The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Krishna R Reddy - One of the best experts on this subject based on the ideXlab platform.
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effect of Ph Control at the anode for the electrokinetic removal of Phenanthrene from kaolin soil
Chemosphere, 2003Co-Authors: Richard E Saichek, Krishna R ReddyAbstract:Polycyclic aromatic hydrocarbon (PAH)-contaminated soils exist at numerous sites, and these sites may threaten public health and the environment because many PAH compounds are toxic, mutagenic, and/or carcinogenic. PAHs are also hydroPhobic and persistent, so conventional remediation methods are often costly or inefficient, especially when the contaminants are present in low permeability and/or organic soils. An innovative technique, electrokinetically enhanced in situ flushing, has the potential to increase soil–solution–contaminant interaction and PAH removal efficiency for low permeability soils; however, the electrolysis reaction at the anode may adversely affect the remediation of low acid buffering capacity soils, such as kaolin. Therefore, the objective of this study was to improve the remediation of low acid buffering soils by Controlling the Ph at the anode to counteract the electrolysis reaction. Six bench-scale electrokinetic experiments were conducted, where each test employed one of three different flushing solutions, deionized water, a surfactant, or a cosolvent. For each of these solutions, tests were performed with and without a 0.01 M NaOH solution at the anode to Control the Ph. The test using deionized water with Ph Control generated a higher electroosmotic flow than the equivalent test performed without Ph Control, but the electroosmotic flow difference between the surfactant and cosolvent tests with and without Ph Control was minor compared to that observed with the deionized water tests. Controlling the Ph was beneficial for increasing contaminant solubilization and migration from the soil region adjacent to the anode, but the high contaminant concentrations that resulted in the middle or cathode soil regions indicates that subsequent changes in the soil and/or solution chemistry caused contaminant deposition and low overall contaminant removal efficiency. 2003 Elsevier Science Ltd. All rights reserved.
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effect of Ph Control at the anode for the electrokinetic removal of Phenanthrene from kaolin soil
Chemosphere, 2003Co-Authors: Richard E Saichek, Krishna R ReddyAbstract:Polycyclic aromatic hydrocarbon (PAH)-contaminated soils exist at numerous sites, and these sites may threaten public health and the environment because many PAH compounds are toxic, mutagenic, and/or carcinogenic. PAHs are also hydroPhobic and persistent, so conventional remediation methods are often costly or inefficient, especially when the contaminants are present in low permeability and/or organic soils. An innovative technique, electrokinetically enhanced in situ flushing, has the potential to increase soil-solution-contaminant interaction and PAH removal efficiency for low permeability soils; however, the electrolysis reaction at the anode may adversely affect the remediation of low acid buffering capacity soils, such as kaolin. Therefore, the objective of this study was to improve the remediation of low acid buffering soils by Controlling the Ph at the anode to counteract the electrolysis reaction. Six bench-scale electrokinetic experiments were conducted, where each test employed one of three different flushing solutions, deionized water, a surfactant, or a cosolvent. For each of these solutions, tests were performed with and without a 0.01 M NaOH solution at the anode to Control the Ph. The test using deionized water with Ph Control generated a higher electroosmotic flow than the equivalent test performed without Ph Control, but the electroosmotic flow difference between the surfactant and cosolvent tests with and without Ph Control was minor compared to that observed with the deionized water tests. Controlling the Ph was beneficial for increasing contaminant solubilization and migration from the soil region adjacent to the anode, but the high contaminant concentrations that resulted in the middle or cathode soil regions indicates that subsequent changes in the soil and/or solution chemistry caused contaminant deposition and low overall contaminant removal efficiency.
Richard E Saichek - One of the best experts on this subject based on the ideXlab platform.
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effect of Ph Control at the anode for the electrokinetic removal of Phenanthrene from kaolin soil
Chemosphere, 2003Co-Authors: Richard E Saichek, Krishna R ReddyAbstract:Polycyclic aromatic hydrocarbon (PAH)-contaminated soils exist at numerous sites, and these sites may threaten public health and the environment because many PAH compounds are toxic, mutagenic, and/or carcinogenic. PAHs are also hydroPhobic and persistent, so conventional remediation methods are often costly or inefficient, especially when the contaminants are present in low permeability and/or organic soils. An innovative technique, electrokinetically enhanced in situ flushing, has the potential to increase soil–solution–contaminant interaction and PAH removal efficiency for low permeability soils; however, the electrolysis reaction at the anode may adversely affect the remediation of low acid buffering capacity soils, such as kaolin. Therefore, the objective of this study was to improve the remediation of low acid buffering soils by Controlling the Ph at the anode to counteract the electrolysis reaction. Six bench-scale electrokinetic experiments were conducted, where each test employed one of three different flushing solutions, deionized water, a surfactant, or a cosolvent. For each of these solutions, tests were performed with and without a 0.01 M NaOH solution at the anode to Control the Ph. The test using deionized water with Ph Control generated a higher electroosmotic flow than the equivalent test performed without Ph Control, but the electroosmotic flow difference between the surfactant and cosolvent tests with and without Ph Control was minor compared to that observed with the deionized water tests. Controlling the Ph was beneficial for increasing contaminant solubilization and migration from the soil region adjacent to the anode, but the high contaminant concentrations that resulted in the middle or cathode soil regions indicates that subsequent changes in the soil and/or solution chemistry caused contaminant deposition and low overall contaminant removal efficiency. 2003 Elsevier Science Ltd. All rights reserved.
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effect of Ph Control at the anode for the electrokinetic removal of Phenanthrene from kaolin soil
Chemosphere, 2003Co-Authors: Richard E Saichek, Krishna R ReddyAbstract:Polycyclic aromatic hydrocarbon (PAH)-contaminated soils exist at numerous sites, and these sites may threaten public health and the environment because many PAH compounds are toxic, mutagenic, and/or carcinogenic. PAHs are also hydroPhobic and persistent, so conventional remediation methods are often costly or inefficient, especially when the contaminants are present in low permeability and/or organic soils. An innovative technique, electrokinetically enhanced in situ flushing, has the potential to increase soil-solution-contaminant interaction and PAH removal efficiency for low permeability soils; however, the electrolysis reaction at the anode may adversely affect the remediation of low acid buffering capacity soils, such as kaolin. Therefore, the objective of this study was to improve the remediation of low acid buffering soils by Controlling the Ph at the anode to counteract the electrolysis reaction. Six bench-scale electrokinetic experiments were conducted, where each test employed one of three different flushing solutions, deionized water, a surfactant, or a cosolvent. For each of these solutions, tests were performed with and without a 0.01 M NaOH solution at the anode to Control the Ph. The test using deionized water with Ph Control generated a higher electroosmotic flow than the equivalent test performed without Ph Control, but the electroosmotic flow difference between the surfactant and cosolvent tests with and without Ph Control was minor compared to that observed with the deionized water tests. Controlling the Ph was beneficial for increasing contaminant solubilization and migration from the soil region adjacent to the anode, but the high contaminant concentrations that resulted in the middle or cathode soil regions indicates that subsequent changes in the soil and/or solution chemistry caused contaminant deposition and low overall contaminant removal efficiency.
Weisheng Zou - One of the best experts on this subject based on the ideXlab platform.
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Ph Control modes in a 5 l stirred tank bioreactor for cell biomass and exopolysaccharide production by tremella fuciformis spore
Bioresource Technology, 2011Co-Authors: Hu Zhu, Shuaishuai Zhang, Chunxu Cao, Ya Zhang, Weisheng ZouAbstract:Abstract The effect of Ph-Control modes on cell growth and exopolysaccharide production by Tremella fuciformis was evaluated in a 5-L bioreactor. The results show that the maximal dry cell weight (DCW) and exopolysaccharide production were 23.57 and 4.48 g L−1 in Ph-stat fermentation, where the maximal specific growth rate (μmax) and specific production rate of exopolysaccharide (PP/X) were 1.03 and 0.24 d−1, respectively; under Ph-shift cultivation, the maximal DCW and exopolysaccharide production were 30.57 and 3.90 g L−1, where the μmax and PP/X were 1.21 and 0.06 d−1. Unlike batch fermentation, maximal DCW and exopolysaccharide production merely reached 15.04 and 2.0 g L−1, where the μmax and PP/X were 0.86 and 0.05 d−1, respectively. These results suggest that a Ph-stat strategy is a more efficient way of performing the fermentation process to increase exopolysaccharide production. Furthermore, this research has also proved that the three-stage Ph-Control mode is effective for cell growth.
Zhonggui Mao - One of the best experts on this subject based on the ideXlab platform.
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production of e poly l lysine using a novel two stage Ph Control strategy by streptomyces sp m z18 from glycerol
Bioprocess and Biosystems Engineering, 2011Co-Authors: Xusheng Chen, Lijuan Liao, Xidong Ren, Lei Tang, Jianhua Zhang, Zhonggui MaoAbstract:The production of e-poly-l-lysine (e-PL) by Streptomyces sp. M-Z18 from glycerol was investigated in a 5-L jar-fermenter. Batch fermentations by Streptomyces sp. M-Z18 at various Ph values ranging from 3.5 to 4.5 were studied. Based on the analysis of the time course of specific cell growth rate and specific e-PL formation rate, a novel two-stage Ph Control strategy was developed to improve e-PL production by shifting the culture Ph from 3.5 to 3.8 after 36 h of cultivation. By applying the strategy, the maximal e-PL concentration and productivity had a significant improvement and reached 9.13 g L−1 and 4.76 g L−1 day−1, respectively, compared with those in one-stage Ph Control process where the Ph value is Controlled at 3.5 (7.83 g L−1 and 3.13 g L−1 day−1). Fed-batch fermentation with two-stage Ph Control strategy was also applied to produce e-PL; final e-PL concentration of 30.11 g L−1 was obtained, being 3.3-fold greater than that of batch fermentation. To our knowledge, it is the first report on production of e-PL from glycerol in fermenter scale and achievement of high e-PL production with two-stage Ph Control strategy.
Qi Zhou - One of the best experts on this subject based on the ideXlab platform.
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effect of initial Ph Control on enhanced biological PhosPhorus removal from wastewater containing acetic and propionic acids
Chemosphere, 2007Co-Authors: Yan Liu, Yinguang Chen, Qi ZhouAbstract:In the literature most of the studies on the effect of Ph on enhanced biological PhosPhorous removal were conducted with the acetate wastewater, and the Ph was Controlled during the entire anaerobic and aerobic stages. This paper investigated the influence of anaerobic initial Ph Control, which will be more practical than the entire process Ph Control strategy, on enhanced biological PhosPhorus removal from wastewater containing acetic and propionic acids. Typical Ph profile showed that both the initial alkaline and acidic Ph tended to neutralize due to the consumption of short-chain fatty acid (SCFA) and intracellular Ph regulation by polyPhosPhate accumulating organisms (PAOs). It was observed that the glycogen degradation and polyhydroxyalkanoates (PhA) accumulation decreased with increasing initial Ph, which disagreed with previous reports. In the literature the metabolisms of both glycogen and PhA by PAOs in the acetate wastewater were independent of Ph. An anaerobic mechanism model was proposed to explain the intra- and extra-cellular Ph buffer nature of PAOs, and to address the reasons for increased polyPhosPhate degradation and decreased PhA synthesis and glycogen degradation at higher Ph. The optimal initial Ph for higher soluble ortho-PhosPhorus (SOP) removal efficiency should be Controlled between 6.4 and 7.2. This Ph Control strategy will be easier to use in practice of wastewater treatment plant.
