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.
Abdolkazem Neisi; Mehdi Vosoughi; Anvar Asadi; Mohammad Javad Mohammadi; Mohammad Shirmardi; Mehdi Fazlzadeh; Amir Zahedi
Volume 23, Issue 3 , July and August 2016, , Pages 478-489
Abstract
Background Many industries can pollute water quality due to their wastewater discharging into water resources. Textile industries are one of the main sources of water pollution. Due to their high toxicity, wastewaters containing dyes cause many environmental problems. Acidic dyes are one of the main ...
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Background Many industries can pollute water quality due to their wastewater discharging into water resources. Textile industries are one of the main sources of water pollution. Due to their high toxicity, wastewaters containing dyes cause many environmental problems. Acidic dyes are one of the main classes of dyes. In this study, nano-alumina and micro-alumina powder have been used for the adsorption of acid red 14 dye.Materials & Methods This study was carried out in the batch system in laboratory scale. Different parameters such as initial dye concentration, pH, and adsorbent dose were examined. Spectrophotometry (UV/VIS Lambda 25 Perkin Elmer, Shelton) was used to quantify the remaining dyes concentration. Adsorption isotherm and kinetic behaviors of adsorbent for acidic dye removal were studied and fitted to different models.Results The result showed that with increasing the contact time, acid red 14 removal efficiency by micro-alumina and nano-alumina powder and amount of adsorption per mass unit (qe) increased to 18 and 40 mg/L, respectively, and when adsorbent dose increased from 0.2 to 1.2 g/L, qe decreased from 23 to 12 and 47 to 39, respectively. With increasing the pH value in examined range, the removal efficiency decreased from 30 to 6 and 60 to 15 for micro-alumina and nano-alumina powder, respectively. The results of the study of adsorption of acid red 14 by micro-alumina and nano-alumina powder revealed that its kinetics obeyed pseudo-second order (R2>0.99 and 0.98, respectively). The results of present study on adsorption of acid red 14 on micro-alumina and nano-alumina powder revealed that isotherm obeyed Langmuir adsorption (R2 >0.99 and 0.98, respectively). Conclusion The present study showed that the nano-alumina rather than mciro-alumina can be a promising adsorbent for the removal of acidic dyes such as acid red 14.