Complexes of chitosan with Mn(Ⅱ) were prepared by adding Mn(OAc)2·4H2O to Chitosan solution. IR, elemental analysis and TG analysis were used to character the complex. The results showed that there were coordina...Complexes of chitosan with Mn(Ⅱ) were prepared by adding Mn(OAc)2·4H2O to Chitosan solution. IR, elemental analysis and TG analysis were used to character the complex. The results showed that there were coordinate bands formed. H2O2 was used to degrade chitosan-Mn(Ⅱ) complex, and the molecular distribution of degraded products were investigated after eliminating Mn(Ⅱ) ions using the cation exchange resin column. The result suggested that the Chitosan could be degraded rapidly, the degradation started from higher molecular weight range, the molecular weight distribution of oligosaccharides was much more narrower than that of degradated products from common methods such as hydrolysis, acidic and oxidizing methods. The index of molecular weight distribution was changed with the average degradability. When exceeding 10 oligosaccharides, the smaller of the DP, the smaller of the index.展开更多
The pyrolysis of coconut shell, coconut shell residue and de-ashed coconut shell residue was studied with the thermogravimetric technique, and the pyrolysis kinetics models were established.It was found that for cocon...The pyrolysis of coconut shell, coconut shell residue and de-ashed coconut shell residue was studied with the thermogravimetric technique, and the pyrolysis kinetics models were established.It was found that for coconut shell residue and de-ashed coconut shell residue, pyrolysis mainly occurred between 280—370℃, and there was only a single peak in their DTG curves.But in the case of raw coconut shell, two stages of 230—300℃ and 300—350℃, were involved in the pyrolysis process, which resulted in two peaks in the DTG curve.Apparent activation energies for the pyrolysis of these three materials were estimated, and the difference of apparent activation energies in the low temperature range was more evident than in the high temperature range and the highest reaction rate appeared in the high temperature stage.When used for making activated carbon, coconut shell residue and de-ashed coconut shell residue have more advantages than coconut shell.The pyrolysis temperature is in a narrow range.The pyrolysis process is easy to control and is noted for energy saving.展开更多
文摘Complexes of chitosan with Mn(Ⅱ) were prepared by adding Mn(OAc)2·4H2O to Chitosan solution. IR, elemental analysis and TG analysis were used to character the complex. The results showed that there were coordinate bands formed. H2O2 was used to degrade chitosan-Mn(Ⅱ) complex, and the molecular distribution of degraded products were investigated after eliminating Mn(Ⅱ) ions using the cation exchange resin column. The result suggested that the Chitosan could be degraded rapidly, the degradation started from higher molecular weight range, the molecular weight distribution of oligosaccharides was much more narrower than that of degradated products from common methods such as hydrolysis, acidic and oxidizing methods. The index of molecular weight distribution was changed with the average degradability. When exceeding 10 oligosaccharides, the smaller of the DP, the smaller of the index.
文摘The pyrolysis of coconut shell, coconut shell residue and de-ashed coconut shell residue was studied with the thermogravimetric technique, and the pyrolysis kinetics models were established.It was found that for coconut shell residue and de-ashed coconut shell residue, pyrolysis mainly occurred between 280—370℃, and there was only a single peak in their DTG curves.But in the case of raw coconut shell, two stages of 230—300℃ and 300—350℃, were involved in the pyrolysis process, which resulted in two peaks in the DTG curve.Apparent activation energies for the pyrolysis of these three materials were estimated, and the difference of apparent activation energies in the low temperature range was more evident than in the high temperature range and the highest reaction rate appeared in the high temperature stage.When used for making activated carbon, coconut shell residue and de-ashed coconut shell residue have more advantages than coconut shell.The pyrolysis temperature is in a narrow range.The pyrolysis process is easy to control and is noted for energy saving.
