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Showing 3 results for Natural Organic Matter

Ma Zazouli, S Nasseri, A Mesdaghinia,
Volume 1, Issue 1 (10-2008)
Abstract

Background and Objectives: Natural organic matters (NOMs) are abundant in natural water resources and in many ways may affect the unit processes in water treatment. Although NOMs are considered harmless but they have been recognized as disinfection by-products (DBPs) precursors during the chlorination process. Formation of DBPs highly depends on the composition and concentration of NOMs. The objective of this study was to determine natural organic matter and its fractions concentrations in the surface water sources of Tehran.Materials and Methods: Water sampling was conducted monthly between May to July in three rivers of Lar, Jajrood and Karaj, as the main drinking water supplying sources in Tehran. Quantitative parameters of pH, EC, UV254 and DOC were studied based on standard methods. The XAD-7 resin method was used for fractionation of NOMs.Results: Results showed that NOM concentrations in Lar, Jajrood and Karaj rivers were 8.53, 12.9 and 11.3 mg/L, respectively. The HPO (hydrophobic) fraction was predominant compared to the HPI (hydrophilic) fraction in water samples. The mean of total percent of HPO and HPI fractions were about 57% and 43%, respectively.Conclusion: Since the hydrophobic NOM fraction exhibits higher trihalomethane formation potential (THMFP) than hydrophilic part, Tehran water chlorination exhibits higher THMFP than haloacetic acid formation potential (HAAFP). The information obtained from this study may be further employed in the design of the control techniques and management strategies for the water treatment plant, especially for DBPs reduction.


M.s Mansoury, H Godini, Gh Shams Khorramabadi,
Volume 8, Issue 2 (8-2015)
Abstract

Background and Objective: Natural organic matters (NOM) are known as precursors to disinfection byproducts. As conventional treatment processes cannot get disinfection by-product standards, novel methods have been increasingly applied for the removal of disinfection by-products precursors. The UV/ZnO process is one of the advanced oxidation processes using photocatalytic technology. The present study aims to investigate the effect of UV/ZnO photocatalytic technology on the NOM removal from aqueous solution. Materials and methods: This study was conducted in a lab-scale batch photocatalytic reactor. The volume of reactor was 1liter and covered with UV lamps. Peristaltic pump was used for complete mixing. Humic acid is a key component of natural organic matter and it was used in this study. Each of the samples taken from the UV/ZnO process and other processes were analyzed for their UV absorbance at 254 nm by spectrophotometric. Initial concentration of Humic acid, contact time, pH, and UV irradiation were investigated. Results: The highest efficiency of the UV/ZnO photocatalytic process for removal of Humic acid from aqueous solution was achieved at initial concentration = 2 mg/L, contact time = 120 min, UV irradiation = 3950 µw/cm2, and pH=3. In this process, the removal efficiency for 2 mg/L humic acid was 100 % at 2h retention time. Conclusion: The research showed that performance of system was increased by increasing contact time and UV irradiation and was decreased by increasing HA initial concentration and pH and UV radiation with ZnO agent could not remove NOM lonely. Photocatalytic system using zinc oxide immobilized on glass have high performance to remove humic acid from aqueous solution. The UV/ZnO process was efficient and environmental friendly for natural organic matter removal.


A Naghizadeh, S Nasseri,
Volume 8, Issue 2 (8-2015)
Abstract

Background and Objective: Natural organic matters (NOMs) are a mixture of chemically complex polyelectrolytes with varying molecular weights, produced mainly from the decomposition of plants and animal residues. Various purification methods are used for removal of NOMs from water. The objective of this study was to remove NOMs from aqueous solution using reformed continuous carbon nanotubes column. Materials and Methods: The removal of NOMs from aqueous solution using reformed continuous carbon nanotubes column was studied. Effect of several variables such as zero point of pH (pHZPC), pH, influent concentration of natural organic matters were studied and different isotherms were assessed. Results: Investigation of pH effect showed that the adsorbability of NOMs increased with decreasing of pH. The experiments indicated that carbon nanotubes (CNT) samples exhibit pHZPC around 6. Results from Freundlich, Langmuir, and BET isotherm experiments revealed that the correlation coefficient R2 in Freundlich model was higher than that of Langmuir. In addition, experiments of continuous flow in different initial concentrations of NOMs showed that the adsorption capacities of CNT were 53.46, 30.40, and 24.75 mg/g for NOMs initial concentrations of 10, 5, and 3 mg/L, respectively. Conclusion: The present study shows that CNTs have high potential for adsorption of NOMs from aqueous solution



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