Robab Mohammadi
Abstract
In this research, Fe3O4, Fe3O4/graphene oxide (Fe3O4/GO) and polyaniline-Fe3O4/GO with various content of polyaniline were prepared and characterized by different analysis methods such as XRD, SEM, EDX, and FT-IR. The prepared samples were used to remove methyl red as an anionic dye from aqueous solutions. ...
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In this research, Fe3O4, Fe3O4/graphene oxide (Fe3O4/GO) and polyaniline-Fe3O4/GO with various content of polyaniline were prepared and characterized by different analysis methods such as XRD, SEM, EDX, and FT-IR. The prepared samples were used to remove methyl red as an anionic dye from aqueous solutions. Polyaniline-Fe3O4/GO nanocomposite showed high catalytic activity, which is partly because of the sensitizing influence of polyaniline and the low recombination rate due to the graphene oxide electron scavenging property. The photodegradation reaction fit well to a Langmuir-Hinshelwood kinetic model implying the reaction rate is depended on initial adsorption step. Also, in polyaniline-Fe3O4/GO samples, the polyaniline content can play a significant role in affecting photocatalytic activity of photocatalysts. Based on results, when the content of polyaniline is more increased above its optimum value, the photocatalytic performance decreased. Furthermore, the efficiency of polyaniline-Fe3O4/GO nanocomposite was investigated to compare between adsorption and photodegradation of methyl red from aqueous solution. Based on results, the removal rate of methyl red via polyaniline-Fe3O4/GO nanocomposite under photocatalytic process was considerably higher than the adsorption process. To understand the nature of adsorption procedure, the equilibrium adsorption isotherms were investigated. The linear correlation coefficients of Langmuir and Freundlich isotherms were obtained. Based on results, Langmuir isotherm model fitted the experimental data better than Freundlich isotherm model. According to the Langmuir isotherm model, the maximum adsorption capacity of polyaniline-Fe3O4/GO nanocomposite for sequestering methyl red was about 101.72 mg g–1.
Hamzeh Adelpour Abdoli; Kamal Alizadeh; Payman Hashemi
Abstract
A magnet-enhanced solid-phase extraction technique utilizing spherical core–shell nanomagnetic agarose particles wasA magnet-enhanced solid-phase extraction technique utilizing spherical core–shell nanomagnetic agarose particles was devised to extract remdesivir from serum samples. These ...
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A magnet-enhanced solid-phase extraction technique utilizing spherical core–shell nanomagnetic agarose particles wasA magnet-enhanced solid-phase extraction technique utilizing spherical core–shell nanomagnetic agarose particles was devised to extract remdesivir from serum samples. These nanomagnetic agarose particles underwent activation through the epichlorohydrin method and were subsequently modified using quercetin dihydrate as a ligand to facilitate remdesivir extraction. To quantify the target analyte, high-performance liquid chromatography (HPLC) was employed following preconcentration via the developed method. The influence of various analytical variables, including pH, ionic strength, magnet passes, and adsorbent quantity, was systematically examined and optimized using a multivariate central composite design approach. Under optimal conditions, five consecutive analyses demonstrated a remdesivir recovery rate of 99.4%, with a relative standard deviation of 3.66%. The method’s detection limit (3σ) for remdesivir was determined to be 0.027 mg L−1. This extraction technique was successfully validated for the quantification of remdesivir in serum samples
hamidreza rahmani; Mohsen Nekoeinia; seyyed hossien banitaba
Abstract
Anthropogenic activities contribute to the accumulation and mobilization of heavy metals within the soil matrix, which functions as a terminal reservoir for these pollutants and thereby poses substantial ecological and human health risks. This study evaluated the impact of a fossil-fueled thermal power ...
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Anthropogenic activities contribute to the accumulation and mobilization of heavy metals within the soil matrix, which functions as a terminal reservoir for these pollutants and thereby poses substantial ecological and human health risks. This study evaluated the impact of a fossil-fueled thermal power plant in Isfahan Province, Iran, on heavy metal accumulation in the surrounding topsoil. Fifty surface soil samples were collected, and the concentrations of eight toxic metals—Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn—were determined. Statistical analyses, including factor analysis and Pearson correlation, revealed three distinct metal groupings: Group I (Ni, Pb, Cd), Group II (Cu, Cr, Co), and Group III (Zn, Mn). Group I metals were associated with both natural and anthropogenic sources, while Groups II and III were primarily linked to geogenic origins. To quantify contamination levels, the contamination factor (CF) and geoaccumulation index (Igeo) were calculated. The results indicated moderate to high contamination levels for Pb and Cd, with Cd exhibiting very high CF values across all samples. Furthermore, multivariate calibration using principal component regression (PCR) and partial least squares regression (PLS) was employed to predict the pollution load index (PLI). Both methods demonstrated accurate and robust performance in predicting the PLI across calibration and prediction datasets, with R² values ranging from 0.861 to 0.965.
Jamaleddin Sheikh; Zarrin Eshaghi
Abstract
In this research, a novel approach was developed for the quantitative analysis of chemical compounds using dye-sensitized solar cells (DSSCs). The analyte under investigation was employed as the sensitizing dye in the DSSC, which was then used as a detector to quantify the target substance. The sample ...
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In this research, a novel approach was developed for the quantitative analysis of chemical compounds using dye-sensitized solar cells (DSSCs). The analyte under investigation was employed as the sensitizing dye in the DSSC, which was then used as a detector to quantify the target substance. The sample solution was simultaneously exposed to the full spectral output of a tungsten lamp, and the DSSC acted as a detector by registering the intensity of absorbed light. This system is conceptually analogous to a conventional UV-Vis spectrophotometer, with the key distinction that it operates without a monochromator, making it a simpler and more cost-effective alternative. Four types of DSSCs were fabricated using different dyes: N719, Bromoethylene Blue, Quinalizarin, and 2,7-Dichlorofluorescein. These solar cells were used in place of the traditional photodetector in a UV-Vis spectrophotometer to investigate the absorption of tungsten lamp light by solutions containing either the same dye as that used in the DSSC or different dyes. Experimental observations revealed that when the solution contained the same dye as the DSSC (i.e., matched dye), the absorption response was logarithmically proportional to the analyte concentration. In contrast, when the solution contained a different dye (i.e., mismatched dye), the system followed the Beer–Lambert law, showing a linear relationship between absorbance and concentration. This technique demonstrates potential for both qualitative and quantitative detection of analytes. For analytical applications, a uniquely fabricated DSSC incorporating the dye of interest serves as a dedicated detector for each specific analyte.
Daryoush Afzali; Elaheh Bagheri
Abstract
Monitoring the blood levels of phenylalanine, an essential amino acid, plays a vital role in the treatment of phenylketonuria. Cu-phthalocyanine (CuPC) and Au nanoparticles (AuNPs)-mediated non-enzymatic carbon paste electrode (CPE) has been developed for the electrochemical monitoring of L-phenylalanine ...
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Monitoring the blood levels of phenylalanine, an essential amino acid, plays a vital role in the treatment of phenylketonuria. Cu-phthalocyanine (CuPC) and Au nanoparticles (AuNPs)-mediated non-enzymatic carbon paste electrode (CPE) has been developed for the electrochemical monitoring of L-phenylalanine (L-phe). The oxidation signal of L-phe was not observed on bare CPE or AuNPs/CPE. Although AuNPs was not involved in the apparition of L-phe oxidation peak, it enhanced the oxidation current. Using AuNPs-CuPC/CPE, we have successfully determined the different concentrations of L-phe with no need to any enzyme on the electrode surface. The performance characteristics of this sensor were accomplished with differential pulse anodic stripping voltammetry (DPASV) and cyclic voltammetry (CV). After optimizing the experimental parameters, L-phe gave a linear response over the concentration range of 1.0-130.0 µM with the detection limit of 0.41 µM. The practical applications of the modified electrode were demonstrated by measuring the concentration of L-phe in blood serum and urine samples.
