Synthesis,characterization of Co_3O_4 and Ag-Co_3O_4 composites and evaluation of their photo-catalytic activities towards photo-degradation of aqueous solution of rhodamine B dye under irradiation of visible light ha...Synthesis,characterization of Co_3O_4 and Ag-Co_3O_4 composites and evaluation of their photo-catalytic activities towards photo-degradation of aqueous solution of rhodamine B dye under irradiation of visible light have been described in this paper.Co_3O_4 was prepared by solid phase mechano chemical process using Co(NO_3)_2·6H_2O and NH_4 HCO_3 as precursor materials.Ag was deposited on Co_3O_4 from AgNO_3 using Calotropis gigantea extract as reducing agent.XRD,SEM and FTIR were used for characterization of prepared composites.Photo-catalytic efficiencies of as-prepared Co_3O_4 and Ag-Co_3O_4 were evaluated for aqueous phase photo-degradation of rhodamine B.It was found that deposition of Ag on Co_3O_4 highly enhanced the photo-catalytic activity of Co_3O_4.Photo-catalytic degradation followed the Eley–Rideal mechanism.About 100% and 91% photo-degradation of 40 ml dye solution achieved at 313 K in 90 and 120 min over 0.05 g of Ag-Co_3O_4 as photo-catalyst using 100 and 200 mg·L^(-1) as initial concentration of dye respectively.展开更多
Mercury-containing catalysts are widely used for acetylene hydrochlorination in China. Surface chemical characteristics of the fresh low-level mercury catalysts and spent low-level mercury catalysts were compared usin...Mercury-containing catalysts are widely used for acetylene hydrochlorination in China. Surface chemical characteristics of the fresh low-level mercury catalysts and spent low-level mercury catalysts were compared using multiple characterization methods. Pore blockage and active site coverage caused by chlorine-containing organics are responsible for catalyst deactivation. The reactions of chloroethylene and acetylene with chlorine free radical can generate chlorine-containing organic species. SiO_2 and functional groups on activated carbon contribute to the generation of carbon deposition. No significant reduction in the total content of mercury was observed after catalyst deactivation, while there was mercury loss locally. The irreversible loss of HgCl_2 caused by volatilization, reduction and poisoning of elements S and P also can lead to catalyst deactivation. Si, Al, Ca and Fe oxides are scattered on the activated carbon. Active components are still uniformly absorbed on activated carbon after catalyst deactivation.展开更多
Most current commercially important hydrocolloids could be considered as dietary fibers.A great deal of research has focused on the bio-function of hydrocolloid materials resulting from their chemical structure,includ...Most current commercially important hydrocolloids could be considered as dietary fibers.A great deal of research has focused on the bio-function of hydrocolloid materials resulting from their chemical structure,including antioxidant properties,bacteriostatic capacity and cancer prevention.However,the colloidal properties of hydrocolloids in water-holding,high viscosity,gelling and indigestion,which are characterized by macromolecules,also contribute to the human health.Therefore,the nutritional value of hydrocolloids deriving from their colloid properties is defined as colloid nutriology.More specifically,hydrocolloids in this study refer to dietary fibers which are metabolically inert or fermented in the colon or large intestine.Based on this conception,this mini-review attempts to elaborate the nutritional value of hydrocolloids resulting from its colloidal properties.展开更多
基金The World Academy of Sciences(TWAS)(13-301 RG/MSN/AS_C) is acknowledged for financial support under COMSTECH-TWAS Grants Program
文摘Synthesis,characterization of Co_3O_4 and Ag-Co_3O_4 composites and evaluation of their photo-catalytic activities towards photo-degradation of aqueous solution of rhodamine B dye under irradiation of visible light have been described in this paper.Co_3O_4 was prepared by solid phase mechano chemical process using Co(NO_3)_2·6H_2O and NH_4 HCO_3 as precursor materials.Ag was deposited on Co_3O_4 from AgNO_3 using Calotropis gigantea extract as reducing agent.XRD,SEM and FTIR were used for characterization of prepared composites.Photo-catalytic efficiencies of as-prepared Co_3O_4 and Ag-Co_3O_4 were evaluated for aqueous phase photo-degradation of rhodamine B.It was found that deposition of Ag on Co_3O_4 highly enhanced the photo-catalytic activity of Co_3O_4.Photo-catalytic degradation followed the Eley–Rideal mechanism.About 100% and 91% photo-degradation of 40 ml dye solution achieved at 313 K in 90 and 120 min over 0.05 g of Ag-Co_3O_4 as photo-catalyst using 100 and 200 mg·L^(-1) as initial concentration of dye respectively.
基金Supported by the National Science Fund for Excellent Young Scholars of China(No.51522405)
文摘Mercury-containing catalysts are widely used for acetylene hydrochlorination in China. Surface chemical characteristics of the fresh low-level mercury catalysts and spent low-level mercury catalysts were compared using multiple characterization methods. Pore blockage and active site coverage caused by chlorine-containing organics are responsible for catalyst deactivation. The reactions of chloroethylene and acetylene with chlorine free radical can generate chlorine-containing organic species. SiO_2 and functional groups on activated carbon contribute to the generation of carbon deposition. No significant reduction in the total content of mercury was observed after catalyst deactivation, while there was mercury loss locally. The irreversible loss of HgCl_2 caused by volatilization, reduction and poisoning of elements S and P also can lead to catalyst deactivation. Si, Al, Ca and Fe oxides are scattered on the activated carbon. Active components are still uniformly absorbed on activated carbon after catalyst deactivation.
基金supported by the National Natural Science Foundation of China(Grant No.31772015)
文摘Most current commercially important hydrocolloids could be considered as dietary fibers.A great deal of research has focused on the bio-function of hydrocolloid materials resulting from their chemical structure,including antioxidant properties,bacteriostatic capacity and cancer prevention.However,the colloidal properties of hydrocolloids in water-holding,high viscosity,gelling and indigestion,which are characterized by macromolecules,also contribute to the human health.Therefore,the nutritional value of hydrocolloids deriving from their colloid properties is defined as colloid nutriology.More specifically,hydrocolloids in this study refer to dietary fibers which are metabolically inert or fermented in the colon or large intestine.Based on this conception,this mini-review attempts to elaborate the nutritional value of hydrocolloids resulting from its colloidal properties.
