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A complex mixture of organic pollutants (EOPs) enters the environment, which has potential impacts on aquatic life and human health.This cross-sectional study investigated dermal and inhalation exp...

The municipal solid waste transfer stations (MSWTSs) affects both the environment and human health. The present study aimed to investigatethe Concentrations of BTEX (benzene, toluene, ethylbenzene ...

Background: Military personnel compared to civilian people are more prone to cardiovascular disease (CVD) however the relationship between dietary fatty acid intake and CVD markers is not well established in them. The aim of this study was to investigate the relationship between dietary fatty acid intake and erythrocyte membrane fatty acid content as well as serum adiponectin and lipid profile in military personnel.Method: Four hundred military personnel were recruited from the population of army individuals in Iran. The dietary fatty acid intake was determined from a food frequency questionnaire (FFQ) completed by each military personnel. Fasting blood samples were also obtained from each individual and fatty acids derived from erythrocyte membrane, serum lipid profile and adiponectin levels were measured. The correlation between dietary fatty acid intake and biochemical parameters were analyzed by univariate regression analysis.Results: There was a negative significant association between total saturated fatty acid, lauric, myristic, palmitic acid and a positive association between eicosapentanoic acid and docosahexanoic acid in erythrocyte-membrane with adiponectin level. Moreover, we found that dietary SFA intake had a significant negative correlation with serum adiponectin level. In addition, dietary SFA intake showed a significant positive correlation with serum total cholesterol and LDL-c levels. In contrary, dietary PUFA and MUFA intake revealed a significant inverse association with serum cholesterol level and LDL-c. Conclusion: We concluded that dietary SCFAs might be associated with lower serum adiponectin and higher cholesterol levels, and suggest that CVD risk factor might be suppressed, by reducing dietary SCFA intake.

Background Physical activity is one of the modulators of the cancer risk and survival factors. Therefore, the aim of this study was considering of pre and post interval exercise training on expression of MCT-1, GLUT-1, PFK-1 and p53 as a key metabolic regulators in azoxymethane-induced experimental colon cancer Methods Forty-eight male BALB/c mice were equally randomized into 6 groups: I: control (C); healthy animals, II: Exercise (E), III: tumor induction (T); animals received AOM for inducing colon cancer, IV: AOM + exercise (TE); animals with colon cancer underwent 8 weeks of the interval training protocol after tumor establishment, V: exercise + AOM (ET); animals received exercise protocol one week before AOM consumption, and (VI) exercise + AOM + exercise (ETE); animals received exercise protocol one week before and after AOM consumption (about 15 weeks) Groups III-VI were weekly-received AOM (as a carcinogenic agent, 10 mg/kg s.c) in three consecutive weeks to induce colon cancer. Interval exercise training was begun at 16–18 m/min, 10–14 min, 5 days/week for 6 weeks. Results The results showed that the tumor significantly increased mRNA and protein of MCT1 in the tumor group compared to the control group (p

Background: Organophosphorus pesticides (OPPs) have a wide application throughout the world and exert adverse effects on human health. Moreover, these chemical compounds are responsible for thousands of deaths per year worldwide. Kinetic and mathematical models could be used to optimize the application of pesticides on fruits and vegetables and monitor their residues. Objectives: The present study aimed to model the dissipation of diazinon and chlorpyrifos in different conditions, such as household conditions (e.g., storage at room and refrigerator temperatures, as well as cooking) and field condition for greenhouse tomatoes. Methods: A multi-residue analysis of diazinon, chlorpyrifos, and their oxon derivatives was established by gas chromatography-tandem mass spectrometry. The limit of quantification (LOQ), recovery, precision, linearity, and the limit of detection (LOD) were evaluated to ensure that the method was able to effectively determine the studied pesticides in the tomato samples. The linear and nonlinear kinetic models were presented for chlorpyrifos and diazinon residues in tomato using zero-order, first-order, and second-order equations. Results: Based on the best fitting models for diazinon in the case of laboratory treatment at the refrigerator, room, and boiling temperatures, the half-lives were calculated as 18.79 days, 11.41 days, and 45.39 min, respectively. The half-life of diazinon was lower than that of chlorpyrifos in both field and laboratory treatments. Conclusion: Modeling the removal of the pesticides indicated that the nonlinear first- and second-order models were the best fitted models for the dissipation of both pesticides in field and post-harvest conditions.

The presented research was to prepare the iron-doped SBA-15 catalyst (Fe-SBA-15) and to apply it as a heterogeneous catalyst in the ultrasound (US) and ultraviolet (UV) processes for developing the heterogeneous activation of peroxymonosulfate and degrading the bisphenol S (BPS). The effect of important reaction parameters on the removal of BPS by the Fe-SBA-15/UV/US/PMS process was investigated. Simultaneous use of US and UV irradiations with Fe-SBA-15 for activation of PMS led to significant degradation of BPS. The BPS degradation rate was developed at the presence of higher PMS and Fe-SBA-15 dosages at pH = 7. It was also found, based on the quenching tests, that both OH• and SO4 •- radicals have a superior role in the degradation of BPS and dominant species are the sulfate radicals. Complete removal of BPS and 67 mineralization degree was obtained at the optimum conditions after 60 min reaction. Based on the activated sludge inhibition assessment, it was detected that the toxicity of the solution significantly decreased in this system. Moreover, according to the BOD5/COD ratio of samples, it was found that the biodegradability of treated samples is improved. Furthermore, it was confirmed that Fe-SBA-15 can be reused in five consecutive cycles and the removal efficiency was acceptable at 94.2. © 2019 Desalination Publications. All rights reserved.

This study aimed to evaluate the feasibility of recycling alum-based sludge (AbS) generated from drinking water treatment facility for turbidity removal. A response surface methodology (RSM)-based modeling and factor analysis were first implemented for assessing the optimal conditions of four independent factors, such as initial turbidity concentration, humic acid (HA) concentration, pH, and AbS dose on the water turbidity removal via the use of AbS as a coagulant agent. The optimum values of the four main variables were determined as initial turbidity concentration = 59.65 NTU, pH = 5.56, AbS dose = 19.71 g/L, and HA concentration = 12.28 mg/L, and at the optimum conditions, the percentage of turbidity removal was obtained as 94.81 (± 1.01)% for real water. At the optimum conditions of AbS usage as a coagulant for real water samples, monitoring of water quality parameters of the process indicated no health-related concerns in terms of hardness (all types), alkalinity, pH, residual aluminum, and even bacteriological (fecal and total coliforms) contamination. The results indicated a potential for AbS recycling in the treatment plant as a coagulant agent, although some requirements should be fulfilled before full-scale application.

Abnormal use of antibiotics and discharging them into the sewage systems bring about serious and dangerous harms to the environment. The present study aims at the feasibility evaluation of amoxicillin removal from the aqueous solutions by means of enzymatic oxidation by taking advantage of response surface method based on Box–Behnken model. The present study is a library research. Therefore, the experiments are carried out in a laboratory for discontinuously evaluating the effects of independent variables such as temperature, pH, contact time, enzyme activity, hydroxybenzotriazole mediator concentration and the antibiotic concentration. The remaining amoxicillin’s concentration has been determined by HPLC device. To implement the experiments, Box–Behnken model was used for measuring the variables’ mutual effects. One-way analysis of variance was used for data analysis. The results showed that enzymatic oxidation output increases with the increase in contact time and enzymatic activity as well as with a decrease in the antibiotic’s concentration. The highest and the lowest removal percentages were 91.5 and 5.36, respectively. According to the high amounts of R2 (0.974) and R2adj (0.955), it can be said that the selected model is appropriate for data analyses. Finally, a quadratic polynomial model was applied as the best model of choice for figuring out the relationships between the main variables and amoxicillin elimination output. Response surface method can be effective in amoxicillin oxidation optimization and laccase can be used for amoxicillin elimination. © 2018 Desalination Publications. All rights reserved.

In this study, diuron abatement in aqueous medium and the remediation of wastewater from a pesticide manufacture were studied by the E-peroxone process, using carbon felt modified with N-doped rGO (N-rGO/CF) as cathode and Ti/PbO2 anode. Compared with the unmodified CF, the N-rGO/CF displayed a higher response current, improved oxygen reduction activity, and larger BET specific surface area. Also, the modified CF provided a higher H2O2 production rate. The influence of several effective parameters on the diuron degradation rate in aqueous medium by the E-peroxone process was systematically explored by central composite design-response surface methodology; the approach suggested the optimal operating condition at pH of 9, applied current of 500 mA, Na2SO4 of 0.05 M, ozone flow of 1 L min−1, and operating time of 15 min to attain the maximum removal of diuron. At the optimal condition, N-rGO/CF cathode increased diuron degradation rate and decreased electrical energy consumption rather than CF cathode, in the E-peroxone system. Radical quenching experiment and degradation pathway of diuron revealed that hydroxyl radicals were the dominant reactive oxidants. A possible degradation mechanism was proposed based on hydroxylated and demethylated products identified during diuron degradation. No significant difference of the electro-generated H2O2 after 10 successive recycles confirms the admirable reusability of N-rGO/CF. The application of the process for pesticide wastewater increased BOD5/COD ratio significantly from 0.041 (for non-treated wastewater) to 0.4 during 90 min treatment, showing a substantial improvement of the biodegradability of the wastewater. Accordingly, the E-peroxone system can be utilized as a promising pretreatment step before a biological process to facilitate and shorten the length of the biological treatment. The findings of this study could offer valuable information for practical applications of the E-peroxone system in the treatment of pesticide-manufacturing wastewater.

In this experimental study, the performance of a fixed bed column containing a mixture of iron and aluminum modified with acid, as a reaction bed, was evaluated for the removal of heavy metals of cadmium, nickel, and copper. The tests were carried out by feeding the columns with aqueous solutions at the concentration of 100 mg/L using four iron/aluminum granular mixtures at various volume ratios (100/0, 50/50, 75/25, 25/75 and 0/100), and pH (3, 5, 7) for a total of 28 column tests. Results showed that metal ion removal was mainly accomplished via redox reactions that initiated the precipitation of mineral phases. At pH 5 and flow rate of 1 mL/min, the removal efficiency of cadmium, nickel, and copper at the 50/50 ratio of modified iron and aluminum was obtained higher than 99% and this removal efficiency could be kept about 50 hours. It seems that the column with the volume ratio of 75/25 of iron and aluminum mixture was the most efficient column for removing the heavy metals with the most suitable iron content and also high hydraulic performance due to the suitable aluminum content. It is therefore seen that the mixture of iron and aluminum can be used as an environmentally and economically viable remediation technology for the subsequent prevention of groundwater contamination.

The present study examined the removal of bisphenol A (BPA) and total organic carbon (TOC) from aqueous solutions by the Fe/CMK-3 as peroxymonosulfate activator used in the sono-photo-catalytic process. The synthesis of Fe/CMK-3 was carried out using the co-precipitation method, and it was characterized by FTIR, XRD, BET, EDX, and TEM. The results showed that the iron nanoparticles were uniformly embedded in the CMK-3 pores. The effect of factors affecting on the removal of BPA and TOC was evaluated by response surface methodology (RSM) with center composite design (CCD). The analysis of variance of the quadratic model showed that the model is significant (p value 99.4) and can be used to optimize the removal efficiency of BPA. Optimization results showed that the highest removal efficiency of BPA (100) and TOC (80.6) was achieved in optimum conditions of pH 7.8, catalyst dose 0.33 g/L, PMS dose 3.35 mmol/L, BPA concentration 39.3 mg/L, and 78.5 min. In addition, statistical analysis of the data showed that, in the studied range, the initial concentration of BPA was the most influential factor, followed by pH and PMS dose. Highest catalytic stability of Fe/CMK-3 showed the potential applicability of catalyst in the treatment of BPA-containing solutions. The quenching test showed that sulfate radical was the main responsible for the removal of BPA. The decrease in IOUR value after the 75-min reaction time indicates that this process has a high ability for oxidation of the pollutant and its intermediates. Generally, the observed results suggest that the Fe-CMK-3/UV/US/PMS system can be a promising procedure for the removal of persistent pollutants such as BPA from aqueous media. Practitioner points: Fe/CMK-3 exhibited prominent catalytic activity and high stability for peroxymonosulfate activation. Effective degradation of bisphenol A was achieved in the Fe-CMK-3/UV/US/PMS system. The effect of five factors at five levels and their interactions during the removal of BPA was evaluated by RSM method coupled with central composite design (CCD). The analysis of variance of the quadratic model showed that the model is very significant (p value

The present study investigates the efficiency of a three-dimensional electro-peroxone (3D/E-peroxone) reactor filled with TiO2-GAC in removing diuron from aqueous solution and in the remediation of real pesticide wastewater. The behavior of the system in terms of the effect of independent variables on diuron was investigated and optimized by RSM-CCD and ANN-GA methods. Both approaches proved to have a very good performance in the modeling of the process and determined the optimum condition of the independent variables as follows: initial pH = 10, applied current = 500 mA, supporting electrolyte = 0.07 M, ozone concentration = 10 mg L−1, and reaction time = 10 min. The 3D/E-peroxone process achieved a synergistic effect in diuron abatement and reduced significantly energy consumption, as compared to its individual components. H2O2 concentration generated in the electrolysis system was notably increased in the presence of TiO2-GAC microparticles. The BOD5/COD ratio of the real pesticide wastewater increased from 0.049 to 0.571 within 90 min treatment. Giving to the considerable enhancement of the biodegradability of the wastewater, this study strongly suggests that the 3D/E-peroxone process can be considered as a promising pretreatment step before a biological treatment process to produce intermediates which are more easily degradable by microorganisms.

In current study, an efficient sample pretreatment method based on combination of salt induced–homogenous liquid–liquid extraction and ternary deep eutectic solvent–based dispersive liquid–liquid microextraction has been developed for the extraction of some antibiotics (oxytetracycline, doxycycline, penicillin G, and chloramphenicol) from milk samples before their analysis with high performance liquid chromatography. In this process, acetonitrile which acts as proteins precipitation agent and extraction/dispersive solvent, simultaneously, is added to the sample containing the analytes. After centrifugation, a homogenous solution (aqueous phase + acetonitrile) is formed upper the precipitated proteins of milk. This solution is passed through a barrel filled with solid sodium sulfate. By doing so, phase separation is occurred and the analytes are extracted into the separated acetonitrile phase which is subsequently taken, mixed with a newly synthesized water–immiscible deep eutectic solvent (phosphocholine chloride:dichloroacetic acid:dodecanoic acid) at μL–level, and hastily injected into deionized water placed into a test tube. After centrifugation, an aliquat of the sedimented phase is removed and injected into the separation system. The method was validated it was found that it had high extraction recoveries (65–81%) and enrichment factors (455–567), low limits of detection (2.0–2.8 μg L−1) and quantification (6.5–9.3 μg L–1), and satisfactory repeatability (relative standard deviation ≤ 8.0%). Finally, the introduced method was utilized in analysis of the studied antibiotics in packed milk samples marketed in Tabriz, Iran.

The dried bed of the world's second largest permanent Hypersaline lake, Lake Urmia, acts as a Hypersaline particle emission source. In the present study we aim to assess the health impact of this disaster and examine the association of Hypersaline particles with total and differential white blood cell counts (WBC) and homocysteine (Hcy), the biomarkers of cardiovascular diseases, in the residents around Lake Urmia. Based on the previous study three regions were selected as clean and polluted regions for ambient particulate matter (APM) from 2008 to 2015. Concentration of APM (PM10, PM2.5 and PM1; particulate matter with aerodynamic diameter of less than 10, 2.5 and 1 µm, respectively) was measured in the selected regions and totally, 123 participants were selected randomly from villagers who have lived in the selected regions for at least eight years. Biomarkers and covariates were measured in the selected regions and were analyzed using multiple linear regression models. We found a statistically significant association between APM and selected biomarkers (Hcy, total WBC, neutrophil, monocyte, lymphocyte and basophile) in the polluted regions. These results are consistent with our hypothesis that long-term exposure to Hypersaline particles originated from drying Urmia Hypersaline Lake is related to increased cardiovascular risk biomarkers. © 2018 Elsevier Inc.

Blending of water from different sources into an urban drinking water distribution system can have unintended impacts, such as corrosion and/or release of corrosion by-products from pipe surfaces. Hamedan, a city in west Iran, receives water from four different sources that have different physical and chemical characteristics. The potential for iron release from iron distribution pipes due to in situ blending of different sources was investigated in this study. A dedicated software was developed to calculate the corrosion indices of different blends expected in different zones of Hamedan’s water distribution system. The calculated corrosion indices, and iron release were verified and correlated to actual conditions through water sampling conducted in different zones of the city. The Langelier index (LI), Ryznar stability index (RSI or RI), Puckorius scaling index (PSI), and the calcium carbonate precipitation potential were found to be −0.60 ± 0.30, 8.63 ± 0.57, 8.18 ± 0.34, and −10.95 ± 6.9 mg Ca...

This study focuses on preparing Antimony Nanoparticle Multi-walled Carbon (ANMWC) composite as an effective adsorbent and then the effect of produced composite in BPA removal from aqueous solutions was studied. ANMWC were prepared using chemical method and characterized with X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and Brunauer–Emmett– Teller (BET). Moreover, the removal efficiency of prepared AMWCNT and Nanoparticle Multi-walled Carbon (MWCNT) in removal of Bisphenol A was investigated. Results revealed that the BPA removal efficiency by AMWCNT increased from 80 to 93 % with the increase of contact time 5 to 60 min. The maximum removal efficiency for the both adsorbents was seen at pH 7, which was 85% for MWCNT and 95% for ANMWC composite. According to the results obtained, pHzpc for both adsorbents was 7. Results showed that the adsorption process followed the pseudo-first order model with a high correlation value and BPA adsorption on MWCNT followed the Langmuir isotherm model. keywords: Bisphenol, Adsorption, Nanoparticle Multi-walled Carbon Nanotubes, composite.

Nano packaging is currently one of the most important topics in food packaging technologies. The aim of the application of this technology in food packaging is increasing shelf life of foods by preventing internal and external corruption and microbial contaminations. Use of silver nanoparticles in food packaging has recently attracted much attention. The aim of this study was to investigate the effect of nano-silver packaging in increasing the shelf life packages of nuts in an In vitro model. In this experimental study, the effects of different nano-silver concentrations (0, 1, 2 and 3 percent) on biological and chemical properties of 432 samples of nuts including walnuts, hazelnuts, almonds and pistachios were evaluated during 0, 3, 6, 9, 12, 15, 18, 21 and 24 months. In most samples, different concentrations of nano-silver (1, 2 and 3 %) significantly reduced total microbial count, mold and coliform counts compared to control group and the 3% nano-silver concentration was more effective than other concentrations (P

The purpose of the study was to investigate the association of leptin gene expression in visceral and subcutaneous adipose tissues with habitual fatty acid intake and its subtypes in adults. Visceral and subcutaneous adipose tissues were gathered from 97 participants aged ≥ 20, who had undergone elective abdominal surgery. Dietary fatty acid intakes including total fatty acids (TFA), saturated fatty acid (SFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), n-3, n-6, and n-9 fatty acids were collected using a valid and reliable food-frequency questionnaire (FFQ). The leptin gene expression in visceral and subcutaneous adipose tissues was measured by Real-Time PCR. After controlling for body mass index (BMI) and insulin, energy-adjusted dietary intake of SFA was positively and MUFA and n-3 fatty acids were negatively associated with subcutaneous and visceral adipose tissues leptin gene expression. Besides, a significant negative association of PUFA, n-6, and n-9 fatty acids with leptin mRNA from visceral adipose tissue were observed. In order to better interpretations of the results, the participants were allocated two groups including non-obese (BMI < 30kg/m2) and obese subjects (BMI ≥ 30kg/m2). Among non-obese participants, the SFA had positive and PUFA had negative association with leptin gene expression in both adipose tissues. Furthermore, in obese participants, n-3, n-6, and n-9 fatty acids had a negative association with visceral leptin gene expression. Habitual intake of SFA, MUFA, and n-3 fatty acids were associated with leptin gene expression in visceral and subcutaneous adipose tissues, suggesting an important role of quality and quantity of fatty acids intake in adipose tissue to regulate leptin expression.

The purpose of this study was to evaluate the removal of 2,4-dichlorophenol (2,4-DCP) from aqueous solutions using microwave irradiation (MW) assisted nanoscale zero-valent copper (CuO) activated persulfate (PS). Effective operational parameters including, pH of the solution, PS concentration, CuO dosage, MW power, and initial 2,4-DCP concentration, were investigated. Results indicated that the MW/PS/CuO system achieved higher efficiency in 2,4-DCP degradation than MW/PS, MW/CuO, and PS/CuO systems. At PS concentration of 0.4 g/L, CuO dosage of 40 mg/L, initial pH of 9 and initial 2,4-DCP concentration of 50 mg/L, complete degradation of 2,4-DCP (>98%) was achieved in reaction time of 90 min. In optimal condition, 80% and 45% of COD and TOC removal rates were respectively obtained within 90 min. Through the use of methanol (MA) and tert-butyl alcohol (TBA) as radical scavengers, sulfate radical was identified as the main radical species generated during the process. Also, the results showed that with an increasing ion strength, 2,4-DCP removal rate slightly decreased. The degradation of 2,4-DCP was pseudo-first-order kinetics. The phenol, 2,4-dichlororesorcinol, 2-chlorohydroquinine, 2-chlorophenol, p-chlorophenol, catechol, hydroquinone, oxalic acid, and acetic acid were identified as the major intermediates of 2,4-DCP degradation. Also, a tentative pathway for degradation of 2,4-DCP using the MW/PS/CuO system was proposed.

Background and purpose: Stability of new synthetic compounds such as Dimethyl phthalate increased their concentration in the environment and food chain and caused health risks. Therefore, achieve effective and efficient methods to removal of pollutants are one of the environmental researchers concern. This study investigates efficiency of heterognous Fenton process using nZVI in dimethylphthalate removal from aqueous solutions. Materials and Methods: This experimental study was conducted in batch reactor in laboratory scale and the efficiency of heterognous Fenton process was analyzed in a batch system with the effect of changes in operating parameters such as reaction time (15 to 120 min), pH (2 to10), H2O2 concentration (0.01 to 1 mmol/L), nZVI dose (0.01 to 0.5 mg/L) and initial concentration of Dimethyl phthalate (2 – 50 mg /L). Then the effect of each heterogeneous Fenton regent in dimethyl phthalateremoval was determined. Results: The results showed that the maximum efficiency of heterognous Fenton process in removal of Dimethyl phthalate is at pH=4. Also in optimal conditions, the parameters affecting reaction was determined as H2O2 concentration 0.1 mmol/L, nZVI dose 0.05 gr/L, Dimethyl phthalate concentration 2 mg/L and 120 minute, amount of Dimethyl phthalate removal was 92.8%. Conclusion: According to the results, heterognous Fenton process using nZVI has an optimal efficiency in removal of Dimethyl phthalate from aquatic solutions and can be considered as an acceptable and low Cost method for the removal of similar compounds.

Despite fossil fuels, the energy supply from biogas process is of renewable energy resources; this kind of energy can be generated in all parts of the world. Thus, the potential of anaerobic co-digestion for production of methane from wastes of an industrial slaughterhouse and fruit and vegetable center in the Hamadan city, west of Iran, was investigated. The digester was operated under the mesophilic (35 - 37°C) condition for a period of 40 days with 3 different C/N ratios (20/1, 30/1 and 40/1). Before operation of digester, the amounts of C and N in the wastes were measured and during the experiments pH and composition of the biogas were determined. The cumulative amounts of the generated total biogas and methane at the 3 examined C/N ratios 20/1, 30/1 and 40/1 were, respectively 181, 201.7 and 162.5 L and 129.8, 149.2 and 114 L. The results indicated that the highest contents of biogas and methane (201.68 and 149.29 L, respectively) were obtained at C/N of 30 within 31 days.

Considering extensive applications of manganese tetroxide nanoparticles in various industries due to its special properties, conducting studies on how to achieve more suitable ways to produce smaller nanoparticles is of great importance. In this study, nanoparticles of manganese tetroxide (Mn3O4) were synthesized by a co-precipitation method. In order to determine the characteristics of the structure, size, and specific surface of the resulting nanoparticles, techniques such as XRD, BET, BJH, FESEM, and FTIR were employed. Also, the nanoparticles were quantified with EDS and their colony size was examined using DLS experiments. The findings revealed a production of crystalline manganese tetroxide nanoparticles with a space group of 141/amd (S.G.) (141) and a molecular weight of 228.81 with the international code of ICSD Card # 89 - 4837. The specific surface area was 32.147 m2 /g with a pore volume of 0.1041 cm3 /g. The XRD and EDX analyses verify the production of the Mn3O4 nanoparticles. The size of the nanostructures is approximately 19 nm. The method used in this study could produce the Mn3O4 nanoparticles in a much easier way without the need for surfactants. Compared to the nanoparticles produced in other studies, the size of the nanoparticles produced in the present study is remarkably smaller. Moreover, less amount of the metal salt was used.

In this study, photocatalytic removal of Cr(VI) and Ni(II) by illuminated TiO2 was investigated with variation of solution pH, contact time, TiO2 dosage and initial Cr(VI) and Ni(II) concentration. From the photocatalytic reaction, near complete elimination of Cr(VI) and Ni(II) occurred from the adsorption of Cr(VI) and Ni(II) on the surface of TiO2 as well as reduction of Cr(VI) and Ni(II) to Cr(III) and Ni(0), respectively. Reduction was recognized as a significant elimination process for the treatment Cr(VI) and Ni(II) from wastewater. Removal of Cr(VI) decreased with increasing pH while removal of Ni(II) increased with increasing pH. TiO2 dosage was also an important parameter for the removal of Cr(VI). As the TiO2 dosage increased up to 1 g l−1, removal of Cr(VI) and Ni(II) was continuously enhanced.

The adsorption of a reactive dye, Ariazol Scarlet 2G (AS2G) (C.I.: Reactive Red 234), onto compost, from aqueous solutions, was studied in a batch system. The effects of initial dye concentration, initial pH and sorbent mass have been studied. Four two-parameter isotherm models–Langmuir, Freundlich, Temkin and Harkins Jura – were used to fit the experimental data using a nonlinear trial-and-error method. The best fi t of the adsorption isotherm data was obtained using the Langmuir model (X 2 = 1.97E−03). A comparison of kinetic models applied to the adsorption of AS2G on compost was evaluated using the pseudo-second order, Elovich and Lagergren first-order kinetic models. Results showed that the pseudo-second order kinetic model was found to agree well with the experimental data. An intra-particle diffusion model analysis showed multi-linearity with two steps and a non-zero intercept which indicated the intra-particle diffusion model is not a dominant rate controlling mechanism in the sorption of AS2G by ...

Chromium (VI) is known to be potentially carcinogenic and mutagenic in humans. A low-cost industrial solid bioadsorbent, bagasse-based activated charcoal (BAC), has been investigated for removal of chromium from aqueous solution. All the experiments were carried out in batch process with laboratory-prepared samples to study the effects of adsorbent dose, contact time, pH and initial concentration of Cr(VI). The removal of chromium ion was found to be highly dependent on the pH of the solution, adsorbent dose and contact time. Also the equilibrium adsorption was analyzed by the Freundlich and Langmuir isotherm models. It was found that the Freundlich isotherm model best described the sorption of chromium by sugar beet bagasse-based activated charcoal (r20.9927). Experimental data of kinetic studies were fitted to pseudo-first-order, pseudo-second-order and modified pseudo-first-order models. The results showed pseudo-second order kinetics was best fitted to the collected data (r20.9893). Optimum conditions for adsorption were determined at pH 2 and a contact time of 180 minutes (92.7% removal). These retention capacities suggest that BAC can provide a simple, effective, and cheap method for removing Cr(VI) ions from effluents and water resources.

The effectiveness of nanofiltration (NF) was compared with granular activated carbon (GAC) and air stripping (AS) using a packed column in water treatment for the removal of chloroform (CHCl 3 ), which is a basic indicator of trihalomethane (THM) compounds in many water resources. Pilot GAC and AS columns were designed and set up with nanofiltration polyamide and cellulose acetate blend spiral-wound modules with MWCO of 300 Da and 600 Da. The study was carried out for the two cases of deionized and chlorinated Tehran tap water. CHCl 3 concentrations for both inlet and outlet samples were detected by gas chromatography (GC) and using electron capture detector (ECD). Results showed that the maximum CHCl 3 removal efficiencies for NF 300 Da, NF 600 Da, GAC and AS packed columns under various operating conditions were 87.8%, 85%, 87.4% and 97.6% for deionized water and 86.1%, 72.3%, 85.1, and 91.2% for chlorinated Tehran tap water, respectively. Although NF, GAC and AS showed acceptable performance for CHCl 3 removal from drinking water, NF was significantly more effective (p < 0.05), providing simultaneously a higher flow rate and simpler operating conditions. This method may be considered for conventional water treatment plant finishing water.

Pentachlorophenol (PCP), which is one of the resistant phenolic compounds, has been classified in the category of EPA’s priority pollutants due to its high toxicity and carcinogenic potential. Therefore, its removal from water and wastewater is very important. Various methods have been studied for removing the compound, among which advanced oxidation processes (AOPs) have attracted much attention because of ease of application and high efficiency. Thus the aim of this study was to investigate the efficiency of the UV/ZrO2/H2O2 process, as an AOP, for PCP removal from aquatic environments. The effects of several parameters such as ultraviolet (UV) exposure time, initial PCP concentration, pH, concentration of zirconium dioxide (ZrO2) nanoparticles, and H2O2 concentration were studied. Kinetics of the reaction was also detected. The concentration of the stated materials in the samples was determined using a spectrophotometer at 500 nm. The results showed that the highest efficiency (approximately 100%) was reached at optimized conditions of pH 6, contact time of 30 minutes, initial PCP concentration of 20 mg/L, the nanoparticles concentration of 0.1 g/L and H2O2 concentration of 14.7 mM/L. Also, the process followed the first order kinetics reaction. The obtained results illustrated that the UV/ZrO2/H2O2 process has a high ability in removing PCP.

Since the process of heterogeneous Fenton is more complex and dynamic than the common Fenton process, control and online monitoring is entirely vital for optimum operation of this system. This study was aimed to investigate the effects of pH, oxidation-reduction potential (ORP) and dissolved oxygen (DO) variations on dimethyl phthalate (DMP) removal from aqueous solutions using the heterogeneous Fenton process with nano zero-valent iron (nZVI). Parameters affecting the process like contact time (5 - 120 minutes), pH (2 - 10), H2O2 concentration (0.01 - 1 mmol/L) nZVI content (0.01 - 0.5 g/L) and initial DMP concentration (2 - 50 mg/L) were also studied. It was found that, at optimum amounts (pH = 4, H2O2 concentration = 0.1 mmol/L, nZVI = 0.05 g/L, initial DMP concentration = 2 mg/L, and contact time = 60 minutes), approximately 98% of the pollutant was removed. This process could treat DMP well from aqueous environments and can be introduced as a cheap and effective method.

The effect of granular coral limestone and Leca as adsorbents for removing Acid Cyanine 5R (AC5R) from aqueous solution was studied. The optimum pH and adsorbent particles size in both adsorbents were determined to be 3 and 297μm, respectively. The optimum dosages of coral limestone and granular Leca were 0.150 and 0.145g/mg of dye, respectively. Also, results have shown that the adsorption efficiency by both coral limestone and Leca increased with the decreasing adsorbent particles size. Moreover, under similar conditions, the maximum removal efficiency by granular coral limestone and Leca was 94% and 88%, respectively. The results revealed that the performance of granular coral limestone was better in AC5R removal than that of Leca granulated under such condition. In total, granular coral limestone and Leca act as suitable adsorbents for removing dye pollutants from an aqueous solution.

Surfactants are one of the main groups of pollutants released into aqueous solutions due to human activities and their harmful effects have been proven on human. In this study, first, magnetic multi-walled carbon nanotubes (MMWCNTs) were synthesized and then, the effects of operating parameters such as surfactant concentration, adsorbent dosage, and pH values were analyzed on the adsorption process. MMWCNTs were characterized by means of X-ray diffraction (XRD) analysis and fourier transform infrared spectroscopy (FTIR). The optimal adsorption conditions were achieved at initial pH = 4.6, adsorbent concentration = 0.5 g/L, and initial SDS concentration = 15 mg/L. In addition, the equilibrium of sorption reached after 120 min and the maximum capacity of SDS for monolayer coverage was found to be 61 mg/g at 25°C. Kinetic studies were performed under optimal conditions and the sorption kinetics was described using the pseudo-second-order kinetic model. The experimental data were studied using Freundlich, Langmuir, and Sips models. Finally, the experimental data were fitted reasonably by Langmuir isotherm. The results demonstrated that MMWCNTs with respect to their high adsorption capacity, relatively low equilibrium time, and capability to be separated from aqueous solutions (after adsorption) could be applied to wastewater treatment.

In this study, ZnO Nano catalyst has been synthesized and examined as photo catalyst for UV-induced removal of Sodium Dodecyl Sulfate (SDS) from aquatic solutions. This anionic surfactant was selected based upon its toxicity, wide use in industrial laundry and as a primary pollutant in municipal waste water systems.This study aimed to investigate removal of surfactant, SDS, in a batch photo catalytic reactor under various operating conditions including ZnO suspension concentration, initial surfactant concentration and initial pH of solution to find out the desired condition for removal of surfactant. ZnO Nano crystals were synthesized using the precipitation method and ZnSO4.7H2O was used as the starting material and NaOH as precipitant. The removal of SDS reactions by UV/ZnO process was performed into a batch photo reactor. In addition, various operating conditions including ZnO suspension concentration, initial surfactant concentration and initial pH of solution were investigated. In total, 98% of surfactant was removed at 40 minute and removal efficiency of SDS increased with increasing pH up to nine and after that with increase in pH, efficiency decreased. Possible roles of inorganic oxidant on the reaction were discussed. The removal of SDS follows pseudo-first order kinetics. Based on the results of this study, ZnO-UV photo catalytic process can be used as an efficient method for further study in detergents removal.

Photocatalytic removal of Cr(VI) and Ni(II) from aqueous solution using synthesized nanoparticle ZnO under ultraviolet (UV) light irradiation was studied in this work. Firstly, nanoparticle ZnO was prepared by the chemical method with an organic chemical inhibitor. Then removal efficiency of Cr(VI) and Ni(II) by nanoparticle ZnO was investigated with variation of the solution pH, ZnO dosage, contact time and initial Cr(VI) and Ni(II) concentration. Maximum removal of Cr(VI) and Ni(II) was observed at near-neutral pH because the reduced photocatalytic activity of ZnO at exceedingly low and high pH values originates from either acidic/photochemical corrosion of the catalyst and/or surface passivation with Zn(OH)2. As the ZnO dosage increased, the removal efficiency of Cr(VI) and Ni(II) was continuously enhanced, but was gradually decreased above 1.25 g/l due to the increased blockage of the incident UV light used for the photocatalytic reaction. The optimum ZnO dosage was determined as 1 g/l. Removal efficiencies of Cr(VI) and Ni(II) decreased as initial Cr(VI) and Ni(II) concentration increased, due to an increased inhibition effect on the surface of ZnO resulting from the decreased reaction sites on the surface of ZnO required for the further photocatalytic reaction.

Antibiotics are used globally and, after use, they enter water sources in different ways. The presence of these compounds in the environment has created concerns about the toxicity of aquatic organisms and the emergence of antibiotic-resistant bacteria. The purpose of this study was to remove cefalexin from aqueous solutions by enzymatic oxidation using response surface methodology (RSM). For this purpose, batch experiments were performed to evaluate the effect of independent variables, including temperature, pH, contact time, enzyme activity, HBT mediator concentration, and antibiotic concentration. The residual cefalexin concentration was determined by HPLC. The Box-Behnken design of experiments and RSM were used to evaluate the overlap between variables. The results showed that the oxidation efficiency increased with increasing contact time and enzyme activity and decreasing antibiotic concentration. The highest and lowest removal percentages were 90.5 and 5.54, respectively. Considering the value of R 2 (0.946) and adjusted R 2 (0.95) in the RSM model, one can state that the selected model is suitable for data analysis. Finally, the second-order polynomial analysis and the quadratic model were used as the best model for finding the relationship between the main variables and cefalexin removal efficiency. The Box-Behnken Design model can be effective for optimizing enzymatic oxidation of cefalexin, and laccase can be used to remove cefalexin. © 2018 Assoc. Brasiliera de Eng. Quimica / Braz. Soc. Chem. Eng. All Rights Reserved.