ABSTRACT
Background and Aim: dendrimers have antibacterial properties and can be used against microbial infections as alternative antibacterial agents with minimal side effects. In this study we evaluated and compared nanostructure macromolecules called Poly [amidoamine] dendrimer generation 4 [PAMAM-G4] with conventional antibiotics in relation to resistance of isolated bacteria from water resources
Materials and methods: 523 samples were collected from 108 water resources and membrane filter method was used for bacterial species isolation. Resistance of isolated species to amoxicillin, erythromycin, tetracycline and ciprofloxacin antibiotics was determined by measuring zones of inhibition and then compared to the resistance of these species to PAMAM-G4 dendrimer as an antibacterial agent. Also we measured maximum inhibitory concentration [MIC] of dendrimer against isolated bacteria
Results: 7.4% of samples showed bacterial contamination. Frequency rates of isolated microbial species were as follows: Escherichia coli [28.2%], Proteus [12.8%], Klebsiella [17.9%], Enterobacter [15.3%], Pseudomonas [17.9%], Bacillus subtilis [5.1%] and Staphylococcus aureus [2.56%]. Gram-negative species revealed high resistance to PAMAM-G4 dendrimer based on the measurement of zones of inhibition. PAMAM-G4 dendrimer didn't have any effect on inhibition of the growth of Enterobacter and Pseudomonas. MIC's against Escherichia coli, Klebsiella and Proteus were 1250, 500 and 1250 [micro]g/ml respectively. Gram-positive species showed a good response to PAMAM-G4 dendrimer, so that the MIC's for Staphylococcus aureus and Bacillus subtilis were 1 and 2.5 [micro]g/ml, respectively
Conclusion: because of increased number of resistant species to conventional antibiotics, PAMAM-G4 can be considered as a potent antibacterial agent against gram-positive bacteria
ABSTRACT
Nowadays, the increasing concentration of pollutants in water resources, especially ground water, has been a matter of concern. Nitrate has been considered as a chemical indicator of water pollution for a long time. The aim of this study was to determine the chemical characteristics of drinking water and changes of nitrate in drinking water in Diwandareh villages. This was a cross-sectional study to determine the quality of drinking water of 30 villages in Divandareh. A total of 60 samples were obtained in two phases from water supplies and were analyzed according to the standard methods. Descriptive statistics, Piper, Schuler and Wilcox diagrams were used to interpret the results. The results showed that apart from nitrate, the concentrations of the other chemical quality parameters were below the standard limits. The mean and standard deviation of nitrate during the first and second stages of sampling in water sources were 26.13 +/- 25.61 mg L[-1] and 28.47 +/- 29.80 mg L[-1], respectively. According to Schuler diagram, the drinking water quality was moderate to good. Although the mean nitrate concentration in 80% of samples was lower than the latest national standard for nitrate, continuation of the current trend, particularly in the agricultural activities and uncontrolled use of groundwater resources in agriculture will change and lower the quality of water. Therefore, monitoring of agricultural practices and fertilizer use are necessary
ABSTRACT
Organic dyes are the major pollutants produced in many industries and have different adverse effects on water resources. The aim of this study was to synthesize a novel adsorbent with high adsorption capacity and evaluate its efficiency in removing organic dyes from aqueous solutions in a batch system. This study was an applied research in which carbon nanotube composite-dendrimer was synthesized and its chemical properties was evaluated by fourier transform infrared spectroscopy. Acid blue 1 dye was selected as a model to evaluate the decolorization capacity of the adsorbent. The effects of the parameters influencing the adsorption process such as initial dye concentration, adsorbent dose, pH and the effect of inorganic salts were also studied. Longmuir and Freundlich isotherm models and pseudo first order and pseudo-second-order kinetic models were used for data evaluation. In this study removal of acid black 1 dye by carbon nanotube-dendrimer composite followed the Longmuir and Freundlich isotherm and pseudo-second-order kinetic models. We also found that the synthesized adsorbent had a maximum adsorbent capacity equal to 690 mg/g, when the concentration of dye was 100 mg/l. We concluded that carbon nanotube composites - dendrimer can be used as an effective adsorbent for removal of dyes form colored effluents