Afshin Takdastan; Azadeh Tashrifat; Roya Mafi Eslami; Azadeh Eslami
Volume 21, Issue 4 , September and October 2014, , Pages 665-674
Abstract
Background: Chromium is one of the toxic heavy metals that exist in trivalent and hexavalent forms in aqueous systems. Hexavalent chromium is highly toxic, carcinogenic and corrosive in nature. Adsorption is an effective method in chromium removal. The aim of this study is investigation of the hexavalent ...
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Background: Chromium is one of the toxic heavy metals that exist in trivalent and hexavalent forms in aqueous systems. Hexavalent chromium is highly toxic, carcinogenic and corrosive in nature. Adsorption is an effective method in chromium removal. The aim of this study is investigation of the hexavalent chromium removal using sugarcane bagasse from synthetic solutions and determining of the sorption kinetics.
Methods: The impact of pH, temperature, contact time, Adsorbent concentration and paricle size on chromium removal was carried out. Langmuir and Freundlich adsorption isotherms with sorption kinetics were investigated. Experiments were carried out with Tagochi method using Qualitik4.
Finding: The maximum chromium removal was achieved in pH=2, temperature of 50C ,500 m adsorbent size, adsorbent concentration of 20g/l equal to 90.1%. Altogether adsorption capacity was increased with increasing temperature and adsorbent concentration and decreased with increasing pH. Adsorbent particle size does not an important effect on removal efficiency. Sugarcane bagasse adsorption kinetics in chromium removal followed by second- order reaction and were in good agreement with Langmuir isotherm.
Conclusion: the results showed appropriate adsorption capacity for sugarcane baggase in hexavalent chromium removal as a significant pollutant.
Amir Masoud Afshar; Alireza Jafarnejadi; Afshin Takdastan; Nematollah Jafarzadeh Haghighi fard; Maruam Torabi fard
Volume 20, Issue 4 , January and February 2014, , Pages 511-520
Abstract
Background: During the last decades efforts related to waste water treatment, has improved significantly in Different places of our country with various climate conditions.
To reach this aim using systems are considered that have appropriate applications technically and economically . One of the low ...
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Background: During the last decades efforts related to waste water treatment, has improved significantly in Different places of our country with various climate conditions.
To reach this aim using systems are considered that have appropriate applications technically and economically . One of the low cost and native options is using Land-plant system for advanced waste water treatment. The aim of this study was determination of efficiency of local soil of Ahvaz and vetiver plant tothe final reduce the organic load from Municipal wastewater treatment .
Materials and Methods: In order to, a pilot including three Lysimeter swere installed in Ahvaz West wastewater treatment plant. ThreeLysimeter were utilized that local soil was used in one of them, local soil with vetiver plant were used in the other one and soil artificial arrangement (local soil, silica sand (0.5-1mm), sand (15-30mm) was used in third Lysimeter. The effluent was transferred from Secondary settling outlet by pump for system that slow current in three filtration rate of 0.2, 0.6, 1 ml/min and three replication in each rate was used.
Results: The average removal efficiency of BOD5 and COD output from three Lysimeter local soil with vetiver plant, local soil without vetiver plant and soil artificial arrangement for filtration rate of 0.2 ml/min were;73.27% ,68.39%,58.91% ,50.34%, 37.62% and 35.9%.For filtration rate of 0.6 ml/min were;49.47%,41.97%, 43.16, 28.31%, 33/68% and 25/55%.For filtration rate of 0.6ml/min; 26.44%,31.44%, 19.95,17.81%, 12.06% and 14.79%, respectively.
Conclusion: The results from this study showed that the best removing percent was assigned to local soil with vetiver plant lysimeter in 0.2 ml/min current. Based on the results of this study, it can be concluded that a land- plant system as advanced treatment had the ability to meet effluent discharge permit limits and was an economical replacement for stabilization ponds and mechanical treatment options.