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Impeachment is an institution that can remove high-ranking officials of the executive who are disqualified and unfit to continue the office. Impeachment could be seen in the constitutional law of all kinds of political systems, including presidentialism, semi-presidentialism and the parliamentary Republic. In some instances of domestic research, we see the fusion of impeachment and interpellation, which sometimes leads to mistakes leading to deduction. Scrutinizing the terminology of impeachment is the solution for such fusion. Accordingly, the question of the research is: what are the elements of impeachment in order to recognize it from interpellation? By the descriptive-analytic method, the research concludes that differences in officials and differences in grounds of removal are the most important elements and parameters for the distinction of these two terms. While impeachment targets officials with protected tenures or terms of office, interpellation is practiced mostly where ministers are subject to the confidence of the parliament. The common ground of Impeachment is removing a person or persons in the government whom the legislature deems unfit to continue in office due to subversive acts against the country and grave violations of public trust, which contain several instances like violations of law, corruption and treason. In addition, the procedure, stages and outcomes of impeachment and interpellation would be distinguished in many aspects. The paper is about to explain impeachment and distinguish it from interpellation.

One of the most widely used polymers in the treatment and absorption of pollutants is polyethylene terephthalate, which optimizes their consumption and protects the environment by purifying water sources. The problem with this polymer is the lack of a functional group on the surface to bind the nanoparticles. Therefore, in this study, we first functionalized the polymer with the carboxylic group by chemical synthesis, then we synthesized silver nanoparticles on them by ultrasonic method. Optimal nanoparticle synthesis conditions were obtained (pH=9 and concentration 0.2 M). Under these conditions, the average particle size was 64 nm. In the second part, modified polymer was used to remove Methyl orange dye. Optimal parameters for removal were investigated (pH=9, temperature of 35 °C and ratio of dye concentration to adsorbent of 5 μM/0.1 g). The highest percentage of paint removal under optimal conditions was 92% after 120 minutes. The antibacterial effect of PET-AgNPs polymer was observed on two types of bacteria, Staphylococcus aureus and Escherichia coli, gram-positive and gram-negative. In the second part, the gold electrode was modified with a combination of PET-AgNPs polymer and carbon nanotubes and was used to detect methyl orange dye. The linear range was 5×10-6 to 2×10-8 M and the detection limit was 7.6×10-9 M. Parameters affecting removal and isotherm and removal kinetics were investigated. The functionalized and modified polymer is well able to measure and remove the contaminant dye and, in addition, it has an antibacterial effect.

Among the methods used to remove heavy metals are membrane processes that, with less use of chemicals, are able to quickly produce high-quality penetration. In this study, a nanocomposite membrane with the ability to separate lead was used. The black titanium dioxide nanoparticle was synthesized using the pyrolysis method. Adsorption experiments were performed using a nanofiltration unit. The results of lead adsorption isotherms showed that the lead adsorption process using the membrane follows the Langmuir model with a correlation coefficient of 0.995. The results of the study of lead metal adsorption kinetics showed that the process of adsorption of lead by the adsorbent follows the quasi-second order kinetics so that the correlation coefficient of the second-order quasi-model is equal to 0.999 which is compared with the quasi-correlation coefficient. The maximum and minimum fluxes between different membranes were related to 0.1 mg/l of titanium dioxide nanoparticles in terms of time and pressure for 50 and 600 minutes and pressures of 45 and 145 bar, with increasing the initial concentration of pollutants, the percentage of adsorption decreases. This can be due to the delay in balancing the adsorbent and the contaminant.

The problem of toxic-metal-contaminated water has become a great environmental concern and presents significant hazards to the public health and economy. In this study, drinking water treatment sludge was activated and used as an efficient, cheap and cost effective sorbent in the removal of Pb (II) ion from water samples. The prepared material was characterized by Fourier transfer infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning electronic microscopy (SEM), surface analysis (BET method) and X-ray fluorescence (XRF) analysis. The effects of various parameters such as the solution pH, adsorption time, adsorbent dosage, and initial metal ion concentration upon adsorption were investigated. Equilibrium isotherm studies were carried out with different initial concentrations of Pb (II), and three models (Langmuir, Freundlich and Temkin isotherms) were utilized to analyze the equilibrium adsorption data. The best adsorption performance was obtained at the following conditions: pH of sample, 7.5; contact time, 15 min; adsorbent dosage, 0.3 g; intitial concentration of Pb (II), 20 mg/L; agitation speed, 200 rpm. The results revealed that the adsorption process obeyed the Langmuir model, with the maximum monolayer capacity (qmax) and the Langmuir constant (KL) calculated as 54.9 mg/g and 0.973 mg/L, respectively. Kinetic studies indicated that the adsorption process followed a pseudo-second-order model based on the obtained R2 values. Comparison study with the other natural adsorbents revealed that the activated sludge has the highest adsorption capacity and provides the lowest adsorption time. Desorption study exhibited that the Pb (II) ions can be desorbed from the adsorbent by 0.25 mol/L HCl solution with a recovery percentage of 98%. The results exhibited that activated sludge is an efficient and cost-effective material for the adsorption of Pb (II).

The potential of the raw cuttlebone nano-powder (CBNP), a biomass waste, as a novel and nontoxic adsorbent for the adsorption of Alizarin Red S (ARS) from water solutions was investigated. To achieve the highest efficiency for the removal of ARS, some affecting factors were optimized. Common techniques (FTIR, FESEM, EDX and XRF) were used to characterize the physicochemical features of the adsorbent. Various kinetic and isotherm models were used to obtain the useful information about the adsorption mechanism of the dye onto the adsorbent. The maximum dye removal efficiency was obtained with the adsorbent amount of 500 mg (in 50 mL) and initial pH of 2 in 10 min for 20 mg/L ARS solution. Under these optimum conditions the complete removal of ARS was obtained while the maximum adsorption capacity was 38.51 mg/g. The well fitness of pseudo-second order kinetic model in the adsorption process was proved by kinetic studies. According to the obtained results, Freundlich isotherm model can suitably describe the adsorption of ARS on the sorbent. The achieved results from this study showed the excellent capability of CBNP for the adsorption of ARS.

Effluents from fish farms have high levels of nitrate and phosphate. In the present study, the removal of nitrate and phosphate from aquatic farm effluent was investigated by nanosilica adsorbent modified with mineral pumice. For this purpose, the desired adsorbent was added to 250 ml of effluent (with 50% and 100% concentration) in laboratory conditions (adsorbent doses of 0.01, 0.05, 0.1, 0.5 and 1 g/l). Nitrate and phosphate concentrations in the effluent were measured before the experiment. According to the results, the highest amount of nitrate and phosphate removal at a dose of 0.5 g/l was selected as the optimal dose, so the nitrate and phosphate removal efficiency was decreased at concentrations higher than this amount, because the available active ingredient was reduced at doses higher than 0.5 g. In this experiment, the optimum contact time of the adsorbent with the contaminant was 45 minutes. It seems that modified nanosilica with mineral pumice has a high ability (86% efficiency) to remove nitrate and phosphate from aquaculture effluents and can be used to purify effluents from aquaculture farms before reuse in the return system or before entering to the environment. [ABSTRACT FROM AUTHOR]

Nowadays, provision of sanitary water is one of the main concerns of the world society, and heavy metals are one of the most important pollutants in water resources. Heavy metals, including copper, can enter the food chain and the body of living organisms and can affect humans through toxic and carcinogenic effects. Therefore, in this study, nanoporous SBA-15 functionalized with di and tetra carboxylic acid was synthesized and used for remove copper ions from aqueous solutions. The adsorbents were characterized by scanning electron microscopy, N2 adsorption-desorption measurements and infrared spectroscopy for investigation of porosity and functional groups of mesoporous silica. Flame atomic absorption spectroscopy was used for determination of ions. Effective parameters on removal process including amount of adsorbent, contact time, pH of solution and presence of other metal ions in the medium, were evaluated and optimized. The best removal efficiency with di and tetra carboxylic acid functionalized SBA-15 was obtained at pH>5 with 10 mg of adsorbent in the stirring time of 15 minutes. The recovery of copper from adsorbents was done with 20 ml solution of nitric acid (3 mol/L). Langmuir and Freundlich adsorption isotherms were evaluated for both adsorbents. According to the Langmuier model, the maximum adsorption capacity of 232.56 and 93.46 mg of copper per gram of adsorbent and correlation coefficients (R2) of 0.857 and 0.9688 for di and tetra carboxylic acid functionalized SBA-15 were obtained, respectively. But, the correlation coefficients (R2) obtained from the fitting of the data using the Friendlich isotherm were 0.991 and 0.972 for di and tetra carboxylic acid functionalized SBA-15 silicas, respectively, which indicates that this model is suitable to explaining the behavior of copper adsorption on both adsorbents. Finally, the removal of copper from real wastewater samples was performed. The results indicate that nanoporous SBA-15 silicas functionalized with di and tetra carboxylic acid are desirable adsorbents for copper ions removal.

In the present study, the electrochemical coagulation process (electrocoagulation) in the mining industry was investigated in order to remove one of the heavy metals, cadmium, from the leaching solution of the copper processing plant. The response surface methodology (RSM) was used to optimize the factors affecting the removal of this metal in the electrocoagulation process. For this purpose, Behnken Box Designv(BBD) was used to optimize the experiments. The effects of three independent parameters such as pH (X1), electrolysis time (X2), current density (X3) were investigated in order to investigate the removal of cadmium from the leaching solution. The quadratic model was used to respond to the cadmium removal efficiency. The most important independent variables and the interaction between them were evaluated using ANOVA test. This study showed that the optimal operating conditions for cadmium removal are 96.96% at initial pH: 6.83, electrolysis time: 116 min and current density: 69.262 A/m2. The results showed that the ability of electrocoagulation process can be considered as a reliable method to remove cadmium from industrial effluents, especially in mineral processing plants.

Introduction and purpose: Cefixime (CFX) is one of the most extensively used antibiotics across the world. Nonetheless, the entrance of this pharmaceutical compound into water resources has posed a serious problem to the environment. With this background in mind, the present study aimed to analyze the effectiveness of CFX removal from aqueous solutions by potato starch. Methods: The current study assessed the effect of four main effective parameters, namely pH (3-9), potato starch dose (0-300mg/L), CFX initial concentration (0-16mg/L), and retention time (20-120min), on CFX removal using Response Surface Methodology (RSM). Results: Under the optimum conditions, the maximum CFX removal efficiency was reported as 65.57%, with the optimum values of pH=4.5, potato starch dose=225mg/L, CFX initial concentration=7.9, and retention time=95min. As demonstrated by the results of RSM, the current study follows the quadratic model (R2=0.987). Conclusion: Considering the appropriate results of CFX removal by potato starch, it is recommended to be used as a successful method to remove this contaminant from water sources.

The purpose of this study is to consider and compare applicability of modified chitosan nano fibers with functionalized mesoporous silica in Elecrtrospinning method for Direct Yellow 12 (D.Y.12) removal from aqueous solutions. Provided nano fibers were monitored and detected by TEM, Fe-SEM, XRD, FT-IR devices and Tensile testing. Subsequently, the effect of different operating parameters was achieving optimum condition for performing the adsorption process: such as nano adsorbent types, adsorbent dose, pH, initial dye concentration, contact time. And ultimately, finding suitable isotherms for adsorption of D.Y.12 was performed. Desirable conditions for removing by mesoporous silica chitosan nano fibers with SBA-15-NH2 adsorbent in 40 minutes contact, pH=2, the amount of adsorbent was 0.05 gr with 20 mg/l initial concentration. Also, the results have shown that D.Y.12 removal is following Langmuir and Freundlich isotherm model. The conclusions of this investigation have shown that CTS/SBA-15-NH2 nano fibers adsorb the D.Y.12 effectively and has great potential for purification of infected waste water with dyes.

Abstract In this research, the adsorption capacity of the Ziziphora plant ash collected from the village of Kib, Jurm township of Badakhshan province of Afghanistan country were studied on the removal of methylene blue from aqueous solutions. At first, the adsorbent was prepared in its natural form and then turned into powder. The powder obtained by the furnace is turned into ash at 500 °C. Natural adsorbent Ziziphora plant ash were characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). In this study, investigated the effects of various factors such as pH, contact time, initial dye of concentration, dose of adsorbent, ionic strength and temperature. Then, the thermodynamic parameters of the adsorption process such as ∆H^°, ∆S^° and ∆G^° were calculated. Thermodynamic investigations showed that the adsorption of methylene blue dye increased by increasing the temperature on the natural adsorbent of the Ziziphora plant ash and that indicating the adsorption process was endothermic. The kinetic adsorption conditions were investigated with first and second order kinetic models and the results showed that the methylene blue absorption process were followed to the second-order kinetics model. The isotherm of the adsorption process were studied using Langmuir, Freundlich, Tamkin and Dobbin-Radskvich models. The results of the experiments showed that the adsorption process followed by Langmuir model with a maximum adsorption capacity (59.1 mg.g-1). Keywords: Removal, Methylene blue, Isotherm, Ziziphora plant ash

In this study, chemical modification of MCM-41 mesoporous structure with {3-(2-aminoethylamino) propyl} trimetoxysilane was used as adsorbent for removal of Rhodamine B and Yellow 13. Adsorbent proficiency in removal of basic dyes was studied with parameters such as sorbent mass, pH, contact time and temperature. The results showed that as sorbent mass in 1-6 mg, contact time in 10-60 min, temperature in 25-65 ºC increased; removal of dyes increased in 60-100% in values. Optimal conditions were determined as sorbent mass in 6 mg, contact time in 60 min, temperature in 60 ºC and pH value in 4 and 8 for Rhodamine B and Yellow 13, respectively. Then, its application was investigated on removal of Rhodamine B and Yellow 13 from pharmacy and textile wastes, respectively. The maximum removal values of Rhodamine B and Yellow 13 in wastes using modified MCM-41 were 97.63 and 96.11%, respectively.

In the present study, Kit-6 silica mesoporous was chemically synthesized on the surface of silica coated magnetite core and functionalized by amine groups to obtained Fe3O4@SiO2@Kit-6 MNCs. The amino functional groups were chemically bonded on the surface of synthesized MNCs by post toluene reflux synthesis method and after characterization by XRD, FT-IR, EDX and SEM , it’s effectiveness as an adsorbent for the removal of reactive yellow160 dye from aqueous solutions was evaluated. Experimental factors affecting the dye removal efficiency such as sorbent weight (0.08 g), ionic strength (without salt addition), pH (4), sample volume (10 ml), and contact time (20 min) were optimized by Taguchi experimental design. The results revealed that removal efficiency of reactive yellow was more than 97% in optimal conditions. Pseudo first order, pseudo second order, intraparticle diffusion and Ilovich models were considered to evaluate the rate parameters. Kinetic data were fully fitted to the pseudo-second order kinetic model. Also, the adsorption equilibrium was represented with Langmuir, Freundlich and Temkin isotherm models. The fitting of data for dye sorption onto the Fe3O4@SiO2@Kit-6-NH2 suggested that the Freundlich model gave a better fit than the Langmuir and Temkin models. The results showed that Fe3O4@SiO2@Kit-‌6 nanocomposite modified with amine groups can be used as an alternative low cost adsorbent for removal of anionic pollutants from aqueous solutions.

Background and Objective: Wastewater from pharmaceutical industry has high chemical oxygen demand as a result of the presence of organic drugs and antibiotics. In order to meet the environmental requirements, several treatment methods like chemical and electrochemical methods have been widely applied due to their high ability to remove organic compounds from pharmaceutical wastewater. Therefore, the present study aimed to evaluate the efficiency of chemical coagulation/Electro-Fenton treatment method to degrade the organic matter-containing pharmaceutical industry wastewater. Materials and Methods: The experimental tests were carried out using batch mode. The chemical coagulation process was evaluated as a function of aluminum chloride concentration (25-300 mg/L) and pH (3-10). The effluent from chemical coagulation process was transferred to Electro-Fenton reactor. Effects of H2O2 concentration (100-4000 mg/L), reaction time (up to 120 min), voltage (10-30 V), and pH (3-10) were evaluated. The removal efficiency was determined in term of COD removal. Results: The results showed that the highest removal of COD in the chemical coagulation was 49% (coagulant dose of 200 mg/L, and pH of 7). In addition, the Electro-Fenton process could be eliminating of 93.5% of COD at the optimum conditions concentration (100 mg/L H2O2, voltage of 20, pH of 3, and contact time of 30 min). Conclusion: According to the results, it can be concluded that the combination of chemical and electrochemical processes was found to be effective methods for treatment of pharmaceutical wastewater in comparison to the application of each process separately. To reach to the maximum removal efficiency, the environmental parameters should be carefully controlled at their optimum values in each single process.

Background and objectives: Zerovalent iron nanoparticles (ZVIN) had high potential for nitrate removal from aqueous solutions due to high surface area and reactivity of them. The aim of this study was nitrate removal from aqueous solutions using environmentally friendly stabilized ZVIN. Methods: ZVIN were synthesized via chemical reduction by sodium borohydride. In order to preventing of ZVIN from being agglomerated these particles were stabilized by natural and green biopolymers of Guar gum and Xantan gum. Results: Xantan gum+ Guar gum stabilized ZVIN had the most efficiency for nitrate reduction from aqueous solutions. Results also revealed optimum contact times for nitrate removal were 100, 50 and 40 minutes for Bare, Guar gum and Xantan gum+ Guar gum stabilized ZVIN respectively. The optimum pH values for nitrate reduction were 2, 5 and 6 for Bare, Guar gum and Xantan gum+ Guar gum stabilized ZVIN respectively. Nitrate removal efficiency increased by increasing of ZVIN dosages (2 to 10 g/L) from 66.01 to 76.06, 83.43 to 91.36 and 89.47 to 96.16 percent for Bare, Guar gum and Xantan gum+ Guar gum stabilized ZVIN respectively. The results showed when nitrate dosages enhanced (from 100 to 400 mg/L) the efficiency of nitrate removal from aqueous solutions decreased from 66.17 to 47.97, 84.26 to 69.06 and 88.65 to 75.49 percent for Bare, Guar gum and Xantan gum+ Guar gum stabilized ZVIN respectively. Conclusion: Results of this study revealed that application of polymeric stabilizers caused increasing zero-valent iron nanoparticle efficiency in nitrate removal from aqueous solution.

The combination of magnetic nanoparticles with other adsorbents not only does not affect their magnetic properties, but also leads to the formation of adsorbents that improve the refining process.The aim of this study was synthesis of magnetic activated carbon by Fe3O4 and investigating its efficiency in adsorption of Lead from aqueous solutions. Magnetic adsorbent prepared by the method of sequestration and physical characteristics and structure of synthesized absorbent were determined by XRD and TEM. To remove the Lead from aqueous solutions, the Box-behnken design (BBD) of response surface methodology (RSM) was employed for optimizing all parameters affecting the adsorption process. The studied parameters were pH(5-9), temperature (25-45 0C) and the amount of adsorbent (0.5-2 g). 15 experimental runs were calculated by using BBD. The optimal condition for removal of Lead by synthesis of magnetic activated carbon by Fe3O4 nanoparticles were pH=7, 450C temperature and The 2 g of adsorbent. Kinetic studies of the adsorption process specified the efficiency of the pseudo second-order kinetic model and showed the optimal time was15 min, respectively. The maximum percentage of Lead removed after 90 min was 86.87%. The adsorption isotherm waswell fitted to Longmire model. The study showed that magnetic activated carbon has a high potential for Remove Lead. Therefore, it is believed that magnetized active carbon by keeping its physical and surface properties could be a suitable method to solve some related problems includingseparation and filtration.

In order to investigate the effect of pectin and dextran polymers on the adsorptive capacity of TiO2/bentonite nanosorbents, two nanocomposites of TiO2/pectin/bentonite and TiO2/dextran/bentonite were made by sol-gel method. Their investigation by FT-IR spectroscopy confirms the expected microstructure, and XRD results confirm the formation of anatase titania crystalline phase and also crystalline structure of bentonite. FESEM images showed the formation of TiO2 nanoparticles. These two nanocomposites were used for removing copper (II) ion from water and the effective factors on removal were investigated that maximum removal for both nanocomposites is in pH=7, adsorption dosage of 0.04g and temperature of 25°C, but contact times for two composites of TiO2/pectin/bentonite and TiO2/dextran/bentonite were equal to 20 and 30 minutes and adsorptive capacity for them were 40.16 and 22.12 mg Cu2+ per gram of adsorbent, respectively. Investigating the effect of interference ions had no considerable influence on removal efficiency. The results show that adsorption of Cu2+ by TiO2/pectin/bentonite and TiO2/dextran/bentonite nanocomposites follows Langmuir and Freundlich isotherms.

High soluability of nitrate ions in water cause the dysfunction of many existing treatment methods in the removal of this very dangerous ion from aqueous media. On the other hand, due to the need for in situ treatment methods, in particular for groundwater, the replacement of old inefficient methods with new compounds is required. In this study, for the first time, the efficiency of activated dendrimer- graphene oxide for nitrate removal from an aquatic solution was investigated. Experiments were performed in a batch reactor and the main factors of pH, reaction time, and concentration of PAMAM-GO were investigated. The highest removal efficiency was obtained as 90% at 0.025mg/L activated dendrimer- graphene oxide, pH of 7.5 and 15 min reaction time. The results showed that nitrate removal by activated dendrimer-graphene oxide is correlated with nanocomposite concentration, contact time, pH and initial concentration of nitrate. It seems that ion exchange between nitrate and chloride is the main mechanism of nitrate removal by activated dendrimer-graphene oxide according to functionalization of activated dendrimer-graphene oxide using hydrochloric acid. This method can be used as a suitable method for in situ removal of nitrate from water and wastewater due to the desirable ability of the nanocomposite and its optimal compatibility with the environment.

Aquaculture is one of the pioneers of healthy food production for humanity. According to the World Food and agriculture Organization (FAO), Aquaculture is the only source that has the most motivation for job creation and poverty eradication, among more than 70 breeding systems for human beings supplying living creatures, aquaculture is the only source. Among the problems of this ammonia wastewater industry is the aquaculture activities that result in the eutrophication of the water they receive, even at low concentrations of ammonia, may also have adverse effects on the tissues and physiological characteristics of rainbow trout. In this study, using coal, a coral shell and an steel wool that is covered with algae-bacterial biofilms and provides a suitable bed for physical and biological removal. The initial concentration of ammonia in the bioreactor was 6 mg / L and each of the media was tested separately. The rate of ammonia reduction in lignite, coral shell and steel wool has been 91.5%, 82.1%, and 78.8% during the 72-hour test period, respectively. The efficiency of ammonia removal in the bioreactor was based on the complement that the interactions of media with biofilm in the direction of physical, chemical and biodegradation, which yielded optimum efficiency compared to similar systems at a shorter time.

Background and aims: In recent years, non- thermal plasma could has yield desirable and successful results, in spite of some challenges and limitations. In particular, in emission control of mobile and stationary sources. CO pollutant, which is emitted from various emission sources is a toxic gas and employee exposure at indoor and outdoor workplaces is one of the main world challenges. The approach of present study is to investigate the key performance parameters of non- thermal plasma in CO treatment efficiency by considering of techno- economic considerations at reactor design. Methods: A coaxial reactor composed of two inner (quartz) and outer (pyrex) tubes as dielectric material, tungsten electrode as cathode and copper foil as anode material has been used. In this study, we have investigated the parameters of temperature, space time, reductant gas, and current intensity of power supply voltage on removal efficiency of the pollutant. Sample size and sampling methods are determined based on the experimental design (i,e,. in two and four level) and ASTM D5835 standard method, Respectively. Data analysis has been done by SPSS software (version 22). Results: The mean conversion of 28- 29% for carbon monoxide is achieved under optimum conditions by temperature of 110 oC, propane to carbon monoxide ratio of 0.05 and SIE of 1000- 1400 j/l. This is one of the main results of present research and suitable primary alternatives at future researches to utilize non- thermal plasma technology. Conclusion: In this study, the key parameters of space time and temperature have been shown significant effect on removal efficiency of pollutant. While, due to molecular- chemical structure of CO gas and complexity of participation during redox reactions in NTP reactor, the presence and concentration of propane gas has no significance effect on treatment efficiency. So, consideration of relevant parameters of electron density, gas mixture properties, and geometric characteristics in designing step could play key role in optimization of temperature conditions and pollutant space time.

Background and Objective: Water pollution due to heavy metals is a critical and increasing problem worldwide. In this study, removal of cadmium and lead heavy metals using a graphene oxide (GO) adsorbent was examined. Materials and Methods: GO nanosheets were synthesized through Hummer’s method, and its characterizations were examined using FTIR, XRD, and SEM. The effect of independent variables pH, contact time and initial concentration of the solution on removal efficiency of Cd2+and Pb2+ using response surface methodology was evaluated according to Box-Behnken experimental design. Applying quadratic model, adsorption rate of Cd2+ and Pb2+ achieved 99%. ANOVA was applied for statistical analysis of responses. Results: According to SEM images, the average size of graphene oxide sheets was 1 to 3 µm. After optimization through RSM, the adsorption capacity for Pb2+ and Cd2+ was 136 mg/g and 68 mg/g, respectively. Examination of the isotherms suggested that Cd2+ and Pb2+ adsorption follows Langmuir and Freundlich isotherm, respectively. Conclusion: the results show that the graphene oxide performed well in removing both Cd2+ and Pb2+ ions from aqueous solutions. The most influential parameters on the above-mentioned heavy metals adsorption were pH of the solution and the initial concentration.

Heavy metals are environmental pollutants that nowadays a lot of efforts are made to remove them. In this research, the sawdust modified with diethylenetriamine as an effective adsorbent for Fe (III) removal from water samples was conducted. First, the sawdust was modified by diethylenetriamine. SEM analysis showed that the particle surface is changed by modification. Then the effective factors in Fe (III) removal such as pH, adsorbent dose, shaker speed and contact time were studied and optimized. The optimum conditions were employed for various Fe (III) concentrations (20–300 mg L-1) and in all cases, the removal rate was significant. The adsorbent has high capacity for Fe (III) removal in a way that it removed more than 95.0±0.3 % of Fe (III) (50 mg/L) by 1.5 g/L of adsorbent in 15 minutes. The Langmuir and Freundlich isotherms were applied to the adsorption process and their constants were evaluated. The adsorption equilibrium data fitted well to Langmuir isotherm. The maximum Langmuir adsorption capacity of Fe (III) ions was 200.0 mg/g. According to kinetics experiments of Fe (III), the adsorption process had more conformity to pseudo-second-order kinetic model. This method was successfully applied for Fe (III) removal from potable water, well water, river water and industrial wastewater samples.

Background: Diazinon is one of the most important pesticides extremely used in agriculture. Since these compounds are resistant to biodegradation, the arrival of these compounds to water resources has become a serious environmental problem. Therefore, in the current work, the removal of diazinon from groundwater was investigated using advanced oxidation processes electro Fenton. Methods: the current work was conducted in lab scale. The effect of operating parameters such as initial concentration of diazinon (1-30 mg.L-1), pH solution(3-9), current density (1-10 mA.cm-2), reaction time (3-30 min), and dosage of H2O2 (20-100 µL.L-1) were investigated. Response surface methodology (RSM) was used to optimize the parameters and suggested model was analyzed using ANOVA. Results: On the optimum condition including initial diazinon concentration of 6.88 mg.L-1, pH solution of 3, the reaction time of 10 min, the current density of 8.18 mA.cm-2, and dosage H2O2 of 83.78 µL.L-1 removal efficiency of diazinon was found to be 98.5 %. Electrical energy consumption (EEC) was found to be 0.524 kWh.m-3. Moreover, the concentration of diazinon in groundwater was found to be 0.934±0.053 µg.L-1. Conclusion: According to the obtained results, electro Fenton process was found to be an efficient technique for successful removal of diazinon and other resistant ungradable organic compound from water sources.

Background and purpose: Fluoride is a major mineral pollutant in groundwater. Long-term exposure to high concentration of fluoride in drinking water causes dental fluorosis, skeletal and non-skeletal fluorosis. Therefore, highly efficient water treatment that could lower the concentration of fluoride in groundwater is a challenge. This study aimed at evaluating the efficiency of Nanofiltration and the effects of pressure and temperature on the removal of fluoride from groundwater. Materials and methods: The study was conducted in laboratory scale by pilot plant using Nanofiltration membrane (FILMTEC-NF90-4040). Raw water fluoride concentration was between 1.50 and 2.17 mg/L and pressures and temperatures were 4 to 12 bars and 10 to 30°C, respectively. Fluoride ion concentration was measured by spectrophotometry using a standard SPADNS method. Results: The lowest and highest efficiency rates in removal of fluoride were 30% and 70%, respectively. We also observed that increase in pressure and temperature increased efficiency and the membrane permeate flow rate. Fluoride concentrations in all water samples were less than standard levels. Conclusion: Nanofiltration was found with favorable efficiency in removal of fluoride from groundwater. Operating pressure and temperature are amongst the parameters that affect the performance of the process and increase the efficiency of fluoride removal by Nanofiltration.

Arsenic is one of the most hazardous pollutants of water resources which threaten human health as well as animals. Therefore arsenic removal from water resources is the priority of health programs. There are several ways to remove arsenic. In this study, reverse osmosis and zero-valent iron nanoparticles methods have been used in a laboratory scale. To perform the test, the variables of temperature, arsenic concentration, pH, iron nanoparticle concentration and mixing time were considered. The results indicated that in both methods of reverse osmosis and iron nanoparticle, through increasing arsenic concentration, arsenic removal efficiency has been also increased. At concentration of 1.5 mg per litre in reverse osmosis method, the maximum efficiency was achieved by 98% and 95.2% removal of arsenic respectively. The effect of temperature and pH were similar in reverse osmosis; by increasing these two variables, arsenic removal percentage also increased. The highest removal rates of 95.98% and 95.56% were observed at pH 9 and Temperature 30oC respectively. The results indicated that in iron nanoparticles method the arsenic removal efficiency increases by increasing mixing time and temperature, while it decreases with increasing pH.

Aniline is an almost undegradable compound found in many industrial effluents. It was the objective of this lab-scale applied-experimental study to determine the efficiency of the dissolved air flotation process in the removal of aniline from aquatic environments. Initially, the optimal conditions of pH and dosage of poly-aluminum chloride were determined using the jar test. The parameters involved in the dissolved air flotation process including coagulant concentration (10, 20, 30, 40, and 60 mg.l‒1), coagulation time (5, 10 , 15, and 20 min), flotation time (5, 10, 15, and 20 s), saturation pressure (3.5 / 3, 4, and 5.4 atmospheres), and turbidity (10, 20, 30, 40, and 60 NTU) on the reduction of COD and aniline were then calculated. Results showed that the dissolved air flotation process was capable of reducing COD and aniline by 86.6% and 95%, respectively (at pH = 6, an initial aniline concentration of 200 mg/ L, a coagulation time of 10 min, a flotation time of 20 s, a saturation pressure of 4 atmospheres, and a concentration of 20 mg/L PAC). It was also shown that removal efficiency declines with increasing turbidity. It may, therefore, be claimed that the dissolved air flotation process is an effective method of removing aniline from aquatic environments.

Nowadays, one of the most important environmental pollution is heavy metals industrial wastewater. Among the various types of heavy metals, chromium is one of the hazardous and toxic environmental pollutants. In order to prevent damage caused by chromium, it seems essential to prevent its entrance to the environment. The purpose of this study was modelling chromium removal using iron oxide nanoparticles through artificial neural network model for estimating the best removal Cr(VI) model. The optimum conditions (more than 90% removal efficiency) achieved were at pH=3, initial concentration of Cr = 10 mg/L; dosage of Fe2O3 = 1 g/L; contact time = 60 minutes, and temperature =25 . After backpropagation (BP) training, the ANN model was able to predict adsorption efficiency with a tangent sigmoid transfer function (Tansig) at hidden layer with 11 neurons and a linear transfer function (Purelin) at out layer. The Levenberg-Marquardt algorithm (LMA) was applied, giving a minimum mean squared error (MSE) for training and cross validation at the ninth place of decimal. The high correlation coefficient (R2ANN = 0.996) between the model and its closeness to the experimental coefficient (R2Exp = 0.998) showed that the model is able to predict the removal of Cr(VI) from aqueous solutions by iron oxide nanoparticles.

Background and Objective: Wastewater from pharmaceutical industry has high chemical oxygen demand as a result of the presence of organic drugs and antibiotics. In order to meet the environmental requirements, several treatment methods like chemical and electrochemical methods have been widely applied due to their high ability to remove organic compounds from pharmaceutical wastewater. Therefore, the present study aimed to evaluate the efficiency of chemical coagulation/Electro-Fenton treatment method to degrade the organic matter-containing pharmaceutical industry wastewater. Materials and Methods: The experimental tests were carried out using batch mode. The chemical coagulation process was evaluated as a function of aluminum chloride concentration (25-300 mg/L) and pH (3-10). The effluent from chemical coagulation process was transferred to Electro-Fenton reactor. Effects of H2O2 concentration (100-4000 mg/L), reaction time (up to 120 min), voltage (10-30 V), and pH (3-10) were evaluated. The removal efficiency was determined in term of COD removal. Results: The results showed that the highest removal of COD in the chemical coagulation was 49% (coagulant dose of 200 mg/L, and pH of 7). In addition, the Electro-Fenton process could be eliminating of 93.5% of COD at the optimum conditions concentration (100 mg/L H2O2, voltage of 20, pH of 3, and contact time of 30 min). Conclusion: According to the results, it can be concluded that the combination of chemical and electrochemical processes was found to be effective methods for treatment of pharmaceutical wastewater in comparison to the application of each process separately. To reach to the maximum removal efficiency, the environmental parameters should be carefully controlled at their optimum values in each single process. [ABSTRACT FROM AUTHOR]

In this study, a simple and efficient method for removal of Cr (VI) from water samples was developed using modified nanoclay. A facile one-step method was employed to produce Dithizone-Montmorillonite (Dz-MMT) composite. The synthesized composite was characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The effectiveness of the composite in Cr (VI) removal from aqueous solutions at different adsorbent dose, solution pH, contact time, and agitation rate were examined. The composite had a high uptake capacity in room temperature and removed Cr (VI) (10 mg/L) of about 98% from aqueous solutions by 3 g/L of adsorbent in 90 min. The equilibrium adsorption isotherm data are tested by applying both Langmuir and Freundlich isotherm models. The composite effectively removed Cr (VI) from water, and the maximum adsorption capacity obtained from the Langmuir equation was 76.9 mg/g. Adsorption kinetics of Cr (VI) on the composite followed the pseudo-second-order kinetic model. The method was applied to the removal of Cr (VI) in tap water, river water, and industrial wastewater samples from different parts of Khouzestan, Iran.

Background and Objective: Water pollution due to heavy metals is a critical and increasing problem worldwide. In this study, removal of cadmium and lead heavy metals using a graphene oxide (GO) adsorbent was examined. Materials and Methods: GO nanosheets were synthesized through Hummer’s method, and its characterizations were examined using FTIR, XRD, and SEM. The effect of independent variables pH, contact time and initial concentration of the solution on removal efficiency of Cd2+and Pb2+ using response surface methodology was evaluated according to Box-Behnken experimental design. Applying quadratic model, adsorption rate of Cd2+ and Pb2+ achieved 99%. ANOVA was applied for statistical analysis of responses. Results: According to SEM images, the average size of graphene oxide sheets was 1 to 3 μm. After optimization through RSM, the adsorption capacity for Pb2+ and Cd2+ was 136 mg/g and 68 mg/g, respectively. Examination of the isotherms suggested that Cd2+ and Pb2+ adsorption follows Langmuir and Freundlich isotherm, respectively. Conclusion: the results show that the graphene oxide performed well in removing both Cd2+ and Pb2+ ions from aqueous solutions. The most influential parameters on the above-mentioned heavy metals adsorption were pH of the solution and the initial concentration. [ABSTRACT FROM AUTHOR]

According to the present heavy metal pollution is a universal phenomenon, thus concerns about long-term effects of these metals, is increasing. The heavy metal cadmium as a toxic element exposure in humans can cause a variety of symptoms, because of its ability to accumulate in various tissues. The objective of this research was to evaluating the performance of the reverse osmosis system in cadmium removal from drinking water. The standard solution made in laboratory scale, then the removal efficiency of cadmium by semi-permeable membrane for reverse osmosis system (model: FT-30), under the influence of parameters concentration, pH and pressure were investigated. The results of this study showed that in the standard temperature 20 ºC , the concentration 50 ppb, pressure 350 (Kpa) and pH of about 6.8, cadmium removal efficiency by reverse osmosis system was above 98 percent. Thus, can be concluded that reverse osmosis, an ideal method to cadmium removal in areas with contaminated water to this metal.

Every day growth of population and industrial activities in recent decades causes to enter excessive amount of pollutants to water resources. Among these pollutants, textile industryâs dyes should be noted which exist in abundance in the sewage. Considering the toxicity of the pollutants, their removal from water resources is necessary. In this research, removal of high demanded dye, reactive red 74, from aqueous solution by zinc oxide nanoparticles was investigated and the affecting parameters such as solution pH, contact time, and sorbent mass on the removal efficiency were determined. In addition, isotherm and kinetic model of the adsorption process were studied. The results showed that the pseudo-second order kinetic equation could best describe the adsorption kinetics and the adsorption process well correlated with Langmuir isotherm.

Background and purpose: Fluoride is a major mineral pollutant in groundwater. Long-term exposure to high concentration of fluoride in drinking water causes dental fluorosis, skeletal and nonskeletal fluorosis. Therefore, highly efficient water treatment that could lower the concentration of fluoride in groundwater is a challenge. This study aimed at evaluating the efficiency of Nanofiltration and the effects of pressure and temperature on the removal of fluoride from groundwater. Materials and methods: The study was conducted in laboratory scale by pilot plant using Nanofiltration membrane (FILMTEC-NF90-4040). Raw water fluoride concentration was between 1.50 and 2.17 mg/L and pressures and temperatures were 4 to 12 bars and 10 to 30°C, respectively. Fluoride ion concentration was measured by spectrophotometry using a standard SPADNS method. Results: The lowest and highest efficiency rates in removal of fluoride were 30% and 70%, respectively. We also observed that increase in pressure and temperature increased efficiency and the membrane permeate flow rate. Fluoride concentrations in all water samples were less than standard levels. Conclusion: Nanofiltration was found with favorable efficiency in removal of fluoride from groundwater. Operating pressure and temperature are amongst the parameters that affect the performance of the process and increase the efficiency of fluoride removal by Nanofiltration. [ABSTRACT FROM AUTHOR]

Background and Objectives: Azolla Filiculoides as a non-living fern was used in a batch system to remove "Basic Blue 3", which is a cationic dye and a carcinogenic agent.Materials and Methods: We used a batch system by applying certain concentrations of dye contaminant and in the presence of a certain amount of adsorbent under optimum conditions. The main groups presenting in the Azolla cell wall were evaluated by acidification and alkalization of Azolla's media and then potentiometric titration with standard basic and acidic solutions. Results: It was observed that the removal efficiency of dye using non-living Azolla in accordance with the Langmuir isotherms was 82% for the initial dye concentration of 200 mg/lit under reaction conditions consisting of contact time 6 h, pH= 6, temperature 25 ˚C, and dose 5 g/lit. Qmax (maximum uptake capacity) by the activated Azolla at three temperatures 5, 25 and 50 ˚C was 0.732, 0.934, and 1.176 mmol/g respectively. ΔG (Gibbs free energy changes) was obtained for these temperatures as -0.457, -0.762, and -1.185 kJ/mol respectively.Conclusion: Removal of basic blue 3 using Azolla is an economically and effective method.

SBA-15 was functionalized with amine (–NH2) and 3-methoxy salicylaldehyde (3-MS) to form a mesoporous silica with Schiff base modified surface (3-MS–SBA-15). The materials were characterized and analyzed by Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), Nitrogen adsorption-desorption (BET), and X-ray diffraction (XRD) spectroscopy. The removal of Cu(II) and Cr(VI) metal ions onto 3-MS-SBA-15 was then studied from their aqueous solutions in order to investigate and optimize the effect of contact time, solution pH, adsorbent dose and temperature in batch system. The equilibrium data were analyzed using the Tempkin, Dubinin- Radashkovich, Langmuir and Freundlich isotherms. Freundlich and Langmuir isotherms were well fitted for Cu(II) and Cr(VI) adsorption process, respectively. The kinetics analyses showed that the total adsorption process was completely fitted with the pseudo-second-order kinetics model. The adsorption depended strongly on temperature, as the adsorption capacity decreased for Cu(II) while increased for Cr(VI) by increasing the temperature of the system, indicating the exothermic and spontaneous nature for Cu(II) and the endothermic and spontaneous nature for Cr(VI).

Arsenic which is present in the underground and surface water is one of the most toxic elements threating human health and animals. Arsenic has been removed in different type of ways. In this study Arsenic removal from drinking water and its decreasing rates were investigated by NZVI (nanoparticle zerovalent iron) to standard limit (I.e. 0.01 mg/lit) . The tests were conducted on reactor containing 100 ml water containing 1mg/L. Arsenic by virtue of Batch method. The mixture was executed in mixing was done an Oultrasnic device in order to have better mixture and complete distribution of nanoparticles in water. Then the arsenic was removed from the water by VATMAN paper of 0.45 Hm. The remained arsenic in the water was measured by ICP device. In this article the influence of the parameters including mixture time , PH ,NZVI and arcenic doses were examined . Having perfomed many tests the results showed that 1 mg arsenic can be removed 100 percent by 0.05 g NZVI in 8 min. It is possible to remove by 98 percent arsenic in 5-10 PH range. Iron nanopaticle way is an effective and rapid way to remove arsenic from water and various conditions have not considerable effect on it.

Abstract Among the pollutants, chromium coming from industrials sewage is a severe danger to environment and living organisms. Therefore, removal of this harmful cation is very important from viewpoint of environment. In this research, nickel oxide nanoparticles with an average size of 18 nm were prepared by chemical precipitation method and after characterizing by X-ray diffraction (XRD) and scanning electron microscopy (SEM), used as the sorbent for removing of Cr(III) from aqueous solutions. Also, the influences of different factors i.e. contact time, pH, sorbent amount and initial concentration of Cr(III) on removal efficiency were investigated. Evaluation of the obtained data with Langmuir and Freundlich isotherms indicates that the adsorption process is in good accordance with Langmuir model. Under optimal conditions, the maximum adsorption capacity of nickel oxide nanoparticles was found 17.5 mg g-1.

In this study the use of nano structured γ-alumina as a new and convince adsorbent for removal of cadmium ions from aqueous solution was investigated. The equilibrium adsorption level was determined as a function of the solution pH, temperature, contact time, initial adsorbate concentration and adsorbent doses. Adsorption isotherms of Cd(II) on adsorbents were determined and correlated with common isotherm equations such as Langmuir, Freundlich and Tempkin models. The isotherm data fitted well to the Langmuir isotherm. The maximum adsorption capacity for Cd(II) on nano structured γ-alumina was 76.92 mg g-1. The adsorption kinetics was investigated and the best fit was achieved by a second-order equation. The thermodynamic parameters such as free energy (ΔG0), enthalpy (ΔH0) and entropy changes (ΔS0) for the adsorption of Cd(II) were computed to predict the nature of adsorption process.

"n 800x600 Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";} Background: Intrauterine insemination (IUI) is a less expensive and less invasive treatment in comparison with other assisted reproductive techniques, and it has been widely used for a variety of indications as well as in the treatment of couples with infertility. The outcome of IUI may be affected by numerous factors but in this study, we evaluated the effects of cervical mucus removal undertaken before IUI on clinical pregnancy rates."n"nMethods : In this randomized clinical trial study, all infertile women who were candidates for IUI and attended Shahid Akbar Abadi Hospital during 2009 and 2010 were recruited. The participants were randomly assigned into two groups. Cervical mucus was removed prior to IUI in patients in group A but in group B, a classic IUI was done without removing the cervical mucus. Pregnancy rates were assessed in the two groups by serum levels of β-HCG and detection of fetus in the uterus. "n"nResults : 291 women including 143 in the classic IUI group and 148 in cervical mucus removal group completed the study. The pregnancy rates were 14.2% (21 pregnancies upon 148 cycles) in the cervical mucus removal group and 7% (10 pregnancies upon 143 cycles) in the control group (P=0.04, OR: 2.199; CI 95%: 0.997-4.85)."n"nConclusion: The findings showed that cervical mucus removal could result in a two-fold increase in pregnancy rate in comparison with classic IUI. Thus, we suggest this practical and noninvasive method to improve pregnancy rate in these patients.

Excessive amounts of fluoride in drinking water pose serious health problems. It is, therefore, essential to remove it from drinking water by appropriate water treatment processes down to standard levels for preventing the health risks associated. The aim of this study was to determine the performance of a kind of hybrid sorbent resin in removing fluoride from water. Batch experiments were performed to investigate adsorption isotherms and the effects of experimental parameters such as contact time (5-120 min) and pH (3-9). Results revealed that fluoride adsorption rate was initially rapid but continued at a slower rate before it reached equilibrium in 120 min. Optimum fluoride removal was observed at a pH range of 3-5.5. The data obtained from the experiments were fitted with Langmiur model.

Removal of toxic heavy metals from wastewater is an important environmental challenge. In this work, the Sheep Gut Waste (SGW) is used as a low-cost adsorbent for the removal of Pb2+, Fe3+, and Cu2+ from aqueous solutions and industrial wastewaters. Bath experiments were used to determine the best adsorption conditions. The effects of contact time, pH, initial metal concentration, and amount of adsorbent on the adsorption process were studied. The time required for the removal of metal ions was about two hour. Effective removal of metal ions was demonstrated at pH values of 4-8. The maximum adsorption capacities of Cu– SGW, Fe- SGW and Pb-SGW were 9.76 mmol g-1, 11.19 mmol g-1, and 3.01 mmol g-1, respectively. Metal adsorption onto SGW was evaluated by Langmuir and Freundlich isotherms. Results indicate that the Langmuir isotherm model is the most suitable one for the adsorption process using sheep gut waste.

Arsenic exists in compounds present in the Earth's crust in various concentrations. High concentrations of arsenic in drinking water may cause skin and lung cancers or other diseases. Unfortunately, in some urban and rural areas inKurdistanProvince(e.g., Delbaran), arsenic concentrations of above 70 ppb are observed in groundwater resources, which is higher than EPA standards. The objective of this study was to evaluate the effects of using membranes for arsenic removal from drinking water. To study the practical effects of different membranes on arsenic removal, five types of membranes, namely, PVD, TFC-SR, FT30, TFC-ULP, and BW30, were used. Based on the two parameters of effluent flux and arsenic removal efficiency (which was above %95), TFC-SR was selected as the best membrane. Atmospheric pressure, temperature, and pH were the parameters tested for this membrane to obtain an optimum atmospheric pressure of 10 bars and an optimum pH level of 7.57. Results also showed that higher temperatures increased both the effluent flux and arsenic removal.

Introduction: water source pollutant, result of direct releasing of metal ions to environment, is one of the most important problems in the world. In this study, efficiency of synthesized iron oxide nanoparticles in presence of extract tangerine Peel was investigated for removal of copper ions in the solution. Methods: Iron oxide nanoparticles were prepared by co-perception method using Tangerine Peel extract. The Tangerine Peel extract used to decrease of nanoparticle size and to prevent of particles coagulation. The effect of different parameter includes initial copper concentration, adsorbent dose, contact time and solution pH was investigated on removal of copper. The experimental data were fitted to Langmuir and Freundlich isotherm models. Results: The results showed that the removal efficiency was increased by increasing of pH and decreased from 88% to 81% by increasing of initial copper concentration from 5 mg/l to 10 mg/l. The most removal percent was 92% when copper concentration was 5 mg/l and adsorbent doze was 0.6 g in 100 ml suspension. Conclusion: The results showed the removal efficiency is depended on to pH. The increase of copper concentration decreased the removal efficiency. Adsorption experimental data were in good accordance with Langmuir isotherm model. The synthesized iron oxide nanoparticles with extract Tangerine Peel is a good adsorbent for removing of heavy metals from aqueous solution. [ABSTRACT FROM AUTHOR]

Background and Objectives: Toxic contaminants such as inorganic anions cause water pollution and create some potential risks to human health and the environment. Nitrate as an inorganic anion is one of the most important sources of pollutants for surface and underground waters. Regarding adsorptive properties of zeolite, it is widely used to absorb water and wastewater pollutants. The aim of this study was to investigate the nitrate removal from the aqueous solutions by using zeolite clinoptilolite modified by surfactants. Materials and Methods: In this laboratory study, the zeolites granulated and modified by surfactant Hexadecyltrimethyl Ammonium Chloride and cetylpyridinium bromide were investigated through the impact of the parameters such as pH (3 to12), time (30 to 300 min), initial concentration of nitrate (20 to 250 mg/L), and adsorbent dose (5 to 20 grams per liter) in a batch laboratory scale. For better understanding of the adsorption process, the experimental data were analyzed with Langmuir and Freundlich isotherm models and kinetic adsorption studies. Results: The results showed that nitrate removal efficiency had a reversed relationship with adsorbent dose and direct contact time,The results also showed that the removal of nitrate from solution is inversely related to the initial nitrate concentration. The maximum nitrate removal efficiency for both absorbents was in pH=7. Time of nitrate removal was obtained by 180 min in equilibrium. The data for both absorbents follow Freundlich adsorption isotherm and pseudo-second degree kinetics. Conclusion: The results of the study showed that the Iranian surfactant-modified zeolites could be used effectively for removal of nitrate. Considering its low cost, easily availability and modification, the zeolites can be used to remove nitrate from underground waters. [ABSTRACT FROM AUTHOR]

Considering contamination of drinking water to arsenic in some villages ofIran. In order to develop a simple method for household water treatment in rural areas, efficiency of modified activated alumina with iron compounds- a product of Alcan Company with trade name of AAFS-50- was studied Equilibrium batch experiments were carried out using shaker incubator and arsenic was analyzed with SDDC method. Effects of initial concentration of arsenic, adsorbent dose, oxidation state of arsenic, pH and oxidation with chlorine on adsorption were studied. Correlation coefficient of Freundlich and Laungmuier isotherms for As(V) and As(III) were 0.964 , 0.991 and 0.970, 0.978 respectively . These results show that adsorption of arsenic on modified activated alumina is compatible with both models specially Laungmuier models. Removal efficiency of As(V) at 0.5 ,1 and 2 hr increased with doubling the adsorbent dose from 44.8 to 72%, 69.6 to 90.8 and 92.4 to 98% ; respectively. Experiments using different concentrations of arsenic showed that adsorption of arsenic on activated alumina are a first order reaction that is, rate of reaction is dependent on intial; concentration of arsenic. Removal efficiency for concentration of 0.250 mg/L of arsenic, with increasing of reaction time from 15 min to 60 min, increased 1.54 times and reached from 61% to 94%. During 2hrs, removal of As(V) and As(III) were 96% and 16% respectively. Using 1.5 mg/L Chlorine as oxidant agent, removal of As(III) was increased to 94%. In the case of pH effect, rate of adsorption increased for arsenite, with increasing of pH to 8 and decreased with more increasing, so that adsorption at pH 14 was equal to pH 2. For arsenate, the most adsorption was observed at pH between 6 to 8 . These results show that by using the studied activated alumina, there will not be need for adjustment of pH and the activated alumina used in this study could have application as a safe adsorbent for removal of arsenic from drinking water in simple household treatment systems in form of adsorptive column.

Background and purpose: Nitrate contamination in aqueous solution has become an increasingly serious environmental problem. Hence, in this study removal of nitrate in aqueous solution was reviewed using electrocoagulation (EC) and electro-fenton (EF) processes for Fe electrodes. Materials and methods: In the present study, an EC and EF reactor in a lab scale to an approximate volume of 1 liter was proposed for removing of nitrate polluted water which was equipped with four Fe-Fe electrodes with dimensions 200 x 20 x 2 mm. The effects of operating parameters such as initial nitrate concentration, applied voltage (10-30 V), initial pH of the solution (3-12), different initial hydrogen peroxide (for EF process) and reaction times (5-30 minutes) were evaluated. Results: The batch experimental results showed that initial nitrate concentration, initial pH of the solution, different applied voltages, initial H2O2 concentration and reaction times were highly effective on the nitrate removal efficiency in these processes. Based on the results, over 88% of nitrate in optimum condition (pH = 8, applied voltage = 30 V, initial nitrate concentration of 100 mg/l) have been removed in EC process. In addition, the application of EF process can remove 93% of nitrate at pH = 3, applied voltage = 30 V, initial nitrate concentration of 100 mg/l and 5 ml H2O2/l. Conclusion: Both EC and EF technologies can highly remove nitrate in aqueous solution. However, it was found that much better nitrate removal efficiency could be achieved by EF process than by EC process at the same condition. [ABSTRACT FROM AUTHOR]

Background and purpose: Ammonia in form of ammonium ions pollutes the acceptor water through industrial, domestic and agricultural wastewater. Ammonium ions are toxic and could decrease the dissolved oxygen in water and endanger the aquatic life. One of the conventional methods for removing ammonia from water and wastewater is exchanging the ions using zeolites. The aim of this study was to assess the efficacy of zeolite Clinoptilolite in removing ammonia from water, in both batch and continuous systems. Materials and methods: In this study batch experiments were exposed to different concentrations of natural Clinoptilolite (5, 10, and 50 g/l) with aqueous solution containing ammonium ions (1, 5and, 10 mg/l) in different exposure times (10 to 240 minutes). The continuous experiments were also conducted at ammonium concentrations of 5 and10 mg/l. Results: The maximum ammonium absorption occurred at pH=7 and in 60 minutes exposure time. Increase in initial concentration of ammonium increased the sorption capacity. Also, sorption capacity decreased when the absorbent material increased. Considering higher correlation coefficient (R2) the isotherm obtained in this study matches the Freundlich isotherm model. The results of column tests showed longer time to reach the breakpoint when initial concentration of ammonium decreased. Breakpoints for ammonium concentrations of 5 and 10 mg/l were 6.45 and 6.32 mg/g, respectively. Conclusion: This study proved that ion exchange using zeolite Clinoptilolite is a low cost method that could result in complete removal of ammonium from water. [ABSTRACT FROM AUTHOR]