Ehsan Daneshvar

Biosorption of hexavalent chromium from aqueous solution by six brown macroalgae

Abstract The biosorption potential of six brown macroalgae viz. Nizamuddina zanardinii, Stoechospermum marginatum, Cystoseira indica, Dictyota cervicornis, Padina australis, and Sargassum glaucescens, for the removal of hexavalent chromium (Cr(VI)) was investigated in the present study. Optimum conditions were determined by studying the effect of initial solution pH, biomass dosage, initial Cr(VI) concentration, and contact time on Cr(VI) removal by the macroalgae. Cr(VI) sorption was found to be highly pH dependent and maximum sorption was obtained at pH 1.0. Freundlich isotherm model showed the best fit with the equilibrium data. The removal rate of Cr(VI) was relatively rapid during the first 30 min, although the rate decreased gradually and the sorption reached equilibrium in about 70 min for S. marginatum, 90 min for N. zanardinii, and 150 min for D. cervicornis, P. australis, S. glaucescens, and C. indica. Different kinetic models such as pseudo-first-order, pseudo-second-order, and intra-particle d...

Application of response surface methodology for the biosorption of Acid Blue 25 dye using raw and HCl-treated macroalgae

AbstractThe present study was conducted to optimize the various experimental conditions, such as biomass loading, initial C.I. Acid Blue 25 (AB25) dye concentration, and initial solution pH for biosorption of dye on raw and HCl-treated brown alga, Padina australis and red alga, Jania adhaerens. Biosorption process was optimized in a batch system under Box–Behnken design. Second-order polynomial equation was successfully used to describe the effects of studied variables on response. The quadratic models exhibited higher R2 values, significant p-values, and insignificant lack-of-fit p-values showed high adequacy for predicting the response. Chemically modified red alga exhibited better AB25 dye biosorption capacity as compared to modified brown alga. Maximum dye removal efficiencies of 77.34, 71.28, 50.56, and 85.19% for P. australis, HCl-treated P. australis, J. adhaerens, and HCl-treated J. adhaerens, respectively, were obtained at optimal conditions. The surface modification on tested algal biomass was f...

Biosorption of toxic acidic dye-Acid Blue 25, by aquatic plants

AbstractThe adsorption of Acid Blue 25 (AB25) ions by aquatic plants, Potamogeton pusillus and Ceratophylum demersum from aqueous solutions was studied. The adsorption was studied as a function of solution pH (2–11), contact time (0–60 min), biomasses dosage (0.1–2.5 g/L), initial dye concentration (30–100 mg AB25 /L), biosorbents particle size (53–500 μm), addition of neutral salts (20–100 mg KNO3/L and 20–100 mg KH2PO4/L), and salinity (0.5–40 g NaCl/L). The results of equilibrium adsorption were successfully described through Freundlich and Temkin isotherm for both of the biosorbents. Maximum adsorption capacity of 183.46 and 129.68 mg/g were observed for P. pusillus and C. demersum, respectively. Different kinetic models including pseudo-first order, pseudo-second order, and intra-particle diffusion were examined, and the pseudo-second order was shown to be the best model to fit the adsorption kinetics data. Thermodynamic parameters demonstrated that adsorption of AB25 ions was spontaneous and endothe...

Hematological parameters of Iranian cichlid Iranocichla hormuzensis: Coad, 1982 (Perciformes) in Mehran River

This study describes the hematological parameters in Iranocichla hormuzensis, an Iranian freshwater cichlid important as ornamental and food fish. Forty fish were captured with seine net at Mehran river Hormozgan province, Iran. Blood was used to determine the total counts of red blood cells (RBC) and white blood cells (WBC), hematocrit, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC) and morphometric data of erythrocytes. The Iranian fish showed lower RBC and WBC values than the other cichlids (Oreochromis niloticus, O. aureus, O. mossambicus, O. hybrid, Cichlasoma dimerus and Cichla monoculus). Hematocrit did not vary among the species, but MCV, MCH and MCHC in I. hormuzensis were higher than those for O. niloticus, O. aureus, O. hybrid, C. dimerus and C. monoculus. These differences may be related to different life habit of fish. This study suggests that I. hormuzensis is well acclimated to the environment being the first report for its hematology. It is also suggested high efficiency in oxygen transportation, and an efficient inflow of oxygen by the gills, indicating the welfare of fish on this environment.