Lead （Pb） chemical fixation is an important environmental aspect for human health. Phosphate rocks （PRs） were utilized as an adsorbent to remove Pb from aqueous solution. Raw PRs and oxalic acid-activated PRs （A...Lead （Pb） chemical fixation is an important environmental aspect for human health. Phosphate rocks （PRs） were utilized as an adsorbent to remove Pb from aqueous solution. Raw PRs and oxalic acid-activated PRs （APRs） were used to investigate the effect of chemical modification on the Pb-binding capacity in the pH range 2.0-5.0. The Pb adsorption rate of all treatments above pH 3.0 reached 90%. The Pb binding on PRs and APRs was pH-independent, except at pH 2.0 in activated treatments. The X-ray diffraction analysis confirmed that the raw PRs formed cerussite after reacting with the Pb solution, whereas the APRs formed pyromorphite. The Fourier Transform Infrared spectroscopy analysis indicated that carbonate （CO32-） in raw PRs and phosphate （PO43-） groups in APRs played an important role in the Pb-binding process. After adsorption, anomalous block-shaped particles were observed by scanning electron microscopy with energy dispersive spectroscopy. The X-ray photoelectron spectroscopy data further indicated that both chemical and physical reactions occurred during the adsorption process according to the binding energy. Because of lower solubility of pyromorphite compared to cerussite, the APRs are more effective in immobilizing Pb than that of PRs.展开更多
Metal ions and fiber are common compounds in the livestock and poultry manure,which will affect the fate of organic compounds in aqueous environment. However,limited research has addressed the effect of coexisting met...Metal ions and fiber are common compounds in the livestock and poultry manure,which will affect the fate of organic compounds in aqueous environment. However,limited research has addressed the effect of coexisting metal ions and fiber on the biodegradation of sulfonamide antibiotics. Accordingly, a compositing study was performed to assess the effect of metal ions(Fe3+and Cu2+) on the biodegradation of sulfadimethoxine sodium salt(SDM) in the presence of fiber. The enhanced adsorption of SDM onto fiber in the presence of metal ions can be attributed to the π+–π electron donor acceptor(EDA) interaction. The microbial(Phanerochaete chrysosprium) could easily attach onto fiber forming attached microbial, and the degradation rates of SDM of immobilized bacteria in the presence of Fe3 +were 100%, which were significantly higher than those of free bacteria(45%). This study indicates that Fe3 +and fiber could enhance the biodegradation of SDM. Fiber acts as adsorbent, carrier, and substrate which enhanced the removal of SDM.展开更多
Strong field concentration may occur between two nearly-touching highcontrast material inclusions due to an incident field.The degree of concentration is characterised by the blowup rate of the underlying gradient fie...Strong field concentration may occur between two nearly-touching highcontrast material inclusions due to an incident field.The degree of concentration is characterised by the blowup rate of the underlying gradient field.This phenomenon has received considerable attention in the literature due to its practical implications in the theory of composite materials.However,most of the existing studies are concerned with the static cases.In this paper,we present a comprehensive numerical investigation of this intriguing phenomenon associated to the Helmholtz system in the quasi-static frequency regime.On the one hand,we present extensive numerical results to corroborate the theoretical findings in[16],and on the other hand,we derive new findings that cannot be handled by the theoretical analysis yet.Our focus is on the static effect,frequency effect,the geometric(curvature)effect to the gradient estimates.展开更多
基金supported by the National Natural Science Foundation of China (No. 41071165)the Special Research Fund for the Doctoral Program of Higher Education, Ministry of Education (No. 20090146110003)
文摘Lead （Pb） chemical fixation is an important environmental aspect for human health. Phosphate rocks （PRs） were utilized as an adsorbent to remove Pb from aqueous solution. Raw PRs and oxalic acid-activated PRs （APRs） were used to investigate the effect of chemical modification on the Pb-binding capacity in the pH range 2.0-5.0. The Pb adsorption rate of all treatments above pH 3.0 reached 90%. The Pb binding on PRs and APRs was pH-independent, except at pH 2.0 in activated treatments. The X-ray diffraction analysis confirmed that the raw PRs formed cerussite after reacting with the Pb solution, whereas the APRs formed pyromorphite. The Fourier Transform Infrared spectroscopy analysis indicated that carbonate （CO32-） in raw PRs and phosphate （PO43-） groups in APRs played an important role in the Pb-binding process. After adsorption, anomalous block-shaped particles were observed by scanning electron microscopy with energy dispersive spectroscopy. The X-ray photoelectron spectroscopy data further indicated that both chemical and physical reactions occurred during the adsorption process according to the binding energy. Because of lower solubility of pyromorphite compared to cerussite, the APRs are more effective in immobilizing Pb than that of PRs.
基金supported by the National Natural Science Foundation of China (No. 21477137)the Frontier Fields during the Thirteenth Five-Year Plan Period of the Institute of Soil Science, Chinese Academy of Sciences (No. ISSASIP 1658)the State Key Research & Development Program of China (No. 2016YFC0501309)
文摘Metal ions and fiber are common compounds in the livestock and poultry manure,which will affect the fate of organic compounds in aqueous environment. However,limited research has addressed the effect of coexisting metal ions and fiber on the biodegradation of sulfonamide antibiotics. Accordingly, a compositing study was performed to assess the effect of metal ions(Fe3+and Cu2+) on the biodegradation of sulfadimethoxine sodium salt(SDM) in the presence of fiber. The enhanced adsorption of SDM onto fiber in the presence of metal ions can be attributed to the π+–π electron donor acceptor(EDA) interaction. The microbial(Phanerochaete chrysosprium) could easily attach onto fiber forming attached microbial, and the degradation rates of SDM of immobilized bacteria in the presence of Fe3 +were 100%, which were significantly higher than those of free bacteria(45%). This study indicates that Fe3 +and fiber could enhance the biodegradation of SDM. Fiber acts as adsorbent, carrier, and substrate which enhanced the removal of SDM.
基金supported by NSFC-RGC Joint Research Grant(No.12161160314)and NSF grant of China(No.11971487)supported by the Hong Kong RGC General Research Funds(Nos.11311122,12301420 and 11300821)+1 种基金the NSFC/RGC Joint Research Fund(No.N CityU 101/21)the France-Hong Kong ANR/RGC Joint Research Grant No.A CityU203/19.
文摘Strong field concentration may occur between two nearly-touching highcontrast material inclusions due to an incident field.The degree of concentration is characterised by the blowup rate of the underlying gradient field.This phenomenon has received considerable attention in the literature due to its practical implications in the theory of composite materials.However,most of the existing studies are concerned with the static cases.In this paper,we present a comprehensive numerical investigation of this intriguing phenomenon associated to the Helmholtz system in the quasi-static frequency regime.On the one hand,we present extensive numerical results to corroborate the theoretical findings in[16],and on the other hand,we derive new findings that cannot be handled by the theoretical analysis yet.Our focus is on the static effect,frequency effect,the geometric(curvature)effect to the gradient estimates.
