewater: Kinetics and isotherms studies
Azadeh Modiri, Shadab Shahsavari, Ali Vaziri Yazdi, Ali Akbar Seifkordi,
Volume 13, Issue 1 (4-2020)
Abstract
Background and Objective:  Arsenic has long been considered as a heavy metal and toxic pollutant due to its potential to harm the human health and the environment. Adsorption is one of the mechanisms for arsenic removal from wastewater. Therefore, the purpose of this research was to investigate the feasibility of synthesized chitosan-zirconium magnetic nano fiber on arsenic adsorption from wastewater and to evaluate its kinetic and isotherm models.
Materials and Methods: Synthesis of nanofibers was performed by electrospinning method and the optimal formulation was determined following the experimental design. Then, kinetics and isotherms of arsenic adsorption on the as synthesized nanofibers were investigated. The prepared nanofiber was characterized using X-ray diffraction (XRD), Field Emission Scanning Electron Microscopes (FESEM), Infrared Fourier Transform (FT-IR) and Vibrational Sampler Magnetic Meter (VSM).
Results: The optimal formulation was obtained: 2.84% chitosan, 0.97% nano-zirconium and 0.94% nano-iron. The adsorption of arsenic on synthetic fibers was found to follow quasi-first-order kinetics and the Freundlich isotherm. Furthermore, the effect of initial concentrations of arsenic, contact time, temperature and pH on arsenic adsorption were surveyed. The optimal condition for nitrate arsenic adsorption was obtained at initial concentration of 70 mg/L, 45 min contact time and at pH 3.
Conclusion: According to the results, the synthesized nanofiber displayed a regular network structure with the distribution of the Zr-nanoparticles in its shape. Also, according to the form of magnetometric analysis, it was found that chitosan-nanosirconium magnetic nanofibers are well magnetized and are free magnetic.  Finally, it can be concluded that the synthesized nanosorbent has a high potential for arsenic removal from industrial effluents.

Page 1 from 1     

© 2024 , Tehran University of Medical Sciences, CC BY-NC 4.0

Designed & Developed by: Yektaweb