Mohammad Taghi Samadi; Reza Shokohi; Samaneh Shanehsaz
Volume 23, Issue 3 , July and August 2016, , Pages 406-415
Abstract
Background Endocrine-Disrupting Compounds are emerging group of trace contaminants detected in wastewater and water resources worldwide. Bisphenol A (BPA) is one of the compounds that can cause serious health problems.Materials and Methods In this study, the removal of BPA from aqueous solutions by multi-walled ...
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Background Endocrine-Disrupting Compounds are emerging group of trace contaminants detected in wastewater and water resources worldwide. Bisphenol A (BPA) is one of the compounds that can cause serious health problems.Materials and Methods In this study, the removal of BPA from aqueous solutions by multi-walled carbon nanotubes was investigated. Experiments were performed in batch reactor and changing effective factors such as pH, contact time, concentration of carbon nanotubes, and concentration of BPA. The concentrations of BPA were measured using UV-VIS spectrophotometer at wavelength of 280 nm.Results The results showed that maximum removal efficiency was 95% at a concentration of 400 mg/L of carbon nanotubes, pH=7, retention time of 60 minutes and BPA concentration of 20 mg/L. The maximum adsorption capacity was found to be 111.6 mg/g and the adsorption data were best fitted to the Freundlich isotherms and pseudo-second order.Conclusion The results showed that carbon nanotubes have a high ability to adsorb BPA in the aquatic environment and can be used as a suitable adsorbent from aqueous solution.
Mohammad Malakootian; Marzie Javdan; Farnaz Iranmanesh; Kamyar Yaghmaeian
Volume 23, Issue 3 , July and August 2016, , Pages 540-549
Abstract
Background Intake of high concentration of fluoride causes health problems in human. Therefore, finding a way for removing excessive fluoride from water is among the most important tasks in water supply projects. How to remove excess fluoride from water is the objective of this project, and as a case ...
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Background Intake of high concentration of fluoride causes health problems in human. Therefore, finding a way for removing excessive fluoride from water is among the most important tasks in water supply projects. How to remove excess fluoride from water is the objective of this project, and as a case study, it was carried out with the aim of investigating the efficiency of bauxite ore in Tash mine in removing fluoride.Materials & Methods The study was performed in a laboratory scale on a synthetic sample collected from the water of Kuhbonan region in the Environmental Health Research Center of Kerman. The adsorbent was prepared from bauxite of Tash mine in Semnan Province. Bauxite analysis was carried out by X-ray fluorescence and diffraction spectrometry methods. The effects of such parameters such as pH, contact time, the adsorbent amount, and different fluoride concentrations on the removal process were investigated. The experiments were performed on real water sample under optimal conditions. To better understand the adsorption process, kinetics and isotherm of the adsorption were investigated, too. The level of fluoride was determined by SPADNS method. For data analysis, Excel software was used.Results The maximum obtained fluoride removal efficiency was 68.20% in a synthetic sample, at pH=7, contact time of 120 minutes, by using 25 g/L bauxite. This level was obtained 45.84% in the real sample under optimal conditions. Adsorption of fluoride followed Langmuir adsorption isotherm equation with a correlation coefficient of 0.991 and second-order model with a correlation coefficient of 0.985.Conclusion Without preliminary preparation, the bauxite of Tash mine can be used as an inexpensive and effective absorbent for removing fluoride from groundwater with low concentrations of fluoride.