In order to decrease the solubility of PbSO4 and enhance lead recovery from PbSO4 bearing wastes, CO was employed as a reductant to transform PbSO4 into Pb S. Reaction system was established and reductive thermodynami...In order to decrease the solubility of PbSO4 and enhance lead recovery from PbSO4 bearing wastes, CO was employed as a reductant to transform PbSO4 into Pb S. Reaction system was established and reductive thermodynamics of PbSO4 was calculated by software HSC 5.0. The effects of gas concentration, reaction temperature, time and mass of sample on reduction of PbSO4 were examined by thermogravimetry(TG) and XRD. Roasting tests further verify the conclusions of thermodynamic and TG analyses. The results show that increasing temperature in the reasonable range and CO content are favorable for the formation of Pb S. The reduction process is controlled by chemical reaction and calculation value of the activation energy is 47.88 k J/mol.展开更多
The aerobic granular sludge was cultivated in a pilot-scale sequencing batch reactor （SBR）, and some of the granules were stored at 8 ℃ for 150 d. Extracellular polymeric substances （EPS） of sludge samples were e...The aerobic granular sludge was cultivated in a pilot-scale sequencing batch reactor （SBR）, and some of the granules were stored at 8 ℃ for 150 d. Extracellular polymeric substances （EPS） of sludge samples were extracted and analyzed during the granulation and storage process. The results show that the contents of protein and EPS increase along with the granulation process, while polysaccharides remain almost unchanged. The content of protein in EPS is almost two-fold larger than that of polysaccharides in granular sludge cultivated with municipal wastewater. Moreover, some of the granules disintegrate during storage, corresponding to the decrease of protein contents in EPS. Three peaks are identified in three-dimensional excitation emission matrix （EEM） fluorescence spectra of the EPS in the aerobic granules. Two peaks （A and B） are attributed to the protein-like fluorophores, and the third （peak C） is related to visible fulvic-like substances. Peak A gradually disappears during storage, while a new peak related to ultraviolet fulvic acid （peak D） is formed. The formation and the stability of aerobic granules are closely dependent on the quantity and composition of EPS proteins. Peak C has no obvious changes during granulation, while the fulvic-like substances present an increase in fluorescence intensities during storage, accompanied with an increase in structural complexity. The fulvie-like substances are also associated with the disintegration of the aerobic granules.展开更多
基金Project(51204210)supported by the National Natural Science Foundation of ChinaProject(2011AA061001)supported by the National High Technology Research and Development Program of ChinaProject(2012BAC12B04)supported by the National Science and Technology Pillar Program during the Twelfth Five-Year Plan of China
文摘In order to decrease the solubility of PbSO4 and enhance lead recovery from PbSO4 bearing wastes, CO was employed as a reductant to transform PbSO4 into Pb S. Reaction system was established and reductive thermodynamics of PbSO4 was calculated by software HSC 5.0. The effects of gas concentration, reaction temperature, time and mass of sample on reduction of PbSO4 were examined by thermogravimetry(TG) and XRD. Roasting tests further verify the conclusions of thermodynamic and TG analyses. The results show that increasing temperature in the reasonable range and CO content are favorable for the formation of Pb S. The reduction process is controlled by chemical reaction and calculation value of the activation energy is 47.88 k J/mol.
基金Project(2006AA06Z318) supported by the National High-Tech Research and Development Program of China
文摘The aerobic granular sludge was cultivated in a pilot-scale sequencing batch reactor （SBR）, and some of the granules were stored at 8 ℃ for 150 d. Extracellular polymeric substances （EPS） of sludge samples were extracted and analyzed during the granulation and storage process. The results show that the contents of protein and EPS increase along with the granulation process, while polysaccharides remain almost unchanged. The content of protein in EPS is almost two-fold larger than that of polysaccharides in granular sludge cultivated with municipal wastewater. Moreover, some of the granules disintegrate during storage, corresponding to the decrease of protein contents in EPS. Three peaks are identified in three-dimensional excitation emission matrix （EEM） fluorescence spectra of the EPS in the aerobic granules. Two peaks （A and B） are attributed to the protein-like fluorophores, and the third （peak C） is related to visible fulvic-like substances. Peak A gradually disappears during storage, while a new peak related to ultraviolet fulvic acid （peak D） is formed. The formation and the stability of aerobic granules are closely dependent on the quantity and composition of EPS proteins. Peak C has no obvious changes during granulation, while the fulvic-like substances present an increase in fluorescence intensities during storage, accompanied with an increase in structural complexity. The fulvie-like substances are also associated with the disintegration of the aerobic granules.
