We have studied the effect of magnesia （MgO） addition （0, 5, 10, and 20 mol%） in zirconia at pH values （7, 9, 11）. The magnesia doped zirconia （MgO-ZrO2） has been synthesized by a co-precipitation method using...We have studied the effect of magnesia （MgO） addition （0, 5, 10, and 20 mol%） in zirconia at pH values （7, 9, 11）. The magnesia doped zirconia （MgO-ZrO2） has been synthesized by a co-precipitation method using ammonium hydroxide as a mineralizer. As-prepared samples were characterized by XRD, FE-SEM, and TG-DSC. The XRD results showed that the quantity of tetragonal phase was increased with increasing pH value during synthesis. On the other hand, a decrease in the crystallite size of tetragonal phase was observed with increasing pH value. Therefore, the FE-SEM micrograph showed a clear decline in the particle size with increasing pH value. As-precipitated at pH-11, the addition of 10 mol% of MgO showed nearly pure tetragonal phase with a crystallite size of-34.16 nm.展开更多
Chitin and chitosan have been applied to biological wastewater treatment.From a number of parallel comparison experiments,it can be concluded that the application of chitin and chitosan can both enhance the biological...Chitin and chitosan have been applied to biological wastewater treatment.From a number of parallel comparison experiments,it can be concluded that the application of chitin and chitosan can both enhance the biological treatment,besides which chitosan is more efficient than chitin.The study on the enhancement mechanism reveals the difference between the two additives:chitosan improves the sludge structure and settlibility,while chitin acts as a kind of carrier for microorganism in the biological treatment system.展开更多
文摘We have studied the effect of magnesia （MgO） addition （0, 5, 10, and 20 mol%） in zirconia at pH values （7, 9, 11）. The magnesia doped zirconia （MgO-ZrO2） has been synthesized by a co-precipitation method using ammonium hydroxide as a mineralizer. As-prepared samples were characterized by XRD, FE-SEM, and TG-DSC. The XRD results showed that the quantity of tetragonal phase was increased with increasing pH value during synthesis. On the other hand, a decrease in the crystallite size of tetragonal phase was observed with increasing pH value. Therefore, the FE-SEM micrograph showed a clear decline in the particle size with increasing pH value. As-precipitated at pH-11, the addition of 10 mol% of MgO showed nearly pure tetragonal phase with a crystallite size of-34.16 nm.
文摘Chitin and chitosan have been applied to biological wastewater treatment.From a number of parallel comparison experiments,it can be concluded that the application of chitin and chitosan can both enhance the biological treatment,besides which chitosan is more efficient than chitin.The study on the enhancement mechanism reveals the difference between the two additives:chitosan improves the sludge structure and settlibility,while chitin acts as a kind of carrier for microorganism in the biological treatment system.
