A macroporous polymeric adsorbent NG-8 was synthesized with divinylbenzene using conventional suspension polymerization technique. Its aminated product NG-9 was prepared by introducing tertiary amino groups into NG-8 ...A macroporous polymeric adsorbent NG-8 was synthesized with divinylbenzene using conventional suspension polymerization technique. Its aminated product NG-9 was prepared by introducing tertiary amino groups into NG-8 for removal of tannin acid from aqueous solutions. NG-9 could be used directly without a wetting process and had higher adsorption capacity than NG-8, which might be attributed to the enhanced adsorbent-adsorbate interaction due to the tertiary amino groups on the polymeric matrix. The Langmuir equation was successfully employed to describe the adsorption process. The adsorption enthalpy change further validated the uptake of tannin acid on NG-9 to be an enhanced physical adsorption because of the Lewis acid-base interaction. In addition, adsorption kinetic studies testified that the tertiary amino groups on the polymer matrix could decrease the adsorption rate maybe for the hindrance of the tertiary amino groups and water clusters built up.展开更多
Studies on the corrosion behaviour of mild steel electrodes in inhibited hydrochloric acid are described. Conventional weight loss measurements show that a maximum concentration of 140 ppm of tannin from Rhizophora ra...Studies on the corrosion behaviour of mild steel electrodes in inhibited hydrochloric acid are described. Conventional weight loss measurements show that a maximum concentration of 140 ppm of tannin from Rhizophora racemosa is required to achieve 72% corrosion inhibition. Similar concentration of tannin: H3PO4 in ratio 1:1 gave 61% inhibition efficiency, whereas efficiency obtained for phosphoric acid as inhibitor in the same environment was 55%. Corrosion rates obtained over six hours of exposure in 1M HCl solution at inhibitor concentrations of 140 ppm are 2 mA/cm2, 2.4 mA/cm2, 2.6 mA/cm2 and 6 mA/cm2 for tannin, tannin/H3PO4 and H3PO4-inhibited and uninhibited specimens respectively. Natural atmospheric exposure studies revealed that specimens treated in H3PO4 resisted corrosion for three weeks, while tannin treated specimens suffered corrosion attack after one week of exposure tests.展开更多
Terminalic acid 1, a new hydrolysable tannin, was isolated from the fruit of Terminalia chebula. Its structure was found to be 1-O-galloyl-2,4-chebuloyl-beta-D-glucopyranose by chemical method and H-1-NMR, C-13-NMR, H...Terminalic acid 1, a new hydrolysable tannin, was isolated from the fruit of Terminalia chebula. Its structure was found to be 1-O-galloyl-2,4-chebuloyl-beta-D-glucopyranose by chemical method and H-1-NMR, C-13-NMR, H-1-H-1 COSY, HMQC, HMBC and FAB-MS spectral analyses.展开更多
Objective:To investigate the changes in total phenols,flavonoids,tannins,vitamin E, β-carotene and antioxidant activity during soaking of three white sorghum varieties.Methods: The changes in total phenols,total ilav...Objective:To investigate the changes in total phenols,flavonoids,tannins,vitamin E, β-carotene and antioxidant activity during soaking of three white sorghum varieties.Methods: The changes in total phenols,total ilavonoids,tannins,phenolic acids compounds,flavonoid components,vitamin E,P-carotene and antioxidant activity during soaking of sorghum grains were determined.Results:Total phenols,total flavonoids,tannins,vitamin E,P-carotene and antioxidant activity in raw sorghum were ranged from 109.21 to 116.70,45.91 to 54.69,1.39 to 21.79 mg/100 g,1.74 to 5.25,0.54 to 1.19 mg/kg and 21.72%to 27.69%and 25.29%to 31.97%,respectively. The above measured compounds were significantly decreased after soaking.p-Hydroxybenzoic acid,vanillic acid,syringic acid and cinnamic acid represent the major phenolic acids in Dorado variety.While ferulic acid,p-coumaric acid,gallic acid and caffeic acid represent the major phenolic acids in Shandaweel-6.On the other hand,protocatechuic acid represents the major phenolic acids in Giza-15.Regarding flavonoids components,Dorado was the highest variety in kampferol and naringenin while Shandaweel-6 was the highest variety in luteolin, apigenin,hypersoid,quercelin and christen.Finally,Giza-15 was the highest variety in catechin. Phenolic acids,flavonoid compounds and antioxidant activities were decreased after soaking. Conclusions:Sorghum varieties have moderate quantities from total phenols,total flavonoids, tannins,phenolic acids compounds,flavonoid components,vitamin E,P-carotene and antioxidant activity which decreased after soaking.展开更多
[Objectives] To establish a method for the determination of tannin in Sanguisorba officinalis L.,and provide guarantee for further control over quality of semi-finished tannin products from Sanguisorba officinalis L. ...[Objectives] To establish a method for the determination of tannin in Sanguisorba officinalis L.,and provide guarantee for further control over quality of semi-finished tannin products from Sanguisorba officinalis L. [Methods] With gallic acid as reference substance,the UV method was used to determine the content of tannin in Sanguisorba officinalis L.,and the methodological examination was done. [Results]With gallic acid as standard,when the concentration of tannin in Sanguisorba officinalis L. was 1. 02-10. 14 μg·m L^(-1),there was a good linear relationship with absorbance,the precision,reproducibility and recovery were in line with the requirements,and the absorbance value was stable within 40 min after coloration. [Conclusions] The method was simple,rapid and accurate in determining the content of tannin in Sanguisorba officinalis L.展开更多
基金This work was supported by the Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection,China(Grant Code JLCBE6006).
文摘A macroporous polymeric adsorbent NG-8 was synthesized with divinylbenzene using conventional suspension polymerization technique. Its aminated product NG-9 was prepared by introducing tertiary amino groups into NG-8 for removal of tannin acid from aqueous solutions. NG-9 could be used directly without a wetting process and had higher adsorption capacity than NG-8, which might be attributed to the enhanced adsorbent-adsorbate interaction due to the tertiary amino groups on the polymeric matrix. The Langmuir equation was successfully employed to describe the adsorption process. The adsorption enthalpy change further validated the uptake of tannin acid on NG-9 to be an enhanced physical adsorption because of the Lewis acid-base interaction. In addition, adsorption kinetic studies testified that the tertiary amino groups on the polymer matrix could decrease the adsorption rate maybe for the hindrance of the tertiary amino groups and water clusters built up.
文摘Studies on the corrosion behaviour of mild steel electrodes in inhibited hydrochloric acid are described. Conventional weight loss measurements show that a maximum concentration of 140 ppm of tannin from Rhizophora racemosa is required to achieve 72% corrosion inhibition. Similar concentration of tannin: H3PO4 in ratio 1:1 gave 61% inhibition efficiency, whereas efficiency obtained for phosphoric acid as inhibitor in the same environment was 55%. Corrosion rates obtained over six hours of exposure in 1M HCl solution at inhibitor concentrations of 140 ppm are 2 mA/cm2, 2.4 mA/cm2, 2.6 mA/cm2 and 6 mA/cm2 for tannin, tannin/H3PO4 and H3PO4-inhibited and uninhibited specimens respectively. Natural atmospheric exposure studies revealed that specimens treated in H3PO4 resisted corrosion for three weeks, while tannin treated specimens suffered corrosion attack after one week of exposure tests.
文摘Terminalic acid 1, a new hydrolysable tannin, was isolated from the fruit of Terminalia chebula. Its structure was found to be 1-O-galloyl-2,4-chebuloyl-beta-D-glucopyranose by chemical method and H-1-NMR, C-13-NMR, H-1-H-1 COSY, HMQC, HMBC and FAB-MS spectral analyses.
基金financially supported by Department of Biochemistry,Faculty of Agriculture.Cario University,and Food Technology Research Institute(FTRI)
文摘Objective:To investigate the changes in total phenols,flavonoids,tannins,vitamin E, β-carotene and antioxidant activity during soaking of three white sorghum varieties.Methods: The changes in total phenols,total ilavonoids,tannins,phenolic acids compounds,flavonoid components,vitamin E,P-carotene and antioxidant activity during soaking of sorghum grains were determined.Results:Total phenols,total flavonoids,tannins,vitamin E,P-carotene and antioxidant activity in raw sorghum were ranged from 109.21 to 116.70,45.91 to 54.69,1.39 to 21.79 mg/100 g,1.74 to 5.25,0.54 to 1.19 mg/kg and 21.72%to 27.69%and 25.29%to 31.97%,respectively. The above measured compounds were significantly decreased after soaking.p-Hydroxybenzoic acid,vanillic acid,syringic acid and cinnamic acid represent the major phenolic acids in Dorado variety.While ferulic acid,p-coumaric acid,gallic acid and caffeic acid represent the major phenolic acids in Shandaweel-6.On the other hand,protocatechuic acid represents the major phenolic acids in Giza-15.Regarding flavonoids components,Dorado was the highest variety in kampferol and naringenin while Shandaweel-6 was the highest variety in luteolin, apigenin,hypersoid,quercelin and christen.Finally,Giza-15 was the highest variety in catechin. Phenolic acids,flavonoid compounds and antioxidant activities were decreased after soaking. Conclusions:Sorghum varieties have moderate quantities from total phenols,total flavonoids, tannins,phenolic acids compounds,flavonoid components,vitamin E,P-carotene and antioxidant activity which decreased after soaking.
文摘[Objectives] To establish a method for the determination of tannin in Sanguisorba officinalis L.,and provide guarantee for further control over quality of semi-finished tannin products from Sanguisorba officinalis L. [Methods] With gallic acid as reference substance,the UV method was used to determine the content of tannin in Sanguisorba officinalis L.,and the methodological examination was done. [Results]With gallic acid as standard,when the concentration of tannin in Sanguisorba officinalis L. was 1. 02-10. 14 μg·m L^(-1),there was a good linear relationship with absorbance,the precision,reproducibility and recovery were in line with the requirements,and the absorbance value was stable within 40 min after coloration. [Conclusions] The method was simple,rapid and accurate in determining the content of tannin in Sanguisorba officinalis L.
