The aim of the research was to develop new products and processes from a manufacturing waste from an Italian metallurgic company.The company produced thin silver metallic films and the production scraps were silver fl...The aim of the research was to develop new products and processes from a manufacturing waste from an Italian metallurgic company.The company produced thin silver metallic films and the production scraps were silver flakes.The possibility to use the silver flakes in water disinfection processes was studied.The antimicrobial activity of the flakes was investigated in batch using Escherichia coli as Gram-negative microorganism model.The flakes did not show any antimicrobial activity,so they were activated with two different processes： thermal activation in reducing atmosphere and chemical activation,obtaining,respectively,reduced flakes （RF） and chemical flakes （CF）.The flakes,activated with either treatment,showed antimicrobial activity against E.coli.The kill rate was dependent on the type of activated flakes.The chemical flakes were more efficient than reduced flakes.The kill rate determined for 1 g of CF,1.0 ± 0.2 min ？1 ,was greater than the kill rate determined for 1 g of RF,0.069 ± 0.004 min ？1 .This was confirmed also by the minimum inhibitory concentration values.It was demonstrated that the antimicrobial capability was dependent on flakes amount and on the type of aqueous medium.Furthermore,the flakes maintained their properties also when used a second time.Finally,the antimicrobial activities of flakes were tested in an effluent of a wastewater treatment plant where a variety of heterotrophic bacteria were present.展开更多
Polymer nanoparticles with dendrimer-Ag shell were prepared and their application in catalytic reduction of 4-nitrophenol （4-NP） was investigated. Cross-linked polystyrene （PS） microspheres were prepared through d...Polymer nanoparticles with dendrimer-Ag shell were prepared and their application in catalytic reduction of 4-nitrophenol （4-NP） was investigated. Cross-linked polystyrene （PS） microspheres were prepared through dispersion copolymerization of styrene, acrylic acid and crosslinking monomer 1, 2- divinylbenzene. PS microspheres with average size of 450 nm and narrow size distribution were used as support for the immobilization of dendrimer-Ag shell, The polyamidoamine （PAMAM） dendrimer shell was successively grafted onto the surface ofPS microspheres through repetitive Michael addition reaction of methyl acrylate （MA） and amidation of the obtained esters with large excess of ethylenediamine （EDA）. Silver nanoparticles were formed directly inside the PAMAM shell through reduction with NaBH4. The resulting PS@PAMAM-Ag nanopartides were packed in a stainless steel column and used successfully for catalytic reduction of 4-NP. This technique for packing catalytic polymer particles in a column could imnrove the efficiency of using the metal catalyst and the tedious seuaration in catalytic reaction.展开更多
基金Lombardia Region for financial support (Progetto Ingenio)
文摘The aim of the research was to develop new products and processes from a manufacturing waste from an Italian metallurgic company.The company produced thin silver metallic films and the production scraps were silver flakes.The possibility to use the silver flakes in water disinfection processes was studied.The antimicrobial activity of the flakes was investigated in batch using Escherichia coli as Gram-negative microorganism model.The flakes did not show any antimicrobial activity,so they were activated with two different processes： thermal activation in reducing atmosphere and chemical activation,obtaining,respectively,reduced flakes （RF） and chemical flakes （CF）.The flakes,activated with either treatment,showed antimicrobial activity against E.coli.The kill rate was dependent on the type of activated flakes.The chemical flakes were more efficient than reduced flakes.The kill rate determined for 1 g of CF,1.0 ± 0.2 min ？1 ,was greater than the kill rate determined for 1 g of RF,0.069 ± 0.004 min ？1 .This was confirmed also by the minimum inhibitory concentration values.It was demonstrated that the antimicrobial capability was dependent on flakes amount and on the type of aqueous medium.Furthermore,the flakes maintained their properties also when used a second time.Finally,the antimicrobial activities of flakes were tested in an effluent of a wastewater treatment plant where a variety of heterotrophic bacteria were present.
基金the Major Project (XK100100433,XK100100540)for Polymer Chemistry and Physics Subject Construction from Beijing Municipal Education Commission(BMEC),for financial support to this work
文摘Polymer nanoparticles with dendrimer-Ag shell were prepared and their application in catalytic reduction of 4-nitrophenol （4-NP） was investigated. Cross-linked polystyrene （PS） microspheres were prepared through dispersion copolymerization of styrene, acrylic acid and crosslinking monomer 1, 2- divinylbenzene. PS microspheres with average size of 450 nm and narrow size distribution were used as support for the immobilization of dendrimer-Ag shell, The polyamidoamine （PAMAM） dendrimer shell was successively grafted onto the surface ofPS microspheres through repetitive Michael addition reaction of methyl acrylate （MA） and amidation of the obtained esters with large excess of ethylenediamine （EDA）. Silver nanoparticles were formed directly inside the PAMAM shell through reduction with NaBH4. The resulting PS@PAMAM-Ag nanopartides were packed in a stainless steel column and used successfully for catalytic reduction of 4-NP. This technique for packing catalytic polymer particles in a column could imnrove the efficiency of using the metal catalyst and the tedious seuaration in catalytic reaction.
