Quality evaluation and stability index determination of Qom rural drinking water resources

Background and Aims: Corrosion and scaling are among the problems that despite science advancement, water facilities are still faced it. Corrosion lead to financial and health losses on water supply system and consumer, scaling also causes clogging and head loss in water supply network. Therefore, the aim of this study is to determine the corrosion and scaling potential of Qom villages water supply sources.Materials and Methods: In cross-sectional study 100 samples in 12 months from 2011 to 2012 were collected to verify the water quality according to 1053 standard of Institute of Standards and Industrial Research of Iran (ISIRI). Then water corrosion and scaling were studied using Langelier, Ryznar, Aggressive and Puckorius indexes.Results: The results showed that the Langelier index, Reynar index, aggressive or corrosion index and index Puckorius were -1.62 (±0.11), 10.5 (±0.17), 12.03 (±0.14) and 9.92 (±0.13) respectively. Physical and chemical parameters of the water showed that the mean pH, TDS, total hardness, turbidity, calcium, magnesium, fluoride, sodium, ammonia, phosphate, and chloride were 7.27, 1205.29 mg/L, 435.661 mg/L CaCO3, 0.747 NTU, 132.29 mg/L, 25.58 mg/L, 0.68 mg/L, 245.50 mg/L, 0.015 mg/L, 0.17 mg/L and 231.22 mg/L respectively.Conclusion: The amounts of color, TDS, turbidity, pH, calcium, magnesium, fluoride and ammonia in the study areas are in satisfactory and acceptable status compared to the internal standard but the amount of phosphate, hardness and chloride in this area were exceeded from permissible limit. Comparison of four stability index also showed that water conditions in all parts of this study are located in corrosive range.Key words: Drinking water, Villages of Qom province, Stability inde

Optimization of phenanthrene contaminated soil washing using Response Surface Methodology

Background and Aims: Soil washing using surfactant is a promising technology for PAHs removal from soil transferring them into liquid phase. The performance of this process is influenced by several factors such as surfactant concentration, washing time, liquid:soil ratio (L/S) and the presence of natural organic matter, which in the present study was totally investigated using the nonionic surfactant Tween 80.Materials and Methods: Surfactant solution with three various concentrations of 500, 2750, 5000 mg/l, at liquid:soil ratios of 10, 20, 30 v/w (ml/g) containing three concentrations of 0, 10, 20 mg/l humic acid (asNOM) was added to phenanthrene contaminated soil samples. The samples were placed on a shaker for timeinterval of 2, 13 and 24 hours, then it was injected to HPLC for phenanthrene concentration analyze. This research was conducted on the basis of central composite design by using response surface method (RSM) in 29 experimental runs.Results: Maximum removal efficiency (77.35%) was achieved under the experimental conditions of 5000 mg/l surfactant concentration, 30 v/w liquid:soil ratio, absence of humic acid and 24 h washing time. Surfactant concentration with impact value of 82.03% was the most effective parameter in phenanthrene removal. L/S was also the other significant factor (P<0.0001), but humic acid and washing time were, statistically,insignificant. The interaction between surfactant concentration and L/S was significant too.Conclusion: Considering the conditions of Iran’s soils containing 3-6 percent organic matter and based on the suggestions of RSM with 95.10% desirability, the optimum conditions for washing high- phenanthrene soil (about 500 mg/kg) with minimum washing time of 2 hours were as 5000 mg/l surfactant concentration, 30 v/w (ml/g) liquid:soil ratio, and 2.1 mg/l humic acid concentration (6.30%).Key words: phenanthrene, soil washing, surfactant Tween 80, optimizatio

COVID-19 control management in central corona hospitals using SWOT and QSPM matrices: A case study in Kashan central hospitals

Background: During the COVID-19 pandemic, hospitals have been the most important centers for the virus spread. Therefore, this study aimed to evaluate the management of infection control in central corona hospitals in Kashan using the quantitative strategic planning matrix (QSPM) matrix. Methods: The existing documents studied the strengths, weaknesses, opportunities, and threats of the organization identified by environmental health experts. The internal and external factors were identified as internal factor evaluation (IFE) and external factor evaluation (EFE) matrices, respectively, then, prioritized and weighted. In the next step, the SWOT matrix was formed and the type of used strategy by the organization was determined, and solutions to improve the current situation were presented by experts. Finally, the attractiveness table was compiled and weighted using the QSPM method to prioritize the proposed strategies. Results: After identifying 25 strengths, 28 weaknesses, 15 opportunities, and 13 threats, weighting was performed, the final score for internal and external factors was 2.6475 and 2.3825, respectively. The final strategy for implementing COVID-19 disease control in the studied hospitals was the Conservative Strategy (WO). Based on this, six control strategies were presented. The priority and attractiveness of each strategy were evaluated using the QSPM matrix. Finally, the strategy of “structuring the system and providing and upgrading the equipment and infrastructure facilities” was implemented as a priority. Conclusion: According to the results, the combination of SWOT (Strengths, Weaknesses, Opportunities, and Threats) and QSPM methods can play an efficient role in identifying and evaluating the factors affecting the management of the COVID-19 pandemic in hospitals and further developing and prioritizing control strategies for this infectious disease. Keywords: COVID-19, Environmental health, Hospitals, Research desig

Application of modified bentonite using sulfuric acid for the removal of hexavalent chromium from aqueous solutions

Background: Environmental contamination by chromium (Cr) has become an important issue due to its adverse effects on human health and environment. This study was done to evaluate the application of modified bentonite using sulfuric acid as an adsorbent in the removal of hexavalent Cr from aqueous solution. Methods: Adsorbent features were determined using x-ray diffraction (XRD), fourier transformed infrared spectroscopy (FTIR) and scanning electron microscope (SEM) techniques. Thereafter, the effect of pH, contact time, adsorbent dosage and different concentrations of Cr was investigated. The experimental data was fitness in terms of kinetic and equilibrium adsorption processes. Results: The maximum capacity (Qm) of Cr(VI) according to Langmuir model was obtained at 4.21 mg/g. The experimental data properly obeyed the Longmuir and pseudo-second-order models. The highest percentage of Cr(VI) adsorption was observed at pH = 3 and the process after 60 minutes reached the equilibrium state. Conclusion: In Langmuir expression, the dimensionless constant separation term (RL) values for the adsorption of Cr onto the modified bentonite was in the range of 0-1, indicating that the adsorption is a favorable process and the modified bentonite has good potential in removing hexavalent Cr using sulfuric acid. Keywords: Modified bentonite, Sulfuric acid, Adsorption, Hexavalent chromium, Aqueous solutio

Evaluation of Efficiency of Persulfate Activated with Ultrasonic Waves in Phenanthrene Degradation from Soil Environments by Central Composite Design Method

Background and Purpose: PAHs and their derivatives have a complex and stable molecular structure with low biodegradability and have from the compounds in the crude oil. The object of this study was to evaluation of efficiency of persulfate activated with ultrasonic waves in Phenanthrene degradation from Soil environments by central composite design. Methods: The soil samples were homogenized and filtered using a 2.0 mm sieve. Then, Phenanthrene solution (PHE) was added into soil sample. In order to carry out the chemical oxidation process, Probe Ultrasonic Wave Generator place out inside the reaction chamber Contains Persulfate/soil slurry environment. A central composite design (CCD) was used for designing and optimizing the operation parameters such as sodium Persulfate concentration, Ultrasound intensity and contact time. The synergy of processes in the system was also studied in optimal conditions. Results: ANOVA results indicated that the effect of persulfate concentration, ultrasound intensity and contact time and binary interactions were significant. The Persulfate concentration, has the most significant effect on the phenanthrene degradation. The highest efficacy of the phenanthrene degradation (%58.05) was obtained in the conditions: initial concentration of persulfate =0.2 mol, ultrasonic waves with power = %70, and contact time = 120 min. By applying S2O8-2 in a separate approach after 120 min the efficiency was 9.2% while at these conditions, the efficiency of the ultrasonic process was only 3.4%. By contrast, the combined PS/US process could remove %58.05 of phenanthrene. Conclusion: The results of this study indicated that, the application of the PS/US process is an effective method for purification of Phenanthrene contaminated soils

Data on modeling of UV/Na2S2O8/FeS2 process in amoxicillin removal using Box-Behnken methodology

Among the pharmaceutical compounds, antibiotics have been paid specific consideration, due to their acute and chronic toxic effects on organisms. Amoxicillin (AMX) is used widely for treatment of bacterial infections. About 80% of amoxicillin excreted unchanged and enters the aquatic environment through different routes including disposal of municipal wastewaters, hospital wastewaters and farm wastewaters. In this study degradation of amoxicillin by UV/Na2S2O8/FeS2 process was evaluated. According to the results, the R-squared and adjusted R-squared were 0.9877 and 0.9828, respectively. The AMX removal efficiency was 93% at optimum conditions. Thus, UV/Na2S2O8/FeS2 process is a useful process for amoxicillin removal. Keywords: Amoxicillin, Box-Behnken, UV/Na2S2O8/FeS

Evaluation of Diazinon Adsorption from Water Solutions Using Magnetic Carbon Nano-Tubes with Fe3O4

Background and objective: Insecticides are one of the most important pollutants in water. Diazinon is one of the phosphorus pesticides that can be found in aquatic ecosystems in Iran. The toxic effect of diazinon is inhibition of the enzyme acetyl cholinesterase (Ache). In this study, MWCNT/ Fe3O4 efficiency was investigated. Materials and Methods: In this study, co-precipitation method was used for the Fe3O4 synthesis on multiwall carbon nanotube. The pH, contact time, adsorbent dose, pollutant concentrations and temperature parameters were investigated. Diazinon was measured by Gas chromatography method. Results: The results showed that the optimum conditions for diazinon removal were pH 6, contact time of 15 minutes, and  adsorption dose of 0.6 g/l. So, the absorption efficiency increases with increasing of temperature and decresing of pollutant concentration. The diazinon adsorption corresponded with Freundlich isotherm (R2> 0.99) more than Langmuir isotherm model (R2> 0.90). Conclusion: The results show that the magnetic carbon nanotubes with Fe3O4 can be suitable adsorbent for diazinon removal from aquatic environment.&nbsp

Enhanced tetracycline degradation with TiO2/natural pyrite S-scheme photocatalyst

Abstract In this study, TiO2 nanoparticles were employed as a photocatalyst for the degradation of tetracycline (TC) under visible light irradiation. The TiO2 nanoparticles were decorated on natural pyrite (TiO2/NP) and characterized using XRD, FTIR, and SEM–EDX methods. This study evaluated the impacts of various operational parameters such as pH, catalyst dosage, initial TC concentration, and light intensity on TC removal. The findings revealed that under optimal conditions (pH 7, catalyst: 2 g/L, TC: 30 mg/L, and light intensity: 60 mW/cm2), 100% of TC and 84% of TOC were removed within 180 min. The kinetics of TC elimination followed a first-order model. The dominant oxidation species involved in the photocatalytic elimination of TC was found to be ·OH radicals in the TiO2/NP system. The reuse experiments showed the high capability of the catalyst after four consecutive cycles. This study confirmed that the TiO2/NP system has high performance in photocatalytic TC removal under optimized experimental conditions

Efficiency of Polymeric Membrane Graphene Oxide-TiO2 for Removal of Azo Dye

Achieving the desired standard of drinking water quality has been one of the concerns across water treatment plants in the developing countries. Processes such as grid chamber, coagulation, sedimentation, clarification, filtration, and disinfection are typically used in water purification plants. Among these methods, unit filtration which employs polymers is one of the new technologies. There have been many studies about the use of semiconductive TiO2 with graphene oxide (GO) on the base of different polymeric membranes for the removal of azo dyes, especially methylene blue (MB). Polymeric GO-TiO2 membranes have high photocatalytic, antifouling property and permeate the flux removal of organic pollutants. The aim of this study was to investigate the characteristics of different polymeric membranes such as anionic perfluorinated polymer (Nafion), cellulose acetate, polycarbonate (PC), polysulfone fluoride (PSF), and polyvinylidene fluoride (PVDF). The result of this study showed that the GO-TiO2 membrane can be used in the field of water treatment and will be used for the removal of polycyclic aromatic hydrocarbons (PAHs) from wastewater

Purification Method of Industrial Waste Water with Hexavalent Chromium Removal

Background and Objective: Common sources of chromium in wastewater are electroplating and leather industries. Thus, the aim of this study is synthesis activated carbon fiber/zinc oxide composite to remove of Cr (VI) from polluted water.Materials and Methods: The immobilization of zinc oxide (ZNO) on activated carbon fiber (ACF) was accomplished by Sol-gel method and synthesized activated carbon fiber composite (ACF/ZNO),was used to reduction of chromium under ultraviolet light from aqueous solution. And characterized by BET, SEM, XRD. After the design of the reactor, hexavalent chromium stock solution, using a solution of potassium dichromate (K2Cr2O7) in distilled water, were prepared. The residual concentration of chromium was analyzed by the 1,5-diphenylcar-bazide method using a spectrophotometer at a wave length of 540 nm.Results: The XRD results showed that a typical hexagonal phase for ZnO. The SEM results showed that zinc oxide were distributed on the ACF surface. It showed that the BET surface area was related to adsorption capacity for composite. Parameters effect, including concentration of pollutants, composite dose and pH were studied.Conclusion: In optimal conditions, initial chromium concentration of 5 mg/l, composite dose 2.5 g/l and a pH of 3, after 120 minutes, system removal efficiency was 85%.</p