Adsorption and Reduction of Chromium(VI) from Aqueous Solution by Multiwalled Carbon Nanotubes

Hu, Jing; Wang, S.W.; Shao, Dadong; Dong, Yuming; Li, J.X.; Wang, X.K.

doi:10.2174/1876397900901010066

“…The results showed that the removal rate increased with decreasing pH due to increased Hcro4-and Cro 4 2-ions that increase the ions in the environment, and it can cause the easier absorption. Hu et al in other study achieved similar results (12). In comparison with other studies conducted in this field, the findings of the current study show that the optimal condition is an acidic environment in which the removal efficiency increases significantly.…”

Section: Discussionsupporting

confidence: 86%

“…The results showed that the Cr removal rate increased with decreasing pH due to the increase in Hcro 4 -and Cro 4 2-ions that increase the ions in the environment, and Cr can be absorbed more easily. Hu et al in other study achieved similar results (12). The maximum absorption rate was achieved in the initial concentration of 50 mg/L, the amount of adsorbent 0.15 g at 70°C and pH 2.6.…”

Section: Introductionsupporting

confidence: 67%

Using Modified Concrete for Removing Chromium From Wastewater

Asrari

¹

,

Nia

²

2016

Jundishapur J Helath Sci

1

0

View full text Add to dashboard Cite

Background: Annual large amounts of wastewater can be entered into the environment from domestic, agricultural, and industrial sources that contain high concentrations of chemical materials and heavy metals. Chromium (Cr) is one of the most important environmental pollutants, which can cause pollution of water resources and disorder in the metabolic activities of living organisms. Objectives: In this study, we used the alteration in the concrete structure by iron oxide nanoparticles and rice husk ash (RHA) to remove Cr as a heavy metal from sewage. Methods: Rice husk ash was used in the structure of concrete as a forty percent by cement weight. Samples were made according to sewage condition and concrete required strength of purification pools. Samples' surface was covered with nanoparticle, RHA, RHA and nanoparticle. Different sewage concentrations of Cr were made from the range of 1 to 1000 ppm. The effects of parameters, such as contact time, adsorbent dose, pH, concentration of Cr in sewage, and Cr absorption were examined. Results: The maximum absorption was obtained 99.7%, in the contact time of 6 hours, dose of adsorbent 20 mg/L, pH 3, and Cr concentration in sewage 10 ppm at the laboratory temperature. Cr absorption followed the Freundlich model of adsorption. Conclusions:The combination of nanoparticles and RHA showed well efficiency for Cr absorption from sewage.

show abstract

“…The results showed that the Cr removal rate increased with decreasing pH due to the increase in Hcro 4 -and Cro 4 2-ions that increase the ions in the environment, and Cr can be absorbed more easily. Hu et al in other study achieved similar results (12). The maximum absorption rate was achieved in the initial concentration of 50 mg/L, the amount of adsorbent 0.15 g at 70°C and pH 2.6.…”

Section: Introductionsupporting

confidence: 67%

“…The absorption rate was high in the early times, but decreases over time, which indicates that the reaction has reached equilibrium. Results of the Singh et al study (2008) on removing Cr (VI) by using zero-valent iron nanoparticles showed that by increasing the contact time between the absorber and Cr (VI), the (12). In comparison with other studies conducted in this field, the findings of the current study show that the optimal condition is an acidic environment in which the removal efficiency increases significantly.…”

Section: Discussionsupporting

confidence: 45%

Using Modified Concrete for Removing Chromium From Wastewater

Asrari

¹

,

Nia

²

2016

Jundishapur J Health Sci

1

0

View full text Add to dashboard Cite

Background: Annual large amounts of wastewater can be entered into the environment from domestic, agricultural, and industrial sources that contain high concentrations of chemical materials and heavy metals. Chromium (Cr) is one of the most important environmental pollutants, which can cause pollution of water resources and disorder in the metabolic activities of living organisms. Objectives: In this study, we used the alteration in the concrete structure by iron oxide nanoparticles and rice husk ash (RHA) to remove Cr as a heavy metal from sewage. Methods: Rice husk ash was used in the structure of concrete as a forty percent by cement weight. Samples were made according to sewage condition and concrete required strength of purification pools. Samples' surface was covered with nanoparticle, RHA, RHA and nanoparticle. Different sewage concentrations of Cr were made from the range of 1 to 1000 ppm. The effects of parameters, such as contact time, adsorbent dose, pH, concentration of Cr in sewage, and Cr absorption were examined. Results: The maximum absorption was obtained 99.7%, in the contact time of 6 hours, dose of adsorbent 20 mg/L, pH 3, and Cr concentration in sewage 10 ppm at the laboratory temperature. Cr absorption followed the Freundlich model of adsorption. Conclusions:The combination of nanoparticles and RHA showed well efficiency for Cr absorption from sewage.

show abstract

“…Acute exposure to Cr(VI) compounds causes nausea, diarrhea, kidney, liver, and gastric damage, internal hemorrhage, lung cancer, ulcer formation, and respiratory problems [11,16,18,19]. The main industries that contribute to water pollution by chromium are mining, leather tanning, textile dyeing, electroplating, metal finishing such as corrosion inhibiting and aluminum coating operations, magnetic tapes, pigments, wood protection, chemical manufacturing, nuclear power plants, electrical and electronic equipment, and catalysis [12,17,18,[20][21][22] which can encompass up to hundreds of mg/L of Cr(VI) while the regulated tolerance values are 0.1 and 0.05 mg/L for discharge into the inland surface and potable waters, respectively [15,17,19,[22][23][24].…”

Section: Introductionmentioning

confidence: 99%