abdolmotaleb seidmohammadi

Metallic coagulants have been used for more coagulation and flocculation of flocs in many wastewater treatment plants (WWTPs) in all parts of the world. The integration of different methods to improve the wastewater treatment process has been considered in recent years. In this case-control study, the effects of four main coagulants (ferric chloride, ferric sulfide, alum, and poly-aluminum chloride) on sludge volume index (SVI) with and without exposure of static magnetic fields (SMFs) have been investigated. Both methods significantly reduced SVI (mL/g), but the combination of SMFs and coagulants was more effective. Ferric chloride could control bulking or reduce SVI to less than 150 mL/g at concentrations of 0.0625 to 2 g/L when the SMFs intensity of 15 mT was used. The control of bulking in other coagulants happened when SMFs were added to coagulants at 0.0625-0.125 g/L concentration of coagulants (P<0.05). With the application of SMFs, the highest reduction of SVI belonged to ferric sulfide (43.60%), followed by ferric chloride (18.40%), poly-aluminum chloride (PACl) (20.19%), and alum (19.80%). Without the application of SMFs, the highest reduction of SVI belonged to ferric chloride (38.36%), followed by alum (34.94%), PACl (25.43%), and ferric sulfide (6.69%).

Mental health status of university students is a critical issue due to its essential role in students’ academic performance. Therefore, this study aimed to evaluate the mental health status of firstyear students at Hamadan University of Medical Sciences in 2020.

All first-year students of Hamadan University of Medical Sciences entered this cross-sectional study through census sampling. Two Questionnaires, the Goldberg’s General Health Questionnaire-12 (GHQ-12) as a screening instrument, and a researcher-made questionnaire were used to collect demographic information. After data collection, the chi-square test and logistic regression coefficient were applied to analyze the data at a significance level of 0.05.

The results showed that out of 875 students, 170 cases (19.4%) suffered from mental disorders, including depressed mood (93.5%) and anxiety attack (22%) as the most and least common disorders, respectively. Fitting the logistic regression model revealed that the highest educational degree (P<0.001, medical residency), admission quotas other than the free quota (P=0.03), high (P=0.04) and low (P=0.01) financial status, and fathers’ unemployment (P=0.04) increased the chance of mental health disorders.

Due to the high rate and negative consequences of mental health problems in university students, it is recommended that university counseling centers provide services for students with a focus on coping with more frequent mental disorders. Finally, it is suggested they have yearly follow-up surveys to recognize the effects of the university environment and different conducted programs on the students’ mental status.

In recent years, due to water shortages and rapid industrial growth, the treatment and reuse of industrial wastewater has become of great importance. Phenol and its derivatives can be mentioned as wastewater pollutants that have a destructive effect on the environment. Pentachlorophenol (PCP) is one of these derivatives that may be carcinogenic to humans, and wastewater treatment containing PCP is required. Therefore, the aim of this study was to remove PCP from aqueous media.

Effective operating parameters such as initial PCP concentration (25, 50, 100, and 150 mg/L), persulfate concentration (25, 50, 75, and 100 mg/L), solution pH (5, 7, 9, and 11), and reaction time (10, 20, 30, and 40 min) were investigated. After the removal of PCP, an experimental design based on an orthogonal array using the Taguchi method was proposed.

Based on the results, 98.78% of PCP in the optimal conditions (initial concentration of PCP of 25 mg/L, concentration of sodium sulfate (Na-PS) of 20 mg/L, pH = 11, and reaction time of 40 min) was removed. In this process, the COD and TOC removal rates were 82.3% and 61%, respectively. Analysis of variance (ANOVA) showed that persulfate is the most effective factor in the removal of PCP in the persulfate/UV process.

Persulfate/UV processes as an advanced oxidation process, powerful and environmentally friendly, can be used in wastewater treatment containing phenolic compounds, including PCP.

This descriptive, cross-sectional study aimed to assess the correlations between the knowledge, attitude, and performance of the students of Hamadan University of Medical Sciences, Iran, regarding waste recycling in 2020-2021. A questionnaire was used for data collection, and the sample population consisted of 70 male and female students. Data were analyzed using SPSS version 21 by Mann-Whitney and Kruskal-Wallis (α=0.05). The sample population included 87.1% women and 12.9% men. In total, 22.9% of students received special training to recognize the adverse effects and management of waste while 77.1% of them received no training. In addition, 22.9% of students reported the contraction of infectious diseases in themselves or others around them due to contact with garbage or contaminated equipment. The marital status had a significant difference with the amount of knowledge of the studied students for determining the type of awareness regarding the importance of recycle waste while gender represented no substantial difference in this regard. Based on the results, a positive correlation was observed between attitude and awareness, as well as the performance with knowledge and attitude. Knowledge, attitude, and performance are meaningful predictors of waste management. According to the results, the importance of waste management should be emphasized to student in the community in terms of the current health conditions. It also seems that the influential factors in waste management should be fully identified in interventional programs, and appropriate interventions should be planned and implemented accordingly.

Considering the importance of alkalinity in pH regulation and its buffering role, in this study, the effect of inlet wastewater alkalinity on the efficiency of the anaerobic unit of the wastewater treatment plant. Moreover, a superior chemical compound in providing alkalinity to wastewater was investigated.

This study was performed in the treatment plant to determine the relationship between input alkalinity and removal efficiencies of COD, BOD5 and TSS. In order to determine the optimal alkali material for superb anaerobic wastewater performance, four common chemical substances including, NaOH, Na2CO3, Ca(OH)2 and MgO were selected and examined using One Factor At Time (OFAT) test method.

According to the results maximum removal efficiencies were obtained 62, 66.6 and 71.2% for COD, BOD5 and TSS, respectively under alkaline condition of 1260 mg/L CaCO3. Furthemore, the optimal dose to supply one unit of alkalinity by Na2CO3, Ca(OH)2 and MgO were 0.53, 0.54 and 0.3 mg/L, respectively. These values were obtained 5 min contact time and mixing rate of 150 rpm. However, for NaOH the optimal dose supply was obtained 0.35 mg/L for 3 min contact time and mixing rate of 100 rpm.

In conclusion, the performance of anaerobic baffled reactor is highly related to the supply of influent alkalinity to the reactor. In addition, the use of MgO can be considered as a suitable alkaline substance to neutralize acidic wastewater and provide alkalinity for ABR system.

In the present study, magnesium oxide/granular activated carbon (MgO/GAC) composite as a catalyst was synthesized using the sol-gel method and its catalytic potential was investigated in the presence of ultraviolet (UV) irradiation for the removal of cephalexin (CLX) in a batch mode reactor. Then, the characterization of the MgO/GAC composite was determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Next, the effect of operational parameters was evaluated, including the pH of the solution (3-11), the dosage of composite (1-6 g/L), initial CLX concentration (20-100 mg/L), and contact time (10-60 minutes). The maximum CLX degradation with an initial concentration of 20 mg/L was as high as 98% at pH=3, 4 g/L of MgO/GAC composite with UV irradiation within 60-minute contact time. In addition, the removal process of CLX could be described by the pseudofirst-order kinetic. Further, the chemical oxygen demand (COD) and total organic carbon (TOC) removal rate were 78% and, 62.3% in optimum conditions, respectively. The results indicated that the UV/MgO/GAC hybrid photocatalytic process can be considered as an efficient alternative for treating the wastewater containing CLX.

Pharmaceuticals, especially antibiotics, are new contaminants that because of their cumulative nature, adverse effects and drug resistance; have created a major environmental concern. The aim of this study was to evaluate UV/peroxymonosulfate (UV/PMS) process efficiency in the removal of cefexime antibiotic from aqueous solution.

This experimental laboratory study was conducted in batch mode. We assessed the effects of main operational parameters such as solution pH (3-9), reaction time (0-30 min), photocatalyst dosage (0.75-2.25 mmol/L), and initial concentration of cefexime (5-25 mg/L) on removal efficiency. Spectrophotometer (HACH DR-5000 UV–Vis) was used to measure the initial and final concentrations of cefexime.

Under optimal condition (pH=7.5, irradiation time=30 min, C0=5 mg/L, and PMS dosage=1.37 mmol/L), use of photocatalytic UV/peroxymonosulfate led to efficient removal of cefexime (93.18%).

The results of this study showed the acceptable performance of peroxymonosulfate process in the removal of cefexime.

Organic aromatic compounds as common environmental pollutants can be existing in the effluent of different industries in concentrations ranging from trace quantities to hundreds of milligrams per liter. Phenol compounds extremely have been used in pharmaceutical, wood industry and paper and dyes industries which introduced to environment via effluents. This study was done to evaluate the efficacy of persulfate activated by Fe2+ in the present of UV for removal of phenol from aqueous solutions. This photocatalytic degradation experiment was performed in batch mode using a 2.5 L cylindrical reactor equipped with low-pressure Hg vapor lamp of 55 W for wavelength production of 253.7 nm. The effects of operating parameters such as pH of the solution (pH: 3-10), different initial persulfate concentration (10-75 mmol/l), initial Fe2+ concentration (5-30 mmol/l) and initial phenol concentration (10-100 mg/l). Concentration changes of phenol were determined using UV–VIS spectroscopy at the wavelength of 500 nm. Degradation of phenol was significantly decreased with increasing of pH from 3 to 10, whereas the highest phenol removal rate was 82% at pH=3 in 45 min contact time. Also, the phenol removal rate is depending on initial persulfate and Fe2+ concentration. The degradation of phenol by this photocatalytic followed first order rate decay kinetics (R2>98%(. Under optimum operational conditions, the removal of TOC was obtained to be 61% in 45 min contact time. This study indicated that activation of persulfate by Fe2+ in the present of UV process could serve as a novel treatment technique for removal of phenol in aqueous solution.

Background and purpose: In order to design an industrial-scale adsorption process, it is necessary to model exact simulation of the dynamic behavior of fixed bed adsorption system. This study aimed at evaluating the performance of fixed bed column using sucrose-modified pumice in removal of metronidazole from aqueous phase. In this experimental study, the adsorbent was prepared from pumice stone and sucrose was used to modify the pumice. The laboratory mode reactor was a cylindrical shape in 20 cm length and 2 cm diameter. Different parameters such as initial concentration, pH of the solution, flow and pumice height in bed were investigated to assess the performance of fixed bed column in removal of metronidazole. Thomas and the Adams–Bohart models were used to evaluate the breakthrough curves of metronidazole removal. According to findings, the BET of modified pumice per gram of adsorbent increased from 8.4 to 35. Decrease in pH and contaminant concentration resulted in increase in bed lifetime. The experimental data were found to fit well with the Thomas model. According to this study, the Thomas model could be used in designing and investigating the amount of adsorbent in real conditions. Also, the fixed bed column can be used as an effective method to remove antibiotics from water.

Using additives such as Balnkit, to increasing the quality color of food and for the fermentation and early preparation of bread dough, has increased in recent years. The purpose of this study was to investigate the concentration of Blankit in Hamadan breads production and risk assessment of food consumption during 2016. In this descriptive-analytical study, Balnkit, concentration in breads produced in Hamadan in 2016 was determined. A total number of 85 samples were randomly collected from all bakeries in two steps. The concentration of Blankit was determined according to ISIRI guideline using spectrophotometer in 560 nm. Then for the evaluation of risk assessment of food consumption, the value of target hazard quotients (THQ) was calculated. The Blankit was not found in 97% of samples and only 3% of samples (Lavash bread) have the Blankit. The calculation of the THQ index showed that value of THQ was 0.0041 whose value is less than 1 and the consumption of bread with this concentration will not endanger. The results of this study showed that the addition of Blankitin bread processing, with regard to the concentrations determined and eliminating it from bread due to the heat, does not pose a threat to the health of the people.

The Azo dyes due to presence of aromatic rings in structure are considered major problems into the environment. In this experimental study, the synergistic effect of persulfate and nano zero-valent iron in degradation of Acid Blue 113 in presence of ultrasonic irradiation was investigated.
The effect of operating parameter such as initial pH, different concentration of S2O82-, nZVI and initial dye using a batch ultrasound reactor at 40 kHz frequency was investigated. After the optimize process, synergistic dye degradation and COD reduction of colored solution was studied. For characterization of the prepared nZVI particle, transmission electron microscope (TEM) image was used.
To remove 99% dye with initial concentration of 50 mg/L, the optimal condition in the end of 30 min of reaction was pH 3, concentration of S2O82- and nZVI 5 mM and 50 mg/L, respectively. In the same of condition with increasing pH to 11 the dye removal efficiency decreased to 17%, respectively. After 120 min of reaction in the optimal condition, the COD reduction was 95%. Synergistic dye degradation in US/S2O82-/Fe0 process was observed 59%. The TEM image of the synthesized nZVI confirmed the nanoscale Creation.
The US/S2O82-/Fe0 combined process due to high synergistic degradation, can be promising process to industrial wastewater treatment.

2, 4-Dichlorophenol is one of the most common and abundant pollutants widely found in various industrial effluent. The obvious effect of this organic compound on health and environment depends on enhancing the degradation efficiency of this aqueous pollutant before wastewater being discharged into the receiving water. Therefore, in this study, removal of 2, 4-dichlorophenol from aqueous solution was investigated through using UV-LED/TiO2 process. In this experimental study, removal of 2, 4-DCP in the presence of TiO2 by using UV-LED in a bench scale reactor was examined. The effects of operational parameters such as pH (3-11), initial concentration of 2, 4-DCP (50-200mg/L), TiO2 concentration (0.003-0.025mol/L) and ionic strength were evaluated. The results indicated that removal of 2, 4-DCP was influenced by different operational parameters. The highest 2, 4-DCP removal rate were obtained at pH=3 by adding 0.012 mol/L of TiO2 to solution with an initial concentration of 50mg/L of 2, 4-DCP which more than 95.82% of 2, 4-DCP was removed. While UV-LED and TiO2 were used separately, the 2, 4-DCP removal efficiency was 32.11% and 36.56%, respectively. Also, the results indicated that maximum COD removal rate was 71.5% in optimum condition and also indicated lack of impact on ionic strength changes for removal of organic material. The results indicated that combined TiO2/UV-LED process in optimal conditions can be used as a new technology for treatment of various industrial wastewater containing 2, 4-DCP.

Phenol is extensively used in various industries and it is mainly discharged to the enviroment from their effluents. In this study, the effectivness of UV activated periodate for removal of phenol in aqueous solutions was investigated.
In this research,experimens were conducted in a bench scale stainless steel reactor equipped with a 55W Hg vapor lamp. The effects of operational parameters such as solution pH (3-10), initial phenol concentration (50-500 mg/L), periodate concentration (8-100 mmol/L) were evaluated. Further, ionic strengh was changed to study its impact on the performance. The final concentration of phenol and mineralization rate were determined using DR-6000 spectrophotometer (at thewavelenght of 500 nm) and COD analysis, respectively.
The findings indicated that the removal of phenol was influenced by different operational parameters. The highest removal rate was obtained at acidic conditions (pH=3), initial periodate concentration of 20 mmol/Land contact time of 60 min, which more than 99.1% of phenol was removed under these optimal conditions. Also,the results showed that maximum COD removal rate was 69% in optimum conditions. It was found that different ionic strengths did not affect the phenol removal rate.
The results indicated that UV activated persulfate process in optimal condition can be used as an alternative technology for treatment of various industrial wastewaters containing phenol.

Introduction and Rock candy is one of the most widely used sugar products in Iran. The use of chemical additives in food products can be a serious threat to human health and environment if it is not accompanied with sufficient monitoring and management. Regarding this, the present study was conducted with the aim of investigating the amount of sodium dithionite residue in the rock candies produced in the candy making plants of Hamadan, Iran.
This descriptive and analytical study was conducted on the rock candies produced in all the active candy making plants of Hamadan in 2015. The sampling was performed for four months in 20 rock candy producing plants. The concentration of sodium dithionite residue was determined according to the guidelines released by the Institute of Standards and Industrial Research of Iran. Data analysis was performed using SPSS version 16 and Excel 2013 software.
According to the results, sodium dithionite was used as an additive in all rock candy making plants investigated in this study. The highest and lowest concentrations of sodium dithionite were 23.85 and 3.2 mg/kg, respectively. Furthermore, the results indicated that in over 37.5% of total sample size, sodium dithionite concentration was higher than the standard value. The mean concentrations of sodium dithionite in the rock candies produced in March, April, May, and June were 9.7±5.84, 9.49±3.7, 9±3.76, and 7.1±2.99 mg/kg, respectively, which were indicative of significant differences between different months in this regard.
As the findings of the present study indicated, the rock candies produced in the majority of the investigated plants had a high sodium dithionite concentration, which was due to the use of unsuitable main ingredients. Therefore, more monitoring and training are needed for the workshop operators.

In recent years, sodium hydro sulfurous anhydride (Dithionite) has been used as an additive for better preservation, increase of visual appearance and improvement of fermentation action in breads products. The purpose of this study was to determine and quantify the concentration of dithionite in breads produced in Hamadan.
In this descriptive study, the concentration of Dithionite in bread in breads produced in Hamadan from July to September 2016 was determined. The study population was the whole of active industrial bakeries in the city of Hamadan. The sampling was conducted after listing the bakeries producing bread by referring randomly to the bakeries and taking samples and transmitting them to the laboratory. Finally, the content of dithionite was quantified based on the Iranian National Standard (no: 2628).
The findings indicated that dithionite concentration in all samples in different months was zero, which meets the standard.
The results of this study indicated that dithionite, as an additive, has not been used in processing of the bread; hence, it cannot be considered as a threat to human health.

Background and Furfural is a toxic chemical that is widely used in refinery and petrochemical industries. Wastewater containing furfural need appropriate treatments before being disposed to the environment in order to avoid the toxic effects of this compound on the environment and human. This study aimed to investigate the efficiency of electrocoagulation process in removal of furfural.
This experimental study was conducted using a Plexiglas reactor with an approximate volume of 500 ml equipped with four Al and Fe electrodes (Anode-Cathode) in monopolar-parallel mode. The effects of operating parameters such as electrodes connection, type of electrodes, pH of solution, applied voltage, furfural initial concentration, and reaction time were evaluated by defined factor of 4×4 using Taguchi L16 orthogonal array in a batch mode. Concentration of furfural was determined using HPLC wavelength of 254 nm. Data analysis was performed in Minitab 16TM software.
Based on the results of the Taguchi method, the optimum conditions for furfural removal included the initial furfural concentration of 100 mg/L, pH= 7, voltage= 10 V, and reaction time= 30 min. The contribution rate of each parameter was determined through ANOVA test. Accordingly, the most and least influential factors were found to be the initial furfural concentration and pH, respectively. Furthermore, in optimum conditions, the furfural removal efficiency of this model was 94.7%.
As the findings of the present study indicated, electrocoagulation process is believed to be an effective method in furfural removal which could remove 95% of furfural in optimum laboratory conditions.

Industrialization has led not only to an increase in water demand, but also to an increase in water pollution due to the discharge of polluted industrial wastewaters with high salt content, and the organic compounds such as phenol into the water bodies.
This study aimed to investigate the efficiency of electrocuagulation and electro-Fenton processes in phenol removal from saline wastewater using Taguchi exprimental design method.
Material and This experimental study was performed in a reactor (1 liter) with synthetic phenolic saline wastewater. In this study for electrocoagulation process, the effects of five operation parameters on phenol removal efficiency including reaction time (20-80 min), electrolyte (1-4%), pH (3-5-7-9), initial phenol concentration (500-1000-1500-250 mg/L) and current density (4-16 mA/cm2) were investigated in four levels by Taguchi L16 orthogonal array. Also for electro-Fenton process, the effects of six operation parameters on removal efficiency in five levels including reaction time (20-80 min), electrolyte (0-4%), pH (2-3-4-6-8), initial phenol concentration (250-500-1000-1500-2000), current density ( 0-16mA/cm2) and hydrogen peroxide (50-300mg/L) were evaluated by Taguchi L25 orthogonal array. The concentration of phenol was determined according to the estandard method in spectrophotometric wavelength of 500 nm.
Experimental data showed that the optimum phenol elimination condition in electrocuagulation process was initial phenol concentration of 250 mg/L, pH = 5, electrolyt = 3%, curent density of 8 mA/cm2 and reaction time of 60 min. The most influential factor in removal efficiency was the initial concentration (63.2%), and the lowest effect belonged to the electrolyt (4.2%).
The optimum phenol removal condition for electro-Fenton process was initial concentration of 250 mg/L, pH:3, electrolyt:2%, hydrogen peroxide:150 mg/L, current density of 8 mA/cm2 and 20 mine contact time. The most influential factor in elimination efficiency was the curent density (29.12%), and the lowest influence on response variable belonged to the reaction time (3.08%).
This study showed the electro-Fenton process was effective in the removal of phenolthat can be used as an appropriate process in wastewater treatment.

In this study, degradation of p-chlorophenol (p-CP) was evaluated using persulfate (PS) activated zerovalent iron (ZVI) based ultraviolet (UV) in a bench scale photoreactor. The effect of operational parameters such as solution pH (3, 7, and 11), reaction time (0-60 minutes), ZVI dosage (0.15, 1.25, 0.5, 1, and 1.5 mM), PS concentration (0.5, 1.5, 2, 2.5, 3, and 4 mM), and initial p-CP concentration (0.22, 0.44, 0.88, 1.32, and 1.76 mM) were examined on the degradation of p-CP in batch experiments. The experimental results indicated that the p-CP removal rate significantly depends on operational parameters. The highest p-CP removal rate was achieved after 45 minutes (> 0.99%) in pH = 3, ZVI = 1 mM, and PS = 3 mM, and with initial p-CP concentration = 0.44 mM. The results revealed that excess amount of PS and ZVI could reversely affect p-CP removal efficiency. In addition, an increase in p-CP initial concentration from 0.22 to 1.76 mM significantly decreased its removal rate. This study indicated that PS activated ZVI based UV process is practically feasible for the effective degradation of p-CP in aqueous solution.

Background and Using catalysts to enhance the efficiency of the ozonation process (known as catalytic ozonation process) has received much attention in recent years. This study aimed at examining the overall feasibility of using catalysts ozone as catalyst in ozonation process for decolorization and mineralization of a real textile wastewater in presence of persulfate.
This experimental study was conducted on a laboratory scale reactor using a semi-batch mode. The effect of persulfate, ozone flow rate, reaction time and catalytic dose in dye and COD was investigated in an optimal state of textile wastewater. To obtain optimization test, the experiment was performed by fractional factorial method at three-level factorial (3k−p) with a high resolution (VI).
In this study, 15 min contact time (P = 0.006) and 0.5g/L dose of catalyst (P=0.029) had the best effect on color removal. Moreover, the interaction of these parameters were found to be significant (P= 0.025). The optimum condition for color removal was achieved at 15 min reaction time, ozone flow rate of 2 L/min, 1.5 mM persulfate and catalyst dosage of 0.5 g/L. Optimum efficiency removal for color and COD in textile wastewater were 96% and 75%, respectively.
Application of nano-magnesium oxide with ozone in presence of persulfate showed synergistic effect and buffering property in decolorization and mineralization of textile wastewater. It also increases the efficacy of color removal and improves mineralization so, there would be no need for pH adjustment.

Polyvinyl acetate (PVAc) is a type of thermoplastic resin generated by a polymerization of vinyl acetate. Effluent of this polymer is highly rich with chemical oxygen demand (COD) and total solids (TS). Due to lack of studies on the above problem, the current study aimed at obtaining a sufficient method for the effluent pre-treatment. In fact, the study discussed PVAC effluent treatment by electrocoagulation (EC) and electroflotation processes.The study considered the effect of various operating parameters such as pH and current density, initial concentration of pollutant, inter-electrode distance, electrolysis times, and types of electrode materials (iron and aluminum); COD and TS removal efficiency and optimal values of operational parameters were calculated. In the study, COD and TS reduction rates in the optimized conditions in batch flow reactor were 83% and 78%, and 80% and 72% for Fe and Al electrodes, respectively. Optimized conditions were taken as 24 mA cm -2, 20 g/L PVAC, and neutral pH in 20 minutes for Al-Al electrodes and 15 minutes for Fe-Fe electrodes, 1 cm distance between electrodes with parallel-type monopole of connection modes. According to the results, electrochemical process with batch flow tends to be a suitable pre-treatment process that is inexpensive, easily operated, and highly sufficient for effluent treatment, which contains polyvinyl acetate.

Dyes are one of the most contaminants in textile industrial wastewater that they are often carcinogenic, mutagenic and non-degradable. Therefore, with regard to environmental aspects, their removal from effluents is very essential. The purpose of this study was the perception of adsorption process and promotion of an economic technology for colored wastewater treatment. Therefore, activated carbon from Oak fruit bark was used as an effective and economic adsorbent. This study was performed at laboratory scale and batch system. At present study, the adsorbent surface properties was evaluated by use of the (FT-IR) test and scanning electronic microscope (SEM). Also, effect of various operating parameters such as pH, contact time, adsorbent dose, initial dye concentration and temperature on dye removal from synthetic wastewater were studied. In this study, maximum removal efficiency of methylene blue were achieved at optimal pH=6, reaction time 180 minutes, and adsorbent dose 2 gl-1. Methylene blue removal efficiency with initial concentration of 100 mg.l-1 was 91.08%. According to results, it was cleared that : Quercus branti activated carbon can be used as an effective and economic adsorbent in waste water treatment processes.

Nowadays, owing to industrial activities heavy metals alongside chemical and physical pollutants are discharged to the environment resulting in extensive pollution of water bodies. Thus, simultaneous reduction of hexa-valent chromium and nitrate using granular zero-valent magnesium was studied. The current experimental study was conducted in 250 ml erlens on a shaker as bench scale. The effects of pH, zero-valent magnesium concentration, initial concentration of chromium and nitrate, contact time, temperature and reduction-oxidation potential were studied. In order to measure chromium and nitrate, the methods of colorimetric and cadmium reduction were applied by using direct reading. The efficiency of hexa-valent chromium and nitrate removal increased with increasing magnesium concentration, initial concentration of pollutants, contact time and temperature, while it decreased when there was an increase in pH value. The highest efficiency was reached in the following conditions: pH=3, magnesium concentration=0.7 g/L, and initial chromium concentration=100 mg/L. The findings showed that the two pollutants interface each other leading to a decrease in the efficiency as the reduction of hexa-valent chromium and nitrate decreased to, respectively, 93.8 and 72% at the optimum conditions and 81 and 46% at the separate simultaneous reduction. Considering there are various pollutants in industrial wastewaters, the results of this study illustrated that zero-valent magnesium can be applied to remove several pollutants simultaneously.

Catalytic ozonation is a new and promising process used to remove the contaminants from drinking water and wastewater. This study aimed to evaluate the catalytic potential of nano-magnesium oxide (nano-MgO) for the removal of humic acids (HA) from water. Mg (NO3)2 solution was used to prepare MgO powder by the calcination method. In a semi-batch reactor, the catalytic ozonation was carried out. The effects of the various operating parameters, including pH, reaction time, T-butyl alcohol (TBA) and phosphate on HA degradation were evaluated. Experimental results indicated that degradation of HA was increased as the pH solution and reaction time were increased. Maximum HA degradation was obtained at pH = 10 and the reaction time of 10 minutes in the catalytic process. The calculated catalytic potential of nano-MgO on ozonation of HA was 60%. Moreover, catalytic ozonation process was not affected by TBA and the main reaction on HA degradation HA have effect take place on MgO surface. According to the results of this study, the developed MgO catalyst is the active and proficient catalyst in HA degradation using the catalytic ozonation process.

Chitosan, a biodegradable polymer, is used as an eco-friendly coagulant in a wide variety of applications in water and wastewater treatment. The present study aimed to investigate the effect of chitosan as a coagulant aid combined with poly aluminum chloride (PAC) to enhance coagulating efficiency for bentonite suspensions. A conventional jar test apparatus was used for the tests. The effect of various operational parameters, such as initial pH of the solution (5-9.5), dosage of chitosan (0.5-3.5 mg/L), dosage of PAC (5-35 mg/L) and initial turbidity (50-200 NTU) were investigated. The maximum turbidity removal rates were obtained as pH 8.5 for PAC and pH 7.5 for combined PAC and chitosan (CPC). The coagulating efficiency of bentonite using PAC and CPA was found to decrease with an increase in the pH value of the solutions. The maximum turbidity removal rate was achieved in coagulating by PAC (30 mg/L) alone, and PAC (20 mg/L) combined with chitosan (2.5 mg/L) as coagulant aid with the removal rate of 87% and 96%, respectively. The optimum dosage of chitosan required to obtain the highest removal rate was 2.5 mg/L. Hence, using chitosan as a coagulant aid can not only reduce the required amount of coagulant (35%) but can also enhance the removal turbidity efficiency.

Natural organic substances in water cause problems during water treatment processes. The potential of these compounds as precursor of trihalomethanes formation has increased the necessity of removing these compounds from water more than ever. In the current study, the effect of chitosan, as a cheap and efficient coagulant, in the electrocoagulation process with iron electrode for removal of humic acid from aqueous solutions was evaluated. In this study, a batch reactor equipped with 4 iron electrodes in dimensions of 2*20*200 mm, with a volume of 1 L and connected to an electrical source was used. The effects of current density, initial humic acid concentration, chitosan concentration and pH in the electrocoagulation process were investigated. Excel software was used to analyze the obtained results. The results indicated pH = 6, current density=40 V, and chitosan concentration= 2 mg/L as the optimal conditions for the process. Also, in the presence of chitosan as a coagulant aid in the electrocoagulation process, after 60 min, the process efficiency reached 68%. Based on the current findings, electrocoagulation process is a suitable process in removal of humic acid. Also, chitosan is an efficient coagulant aid in the electrocoagulation process with iron electrode and increases the process efficiency.