Arash Asfaram

Bio: Arash Asfaram is an academic researcher from Yasouj University. The author has contributed to research in topics: Adsorption & Central composite design. The author has an hindex of 57, co-authored 143 publications receiving 7536 citations. Previous affiliations of Arash Asfaram include Islamic Azad University.

Removal of basic dye Auramine-O by ZnS:Cu nanoparticles loaded on activated carbon: optimization of parameters using response surface methodology with central composite design

Abstract: This research is focused on the ultrasound-assisted removal of Auramine-O (AO) dye from aqueous solutions using ZnS:Cu nanoparticles loaded on activated carbon (ZnS:Cu-NP-AC) as an adsorbent. ZnS:Cu nanoparticles were synthesized and characterized using FESEM (Field-Emission Scanning Electron Microscopy) and XRD (X-Ray Diffraction) analysis. The experiments were designed by response surface methodology. A quadratic model was used to predict the variables. Analysis of variance was used for investigation of variables and interaction between them. High F-value (48.91), very low P-value (<0.00001), non-significant lack of fit, and the determination coefficient (R2 = 0.977) demonstrate good correlation between experimental and predicted values of the response. The highest removal percent attained was 99.76%, and the optimum parameters achieved are: adsorbent amount (0.02 g), initial dye concentration (20 mg L−1), sonication time (3 min) and pH = 7. Adsorption processes of AO by ZnS:Cu-NP-AC could be well described by a Langmuir isotherm and a pseudo-second-order kinetic model. The maximum adsorption capacity of AO by ZnS:Cu-NP-AC was determined as 183.15 mg g−1, suggesting a highly promising potential for ZnS:Cu-NP-AC to be used as a new adsorbent.

Response surface methodology approach for optimization of simultaneous dye and metal ion ultrasound-assisted adsorption onto Mn doped Fe3O4-NPs loaded on AC: kinetic and isothermal studies

Abstract: In the present work, the usefulness of ultrasonic power as a dispersion and mixing tool to accelerate the adsorption of Safranin O (SO), methylene blue (MB), Pb2+ ions and Cr3+ ions onto the novel composite Fe3O4-NPs-AC adsorbent was investigated. This new material was extensively characterized and analyzed by different techniques such as XRD, FESEM, Raman spectroscopy and FT-IR. Central composite design (CCD) based on designed runs revealed that adsorbent mass, sonication time, MB concentration, SO concentration, Pb2+ ion and Cr3+ ion concentration and some of their interactions have significant contributions to the target compounds removal percentages. A combination of response surface methodology and Design-Expert software was used to qualify and estimate the influence and magnitude of each terms contribution to the response. An optimization study using the following investigated increments of the effective variables, adsorbent mass (0.01–0.03 g), sonication time (2–6 min), initial dye concentration (5–25 mg L−1), and initial metal ion concentration (20–60 mg L−1), revealed that fixing the experimental variables at 0.025 g of Mn–Fe3O4-NPs-AC, with a 3 min sonication time, and 20 mg L−1 of MB, 10 mg L−1 of SO, 38 mg L−1 of Pb2+ ions and 42 mg L−1 of Cr3+ ions at room temperature lead to the achievement of the best characteristics and performance. Conduction of 32 experiments according to the limitations of CCD and a subsequent analysis of variance (ANOVA) gave useful information about the significant and also approximate contributions of each term (main and interaction of variables) in an empirical equation for the expected response. The results indicate that the R2 values are more than 0.988 and the adjusted R2 values are in reasonable agreement with R2. Under the optimal conditions, the MB, SO, Pb2+ ion and Cr3+ ion removal efficiencies reached 99.54%, 98.87%, 80.25% and 99.54% after 3 min, while their equilibrium data with high performance can be represented by Langmuir isotherms and a pseudo second-order kinetic model. The maximum adsorption capacities for the single component system, 229.4 mg g−1 for MB, 159.7 mg g−1 for SO, 139.5 mg g−1 for Pb2+ ions and 267.4 mg g−1 for Cr3+ ions, support the high efficiency of Mn–Fe3O4-NPs-AC as a new adsorbent.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Efficient techniques for the removal of toxic heavy metals from aquatic environment: A review

Abstract: The controversy related to the environment pollution is increasing in human life and in the eco-system. Especially, the water pollution is growing rapidly due to the wastewater discharge from the industries. The only way to find the new water resource is the reuse of treated wastewater. Several remediation technologies are available which provides a convenience to reuse the reclaimed wastewater. Heavy metals like Zn, Cu, Pb, Ni, Cd, Hg, etc. contributes various environmental problems based on their toxicity. These toxic metals are exposed to human and environment, the accumulation of ions takes place which causes serious health and environmental hazards. Hence, it is a major concern in the environment. Due to this concern, the significance of developing technology for removing heavy metals has been increased. This paper contributes the outline of new literature with two objectives. First, it provides the sketch about treatment technologies followed by their heavy metal capture capacity from industrial effluent. The treatment performance, their remediation capacity and probable environmental and health impacts were deliberated in this review article. Conclusively, this review paper furnishes the information about the important methods incorporated in lab scale studies which are required to identify the feasible and convenient wastewater treatment. Moreover, attempts have been made to confer the emphasis on sequestration of heavy metals from industrial effluent and establish the scientific background for reducing the discharge of heavy metals into the environment.