دکتر علی نقی زاده

The turbidity of treated water is measured as an important parameter in determining the quality of drinking or industrial water in all treatment plants. Due to the importance of the prevalence of pathogens such as Giardia and Cryptosporidium, which cause dangerous diseases such as dysentery, the relationship between reducing turbidity and increasing the elimination of these microorganisms has been proven in studies.

In this study, an artificial neural network (ANN) model and multiple linear regression(MLR) were developed and their performance was compared to predict the turbidity of treated water of Tabas water treatment plant. Total dissolved solids, pH, temperature and input turbidity of raw water were used as input parameters of the models in the predictions. The best backpropagation algorithm and number of neurons were determined to optimize the model architecture.

The results showed that the Levenberg–Marquardt algorithm was selected as the best algorithm and the number of optimal neurons was determined to be 16.Also, the results of the sensitivity analysis of the neural network model showed that the input turbidity with a value of 29% is the most important parameter in the development of the ANN model.

The results of correlation coefficient of MLR and ANN models were obtained for training data 0.63 and 0.8921 and for testing data 0.60 and 0.8571, respectively, which show the superiority of ANN model in Predicting the turbidity of the output of Tabas water treatment plant.

Adding salt to foods including bread along with improving its taste can cause problems such as high blood pressure; therefore, considering the importance of the presence of salt in bread, the purpose of this study was to investigate the amount of bread salt in bakeries in South Khorasan province in 2014-2018.
 

This descriptive-analytical and retrospective study was performed by random sampling method on bakeries in South Khorasan province in the period of 2014-2018. The measurement of the salt level was done according to the standards of the Iranian Institute of Standards and Industrial Research. The data were analyzed by using variance analysis tests and Tukey's post-hoc test.

2577 loaves of bread were sent to the food laboratory of South Khorasan province during the years 2014-2018, which is the total average amount of salt In Lavash bread, it was equal to 1.63 ± 0.57 g, Taftoon was 1.51 ± 0.53 g, and in Sangag bread, it was 1.42 ± 0.56 g. The mean results of salt levels in different years had significantly different (p <0.001).

The amount of salt consumed was the highest in terms of changes in the average consumption of bread in 2016, which seems to be due to the lack of awareness of bakers about changing the standard of salt in that year. In this regard, the adoption of preventive and regulatory programs by the Food and Drug Administration can be a guide.

 Background radiation exists naturally in the environment and human has been always exposed to it. These rays can affect living creatures and cause chromosomal damage, and genetic and somatic diseases. Hot water springs are a major source of background radiation. This study aimed at investigating the absorbed dose of environmental gamma and determining the annual effective dose of hot water springs in South Khorasan province, Iran, during summer and autumn of 2018.

In order to measure the peripheral gamma of hot springs, the X5C PLUS dosimeter was used. Dosimetry was performed for all outdoor and indoor hot springs in two seasons (summer and autumn). The data for gamma irradiation were calculated and reported as nano-sievert per hour and annual effective dose in milli-sievert per year. Data analysis was done in Excel and SPSS applying ANOVA.

In current study, the highest and lowest mean gamma radiation were found in Dig Rostam and Tabas hot springs, respectively. The mean effective dose in all outdoor hot springs was significantly lower than that in indoor hot springs (P <0.001).

The average gamma background radiation and the annual effective dose was lower than international standards in all outdoor hot springs, but in Ferdos and Sarbisheh hot springs (indoor) the mean values were higher than the standards which could be a threat for their customers and staff.

Humic substances include natural organic polyelectrolyte materials that formed most of the dissolved organic carbon in aquatic environments. Reaction between humic substances and chlorine leading to formation of disinfection byproducts (DBPs) those are toxic, carcinogenic and mutagenic. The aim of this study was investigation of isotherms, kinetics and thermodynamics of humic acid removal process by nano chitosan from aquatic environment.
This practical research was an experimental study that performed in a batch system. The effect of various parameters such as pH, humic acid concentration, contact time, adsorbent dosage, isotherms, thermodynamics and Kinetics of humic acid adsorption process were investigated. Humic acid concentration measured using spectrophotometer at wave length of 254 nm.
The results of this research showed that maximum adsorption capacity of nanochitosan that fall out in concentration of 50 mg/l and contact time of 90 minutes was 52.34 mg/g. Also, the maximum adsorption was observed in pH = 4 and adsorbent dosage 0.02 g. Laboratory data show that adsorption of humic acid by nanochitosan follow the Langmuir isotherm model. According to result of thermodynamic study, entropy changes (ΔS) was equal to 2.24 J/mol°k, enthalpy changes (ΔH) was equal to 870 kJ/mol and Gibbs free energy (ΔG) was negative that represent the adsorption process is spontaneous and endothermic. The kinetics of adsorption has a good compliant with pseudo second order model.
Regarding to results of this study, nano chitosan can be suggested as a good adsorbent for the removal of humic acids from aqueous solutions.

Fluoride is one of the essential elements of water that is introduced into water sources through several natural and human activities. Maximum contaminant level for fluoride in drinking water is set at 1.5 mg/L by WHO. In the present research, defluorination of aqueous solutions using graphene oxide nanoparticles is discussed.
In the present study, effects of pH, contact time, fluoride initial concentration, adsorbent dosage, temperature as well as presence of sulfate anions in the performance of graphene oxide nanoparticles in removing of fluoride from aqueous solutions were investigated .Besides, investigation of thermodynamic, synthetic, and Langmuir and Freundlich adsorption isotherm were employed for the process.
Maximum adsorption capacity occurred in the first 15 minutes .for the adsorbent with pH=3 and initial fluoride concentration of 10 mg/L. The results also showed that adsorption of fluoride by graphene oxide was well in accord with Langmuir isotherm. . .Furthermore, increasing of temperature led to reducing the adsorption capacity that was indicative of exothermic adsorption reaction. Moreover, it was found that the process followed the pseudo- second order kinetic.
Graphene oxide nanoparticles have higher removal capacity for fluoride in acidic conditions, ambient temperature and higher fluoride concentration.

One of the notorious air pllutants on which air quality is determined is carbon monoxide (CO). The aim of the present study was to measure the concentration of CO outdoor and indoor urban environments and compare it with air quality standards within buildings and open spaces.
This research was a descriptive-analytical study of CO estimation in outdoor and indoor air of Birjand. Concentration of CO at the height of 150 cm and in the closest street leading to the specific building and also¡ inside the building (i.e.drawing room)-at the hight of 75 cm was measured using a CO meter. For data analysis¡ statistical softwares SPSS (V:18) and Excel were used applying Mann-Whitney¡ Friedman¡ and Wilcoxon statistical tests.
It was found that the highest concentrations of CO in the outdoor air in Birjand were 11 and 10 ppm in December and March¡ respectively. And highest concentrations of CO in indoor air were 11 and 9 ppm in February¡ respectively. But¡ in general¡ the average concentration of CO measured in outdoor and indoor air quality in both months were less than the standard measure air pollution outside (9ppm) and the quality of indoor air pollution (25ppm).
Regarding to results of the present study¡ concentrations of indoor and outdoor CO of Birjand air were in standard ranges.

One of the most important issues of today’s world is water scarcity and pollution of the environment with heavy metals. This study aimed to investigate the removal of lead and cobalt ions by functionalized and non-functionalized single-walled carbon nanotubes from aqueous solution. The present research was an experimental and laboratory -scale study to evaluate the removal of lead and cobalt from aqueous solution with functionalized and non- functionalized single-walled carbon nanotubes in a batch system. Samples were prepared in lab and in synthetic scale. Factors such as pH, adsorbent dosage, lead and cobalt concentrations, reaction time and reaction temperature were investigated. The concentration of metal ions was measured using atomic absorption spectrometry. According to the results, functionalization of single-walled nanotubes, increasing the adsorbent dosage, temperature, pH and initial concentrations of lead and cobalt resulted in increased removal of lead and cobalt. Most of the removal of studied metal ions was in 75 mg of adsorbent dosage, 3 mg/L of lead and cobalt, as well as 15 and 10 minutes of contact time at 35 ° C for cobalt and lead, respectively. Furthermore, the results showed better agreement with Langmuir isotherm. It was found that, compared with non- functionalized nanotubes, functionalized nanotubes revealed higher adsorption capacity.

Currently، several methods are used to remove heavy metals from aqueous solutions; one of which is the adsorption process. Graphene oxide nanoparticles، due to their high adsorption capacity، have caused major concerns. The current study aimed at assessing the role of these particles in removing Chromium and Lead from aqueous solutions. This empirical study investigated the effect of the initial concentration of pollutants، their PH، adsorbent dose، time and temperature on graphen oxide nanoparticles capacity in removing Chromium and Lead from aqueous solutions. Maximum adsorption efficiency occurred at PH=9 with initial concentration of 4 mg/L and at PH=3 with initial concentration of 3 mg/L for Lead and chromium، respectively. Maximum efficiency of Lead and Chromium adsorption by graphen oxide occurred at 0. 01 g dosage of the adsorbent and after 15 minutes of contact time; i. e. 90% and 42. 33%، respectively. Results showed that adsorption of the two metals was better in accord with Freundlich isotherm. Thermodynamic reaction results revealed that Cr adsorption reaction was exothermic and that of Pb was endothermic. The adsorbent Graphen Oxide has got a favorable role in removal of the two contaminants; Lead and Chromium from aqueous solutions and waste waters.

Presence of arsenic in water sources results in different health problems including; skin problems، cancer، and hypertension. This study was aimed to investigate the amount of arsenic removal from aqueous solution using carbon nanotubes in a continuous adsorption column. This was an applicable study and compares pre- and post-conditions. The influence of independent variables including dosage of carbon nanotubes، contact time، and breakthrough point on capacity of arsenic adsorption were studied. Adsorption capacities of single wall and multiwall carbon nanotubes were about 148 and 95 mg/g، respectively. The experimental data were analyzed using Langmuir and Freundlich isotherm models and equilibrium data indicate that Langmuir isotherm model to fit best for describing arsenic adsorption behavior on carbon nanotubes. Carbon nanotubes can be considered as an efficient adsorbent for the removal of arsenic from large volume of aqueous solutions.