The Experts below are selected from a list of 378 Experts worldwide ranked by ideXlab platform
Pedram Fatehi - One of the best experts on this subject based on the ideXlab platform.
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flocculation of thermomechanical pulping spent liquor with Polydiallyldimethylammonium Chloride
Journal of Environmental Management, 2017Co-Authors: Pedram FatehiAbstract:Abstract Currently, the dissolved lignocelluloses in the spent liquor (SL) of a thermomechanical pulping process are treated in wastewater treatment systems and thus they are wasted. In this work, Polydiallyldimethylammonium Chloride (PDADMAC), with different molecular weights, was used for flocculating lignocelluloses of SL and thus isolating them from SL. Results showed that the maximum removals were 38% via treating SL with 100 mg/L of PDADMAC (with 1045 kg/mol molecular weight) at 25 °C for 30 min. The focused beam reflectance measurement of the flocculation process revealed that the chord length of the flocs with the maximum square weighted counts was increased from 70 to 100 μm and also their maximum square weighted counts was increased from 5 to 25 μm 2 /s. The flocs contained 60.71–74.41 wt% PDADMAC, the balance of lignocelluloses and the heating value of 24–25 MJ/kg. The high molecular PDADMAC generated flocs with more organics and a higher heating value.
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production of modified bentonite via adsorbing lignocelluloses from spent liquor of nssc process
Bioresource Technology, 2014Co-Authors: Farshad Oveissi, Pedram FatehiAbstract:In this work, the adsorption of lignocelluloses from spent liquor (SL) of neutral sulfite semi chemical (NSSC) pulping process on bentonite was investigated. It was observed that 0.26g/g of lignin and 0.27g/g of hemicelluloses from SL were adsorbed on bentonite under the conditions of 50°C, 100rpm and 40g/gSL/bentonite after 3h of treatment. The adsorptions of lignin and hemicellulose were increased to 1.8g/g and 0.45g/g, respectively, via adding 15mg/g of Polydiallyldimethylammonium Chloride (PDADMAC) in the system of SL/bentonite. The turbidity and COD removals were improved from 69% to 93% and from 25% to 38% by adding PDADMAC to the SL/bentonite system, respectively. The increase in the heating value of bentonite (from 0 to 15.4MJ/kg) confirmed the adsorption of lignocelluloses. The modified bentonite can be used as filler in corrugated medium paper production or as fuel.
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a combined adsorption and flocculation process for producing lignocellulosic complexes from spent liquors of neutral sulfite semichemical pulping process
Bioresource Technology, 2014Co-Authors: Mehdi Dashtban, Allan Gilbert, Pedram FatehiAbstract:Abstract The spent liquor (SL) of a neutral sulfite semichemical pulping process contains lignocelluloses that are currently treated in a waste water system. In this work, an adsorption process using activated carbon (AC) was considered for isolating the lignin and hemicelluloses from SL. The maximum adsorptions of 0.9 g/g lignin and 0.43 g/g of hemicelluloses on AC were achieved under the conditions of 30 °C, pH 7 and 3 h with SL/AC weight ratio of 90. The addition of Polydiallyldimethylammonium Chloride (PDADMAC) to the SL/AC system significantly improved the adsorption of lignin to 2.5 g/g on AC. The molecular weight of PDADMAC considerably affected the results in that the higher MW PDADMAC led to less lignin, but more hemicelluloses, turbidity and chemical oxygen demand removals from the SL. The thermal analysis also revealed that the higher MW PDADMAC generated precipitates with a lower incineration temperature and heating value.
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adsorption of lignocelluloses of model pre hydrolysis liquor on activated carbon
Bioresource Technology, 2013Co-Authors: Pedram Fatehi, Jennifer RyanAbstract:The main objective of this work was to study the adsorption behavior of various components dissolved in the pre-hydrolysis of kraft process on activated carbon. In this work, model prehydrolysis liquor (PHL) solutions (MPHL)s were prepared via mixing various commercially available monosugars, xylan, lignin and furfural; and their adsorption performance on activated carbon (AC) was investigated. In singular (one component) MPHL/AC systems, furfural had the maximum and xylose had the minimum adsorption, and the adsorption of monosugars was basically similar on AC. Also, Polydiallyldimethylammonium Chloride (PDADMAC) was added (0.5 g/l) to singular xylan or lignin MPHL/AC system, which increased the lignin and xylan adsorptions to 350 and 190 mg/g on AC, respectively.
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removal of inhibitors from pre hydrolysis liquor of kraft based dissolving pulp production process using adsorption and flocculation processes
Bioresource Technology, 2012Co-Authors: Pedram Fatehi, Yonghao NiAbstract:Abstract A process for removing inhibitors from pre-hydrolysis liquor (PHL) of a kraft-based dissolving pulp production process by adsorption and flocculation, and the characteristics of this process were studied. In this process, industrially produced PHL was treated with unmodified and oxidized activated carbon as an absorbent and Polydiallyldimethylammonium Chloride (PDADMAC) as a flocculant. The overall removal of lignin and furfural in the developed process was 83.3% and 100%, respectively, while that of hemicelluloses was 32.7%. These results confirmed that the developed process can remove inhibitors from PHL prior to producing value-added products, e.g. ethanol and xylitol via fermentation.
Philip C Bevilacqua - One of the best experts on this subject based on the ideXlab platform.
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template directed rna polymerization and enhanced ribozyme catalysis inside membraneless compartments formed by coacervates
Nature Communications, 2019Co-Authors: Raghav R Poudyal, Rebecca M Guthmetzler, Andrew Veenis, Erica A Frankel, Christine D Keating, Philip C BevilacquaAbstract:Membraneless compartments, such as complex coacervates, have been hypothesized as plausible prebiotic micro-compartments due to their ability to sequester RNA; however, their compatibility with essential RNA World chemistries is unclear. We show that such compartments can enhance key prebiotically-relevant RNA chemistries. We demonstrate that template-directed RNA polymerization is sensitive to polycation identity, with Polydiallyldimethylammonium Chloride (PDAC) outperforming poly(allylamine), poly(lysine), and poly(arginine) in polycation/RNA coacervates. Differences in RNA diffusion rates between PDAC/RNA and oligoarginine/RNA coacervates imply distinct biophysical environments. Template-directed RNA polymerization is relatively insensitive to Mg2+ concentration when performed in PDAC/RNA coacervates as compared to buffer, even enabling partial rescue of the reaction in the absence of magnesium. Finally, we show enhanced activities of multiple nucleic acid enzymes including two ribozymes and a deoxyribozyme, underscoring the generality of this approach, in which functional nucleic acids like aptamers and ribozymes, and in some cases key cosolutes localize within the coacervate microenvironments.
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template directed rna polymerization and enhanced ribozyme catalysis inside membraneless compartments formed by coacervates
Nature Communications, 2019Co-Authors: Raghav R Poudyal, Rebecca M Guthmetzler, Andrew Veenis, Erica A Frankel, Christine D Keating, Philip C BevilacquaAbstract:Membraneless compartments, such as complex coacervates, have been hypothesized as plausible prebiotic micro-compartments due to their ability to sequester RNA; however, their compatibility with essential RNA World chemistries is unclear. We show that such compartments can enhance key prebiotically-relevant RNA chemistries. We demonstrate that template-directed RNA polymerization is sensitive to polycation identity, with Polydiallyldimethylammonium Chloride (PDAC) outperforming poly(allylamine), poly(lysine), and poly(arginine) in polycation/RNA coacervates. Differences in RNA diffusion rates between PDAC/RNA and oligoarginine/RNA coacervates imply distinct biophysical environments. Template-directed RNA polymerization is relatively insensitive to Mg2+ concentration when performed in PDAC/RNA coacervates as compared to buffer, even enabling partial rescue of the reaction in the absence of magnesium. Finally, we show enhanced activities of multiple nucleic acid enzymes including two ribozymes and a deoxyribozyme, underscoring the generality of this approach, in which functional nucleic acids like aptamers and ribozymes, and in some cases key cosolutes localize within the coacervate microenvironments. Membraneless compartments have been theorized to be prebiotic micro-compartments as they spontaneously encapsulate RNA and proteins. Here, the authors report membraneless compartments can enhance RNA chemistries, affecting template directed RNA polymerization and stimulating nucleic acid enzymes.
Yonghao Ni - One of the best experts on this subject based on the ideXlab platform.
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removal of inhibitors from pre hydrolysis liquor of kraft based dissolving pulp production process using adsorption and flocculation processes
Bioresource Technology, 2012Co-Authors: Pedram Fatehi, Yonghao NiAbstract:Abstract A process for removing inhibitors from pre-hydrolysis liquor (PHL) of a kraft-based dissolving pulp production process by adsorption and flocculation, and the characteristics of this process were studied. In this process, industrially produced PHL was treated with unmodified and oxidized activated carbon as an absorbent and Polydiallyldimethylammonium Chloride (PDADMAC) as a flocculant. The overall removal of lignin and furfural in the developed process was 83.3% and 100%, respectively, while that of hemicelluloses was 32.7%. These results confirmed that the developed process can remove inhibitors from PHL prior to producing value-added products, e.g. ethanol and xylitol via fermentation.
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recovery of lignocelluloses from pre hydrolysis liquor in the lime kiln of kraft based dissolving pulp production process by adsorption to lime mud
Bioresource Technology, 2011Co-Authors: Jing Shen, Pendar Soleimani, Pedram Fatehi, Yonghao NiAbstract:Abstract Dissolved lignocelluloses from the pre-hydrolysis liquor (PHL) of kraft-based dissolving pulp production process were recovered by adsorption to lime mud produced in the causticizing plant of the kraft process. The adsorption of lignocelluloses was a fast process, and could be completed within one hour. The addition of Polydiallyldimethylammonium Chloride (PDADMAC) significantly increased the amounts of adsorbed lignin and hemicelluloses, which more than doubled at the PDADMAC dosage of 0.1% (based on the weight of PHL). The measured heating values of the adsorbed lignocelluloses indicate that adsorption of lignocelluloses to lime mud may result in the energy saving of the lime kiln. The process proposed in this study could also be adapted to decrease inhibitor concentrations (lignin and acetic acid) if the dissolved hemicelluloses in the PHL were used to produce value-added products, e.g., ethanol, xylitol, based on the fermentation process.
Erica A Frankel - One of the best experts on this subject based on the ideXlab platform.
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template directed rna polymerization and enhanced ribozyme catalysis inside membraneless compartments formed by coacervates
Nature Communications, 2019Co-Authors: Raghav R Poudyal, Rebecca M Guthmetzler, Andrew Veenis, Erica A Frankel, Christine D Keating, Philip C BevilacquaAbstract:Membraneless compartments, such as complex coacervates, have been hypothesized as plausible prebiotic micro-compartments due to their ability to sequester RNA; however, their compatibility with essential RNA World chemistries is unclear. We show that such compartments can enhance key prebiotically-relevant RNA chemistries. We demonstrate that template-directed RNA polymerization is sensitive to polycation identity, with Polydiallyldimethylammonium Chloride (PDAC) outperforming poly(allylamine), poly(lysine), and poly(arginine) in polycation/RNA coacervates. Differences in RNA diffusion rates between PDAC/RNA and oligoarginine/RNA coacervates imply distinct biophysical environments. Template-directed RNA polymerization is relatively insensitive to Mg2+ concentration when performed in PDAC/RNA coacervates as compared to buffer, even enabling partial rescue of the reaction in the absence of magnesium. Finally, we show enhanced activities of multiple nucleic acid enzymes including two ribozymes and a deoxyribozyme, underscoring the generality of this approach, in which functional nucleic acids like aptamers and ribozymes, and in some cases key cosolutes localize within the coacervate microenvironments.
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template directed rna polymerization and enhanced ribozyme catalysis inside membraneless compartments formed by coacervates
Nature Communications, 2019Co-Authors: Raghav R Poudyal, Rebecca M Guthmetzler, Andrew Veenis, Erica A Frankel, Christine D Keating, Philip C BevilacquaAbstract:Membraneless compartments, such as complex coacervates, have been hypothesized as plausible prebiotic micro-compartments due to their ability to sequester RNA; however, their compatibility with essential RNA World chemistries is unclear. We show that such compartments can enhance key prebiotically-relevant RNA chemistries. We demonstrate that template-directed RNA polymerization is sensitive to polycation identity, with Polydiallyldimethylammonium Chloride (PDAC) outperforming poly(allylamine), poly(lysine), and poly(arginine) in polycation/RNA coacervates. Differences in RNA diffusion rates between PDAC/RNA and oligoarginine/RNA coacervates imply distinct biophysical environments. Template-directed RNA polymerization is relatively insensitive to Mg2+ concentration when performed in PDAC/RNA coacervates as compared to buffer, even enabling partial rescue of the reaction in the absence of magnesium. Finally, we show enhanced activities of multiple nucleic acid enzymes including two ribozymes and a deoxyribozyme, underscoring the generality of this approach, in which functional nucleic acids like aptamers and ribozymes, and in some cases key cosolutes localize within the coacervate microenvironments. Membraneless compartments have been theorized to be prebiotic micro-compartments as they spontaneously encapsulate RNA and proteins. Here, the authors report membraneless compartments can enhance RNA chemistries, affecting template directed RNA polymerization and stimulating nucleic acid enzymes.
Raghav R Poudyal - One of the best experts on this subject based on the ideXlab platform.
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template directed rna polymerization and enhanced ribozyme catalysis inside membraneless compartments formed by coacervates
Nature Communications, 2019Co-Authors: Raghav R Poudyal, Rebecca M Guthmetzler, Andrew Veenis, Erica A Frankel, Christine D Keating, Philip C BevilacquaAbstract:Membraneless compartments, such as complex coacervates, have been hypothesized as plausible prebiotic micro-compartments due to their ability to sequester RNA; however, their compatibility with essential RNA World chemistries is unclear. We show that such compartments can enhance key prebiotically-relevant RNA chemistries. We demonstrate that template-directed RNA polymerization is sensitive to polycation identity, with Polydiallyldimethylammonium Chloride (PDAC) outperforming poly(allylamine), poly(lysine), and poly(arginine) in polycation/RNA coacervates. Differences in RNA diffusion rates between PDAC/RNA and oligoarginine/RNA coacervates imply distinct biophysical environments. Template-directed RNA polymerization is relatively insensitive to Mg2+ concentration when performed in PDAC/RNA coacervates as compared to buffer, even enabling partial rescue of the reaction in the absence of magnesium. Finally, we show enhanced activities of multiple nucleic acid enzymes including two ribozymes and a deoxyribozyme, underscoring the generality of this approach, in which functional nucleic acids like aptamers and ribozymes, and in some cases key cosolutes localize within the coacervate microenvironments.
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template directed rna polymerization and enhanced ribozyme catalysis inside membraneless compartments formed by coacervates
Nature Communications, 2019Co-Authors: Raghav R Poudyal, Rebecca M Guthmetzler, Andrew Veenis, Erica A Frankel, Christine D Keating, Philip C BevilacquaAbstract:Membraneless compartments, such as complex coacervates, have been hypothesized as plausible prebiotic micro-compartments due to their ability to sequester RNA; however, their compatibility with essential RNA World chemistries is unclear. We show that such compartments can enhance key prebiotically-relevant RNA chemistries. We demonstrate that template-directed RNA polymerization is sensitive to polycation identity, with Polydiallyldimethylammonium Chloride (PDAC) outperforming poly(allylamine), poly(lysine), and poly(arginine) in polycation/RNA coacervates. Differences in RNA diffusion rates between PDAC/RNA and oligoarginine/RNA coacervates imply distinct biophysical environments. Template-directed RNA polymerization is relatively insensitive to Mg2+ concentration when performed in PDAC/RNA coacervates as compared to buffer, even enabling partial rescue of the reaction in the absence of magnesium. Finally, we show enhanced activities of multiple nucleic acid enzymes including two ribozymes and a deoxyribozyme, underscoring the generality of this approach, in which functional nucleic acids like aptamers and ribozymes, and in some cases key cosolutes localize within the coacervate microenvironments. Membraneless compartments have been theorized to be prebiotic micro-compartments as they spontaneously encapsulate RNA and proteins. Here, the authors report membraneless compartments can enhance RNA chemistries, affecting template directed RNA polymerization and stimulating nucleic acid enzymes.