26 research outputs found

    Photocatalytic degradation and mineralization of diazinon in aqueous solution using nano-TiO2(Degussa, P25): kinetic and statistical analysis

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    Abstract: In this study, photocatalytic degradation of diazinon was investigated using nano-TiO2, Degussa P25, as a photocatalyst and the effects of some operational parameters such as aeration, pH, photocatalyst concentration, and the irradiation time were also examined. Dispersive liquid-liquid microextraction technique was used to extract and pre-concentration of residual diazinon from the liquid samples and all experiments were carried out by gas chromatography. Amount of degradation and mineralization were determined by gas chromatograph with flame ionization detector (GC/FID) and COD measurements, respectively. The optimum condition for degradation of diazinon has been obtained in the pH 6, [nano-TiO2] = 0.2 g/L, and [time] = 120 min. In the optimal condition the removal efficiency of diazinon and COD were 99.64 and 65%, respectively. The results have shown that the nano-TiO2, aeration and time of reaction have a positive effect on photocatalytic degradation of diazinon and COD removal. Statistical analysis showed that the maximum removal of diazinon and COD were due to UV irradiation (71%, 41%), exposure time (16%, 39%), aeration (7%, 4%), and increased concentration of nano-TiO2 (0.4%, 2%), respectively; and the kinetics of photodegradation were found to follow a first-order kinetic model and the constant rate, at optimal condition, was 0.038 (min−1). © 2014 Balaban Desalination Publications. All rights reserved

    Heterogeneous catalytic ozonation of 2, 4-dinitrophenol in aqueous solution by magnetic carbonaceous nanocomposite: catalytic activity and mechanism

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    Herein, the catalytic properties of a carbonaceous nanocomposite in the catalytic ozonation process (COP) of 2, 4-dinitrophenol (2, 4-DNP) were investigated and the results were compared with those obtained from single ozonation process (SOP). Magnetic carbonaceous nanocomposite, as a novel catalyst, was applied to optimize the condition for the removal of 2, 4-DNP in the COP, and the influential parameters such as pH, catalyst dosage, addition of radical scavengers, and durability were all evaluated. The results showed that the degradation efficiency of 2, 4-DNP and COD in the COP (98.2, 92) was higher compared to the SOP (75, 61) and the highest catalytic potential was achieved at an optimal pH of 6. The first-order modeling demonstrated that the reactions were dependent on the concentration of the catalyst, with the kinetic constants varying from 0.022 (1/min) in the SOP to 1.377 (1/min) in the COP at the catalyst dosage of 4 g/L and the optimum concentration of catalyst (2 g/L). The addition of radical scavenger noticeably diminished the removal efficiency of 2, 4-DNP in the SOP from 75 down to 54, while the corresponding values for the COP dropped from 98.2 to 93. Furthermore, a negligible reduction in the catalytic properties of the catalyst was observed (~5) after five-time reuse. The results also revealed that the applied method is effectively suitable for the removal of 2, 4-DNP contaminant from industrial wastewaters. © 2015 Balaban Desalination Publications. All rights reserved

    Functional impairment of systemic scleroderma patients with digital ulcerations: Results from the DUO registry

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    Demographic, clinical and antibody characteristics of patients with digital ulcers in systemic sclerosis: data from the DUO Registry

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    OBJECTIVES: The Digital Ulcers Outcome (DUO) Registry was designed to describe the clinical and antibody characteristics, disease course and outcomes of patients with digital ulcers associated with systemic sclerosis (SSc). METHODS: The DUO Registry is a European, prospective, multicentre, observational, registry of SSc patients with ongoing digital ulcer disease, irrespective of treatment regimen. Data collected included demographics, SSc duration, SSc subset, internal organ manifestations, autoantibodies, previous and ongoing interventions and complications related to digital ulcers. RESULTS: Up to 19 November 2010 a total of 2439 patients had enrolled into the registry. Most were classified as either limited cutaneous SSc (lcSSc; 52.2%) or diffuse cutaneous SSc (dcSSc; 36.9%). Digital ulcers developed earlier in patients with dcSSc compared with lcSSc. Almost all patients (95.7%) tested positive for antinuclear antibodies, 45.2% for anti-scleroderma-70 and 43.6% for anticentromere antibodies (ACA). The first digital ulcer in the anti-scleroderma-70-positive patient cohort occurred approximately 5 years earlier than the ACA-positive patient group. CONCLUSIONS: This study provides data from a large cohort of SSc patients with a history of digital ulcers. The early occurrence and high frequency of digital ulcer complications are especially seen in patients with dcSSc and/or anti-scleroderma-70 antibodies

    Cutaneous lesions of the groin area and its related factors, Razi hospital, Tehran

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    Background: The traditional classification of dermatologic diseases is based on etiology and clinical appearance, however, regional approach could be an appropriate alternatrive in clinical or research affairs. The present study was conducted in a dermatologic clinic in Razi hospital, Tehran to determine the frequency of cutaneous lesions of groin area and proposed the importance of a regional approach.Materials and methods : This cross sectional study was performed on 3401 patients referring consecutively. Diagnosis was made by clinical and paraclinical studies, if necessary biopsy was also taken. Meanwhile, sex, age and body mass index were all recorded. Results: Of 3401 patients, 3.9 had cutaneous lesions of groin area. Dermatophytosis, erythrasma, and seborrheic dermatitis were reported in 17.2, 14.9, and 14.9 of individuals. Lesions had shown significant differences according to the sex, and type of lesions.Conclusion : Cutaneous lesions of groin area are relatively common. Further regional approach studies are strongly recommended

    Heavy metal contamination in the effluent and sludges of wastewater treatment plant in Gorgan, Iran

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    Background and purpose: Environmental pollution by heavy metals and their transfer to soil and crops are a growing global problem. This study aimed to measure the concentrations of heavy metals in wastewater and sludge wastewater treatment plant in Gorgan, Iran. Materials and methods: In this cross-sectional study, 176 samples of effluent, and returned and dried sludges were analyzed in wastewater treatment plant in Gorgan, during six months in 2016. The concentration of Pb, Cd, Ni, and Cr were determined using polarography (Metrohm797 AV) and furnace atomic adsorption spectroscopy (AA 240 Varian Co.) in the laboratory of Health Faculty in Golestan University of Medical Sciences. Results: The average concentrations of Pb, Cd, Ni, and Cr in the effluent were 0.105 ± 0.06, 0.0089 ± 0.008, 0.095 ± 0.108, and 0.102 ± 0.175 mg/L, respectively. The concentrations of Pb, Cd, Ni, and Cr in returned sludge were 323.48 ± 217.65, 2.44 ± 3.3, 354.14 ± 322.79, and 388.53 ± 252.59 mg1/kg of dry weight, respectively. Also, in dried sludge, the average concentrations of lead, cadmium, nickel, and chromium were 58.48±2.67, N.D, 30.31±1.98, and 506.25±813.81 mg/kg of dry weight, respectively. Conclusion: The concentrations of heavy metals in wastewater effluent and dried sludge, except in returned sludge, were below the standards. Due to long-term use of effluents, necessity of treatment of other parameters, and the effect of bioaccumulation of metals in sludge, caution should be taken for their agricultural application. Also, because of importance of this type of contaminants in soil and food products, continuous monitoring by water companies is highly necessary. © 2017, Mazandaran University of Medical Sciences. All rights reserved

    Heavy metal contamination in the effluent and sludges of wastewater treatment plant in Gorgan, Iran

    Get PDF
    Background and purpose: Environmental pollution by heavy metals and their transfer to soil and crops are a growing global problem. This study aimed to measure the concentrations of heavy metals in wastewater and sludge wastewater treatment plant in Gorgan, Iran. Materials and methods: In this cross-sectional study, 176 samples of effluent, and returned and dried sludges were analyzed in wastewater treatment plant in Gorgan, during six months in 2016. The concentration of Pb, Cd, Ni, and Cr were determined using polarography (Metrohm797 AV) and furnace atomic adsorption spectroscopy (AA 240 Varian Co.) in the laboratory of Health Faculty in Golestan University of Medical Sciences. Results: The average concentrations of Pb, Cd, Ni, and Cr in the effluent were 0.105 ± 0.06, 0.0089 ± 0.008, 0.095 ± 0.108, and 0.102 ± 0.175 mg/L, respectively. The concentrations of Pb, Cd, Ni, and Cr in returned sludge were 323.48 ± 217.65, 2.44 ± 3.3, 354.14 ± 322.79, and 388.53 ± 252.59 mg1/kg of dry weight, respectively. Also, in dried sludge, the average concentrations of lead, cadmium, nickel, and chromium were 58.48±2.67, N.D, 30.31±1.98, and 506.25±813.81 mg/kg of dry weight, respectively. Conclusion: The concentrations of heavy metals in wastewater effluent and dried sludge, except in returned sludge, were below the standards. Due to long-term use of effluents, necessity of treatment of other parameters, and the effect of bioaccumulation of metals in sludge, caution should be taken for their agricultural application. Also, because of importance of this type of contaminants in soil and food products, continuous monitoring by water companies is highly necessary. © 2017, Mazandaran University of Medical Sciences. All rights reserved

    Photocatalytic degradation and mineralization of diazinon in aqueous solution using nano-TiO<inf>2</inf>(Degussa, P25): kinetic and statistical analysis

    No full text
    Abstract: In this study, photocatalytic degradation of diazinon was investigated using nano-TiO2, Degussa P25, as a photocatalyst and the effects of some operational parameters such as aeration, pH, photocatalyst concentration, and the irradiation time were also examined. Dispersive liquid-liquid microextraction technique was used to extract and pre-concentration of residual diazinon from the liquid samples and all experiments were carried out by gas chromatography. Amount of degradation and mineralization were determined by gas chromatograph with flame ionization detector (GC/FID) and COD measurements, respectively. The optimum condition for degradation of diazinon has been obtained in the pH 6, nano-TiO2 = 0.2 g/L, and time = 120 min. In the optimal condition the removal efficiency of diazinon and COD were 99.64 and 65%, respectively. The results have shown that the nano-TiO2, aeration and time of reaction have a positive effect on photocatalytic degradation of diazinon and COD removal. Statistical analysis showed that the maximum removal of diazinon and COD were due to UV irradiation (71%, 41%), exposure time (16%, 39%), aeration (7%, 4%), and increased concentration of nano-TiO2 (0.4%, 2%), respectively; and the kinetics of photodegradation were found to follow a first-order kinetic model and the constant rate, at optimal condition, was 0.038 (min�1). © 2014 Balaban Desalination Publications. All rights reserved
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