فرایندهای استخراج جدید و میکرواستخراج؛ تهیه نمونه؛ تکنیک های جداسازی برای گونههای سمی؛ آنالیز حرارتی
Rahil Sayadipour; Homa Shafiee Khani
Abstract
Wastewater from the textile industry is classified as the most polluting of all the industrial sectors. Among these, azo dyes are one of the most important pollutants which have many toxic effects, especially carcinogenicity and mutagenicity. Thus, it is necessary to develop a powerful, eco-friendly ...
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Wastewater from the textile industry is classified as the most polluting of all the industrial sectors. Among these, azo dyes are one of the most important pollutants which have many toxic effects, especially carcinogenicity and mutagenicity. Thus, it is necessary to develop a powerful, eco-friendly and effective photodegradation process for the removal of azo dyes. In this study, aluminum-doped cobalt ferrite (AlCoFe₂O₄) nanoparticles were synthesized via co-precipitation as a green photocatalyst for the degradation of anionic and cationic azo dyes. The nanoparticles were characterized using XRD, EDS, DRS, FESEM, and VSM. The results of XRD showed that the nanoparticles had a cubic structure with an average diameter size less than 45 nm. The low remanent magnetization and coercivity of the nanoparticles in VSM was consistent with soft magnetic properties. Moreover, the magnetic properties of AlCoFe2O4 nanoparticles enable easy separation of the photocatalyst from the reaction medium using an external magnetic field. In addition, high absorption of AlCoFe2O4 in the visible light region makes it possible to increase photocatalytic performance of the photocatalyst under the influence of visible light. Photocatalytic tests using Methyl Orange (MO) and Bismarck Brown (BB) dyes showed that degradation strongly depends on pH (optimal pH ≈ 3 and 9 for MO and BB respectively), adsorption of dye molecules on the catalyst surface, and catalyst dosage (0.05 g) .Under optimized conditions, MO degradation reached 100% under UV irradiation, while BB degradation reached 98%. The photocatalyst maintained high performance over at least five cycles, demonstrating stability and recyclability.
Homa Shafieekhani; Ali Moadelli; Firoozeh Aminipour
Abstract
In this paper, magnetic nanoparticles functionalized by triazene ligand were prepared for extraction/preconcentration of trace amounts of mercury ions in water samples former on its determination with UV-Vis spectrophotometry. The modified magnetic nanoparticles were characterized by the various techniques ...
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In this paper, magnetic nanoparticles functionalized by triazene ligand were prepared for extraction/preconcentration of trace amounts of mercury ions in water samples former on its determination with UV-Vis spectrophotometry. The modified magnetic nanoparticles were characterized by the various techniques such as Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM) and X –Ray Diffractometry (XRD). In the separation process, aqueous solution of Hg2+ ion was mixed with Fe3O4 magnetite nanoparticles modified with (E)-1-(2-Ethoxyphenyl)-3-(4-nitrophenyl)triaze-1-ene (ENT), (MNPs@SiO2-ENT) and then external magnetic field was applied for isolation of magnetite nanoparticles containing mercury ions. Experimental conditions for effective adsorption including pH, ENT amount, Fe3O4 NPs amounts, and eluent type have been studied and established. Under the optimal extraction and preconcentration conditions, calibration curve was linear in the range of 4–80 µgL-1 with r2 = 0.9992 (n=20), the limit of detection (LOD) 1.05µg L-1 and enrichment factor was 38, respectively. This technique was successfully used for the determination of Hg (II) in aqueous samples.
