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.
Abdolmotalleb Seyyed Mohammadi; Ghorban Asgari; MohammadTaghi Samadi; Ali Pour Mohammadi; Ali Faramarzi Govhar
Volume 22, Issue 4 , September and October 2015, , Pages 571-580
Abstract
Background and aim: Humic Acid (HA) is one of the polyelectrolyte compounds which cause many problems in water treatment process. In present study, UV/IO4- as a novel advance oxidation process, was used for removing HA. Material and methods: In present research, a batch reactor in lab scale was used.This ...
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Background and aim: Humic Acid (HA) is one of the polyelectrolyte compounds which cause many problems in water treatment process. In present study, UV/IO4- as a novel advance oxidation process, was used for removing HA. Material and methods: In present research, a batch reactor in lab scale was used.This reactor with useful volume of 2.5 L, made of stainless steel, which equipped with a low pressure Hg vapor lamp. In this study the effect of some parameters including pH, initial HA concentration, IO4- concentration and Fe (0) nanoparticles concentration were investigated. HA concentration was determined using Spectrophotometer at an absorbance wavelength of 254 nm. Results: According to the results, pH 3, periodate concentration 125 mg/L and Fe (0) Nano particles 12.5 mg/L were determined as optimum conditions. Moreover, results indicated that in presence of UV coupled with Periodate removal efficiency of HA increased to 66.08%, and the increase of Fe (0) Nano particles can led to increase HA removal (73.3%). Conclusion: Results show thatthe presence of UV letto increase in the activation of periodate, on the other hands, the presence of Fe (0) Nano particles led to further activation of periodate subsequently cause the increasing HA removal.
Mohammadtaghi Samadi; Monireh Tarlani Azar; Halimeh Almasi; Samaneh Shanehsaz; Roya Harati
Volume 22, Issue 4 , September and October 2015, , Pages 699-707
Abstract
Background & Objectives: Fluoride concentration in drinking water is one of the effective parameters in human health, and the majority of the body's requirement for fluoride is supplied through drinking water. Fluoride in low concentration is essential for human but in high concentration is very ...
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Background & Objectives: Fluoride concentration in drinking water is one of the effective parameters in human health, and the majority of the body's requirement for fluoride is supplied through drinking water. Fluoride in low concentration is essential for human but in high concentration is very hazardous for human health. In the present study, the efficiency of modified-clay and lime-marl as adsorbents was investigated for the elimination of fluoride from aqueous solution. Material & Methods: This experimental study was conducted at the Hamedan University of Medical Sciences in 2014. The effects of several parameters such as pH (4, 7 and 10), the adsorbent dosage (1, 5 and 10 g/L), initial concentration of fluoride (5, 10 and 15 mg/L), contact time (15-120 min) on the removal have been studied. Also, the structural characteristics of both adsorbents were evaluated using X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR). Results: According to the results obtained, the removal efficiency of fluoride, at concentration 10 mg/L and the approximate time of 60 min, in the case of clay-modified adsorbent is 95.23% and in the case of lime-marl adsorbent is about 28.71%. Langmuir and Freundlich coefficients were determined in the optimum conditions, and the adsorption isotherm could be described by the Langmuir model(R2=0.9907). Kinetic study showed that the equilibrium time was 60 min. The adsorption kinetics fitted well with the Ho pseudo second-order kinetic model (R2=0.994). Conclusion: According to our finding, it is proposed that the adsorption process of fluoride by clay-modified is very efficient and economics for fluoride removal from aqueous solution.