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Noemí E. Zaritzky - One of the best experts on this subject based on the ideXlab platform.
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effect of operating conditions on the chemical phosphorus removal using Ferric Chloride by evaluating orthophosphate precipitation and sedimentation of formed precipitates in batch and continuous systems
Chemical Engineering Journal, 2012Co-Authors: Alejandro H. Caravelli, Noemí E. Zaritzky, Carolina De GregorioAbstract:Chemical phosphate removal by Fe(III) involves the precipitation of Ferric phosphate and subsequent sedimentation of Fe–P particles. Physical–chemical factors that affect the phosphorus (P) precipitation are well known; however, the factors affecting the sedimentation of Fe–P precipitates have been poorly studied. The aims of this work were: (a) To study the effect of pH, presence of biomass (3.0 g TSS/L) and settling time on the orthophosphate precipitation by Ferric Chloride in a batch system. (b) To determine the effect of these factors on the sedimentation of the formed Fe–P particles. (c) To evaluate the performance of a laboratory-scale continuous activated sludge (AS) reactor operated with phosphorus simultaneous precipitation by Ferric Chloride under the optimum operating conditions determined from previous batch assays. Results from batch studies showed that presence of AS biomass and prolonged settling times favored the P removal. According to the proposed equation, in presence of biomass, the settling rate of the Fe–P precipitates was 3–7 times higher than that corresponding to phosphate buffer system. In the continuous system, Fe–P precipitates were gradually incorporated to the biomass, improving the reactor performance. However, a gradual shift of the size distribution from large to poorly settling small flocs was observed. The system operated at a sludge age of 21 days achieved more rapidly better performance than at 40 days. This last system showed bad flocculation exhibiting smaller flocs than the reactor with younger sludge. Simultaneous determination of the accumulation rate of fixed solids, and floc size distribution allows monitoring these systems.
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Phosphorous removal in batch systems using Ferric Chloride in the presence of activated sludges
Journal of Hazardous Materials, 2009Co-Authors: Alejandro H. Caravelli, Edgardo Martin Contreras, Noemí E. ZaritzkyAbstract:Abstract The objectives of this work were: (a) to analyze the effect of alkalinity, pH and initial Fe:P molar ratio (Fe0:P0) on the precipitation of orthophosphate using Ferric Chloride in the presence of activated sludge in order to represent conditions of simultaneous precipitation, and in exhausted wastewater to simulate conditions of post-precipitation, (b) to compare the experimental results with predictions obtained from a chemical equilibrium model, and (c) to propose a mechanistic model to determine the dose of coagulant required to achieve a given orthophosphate removal degree at constant pH. Results showed that the presence of biomass did not affect the orthophosphate precipitation; however, addition of Ferric Chloride caused a drop of pH to values not compatible with the normal activity of activated sludges. For this reason, the wastewater was supplemented with NaHCO3; when 1 g L−1 NaHCO3 was added, orthophosphate removals higher than 97% and pH above 6.2 were obtained using Fe0:P0 = 1.9. Precipitation assays at constant pH showed that Fe(III) hydrolysis and FePO4 precipitation reaction compete with each other. Calculations using a chemical equilibrium model (CHEAQS) predicted that Ferric phosphate precipitation should not take place if pH is higher than about 7.8. However, experimental results showed that Ferric phosphate precipitation occurred even at pH 9. For this reason, a mechanistic model was proposed to predict orthophosphate concentrations as a function of Fe0:P0 at constant pH. The model can be applied to calculate the minimum Fe(III) concentration required to achieve a given discharge limit for orthophosphate as a function of its initial concentration and pH.
Adharvana M Chari - One of the best experts on this subject based on the ideXlab platform.
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polymer pvp supported Ferric Chloride an efficient and recyclable heterogenous catalyst for one pot synthesis of 4 3h quinazolinones under solvent free conditions
Organic Chemistry: An Indian Journal, 2006Co-Authors: K Mukkanti, Adharvana M Chari, D Shobha, Prakash Mms KinthadaAbstract:An efficient synthesis of 4(3H)-quinazolinones by coupling of anthranilic acid, ortho esters and amines using Polymer supported Ferric Chloride catalyst under solvent free conditions is described. This new approach consistently has the advantage of excellent yields (80-97%) and short reaction times of 5-15 min.
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polymer pvp supported Ferric Chloride an efficient and recyclable heterogeneous catalyst for high yield synthesis of 1 5 benzodiazepine derivatives under solvent free conditions and microwave irradiation
Catalysis Communications, 2005Co-Authors: Adharvana M Chari, K SyamasundarAbstract:Abstract Polymer (PVP) supported Ferric Chloride catalyzes efficiently the condensation of o -phenylenediamines with ketones under solvent free conditions to afford the corresponding 1,5-benzodiazepine derivatives in high yields. The reaction proceeds efficiently under ambient conditions giving excellent yields (85–96%).
J E Dutrizac - One of the best experts on this subject based on the ideXlab platform.
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the precipitation of hematite from Ferric Chloride media
Hydrometallurgy, 1997Co-Authors: P A Riveros, J E DutrizacAbstract:The precipitation of hematite from Ferric Chloride media was systematically investigated in a series of autoclave experiments. The minimum temperature to form hematite in the absence of hematite seed is ∼ 125°C; akaganeite, β-FeO · OH, is precipitated at lower temperatures for the 65% Fe, < 0.5% Cl and less than 0.1% of Na, Ca, Zn or Pb. The precipitated hematite is very fine, but its filterability is greatly improved by the presence of hematite seed.
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the effect of the iron content of sphalerite on its rate of dissolution in Ferric sulphate and Ferric Chloride media
Hydrometallurgy, 1991Co-Authors: Palencia I Perez, J E DutrizacAbstract:Abstract Fifteen sphalerite samples having solid solution iron contents ranging from 0.04 to 14.7% Fe were leached at 20–90%C in both 0.3 M Fe(SO41.5−0.3 M H2SO4 and 0.3 M FeCl3-0.3 MHCl media. Linear kinetics were observed for all the sphalerites in both leaching systems. The sphalerite leaching rate increased in a linear manner with increasing iron content. At 80°C in the Ferric sulphate system, the rate, as defined by k=(1 −1 (1 − α) 1 3 )/t , increased from 0.38 gg−1 m−2 h−1 to 4.33 g g−1 m−2 h−1 as the iron content of the sphalerite increased from 0.04 to 12.5% Fe; the corresponding values in the Ferric Chloride system went from 0.26 g g−1 m−2 h−1 to 9.73 g g−1 m−2 h−1. Activation energies in the 39–81 kJ/mol range were observed in both systems. The activation energy decreased as the iron content of the sphalerite increased. The kinetics of sphalerite dissolution are similar in both the Fe(SO4)1.5H2SO4 and FeCl3HCl system, and the sphalerite leaching reaction seems to be controlled by charge transfer at the sphalerite surface.
K Syamasundar - One of the best experts on this subject based on the ideXlab platform.
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polymer pvp supported Ferric Chloride an efficient and recyclable heterogeneous catalyst for high yield synthesis of 1 5 benzodiazepine derivatives under solvent free conditions and microwave irradiation
Catalysis Communications, 2005Co-Authors: Adharvana M Chari, K SyamasundarAbstract:Abstract Polymer (PVP) supported Ferric Chloride catalyzes efficiently the condensation of o -phenylenediamines with ketones under solvent free conditions to afford the corresponding 1,5-benzodiazepine derivatives in high yields. The reaction proceeds efficiently under ambient conditions giving excellent yields (85–96%).
Jan Barta - One of the best experts on this subject based on the ideXlab platform.
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chemical composition and nutritional value of protein concentrates isolated from potato solanum tuberosum l fruit juice by precipitation with ethanol or Ferric Chloride
Journal of Agricultural and Food Chemistry, 2009Co-Authors: Veronika Bartova, Jan BartaAbstract:Effects of protein precipitators, ethanol and Ferric Chloride, on yield, resolubility, chemical composition and nutritional value of protein concentrates isolated from industrial potato fruit juice (PFJ) were studied. Optimum precipitating concentrations of ethanol and Ferric Chloride in PFJ were 4 M (23.1% v/v) and 20 mM (2% w/v), resulting in yield of 69% and 86.5% of total protein, respectively. Contents of total glycoalkaloids and potassium in both protein concentrates were significantly lower (P < 0.05) as compared with contents in PFJ dry matter. Both protein concentrates exhibited high nutritional value; values of essential amino acid index (EAAI) were 81.7% and 82.7%, respectively. Fraction of patatin proteins (39−43 kDa) represented with EAAI value of 86.1% the nutritionally improving protein component. Lipid acyl hydrolase activity of patatin family was not negatively affected by cooled ethanol precipitation. It can be thus suggested that biological and enzymatic activities of this protein famil...
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chemical composition and nutritional value of protein concentrates isolated from potato solanum tuberosum l fruit juice by precipitation with ethanol or Ferric Chloride
Journal of Agricultural and Food Chemistry, 2009Co-Authors: Veronika Bartova, Jan BartaAbstract:Effects of protein precipitators, ethanol and Ferric Chloride, on yield, resolubility, chemical composition and nutritional value of protein concentrates isolated from industrial potato fruit juice (PFJ) were studied. Optimum precipitating concentrations of ethanol and Ferric Chloride in PFJ were 4 M (23.1% v/v) and 20 mM (2% w/v), resulting in yield of 69% and 86.5% of total protein, respectively. Contents of total glycoalkaloids and potassium in both protein concentrates were significantly lower (P < 0.05) as compared with contents in PFJ dry matter. Both protein concentrates exhibited high nutritional value; values of essential amino acid index (EAAI) were 81.7% and 82.7%, respectively. Fraction of patatin proteins (39-43 kDa) represented with EAAI value of 86.1% the nutritionally improving protein component. Lipid acyl hydrolase activity of patatin family was not negatively affected by cooled ethanol precipitation. It can be thus suggested that biological and enzymatic activities of this protein family are utilizable after this type of precipitation.