فهرست مطالب عبدالمطلب صید محمدی

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.

Dyes are one of the most important pollutants in textile wastewater (TWW). Use of advanced oxidation processes (AOPs) as an efficient method can be useful for removal of these pollutants from the effluent of textile wastewater. In this study we evaluated the efficiency of the persulfate activation process, using ultraviolet (UV), in the presence of granular activated carbon (GAC) for removal of methylene blue dye (MBD). Also, we studied the effect of operating parameters on dye removal.

This experimental study was performed in a pilot-scale batch photoreactor. The effect of operating parameters including solution pH (between 3 and 9), dosage of granular activated carbon (0.6-5 mg/L), persulfate concentration (0.2-2 mmol/L), initial concentration of methylene blue dye (50-400 mg/L), and contact time (2-30 minutes) were evaluated. The final concentration of methylene blue dye was measured by using DR-6000 device. Mineralization of the process, in optimal conditions, was determined by measuring COD and TOC.

The highest efficiency of the process for removal of methylene blue dye (99% dye removal at an initial concentration of 50mg/L) was observed at pH = 3, granular activated carbon dose of 1 g/L, optimal persulfate concentration of 1 mmol/L, and after a 20-minute contact time. The removal rates of COD and TOC were 71% and 69.9%, respectively, and the decomposition rate of methylene blue dye was based on the first-order reaction (R2 = 0.99).

Considering the results of this study, the combined process had a significant efficiency to remove methylene blue dye and can be used as an efficient method for removal of the dye from the effluent of textile wastewater.

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.

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.

4-chlorophenol (4-CP) is one of the seriously toxic chlorophenol compounds found in the effluent wastewater generated by oil refineries, pharmaceutical factories, and paper and leather producers which introduced into surface and ground water resources. This research aimed to study the feasibility of nZVI nanoparticles in activation of H2O2 and persulfate under UVA-LED irradiation based on Taguchi experimental design for 4-CP removal. This experimental study was conducted using a lab-scale batch reactor equipped with 18 ultraviolet light emitting diodes lamps with a wavelength of 390 nm. The effects of operating parameters such as pH of solution, contact time, dosage of nZVI, dosages of H2O2 and persulfate and different initial 4-CP concentration were evaluted by difiend factor of 4*4 using Taghuchi L-16 orthogonal array. Based on the results of the Taguchi method, the optimum conditions for removal of 4-CP in nZVI activated persulfate process included the initial 4-CP concentration of 25 mg/L, pH=3, reaction time of 60 min, nZVI and persulafte respective dosages of 2 and 2 mM. The highest removal efficiency and S/N values for this process were 51.83% and 34.29%, respectively. Also, optimum conditions for removal of 4-CP in nZVI activated H2O2 process were the initial 4-CP concentration of 25mg/L, pH=3, reaction time of 30 min, nZVI and H2O2 dosages of 0.75 and 1 mM. In this condition, the highest removal efficiency and S/N values were 81.76% and 38.25%, respectively. In both processes in this case, under acidic conditions, an increase in the active catalyst (Fe2+) activated more and more oxidants (radical hydroxide and radical sulfate) in both reactants, resulting in better efficiency of processes in these conditions. UVA-LED/H2O2/nZVI process could serve as a new and feasible approach for the degradation of 4-CP as well as other organic contaminants containing wastewater due to high efficiency, low contact time and need to the lowest oxidants agents. UVA-LED/H2O2/nZVI process could serve as a new and feasible approach for the degradation of 4-CP as well as other organic contaminants containing in wastewater due to high efficiency, low contact time and need to the lowest oxidants agents.

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.

Malathion known as one of the most used organophosphates, with contact, digestive, fumigants and non-systemic properties has detrimental effects on ones nervous system. Recently use of photocatalyctic processes has grown widely because of its desirable ability to remove organic pollutants. In this study efficiency of photocatalytic process with persulfate and hydrogen peroxide for the removal of malathion was studied.
this study was carried out in laboratory scale and in batch flow reactors of steel which the low-pressure mercury vapor lamps of 55 watts was placed in it. The influence of parameters such as pH(3-9), H2O2(1-8Mm/l), perslfate dose(0.01-0.05 gr/l), and malathion (1-60 mg/l) was investigated. The malathion concentration in solution has been determined with the HPLC.
the results of this study showed that the discussed process has high efficiency in compare with other done studies, so that in optimum conditions – pH=3, concentration of persulfate 0.03 gr, consumed hydrogen peroxide 3mM and initial concentration of malathion 30mg/l – this process after 30 and 60 minutes, removed respectively 99.94% of malathion and 88.31% of COD.
photocatalytic process with persulfate and hydrogen peroxide as one of the advanced oxidation process alternatives has a high potential in reducing pollution load of different industries, including manufacture of pesticides and can be effective as a method for wastewater treatment and reduce the environmental problems.

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.

Textile industries, due to a high volume of wastewater and harmful environmental factors such as a variety of dyes, are significant industries in industrial wastewaters treatment. So, the aim of this study was to examine the efficiency of dye removal from the textile industry wastewater using the titanium dioxide photocatalytic process under UV-LED light irradiation (UV-LED/TiO2) in the treatment of the Nakh Rang factory wastewater in Hamadan City, Iran.
In this experimental study, in every experiment, 100 mL sample was placed inside the LED reactor to expose to the UV light and TiO2. The effects of some parameters such as contact time, pH and dosage of TiO2 were examined, and decomposition kinetics and the synergistic effects were also determined for each process.
The results of the experiments showed that the UV-LED/TiO2 process can remove the dye from textile wastewater with the efficiency of 80.23% and can also remove the chemical oxygen demand (COD) with the efficiency of 64.75% under the optimum conditions and during 120 minutes. Also, the reaction of dye decomposition in this wastewater was a first-order kinetic function.
The results of this study show that the UV-LED/TiO2 can be used effectively to remove the dye and reduce the COD of the textile industry wastewater under optimal operating conditions.

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.

Main sources of 4-Chlorophenol wastewater are petroleum industry, coal, paper and resin production. The aim of this study was to compare the performance of raw and cationic surfactant modified nanoclay in removal of 4-Chlorophenol from aqueous solutions.
The influence of contact time, initial pH of solution, adsorbent dosage and 4-Chlorophenol concentration as effective parameters in adsorption process and the influence of modification solution pH and surfactant loading rates were investigated. The modified nanoclay was characterized by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) spectroscopy. Finally, the isotherm and adsorption kinetics were investigated.
The removal efficiency of 4-Chlorophenol was increased by increasing the initial pH from 3 to 11, so that after of 120 min, the absorption efficiency at an initial 4-Chlorophenol concentration of 100 mg/L and 0.25 g adsorbate was 26 and 95.5 % at pH 3 and 11, respectively. Under the same conditions the removal efficiency for the raw nanoclay was 2 and 9% at pH 3 and 11, respectively. The FTIR and XRD analyses revealed that the nanoclay structural changed from hydrophilic to hydrophobic and the interlayer spacing was increased. The adsorption of 4-Chlorophenol on raw and modified nanoclay was consistent with Langmuir and pseudo-second-order kinetics. The maximum absorption capacity of raw and modified nanoclay was 0.5 and 25.77 mg/g, respectively
The modification of nanoclay with cationic surfactant increased the adsorption efficiency of 4-Chlorophenol.

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.

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.

The percence of organic compounds resistant to biodegradation has become one of the most important environmental challenges in the chemical and petrochemical industry in this century. Phenol or hydroxyl benzene as an aromatic hydrocarbon discharged into the environment through certian industrial effluents which, thereby, pollutes water resources. This study examined the performance evalution of oxidizing agents of peroxide hydrogen, persulfate and periodate activated by ultrasound for removal of phenol from aqueous solutions.
In this experimental study, the treatability of polluted effluent using US/S2O8, US/IO4 and US/H2O2 with a frequency of 40 kHz for the treatment of contaminated aqueous phenolic compounds were investigated. The effects of operational parameters such as the concentration amount of persulfate(0.001-0.005 M), peroxide hydrogen (0.004-0.1M),and periodate (0.001-0.005 M),, in different contact times in pH of (3,7 and 10) and the impact of changes in the ionic strength in the contact times were selected as the variables of the study.
The results of this study showed that increasing the concentration of oxidation significantly increases the removal efficiency and then a decreasing trend was observed in the removal of phenol. So that, optimal concentration of persulfate, periodate,and hydrogen peroxide were selected as 0.003M 0.004M 0.1 M/l, respectively. Study of different changes of pH showed that all three processes had the most removal efficiency at pH= 3 and ionic strength has reduced the US/S2O8 process efficiency and had no effect on the other processes.
The results of this study indicated that combined ultrasonic and persulfate process in the optimal conditions had the highest efficiency compared to the other processes. Therefore, persulfate can be used as a good oxidizer together with ultrasonic waves to remove phenol in aqueous solutions.

Background and Metronidazole is a serious environmental pollutant due to high consumption and persistence in biological degradation. This study aimed at removal of metronidazole using ozone (O3) activated persulfate (PS) in presence of ultrasound (US).
A laboratory scale study was carried out in batch reactor using US irradiation and O3 generator apparatuses. The effects of operating parameters such as pH of the solution, different initial concentrations of persulfate, initial metronidazole concentration, different ion strength, and radical scavenger were evaluated. Metronidazole concentration was determined using DR-5000 Spectrophotometer in 320 nm wavelength.
The results showed that removal of metronidazole decreased by increasing the pH of solution from 3 to 11. The removal rate of metronidazole was dependent on initial PS dosages and the highest rate of removal was found in 500 mg/l (94.7%), but in higher concentrations the removal rate decreased. Also, the metronidazole removal rate decreased by increase in initial concentration of metronidazole. The COD removal rate in optimum condition was 56%.
Activation of PS by US/O3 process could serve as a novel treatment for removal of metronidazole in aqueous solution.

Residual Azo dyes pose a major environment problem due to the benzene rings present in their structure. In this experimental study, the efficiencies of the US/H2O2/Fe2 and US/S2O82‒/Fe2 processes in degrading Acid Blue 113 Azo were investigated. For this purpose, the effects of the parameters involved in these processes such as initial solution pH in the range of 3 to 11, different concentrations of H2O2, and ‒S2O82 in the range of 1 to 10 mM, those of FeSO4 in the range of 0.1 to 1 mM, and different initial dye concenterations were investigated in a batch ultrasound reactor operated at 40 kHz. Also, the effects of aeration on process efficiency and fluctuations in the dye UV-Vis spectrum were investigated under optimum conditions. Based on the results obtained, dye removal efficiency decreased considerably in both processes with increasing pH such that maximum removal efficiency was obtained at pH 3 in both processes. Similarly dye removal efficiency decreased in both processes when FeSO4 concentration rose above 0.5 mM. The optimum conditions in the US/H2O2/Fe2 process to achieve a removal efficiency of 93.5% for an initial dye concentration of 50 mg/L involved H2O2 and FeSO4 concentrations of 2.5 and 0.05 mM, respectively. Under the same optimal conditions, the efficiency of the US/S2O82‒/Fe2 process was found to be 94.3% for a S2O82‒ concentration of 2.5 nM. These results suggest that the US/S2O82‒/Fe2 is more effective than the US/H2O2/Fe2 in reducing the 567 nm peak of the dye structure. Finally, examination of the changes in the UV-Vis spectra of Acid Blue 113 showed that the US/H2O2/Fe2 process led to greater declines in the 276 and 203 nm peaks.

Antibiotics can cause negative impacts on animals and bacterial resistance by entering to the environment. Catalytic ozonation process is a method for increasing the efficiency of the simple ozonation. This study evaluated the efficiency of catalytic ozonation process with activated carbon modified with MgO to remove metronidazole from aqueous solutions in a fluidized bed reactor.
Catalytic ozonation experiments were performed in a fluidized bed reactor. Impact of pH, reaction time, catalyst dosage, initial concentration, radical scavengers and hydroxyl radicals was found. The degradation kinetic of metronidazole was determined as well as FTIR spectra of the catalysts. The concentration change of metronidazole was determined by HPLC.
The results showed that the catalyst prepared increases metronidazole decomposition rate as high as 7.32 times, compared to conventional ozonation. The optimum pH of 10, the optimal dose of 1.5 g/L of catalyst and the optimum time of 30 min were determined. The results of radical scavengers’ effect showed the main reactions of metronidazole decomposition are on the catalyst surface.
The results showed that, due to the high performance activated carbon coated with MgO in catalytic ozonation process, increased removal of metronidazole, compared with simple ozonation, and easy access to raw materials, the use of these catalysts in ozonation process are recommended to increase efficiency and accelerate the metronidazole decomposition reaction and similar compounds.

Nowadays, synthetic azo compounds as environmental pollutants are widely used in different application. In this research the treatability of effluent polluted with reactive black 5 azo dye using electrocoagulation (EC) and electrocoagulation/ flotation (ECF) processes with aluminum electrodes investigated in a lab scale batch experimental reactor.
In present study an electrocoagulation flotation reactor in a lab scale to an approximate volume of 1 liter which is equipped with four Al0Al electrodes with dimensions of 200*20*2 mm was proposed. The effects of operational parameters such as initial pH, current density, contact time, initial dye concentrations and flotation were evaluated.
Findings: The results indicated that the highest dye removal rates in the EC process were observed in natural pH of solutions, 12.71 mA/Cm2 current density and 100 mg/l initial dye concentration at 30 min contact time. In these conditions up to 81% of dye was removed in the EC process. Based on the result obtained in this study, it was found that much higher dyes removal could be achieved by ECF (86%) process than that by EC process in the same conditions.
EC and ECF processes using aluminum electrodes for dye removal could be a promising process.

Raw water is one of the main sources of water supply in some communities. Filteration of surface water resources is a challenging point in the rainy seasons due to the highly turbidity. This study was done to evaluate the removal of turbidity in raw water using chitosan in electrocoagulation process using aluminum electrodes. In this the descriptive –analytical study, a Plexiglas electrocoagulation reactor in a lab scale to an approximate volume of 6 liter which was equipped with four aluminum electrodes having dimension of 200×20×2 mm was proposed. The effects of operating parameters including pH (5 to 9), applied voltage (10 to 30 V), the initial turbidity (100-600 NTU), initial chitosan concentration (0.5-2 mg/L) and contact time (5 to 30 min) were evaluated. Turbidity removal efficiency was over 100% (pH=7, applied voltage=30 V and initial turbidity concentration of 100NTU) in the application of electrocoagulation with chitosan but in the application of electrocoagulation without chitosan removed 87% of turbidity in the same condition. Chitosan as coagulant aid in low amount can increase turbidity removal efficiency rather than application of electrocoagulation alone.