فهرست مطالب

  • Volume:6 Issue: 2, 2020
  • تاریخ انتشار: 1399/05/05
  • تعداد عناوین: 8
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  • Razieh Hosseini, Mohammad Hossein Sayadi*, Hossein Shekari Pages 66-74

    The research was conducted with an aim to assess the efficiency of copper oxide nanoparticles as an adsorbent to remove Ni and Cr. The effect of pH, adsorbent dosage, contact time, initial concentration of metals (Ni and Cr) on the adsorption rate was evaluated and removal of these elements from aqueous solutions was measured using Atomic Absorption Spectrum System (Conter AA700). Moreover, the kinetic and isotherm besides thermodynamic adsorption models were assessed. The highest Ni and Cr removal rate occurred at an optimal pH of 7, and an initial concentration of 30 mg/L, a time period of 30 minutes, and 1 g/L of copper oxide nanoparticles. In fact, with the increase of adsorbent dosage and contact time, the removal efficiency increased and with initial concentration increase of Ni and Cr ions, the removal efficiency reduced. The correlation coefficient of isotherm models viz. Langmuir, Freundlich, Temkin, Redlich-Peterson, and Koble-Corrigan showed that Ni and Cr adsorption via copper oxide nanoparticles better follows the Langmuir model in relation to other models. The results showed that kinetic adsorption of Ni and Cr via copper oxide nanoparticles follows the second order pseudo model with correlation coefficients above 0.99. In addition, the achieved thermodynamic constants revealed that the adsorption process of metals (i.e., Ni and Cr) via copper oxide nanoparticles was endothermic and spontaneous and the reaction enthalpy values for these metals were 17.727 and 11.862 kJ/mol, respectively. In conclusion, copper oxide nanoparticles can be used as effective and environmentally compatible adsorbents to remove Ni and Cr ions from the aqueous solutions

    Keywords: Ni, Cr, Thermodynamics, Adsorption
  • Maryam Ravanbakhsh, Yaser Tahmasebi Birgani*, Maryam Dastoorpoor, Kambiz Ahmadi Angali Pages 75-82

    Discriminant analysis (DA) and principal component analysis (PCA), as multivariate statistical techniques, are used to interpret large complex water quality data and assess their temporal and spatial variation in the basin of the Zohreh river. In this study, data sets of 16 water quality parameters collected from 1966 to 2013) in 4 stations (1554 observations for each parameter) were analyzed. PCA for data sets of Kheirabad, Poleflour, Chambostan and Dehmolla stations resulted in 4, 4, 4, and 3 latent factors accounting for 88.985%, 93.828%, 88.648%, and 88.68% of the total variance in water quality parameters, respectively. It is indicated that total dissolved solids (TDS), electrical conductivity (EC), chlorides (Cl−), sodium (Na), sodium absorption ratio (SAR), and %Na were responsible for water quality variations which are mainly related to natural and anthropogenic pollution sources including climate effects, gypsum, and salt crystals in the supratidal of Zohreh river delta, fault zones of Chamshir I and II, drainage of sugarcane fields, and domestic and industrial wastewaters discharge into the river. DA reduced the data set to only seven parameters (discharge, temperature, electrical conductivity, HCO3-, Cl-, %Na, and T-Hardness), affording more than 58.5% correct assignations in temporal evaluations and describing responsible parameters for large variations in the quality of the Zohreh river.

    Keywords: Zohreh River, Water quality, Principal component analysis, Discriminant analysis, Iran
  • Mohamad Parsi Mehr, Samar Mortazavi* Pages 83-91

    Grape is a strategic product in the county of Malayer. Despite the great importance and existence of polluted resources in the vicinity of vineyards in Malayer, there are few studies conducted in this regard. To evaluate the pollution level of toxic elements in these vineyards, 20 sampling stations were selected randomly and samples of garden soil and leaves of grapevine species were collected. After the acidic digestion of the samples, the concentrations of the heavy metals were measured using atomic absorption spectrometer. Then, the indices of contamination factor (Cf), geoaccumulation index (Igeo), biological accumulation coefficient (BAC), and ecological risk index (RI) were calculated. According to the results obtained for Igeo and Cf indices, the soil in the study region was moderately contaminated with copper. However, the ecological risk index and BAC of the studied region were low. To investigate the spatial distribution of copper in the studied region, the spatial distribution map was prepared. To locate the source of copper contamination and investigate the effect of various land uses on the amount of contamination, land use map (LUM) of vineyards was generated. To this end, images were downloaded from Landsat Satellite, and after the exertion of various corrections on the images based on the supervised classification method, the LUM with agricultural, residential, vineyard, brick furnace and pasture classes was prepared. The comparison of the LUM and the copper contamination map illustrated that the copper contamination was higher in the places with urban and adobe furnace land-use types.

    Keywords: Vineyard pollution, Environmental pollution, Heavy metals, Land use
  • Maryam Bayat Varkeshi, Kazem Godini, Mohammad Parsi Mehr *, Maryam Vafaee Pages 92-99

    A reliable model for any wastewater treatment plant (WWTP) is essential to predict its performance and form a basis for controlling the operation of the process. This would minimize the operation costs and assess the stability of environmental balance. This study applied artificial neural network-genetic algorithm (ANN-GA) and co-active neuro-fuzzy logic inference system (CANFIS) in comparison with ANN for predicting the performance of WWTP. The result indicated that the GA produces more accurate results than fuzzy logic technique. It was found that GA components increased the ANN ability in predicting WWTP performance. The normalized root mean square error (NRMSE) for ANN-GA in predicting chemical oxygen demand (COD), total suspended solids (TSS) and biochemical oxygen demand (BOD) were 0.15, 0.19 and 0.15, respectively. The corresponding correlation coefficients were 0.891, 0.930 and 0.890, respectively. Comparing these results with other studies showed that despite the slightly lower performance of the current model, its requirement for a lower number of input parameters can save the extra cost of sampling.

    Keywords: Artificial neural network, Wastewater, Fuzzy logic, Genetic algorithm
  • Shuaibu Musa*, Suleiman Ola Idris, David A. Onu, Ahmed B. Suleiman Pages 100-105

    Two metal-amino acid complexes, Cr(III)-alanine and Cr(III)-valine, were synthesized and characterized by IR spectroscopy, powder X-ray diffraction (XRD) analysis, magnetic susceptibility, and molar conductivity measurements. Molar conductivity measurements indicated that the composition of the metal complexes corresponds to a metal-amino acid ligand ratio of 1:3. The IR spectra indicated that the amino acids act as bidentate ligands with coordination involving the carboxyl oxygen and the nitrogen of the amino group. Magnetic susceptibility measurements revealed a six-coordinate local symmetry around the Cr(III) ions which depicted that the complexes were paramagnetic with magnetic moment values ranging from 5.10 to 6.00 BM. Powder XRD studies confirmed that the amino acid complexes were crystalline with monoclinic crystal structure. The in vitro biological activity of the investigated chromium(III) complexes with alanine and valine was tested against Bacillus subtilis, Staphylococcus aureus, Salmonella typhi, Pseudomonas aeruginosa, and Escherichia coli. All the microorganisms were standardized using 0.5 McFarland standard. The antimicrobial studies showed that the ligands were biologically active with an inhibition zone range of 10-17 mm and their metal complexes showed significantly enhanced antimicrobial sensitivity with an inhibition zone range of 12-21 mm. The standard drug showed slightly better activity with an inhibition zone range of 24-38 mm.

    Keywords: Synthesis, Characterization, XRD, Biological activity
  • Hassan Rezaei*, Saeedeh Rastegar, Sanaz Naseri Pages 106-112

    Developing an adsorbent with natural components is one of the effective methods to reduce the amount of wastewater pollutants. Wastewater reuse can improve the quality of water prior to entering the natural environment. The aim of this study was to evaluate the efficiency of chitosan nano-composite and activated carbon adsorbent in the removal of nitrite, phosphate, and ammonia pollutants from fish farms of Aq-Qala. To prepare the adsorbents, the shrimp shells were converted to nano-chitosan. The date palm kernel was prepared and activated with oxalic acid in pyrolysis furnace by injecting nitrogen gas into activated carbon, then, the nano-composite was prepared from nanochitosan and activated carbon. A field-laboratory study was conducted during the winter of 2018, and then, batches of synthesized nano-composite were investigated and the effects of pH, initial effluent concentration, and adsorption time were investigated. The experiments were performed in the pH range of 5-8, effluent concentration of 25-100 mg/L, and contact time of 15-90 minutes. The results showed that at optimum conditions (pH of 7, effluent concentration of 50 mg/L, and contact time of 60 minutes), the highest removal percentage and adsorption capacity for nitrite, phosphate, and ammonia contaminants were 99.98%, 99.77%, and 65.65%, and 6.65, 6.14, and 7.32 mg/g , respectively. Due to the high removal percentage (99.98%) of the chitosan and activated carbon nano-composite, the adsorbent was highly capable of removing pollutants (nitrite, phosphate, and ammonia).

    Keywords: Adsorbent, Activated carbon, Nano-composite, Wastewater, Chitosan
  • Hossein Alidadi, Sima Zamand, Aliasghar Najafpoor, Hamid Heidarian, Aliakbar Dehghan, Maryam Sarkhosh, Vahid Taghavimanesh* Pages 113-118

    This study aimed to investigate the levels of heavy metals in the lipstick products. In general, 30 samples were randomly selected from Mashhad markets. Analysis of variance (ANOVA) and t test were used to compare color and price variables. Based on the results, the mean concentrations of studied elements were as follows: Cd (ND-0.52 µg/g), Cr (0.25-76.35 µg/g), Ni (ND-20.12 µg/g), Zn (ND-224.22 µg/g), Pb (ND-44.77 µg/g), and Hg (ND-0.32 µg/g). The presence of toxic metals in the samples, and on the other hand, continuous use and unintended ingestion of these metals can lead to their biological accumulation in the human body, thereby causing the development of different diseases. Hence, it deems necessary to apply suitable actions for the improvement of quality control over these products.

    Keywords: Lipstick, Heavy metals, Contamination, Mashhad
  • Masoumeh Moghaddam Arjmand* Pages 119-123

    The sanitation of the hospital environment for the purpose of preventing the transmission of nosocomial infections has a major role in reducing the infection of hospitalized patients with the bacteria living on hospital surfaces. The excessive use of chemical detergents in recent decades has led to microbial resistance in nosocomial infectious bacteria. Researchers’ attention has therefore been drawn to the use of probiotics for disinfecting hospital surfaces. The present study was conducted to assess the potential effectiveness of probiotic products in controlling the contamination of inert surfaces in the environment and medical instruments in health centers and investigate the claim that the antagonistic property of probiotic microorganisms offers an effective method for controlling nosocomial infections and a suitable alternative to conventional disinfection methods. A search was carried out for relevant articles published from 2000 to 2018 in databases including ISI, PubMed, Scopus, EMBASE, and Google Scholar, using the keywords "nosocomial infections", "disinfection", "sanitation", "probiotics" and "infected surfaces". The articles published from 2000 to 2018 confirmed the greater effectiveness of probiotic disinfection (by up to 90%) compared to conventional chemical disinfection in controlling nosocomial infections. Nevertheless, more extensive studies are needed on probiotics to determine the possibility of replacing good bacteria with bad bacteria in future decades.

    Keywords: Nosocomial infection, Disinfection, Probiotic, Infected surfaces, Pathogens