Hossein Esmaeili

Adsorption behavior of Cu(II) and Co(II) using chemically modified marine algae

ABSTRACT In this study, brown algae-modified biomass Padina sanctae crucis was used for copper (Cu(II)) and cobalt (Co(II)) heavy metal ions adsorption in synthetic wastewater. The effects of solution pH and adsorption efficiency for Cu(II) and Co(II) removal from aqueous solutions were studied. In order to study the kinetic behavior of adsorption, pseudo-first-order, pseudo-second-order kinetic models, liquid film penetration, and Ritchie second-order models were used. The results showed that the pseudo-second-order kinetic model was able to describe adsorbent behavior in comparison to the other models. Moreover, in order to study adsorbent equilibrium behavior, Langmuir and Freundlich isothermal models were used. Based on the Langmuir model, the adsorption capacity of Co(II) and Cu(II) was determined and their values were 13.73 and 13.996 mg/g, respectively. It was shown that both metal ions adsorption process is favorable and adsorption is physical. In this research, thermodynamic parameters were also studied in order to determine Gibbs free energy for both metal ions which were negative, indicating that metal ions adsorption process is spontaneous and the degree of self-adsorption increases as temperature increases.

Zinc, nickel, and cobalt ions removal from aqueous solution and plating plant wastewater by modified Aspergillus flavus biomass: A dataset

The biomass of Aspergillus flavus was modified by calcium chloride to achieve a bioadsorbent for treating nickel, cobalt, and zinc ions from aqueous solutions. The information of pH, bioadsorbent dose, contact time, and temperature effect on the removal efficiency are presented. The data of Freundlich and Langmuir isotherm and pseudo-first-order and pseudo-second-order kinetic models are also depicted. The data showed that the maximum bioadsorption capacity of nickel, cobalt, and zinc ions is 32.26, 31.06 and 27.86 mg/g, respectively. The suitability of the bioadsorbent in heavy metals removal at field condition was tested with a real wastewater sample collected from a plating plant in the final part of this dataset. Based on the findings, the bioadsorbent was shown to be an affordable alternative for the removal of metals in the wastewater.

Adsorptive performance of calcined Cardita bicolor for attenuating Hg(II) and As(III) from synthetic and real wastewaters

The first application of calcined Cardita bicolor oyster shell (CCBS) for Hg(II) and As(III) adsorption from synthetic and real wastewaters was tested. The main elements in CCBS structure were carbon, oxygen, magnesium, phosphor, and calcium. Effects of different parameters like initial pH, contact time, temperature, and CCBS dosage were assessed. The results showed that the maximum recovery of Hg(II) and As(III) adsorption was determined as C0=10 mg/L, t=80 min, T=25 °C, CCBS dosage=5 g/L, and pH=6 (for mercury ion) and 7 (for arsenic ion). In these conditions, 95.72% Hg(II) and 96.88% As(III) were removed from aqueous solution. The correlation coefficient (R2) values for both adsorbates were obtained >0.98 and >0.96 for Langmuir and Freundlich isotherm models, respectively. Pseudo-second-order kinetic model was more capable to describe kinetic behavior of adsorption process of both metal ions in comparison with pseudo-first-order model. The half life (t1/2) value for Hg(II) and As(III) with initial concentration of 10 mg/L was 4.032 and 4.957 min, respectively. Moreover, thermodynamic parameters of enthalpy (ΔHo), entropy (ΔSo), and Gibbs free energy (ΔGo) were investigated. Two real wastewaters obtained from a leather factory and a landfill leachate were successfully treated using CCBS. The results confirmed that adsorption process of metals ions was exothermic and spontaneous.

Adsorption of methyl violet from aqueous solution using brown algae Padina sanctae-crucis

Abstract Objective The presence of dyes in the water is toxic and harmful to human body so, it must be removed from the water. In the present study, the removal of methyl violet (MV) from aqueous solutions using brown algae “Padina sanctae-crucis” was investigated. Materials and methods The rate of adsorption was investigated under various parameters such as contact time (5–200), pH (2–11), dye concentration (10–60 mg/L), amount of adsorbent (0.25–5 g/L) and temperature (25–45°C). Results The maximum adsorption was achieved in 10 mg/L, pH=8 and adsorbent dose 2 g/L and 80 min contact time for removal of MV from aqueous solutions. Kinetic studies showed that the pseudo second-order model describes adsorbent kinetic behavior better. Besides, experimental data have been modeled using Langmuir and Freundlich isotherms and the results showed that both models are proper to describe adsorption isotherm behavior. In addition, the equilibrium study shows that the adsorption was physical and favorable. Moreover, a thermodynamic study revealed that the adsorption process is exothermic and spontaneously in nature. Furthermore, Maximum adsorption capacity using adsorbent was 10.02 mg/g. Conclusions It could be concluded that the P. sanctae-crucis biomass is a good adsorbent for removing MV dyes from aqueous solutions.

Turbulent combined forced and natural convection of nanofluid in a 3D rectangular channel using two-phase model approach

The nanofluid is a mixture of base fluid and solid nanoparticles in nanosize. The heat transfer generated by the nanofluid is more than the base fluid and its lowering pressure drop, which is why its use is increasing. In this paper, the effect of volume fraction, aspect ratio and diameter of the nanoparticles on the turbulent mixed convection in a three-dimensional rectangular channel is numerically investigated. The boundary conditions are constant heat flux, and governing equations are numerically solved by the mixture model. Base fluid in this study, water and aluminum oxide are used as nanoparticles. In this study, all physical properties are considered constant and the effects of volume fraction, aspect ratio and diameter of the particles on the thermal and hydrodynamic parameters of the fluid were studied.

Adsorptive Behavior of Methylene Blue onto Sawdust of Sour Lemon, Date Palm, and Eucalyptus as Agricultural Wastes

Abstract In the present study, to remove methylene blue (MB) from aqueous solution, some agricultural residues and cheap bioadsorbents such as sawdust of palm trees, eucalyptus, and sour lemon were used. To do this, significant parameters like contact time, temperature, pH, initial concentration, and adsorbent dosage were checked. The results affirmed that the best conditions for MB adsorption from aqueous solution were obtained such as the temperature of 25 °C, pH of 8, adsorbent dosage of 2g/L, contact time of 120 minutes, and dye concentration of 5 mg/l which under these conditions the adsorption efficiencies determined were 95.8, 93.4, and 92.8% using sawdust of palm tree, eucalyptus, and sour lemon, respectively. Also, the equilibrium behavior of adsorbents showed that the Freundlich model could better predict the adsorption behavior of the process due to having a larger correlation coefficient (R2). The maximum biosorption capacities by Langmuir isotherm model were also obtained 54, 53.5, and 52.4 mg/g for sawdust of palm trees, eucalyptus, and lemon, respectively, which were significant amounts. In addition, kinetic behavior of adsorption showed that pseudo-second-order model can describe the kinetics of the adsorption process better than the pseudo-first-order model. Moreover, kinetic, equilibrium, and thermodynamic behaviors of adsorption affirmed that the biosorption process was desirable, physisorption, spontaneous, and exothermic. GRAPHICAL ABSTRACT