Zeolitites (ZTs) are rocks containing more than 50% of zeolite minerals and are known to be a suitable material for agricultural purposes by improving soil physicochemical properties and nitrogen (N) use efficiency. H...Zeolitites (ZTs) are rocks containing more than 50% of zeolite minerals and are known to be a suitable material for agricultural purposes by improving soil physicochemical properties and nitrogen (N) use efficiency. However, little is known about their effects on soil microbial biomass. This study aimed to evaluate short-term effects of different chabazite-rich ZT (CHAZT) amendments on soil microbial biomass and activity. A silty-clay agricultural soil was amended in three different ways, including the addition of natural (5% and 15%) and NH_4^+-enriched (10%) CHAZT. Soil dissolved organic carbon (C), total dissolved N, NH_4^+, NO_3^-, NO_2^-, microbial biomass C and N, and ergosterol were measured periodically over 16 d in a laboratory incubation. To verify the microbial immobilization of the N derived from NH_4^+-enriched CHAZT, a high15N source was used for enriching the mineral to measure the microbial biomass δ15N signature. An increase in the ergosterol content was observed in the soil amended with 5% natural CHAZT. However, no similar result was observed in the soil amended with 15% natural CHAZT, suggesting that the fungal biomass was favored at a lower CHAZT application rate. In the soil amended with NH+ 4-enriched CHAZT, microbial biomass N was related to NO_3^-production over time and inversely related to NH_4^+, suggesting high nitrification process. Isotopic measurements on microbial biomass confirmed immediate assimilation of N derived from NH_4^+-enriched CHAZT. These results suggested that the NH_4^+-enriched CHAZT used in this study supplied an immediately available N pool to the microbial biomass.展开更多
CuY zeolite is a promising catalyst in the field of manufacturing dimethyl carbonate(DMC) through oxidative carbonylation of methanol. Cu^+ exchanged with Br?nsted acid sites are supposed to be active for this reactio...CuY zeolite is a promising catalyst in the field of manufacturing dimethyl carbonate(DMC) through oxidative carbonylation of methanol. Cu^+ exchanged with Br?nsted acid sites are supposed to be active for this reaction. However, the location of Cu^+ in small cages can not interact with reactants because of steric hindrance, which lead to a waste of Cu species. In this work, NH_4F solution was used to modify the pore structure of zeolite Y by etching the framework T atoms. Physical and chemical adsorption of probe molecules with different size are used to determine the changes of porosity as well as the accessibility of Cu^+ sites. At an optimized etching time, the small cages were opened with maintained zeolitic framework. As a result, more Cu^+ species located in small cages become accessible to reactants, which contributes to the enhanced activity in this reaction.展开更多
基金co-funded by the EU-funded Zeo LIFE project, European Union (No. LIFE10 ENV/IT/000321)UNIFE young researchers grant 2015+1 种基金the EU-funded Eclaire project, European Union (No. FP7-Env.2011.1.1.2-1 282910)project Nitro Austria, Austrian Climate Research Programme (No. KR14AC7K11916)
文摘Zeolitites (ZTs) are rocks containing more than 50% of zeolite minerals and are known to be a suitable material for agricultural purposes by improving soil physicochemical properties and nitrogen (N) use efficiency. However, little is known about their effects on soil microbial biomass. This study aimed to evaluate short-term effects of different chabazite-rich ZT (CHAZT) amendments on soil microbial biomass and activity. A silty-clay agricultural soil was amended in three different ways, including the addition of natural (5% and 15%) and NH_4^+-enriched (10%) CHAZT. Soil dissolved organic carbon (C), total dissolved N, NH_4^+, NO_3^-, NO_2^-, microbial biomass C and N, and ergosterol were measured periodically over 16 d in a laboratory incubation. To verify the microbial immobilization of the N derived from NH_4^+-enriched CHAZT, a high15N source was used for enriching the mineral to measure the microbial biomass δ15N signature. An increase in the ergosterol content was observed in the soil amended with 5% natural CHAZT. However, no similar result was observed in the soil amended with 15% natural CHAZT, suggesting that the fungal biomass was favored at a lower CHAZT application rate. In the soil amended with NH+ 4-enriched CHAZT, microbial biomass N was related to NO_3^-production over time and inversely related to NH_4^+, suggesting high nitrification process. Isotopic measurements on microbial biomass confirmed immediate assimilation of N derived from NH_4^+-enriched CHAZT. These results suggested that the NH_4^+-enriched CHAZT used in this study supplied an immediately available N pool to the microbial biomass.
基金financial supports from the National Natural Science Foundation of China NSFC, Nos. U1510203, 21406120, 21325626
文摘CuY zeolite is a promising catalyst in the field of manufacturing dimethyl carbonate(DMC) through oxidative carbonylation of methanol. Cu^+ exchanged with Br?nsted acid sites are supposed to be active for this reaction. However, the location of Cu^+ in small cages can not interact with reactants because of steric hindrance, which lead to a waste of Cu species. In this work, NH_4F solution was used to modify the pore structure of zeolite Y by etching the framework T atoms. Physical and chemical adsorption of probe molecules with different size are used to determine the changes of porosity as well as the accessibility of Cu^+ sites. At an optimized etching time, the small cages were opened with maintained zeolitic framework. As a result, more Cu^+ species located in small cages become accessible to reactants, which contributes to the enhanced activity in this reaction.
