Afshin Takdastan; Mehdi Jolanejad; Abdolkazem Neisi; Mehrnosh Abtahi; Sahand Jorfi
Volume 23, Issue 4 , September and October 2016, , Pages 698-705
Abstract
Background Chromium and cadmium are two heavy metals having adverse effects on the health and environment, which are released to environment by waste streams. Because of high solubility, they are absorbed by living organisms and through food chain accumulate in human body. This study aimed to determine ...
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Background Chromium and cadmium are two heavy metals having adverse effects on the health and environment, which are released to environment by waste streams. Because of high solubility, they are absorbed by living organisms and through food chain accumulate in human body. This study aimed to determine the efficiency of the polyferric sulfate (PFS) in removing of Cr6+ and Cd2+ from aqueous solutions.Methods & Materials This study was investigated in bench scale using a jar test apparatus. The effect of pH (4-11), dose of coagulants (10-200 mg/l), initial amount of metals (1-100 mg/l) and settling time (15-9 min) were investigated. Cr and Cd concentration were determined by atomic absorption spectroscopy.Results The result showed that the maximum removal efficiency was 52.82% for Cr and 93.13% for Cd, at pH values of 6 and 9, coagulant dosage of 100 and 50 mg/l, respectively, and settling time for 30 min. Conclusion Coagulation and sedimentation by use of polyferric sulfate can be considered as an efficient process for removal of Cd and pretreatment of Cr.
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.