Medipolymorphol, a new sterol isolated from the whole plant of Medicago polymorpha Roxb was used as corrosion inhibitor for 316 stainless steel in 5% HCI at room temperature. Electrochemical techniques have been found...Medipolymorphol, a new sterol isolated from the whole plant of Medicago polymorpha Roxb was used as corrosion inhibitor for 316 stainless steel in 5% HCI at room temperature. Electrochemical techniques have been found to be reliable in evaluating corrosion characteristics of the system. Several techniques have been used including Tafel, linear polarization, potentiodynamic polarization, and open circuit potential (OCP) studies. The additives simultaneously deaccelerated the anodic process, intensified the cathodic process and provided a stable passive state, giving good inhibition efficiencies to stainless steel electrodes. In addition, adsorption isotherm have been fitted for the inhibitor under investigation.展开更多
A comprehensive<em> in vitro</em> study on single and sequential extraction methods for Cu exraction by different extractants of distinct chemical nature from some peat soils of Bangladesh was conducted to...A comprehensive<em> in vitro</em> study on single and sequential extraction methods for Cu exraction by different extractants of distinct chemical nature from some peat soils of Bangladesh was conducted to assess the pattern of metal-extractability in drying and wetting sequences. Samples were collected from peat basins of two different districts of Bangladesh (Gopalgonj and Bagerhat) and an incubation study was designed and conducted in which soils were incubated to three alternate drying and wetting cycles for 21 days. Single and sequentially extracted Cu ions in all three cycles and by all three selective extractants were compared. Maximum amount of Cu was extracted in drying days and 1M HCl extracted the largest proportion of Cu from all the soils in each incubation time. Conversely, 1M NH<sub>4</sub>Cl was the least effective extractant for extracting Cu by both single and sequential process in either day of incubation. Considerable amount of Cu was extracted by 0.005 M DTPA in dry periods. In general, single extraction was found to be more effective in extracting Cu in the alternate drying and wetting cycles from the peat soil samples except for 1M HCl in initial drying days.展开更多
[Objectives] To study the optimal conditions for extracting procyanidins fromLycium ruthenicum Murr. with sub-critical fluid R134 a( 1,1,1,2-tetrafluoroethane) in 1 L extraction kettle. [Methods]Taking the extraction ...[Objectives] To study the optimal conditions for extracting procyanidins fromLycium ruthenicum Murr. with sub-critical fluid R134 a( 1,1,1,2-tetrafluoroethane) in 1 L extraction kettle. [Methods]Taking the extraction rate of procyanidins as an indicator,the influence of pressure,temperature,and extraction time on extraction rate of procyanidins fromL. Ruthenicum Murr. was studied by single factor experimental methods and orthogonal array design. [Results]The order of factors affecting extraction rate of procyanidins was extraction temperature > extraction pressure > extraction time. The optimum extraction conditions were as follows: the extraction rate of procyanidins fromL. ruthenicum Murr. was the highest with extraction pressure of 1. 2 MPa,extraction temperature of 50℃ and extraction time of 90 min. The content of procyanidins in L. ruthenicum Murr. from different producing areas was determined by vanillin-HCl method under the optimal conditions. [Conclusions] The method has the advantages of easy operation,good selectivity,low extraction temperature and high extraction efficiency,which is suitable for extraction of procyanidins in L. ruthenicum Murr.展开更多
文摘Medipolymorphol, a new sterol isolated from the whole plant of Medicago polymorpha Roxb was used as corrosion inhibitor for 316 stainless steel in 5% HCI at room temperature. Electrochemical techniques have been found to be reliable in evaluating corrosion characteristics of the system. Several techniques have been used including Tafel, linear polarization, potentiodynamic polarization, and open circuit potential (OCP) studies. The additives simultaneously deaccelerated the anodic process, intensified the cathodic process and provided a stable passive state, giving good inhibition efficiencies to stainless steel electrodes. In addition, adsorption isotherm have been fitted for the inhibitor under investigation.
文摘A comprehensive<em> in vitro</em> study on single and sequential extraction methods for Cu exraction by different extractants of distinct chemical nature from some peat soils of Bangladesh was conducted to assess the pattern of metal-extractability in drying and wetting sequences. Samples were collected from peat basins of two different districts of Bangladesh (Gopalgonj and Bagerhat) and an incubation study was designed and conducted in which soils were incubated to three alternate drying and wetting cycles for 21 days. Single and sequentially extracted Cu ions in all three cycles and by all three selective extractants were compared. Maximum amount of Cu was extracted in drying days and 1M HCl extracted the largest proportion of Cu from all the soils in each incubation time. Conversely, 1M NH<sub>4</sub>Cl was the least effective extractant for extracting Cu by both single and sequential process in either day of incubation. Considerable amount of Cu was extracted by 0.005 M DTPA in dry periods. In general, single extraction was found to be more effective in extracting Cu in the alternate drying and wetting cycles from the peat soil samples except for 1M HCl in initial drying days.
基金Supported by 2016 Instrument Functional Development Project of Lanzhou Regional Center of Resources and Environmental Science Instrument,CAS(2018gl11)
文摘[Objectives] To study the optimal conditions for extracting procyanidins fromLycium ruthenicum Murr. with sub-critical fluid R134 a( 1,1,1,2-tetrafluoroethane) in 1 L extraction kettle. [Methods]Taking the extraction rate of procyanidins as an indicator,the influence of pressure,temperature,and extraction time on extraction rate of procyanidins fromL. Ruthenicum Murr. was studied by single factor experimental methods and orthogonal array design. [Results]The order of factors affecting extraction rate of procyanidins was extraction temperature > extraction pressure > extraction time. The optimum extraction conditions were as follows: the extraction rate of procyanidins fromL. ruthenicum Murr. was the highest with extraction pressure of 1. 2 MPa,extraction temperature of 50℃ and extraction time of 90 min. The content of procyanidins in L. ruthenicum Murr. from different producing areas was determined by vanillin-HCl method under the optimal conditions. [Conclusions] The method has the advantages of easy operation,good selectivity,low extraction temperature and high extraction efficiency,which is suitable for extraction of procyanidins in L. ruthenicum Murr.
