Mg-5Zn-0.3Ca/nHA biocomposites were prepared from pure Mg,Zn,Ca and nano-hydroxyapatite(nHA)powders by powder metallurgy method.The effect of various mass fractions of nHA(1%,2.5%,5%)as reinforcement on the corrosion ...Mg-5Zn-0.3Ca/nHA biocomposites were prepared from pure Mg,Zn,Ca and nano-hydroxyapatite(nHA)powders by powder metallurgy method.The effect of various mass fractions of nHA(1%,2.5%,5%)as reinforcement on the corrosion properties of Mg-5Zn-0.3Ca alloy was investigated.The corrosion resistance of biocomposite samples was investigated by immersion tests and electrochemical techniques in SBF solution.The results showed that the corrosion resistance of Mg alloy was improved by adding 1%and 2.5%nHA.Bioactive nHA motivated the formation of stable phosphate and carbonate layers on surface and improved corrosion resistance of nanocomposites.However,addition of large contents of nHA in Mg alloy as reinforcement increased the density of this precipitated layer,so gases produced from localized corrosion were accumulated underneath this layer and decreased its adhesiveness and lowered its corrosion resistance.Indirect cytotoxicity evaluation for Mg alloy and its nanocomposites also showed that their extraction was not toxic and nanocomposite with 1%nHA indicated almost similar behavior as negative control.展开更多
Chitosan composites and derivatives have gained wide attentions as effective biosorbents due to their low costs and high contents of amino and hydroxyl functional groups.They have showed significant potentials of remo...Chitosan composites and derivatives have gained wide attentions as effective biosorbents due to their low costs and high contents of amino and hydroxyl functional groups.They have showed significant potentials of removing metal ions,dyes and proteins from various media.Chemical modifications that lead to the formation of the chitosan derivatives and chitosan composites have been extensively studied and widely reported in literatures.The aims of this review were to summarize the important information of the bioactivities of chitosan,highlight the various preparation methods of chitosan-based active biosorbents,and outline its potential applications in the adsorption of heavy metal ions,dyes and proteins from wastewater and aqueous solutions.展开更多
文摘Mg-5Zn-0.3Ca/nHA biocomposites were prepared from pure Mg,Zn,Ca and nano-hydroxyapatite(nHA)powders by powder metallurgy method.The effect of various mass fractions of nHA(1%,2.5%,5%)as reinforcement on the corrosion properties of Mg-5Zn-0.3Ca alloy was investigated.The corrosion resistance of biocomposite samples was investigated by immersion tests and electrochemical techniques in SBF solution.The results showed that the corrosion resistance of Mg alloy was improved by adding 1%and 2.5%nHA.Bioactive nHA motivated the formation of stable phosphate and carbonate layers on surface and improved corrosion resistance of nanocomposites.However,addition of large contents of nHA in Mg alloy as reinforcement increased the density of this precipitated layer,so gases produced from localized corrosion were accumulated underneath this layer and decreased its adhesiveness and lowered its corrosion resistance.Indirect cytotoxicity evaluation for Mg alloy and its nanocomposites also showed that their extraction was not toxic and nanocomposite with 1%nHA indicated almost similar behavior as negative control.
基金financially supported by Ocean Public Welfare Scientific Research Special Appropriation Project(201005020)Fundamental Research Funds for the Central Universities and Program for Changjiang Scholars and Innovative Research Team in University(IRT1188)
文摘Chitosan composites and derivatives have gained wide attentions as effective biosorbents due to their low costs and high contents of amino and hydroxyl functional groups.They have showed significant potentials of removing metal ions,dyes and proteins from various media.Chemical modifications that lead to the formation of the chitosan derivatives and chitosan composites have been extensively studied and widely reported in literatures.The aims of this review were to summarize the important information of the bioactivities of chitosan,highlight the various preparation methods of chitosan-based active biosorbents,and outline its potential applications in the adsorption of heavy metal ions,dyes and proteins from wastewater and aqueous solutions.
