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مرکز اطلاعات علمی SID1
اسکوپوس
دانشگاه غیر انتفاعی مهر اروند
ریسرچگیت
strs
Author(s): 

Issue Info: 
  • Year: 

    2018
  • Volume: 

    207
  • Issue: 

    -
  • Pages: 

    255-266
Measures: 
  • Citations: 

    391
  • Views: 

    3416
  • Downloads: 

    16455
Keywords: 
Abstract: 

Yearly Impact:

View 3416

Download 16455 Citation 391 Refrence 0
Author(s): 

ONWEREMADU E.U. | NWUFO M.I.

Issue Info: 
  • Year: 

    2009
  • Volume: 

    1
  • Issue: 

    1
  • Pages: 

    8-14
Measures: 
  • Citations: 

    419
  • Views: 

    22244
  • Downloads: 

    21379
Keywords: 
Abstract: 

Yearly Impact:

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Issue Info: 
  • Year: 

    2017
  • Volume: 

    10
  • Issue: 

    3
  • Pages: 

    141-148
Measures: 
  • Citations: 

    0
  • Views: 

    55217
  • Downloads: 

    78683
Abstract: 

green nano pigments of Cr2O3 and CoCr2O4 were successfully prepared by polyol method followed by calcination at 770 ° C. The Cr2O3 and CoCr2O4 samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), dynamic light scattering (DLS), UV– Vis spectroscopy and CIEL*a*b* colorimetry methods. Dynamic light scattering analysis confirmed the formation of nanoparticles in suspensions. XRD data of Cr2O3 and CoCr2O4 powders displayed the formation of crystallized rhombohedral and spinel structures, respectively. The calculated average crystallite size of Cr2O3 and CoCr2O4 is ~54 and 39 nm, respectively. The SEM results showed that the average size of Cr2O3 and CoCr2O4 nano pigments is about 70-80 nm, while CoCr2O4 nano pigments were more agglomerated than Cr2O3. The calorimetric and DRS data confirmed the formation of green pigments in both samples. Prog. Color Colorants Coat. 10 (2017), 141-148© Institute for Color Science and Technology.

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گارگاه ها آموزشی
Author(s): 

ZAROUAL Z. | CHAAIR H. | ESSADKI A.H.

Journal: 

CHEMICAL ENGINEERING

Issue Info: 
  • Year: 

    2009
  • Volume: 

    148
  • Issue: 

    -
  • Pages: 

    488-495
Measures: 
  • Citations: 

    457
  • Views: 

    23601
  • Downloads: 

    28498
Keywords: 
Abstract: 

Yearly Impact:

View 23601

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Issue Info: 
  • Year: 

    2011
  • Volume: 

    8
  • Issue: 

    3 (31)
  • Pages: 

    631-638
Measures: 
  • Citations: 

    0
  • Views: 

    144217
  • Downloads: 

    80608
Abstract: 

In this study, adsorption of copper and CHROMIUM was investigated by residue of brewed tea (Tea Waste) from aqueous solutions at various values of pH. It was shown that adsorbent dose, copper and CHROMIUM ion concentrations in such solutions influence the degree of these heavy metal ions’ obviation. The adsorption level of the prepared solutions was measured by visible spectrophotometer. The tea residue adsorbed copper (II) and CHROMIUM (VI) ions at initial solution pH by 25 % and 3 %, respectively. During the experiments the peak adsorption occured in hydrated copper nitrate aqueous solution at pH range of 5-6. Likewise the maximum adsorption appeared in potassium chromate aqueous solution at pH range of 2-3. In addition, tea residue adsorbed about 60 mg/g of copper (II) ion at pH=5, while CHROMIUM adsorption was registered at about 19 mg/g at pH=2. The data obtained at the equilibrium state, was compared with Langmuir and Freundlich models. Results showed that regarding the kinetics of adsorption, the uptake of copper (II) and CHROMIUM (VI) ions by tea residue was comparatively faster, with the adsorption process exhaustion completed within the first 20 min of the experiments. Furthermore, results revealed that adsorption data concerning the kinetic phase is closely correlated with a pseudo-second order model with R2 > 0.99 for copper (II) and CHROMIUM (VI) ions.

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Issue Info: 
  • Year: 

    2008
  • Volume: 

    5
  • Issue: 

    4
  • Pages: 

    277-282
Measures: 
  • Citations: 

    922
  • Views: 

    182881
  • Downloads: 

    70709
Abstract: 

Removal of CHROMIUM can be accomplished by various methods but none of them is cost-effective in meeting drinking water standards. For this study, granular ferric hydroxide was used as adsorbent for removal of hexavalent CHROMIUM. Besides, the effects of changing contact time, pH and concentrations of competitive anions were determined for different amounts of granular ferric hydroxide. It was found that granular ferric hydroxide has a high capacity for adsorption of hexavalent CHROMIUM from water at pH£7 and in 90 min contact time. Maximum adsorption capacity was determined to be 0.788 mg Cr+6/g granular ferric hydroxide. Although relatively good adsorption of sulfate and chloride had been specified in this study, the interfering effects of these two anions had not been detected in concentrations of 200 and 400 mg/L. The absorbability of hexavalent CHROMIUM by granular ferric hydroxide could be expressed by Freundlich isotherm with R2>0.968. However, the disadvantage was that the iron concentration in water was increased by the granular ferric hydroxide. Nevertheless, granular ferric hydroxide is a promising adsorbent for CHROMIUM removal, even in the presence of other interfering compounds, because granular ferric hydroxide treatment can easily be accomplished and removal of excess iron is a simple practice for conventional water treatment plants. Thus, this method could be regarded as a safe and convenient solution to the problem of CHROMIUM-polluted water resources.

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strs
Author(s): 

SOLGI EISA | ZAMANIAN ALI

Issue Info: 
  • Year: 

    2020
  • Volume: 

    9
  • Issue: 

    2
  • Pages: 

    97-108
Measures: 
  • Citations: 

    0
  • Views: 

    25369
  • Downloads: 

    28014
Abstract: 

Background & Aims of the Study: Heavy metals and its compounds are toxic pollutants that have priority in the studies due to their potential harm to human health. Materials and Methods: This study evaluated the potential of a chicken feather for the removal of nickel and CHROMIUM from aqueous solutions. The chicken feather was prepared from aviculture for nickel and CHROMIUM removal from aqueous solutions. The effects of pH, contact time, adsorbent dosage, and initial metal concentration on Ni and Cr removal were also evaluated in this study. Freundlich and Langmuir isotherm models were used to characterize the biosorption of the mentioned metals onto the chicken feather. Results: Based on the findings, the maximum removal of metals was found in a contact time of 3 h, 1 g/L of adsorbent, pH 5 (for Ni) and 6 (for Cr), and concentration of 1 mg/l of metals. According to the Langmuir isotherms, the maximum biosorption capacities (qm) of Cr and Ni were 22. 3 and 119. 05 mg/g, respectively. Conclusion: The results showed that chicken feathers can absorb CHROMIUM and nickel at low concentrations. However, the ability and possibility of the use of the chicken feather are limited for the treatment of contaminated wastewater at high concentrations.

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Author(s): 

MISHRA A. | DUBEY A. | SHINGHAL S.

Issue Info: 
  • Year: 

    2015
  • Volume: 

    12
  • Issue: 

    4
  • Pages: 

    0-0
Measures: 
  • Citations: 

    0
  • Views: 

    72169
  • Downloads: 

    30077
Abstract: 

Metal biosorption on plant-based materials and agricultural wastes is a well practiced but a complex process affected by several factors. The biosorption of CHROMIUM(VI) from aqueous solution onto waste plant biomass of Portulaca Oleracea was studied in the present work. Batch studies were carried out to examine the effects of process parameters. Influence of altering various process parameters was studied. The biosorption process was fast, and equilibrium was achieved in 45 min of contact time. It was found that the biosorption capacity of plant material depends on many factors mainly on solution pH, with a maximum biosorption capacity for CHROMIUM at pH 2. The biosorption kinetics was tested with pseudo-first-order and pseudo-second-order reaction, and results showed that biosorption followed pseudo-second-order rate expression. Experimental equilibrium data were applied to two different isotherm models. Isotherm tests showed that equilibrium sorption data were better represented by Langmuir model, and the sorption capacity of plant biomass was found to be 54.945 mg/g. Thermodynamic parameters like DG 0, DH 0 and DS 0 were also evaluated, and it was found that the biosorption was spontaneous and endothermic in nature. Plant biomass was found to be an effective adsorbent for CHROMIUM (VI) from aqueous solution. This study indicated that plant biomass could be used as an efficient, cost-effective and environmentally safe biosorbent for the treatment of CHROMIUM containing aqueous solutions.

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Issue Info: 
  • Year: 

    2012
  • Volume: 

    14
  • Issue: 

    5 (68)
  • Pages: 

    77-83
Measures: 
  • Citations: 

    0
  • Views: 

    886
  • Downloads: 

    268
Abstract: 

BACKGROUND AND OBJECTIVE: Personal protective equipments (PPE) are common equipments for control of workers exposure to harmful agents in work environment. Regarding to the critical role of the filter collection efficiency under hazardous conditions such as exposure to carcinogen materials, this study was performed to determine the effect of different factors on efficiency of respirator filters in removing hexavalent CHROMIUM mist.METHODS: In this quasi-experimental study, homogenous CHROMIUM mist at different conditions (concentration 1.25 and 2.5 mg/m3, relative humidity 50 and 80%, and temperature 0-5 and 35-40 oC) passed through two types of respirator filters (MSA and Spasciani). All samples (n=384) were collected, using NIOSH 7600 test method at upstream and downstream of respiratory filters, simultaneously and analyzed, using an atomic absorption spectrometer and inductively coupled plasma (ICP), respectively.FINDINGS: Although type of filter had significant effect on hexavalent CHROMIUM mist removal, the ANOVA test results indicated that the increase of CHROMIUM mist concentration and relative humidity resulted a significant decrease in removal efficacy 0.53% and 0.42%, respectively (p<0.001). The temperature had not significant effect on filter efficiency.CONCLUSION: Increase of hexavalent CHROMIUM mist concentrations and relative humidity has significant negative effect on collection efficiency of respirator filters.

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Author(s): 

POORNIMA K. | KARTHIK L.

Issue Info: 
  • Year: 

    2010
  • Volume: 

    2
  • Issue: 

    -
  • Pages: 

    95-99
Measures: 
  • Citations: 

    466
  • Views: 

    40511
  • Downloads: 

    30210
Keywords: 
Abstract: 

Yearly Impact:

View 40511

Download 30210 Citation 466 Refrence 0
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