Biochar modified by metal ions—particularly Mg—is typically used for the effective recovery of phosphorous.In this study,MgO-modified biochars were synthesized via the direct co-pyrolysis of MgO and raw materials su...Biochar modified by metal ions—particularly Mg—is typically used for the effective recovery of phosphorous.In this study,MgO-modified biochars were synthesized via the direct co-pyrolysis of MgO and raw materials such as rice straw,corn straw,Camellia oleifera shells,and branches from garden waste,which were labeled as MRS,MCS,MOT,and MGW,respectively.The resulting phosphate(PO)adsorption capacities and potential adsorption mechanisms were analyzed.The PO adsorption capacities of the biochars were significantly improved after the modification with MgO:MRS(24.71±0.32 mg/g)>MGW(23.55±0.46 mg/g)>MOT(15.23±0.19 mg/g)>MCS(14.12±0.21 mg/g).PO adsorption on the modified biochars was controlled by physical adsorption,precipitation,and surface innersphere complexation processes,although no electrostatic attraction was observed.Furthermore,PO adsorbed on modified biochars could be released under acidic,alkaline,and neutral conditions.The desorption efficiency of MRS was modest,indicating its suitability as a slow-release fertilizer.展开更多
LaFeO3 is a p-type semiconductor catalytic material of perovskite structure(ABO3).Its magnetic and photocatalytic properties have been widely investigated,but the gas sensing properties are seldom reported,especially ...LaFeO3 is a p-type semiconductor catalytic material of perovskite structure(ABO3).Its magnetic and photocatalytic properties have been widely investigated,but the gas sensing properties are seldom reported,especially for toxic and noxious gases of NO2 and CO.The nanocomposites of LaFeO3 and LaFe1-xMgxO3(x=0.02,0.04,0.06)were prepared by various methods of the wet chemical process and their exact composition,crystal structures,grain sizes,specific surfaces,morphology and the electronic interaction between components were characterized by EDX,XRD,BET,SEM and XPS analysis.The sensors based on these nanocomposites have been fabricated to examine the sensing responses to gases,and the results show that these sensors exhibited high response to both oxidizing gas(NO2)and reducing gas(CO),and the response was greatly enhanced by the surface modification of MgO.The additive method,amount of additives,and their effects on the LaFeO3 structure and gas response have been analyzed and discussed by temperature-programmed desorption(TPD)and X-ray photoelectron spectroscopic(XPS)analysis.展开更多
基金financially supported by Basic and Applied Basic Research Foundation of Guangdong Province(2022A1515010941)Science and technology plan projects of Guangzhou(202206010069)+1 种基金Meizhou Science and Technology Project(2021A0304001)Key-Area Research and Development Program of Guangdong Province(2020B020215003).
文摘Biochar modified by metal ions—particularly Mg—is typically used for the effective recovery of phosphorous.In this study,MgO-modified biochars were synthesized via the direct co-pyrolysis of MgO and raw materials such as rice straw,corn straw,Camellia oleifera shells,and branches from garden waste,which were labeled as MRS,MCS,MOT,and MGW,respectively.The resulting phosphate(PO)adsorption capacities and potential adsorption mechanisms were analyzed.The PO adsorption capacities of the biochars were significantly improved after the modification with MgO:MRS(24.71±0.32 mg/g)>MGW(23.55±0.46 mg/g)>MOT(15.23±0.19 mg/g)>MCS(14.12±0.21 mg/g).PO adsorption on the modified biochars was controlled by physical adsorption,precipitation,and surface innersphere complexation processes,although no electrostatic attraction was observed.Furthermore,PO adsorbed on modified biochars could be released under acidic,alkaline,and neutral conditions.The desorption efficiency of MRS was modest,indicating its suitability as a slow-release fertilizer.
基金Supported by the National Natural Science Foundation of China(Grant Nos.20706004 and 50872007)Beijing Natural Science Foundation(Grant Nos.8091003 and 8092022)
文摘LaFeO3 is a p-type semiconductor catalytic material of perovskite structure(ABO3).Its magnetic and photocatalytic properties have been widely investigated,but the gas sensing properties are seldom reported,especially for toxic and noxious gases of NO2 and CO.The nanocomposites of LaFeO3 and LaFe1-xMgxO3(x=0.02,0.04,0.06)were prepared by various methods of the wet chemical process and their exact composition,crystal structures,grain sizes,specific surfaces,morphology and the electronic interaction between components were characterized by EDX,XRD,BET,SEM and XPS analysis.The sensors based on these nanocomposites have been fabricated to examine the sensing responses to gases,and the results show that these sensors exhibited high response to both oxidizing gas(NO2)and reducing gas(CO),and the response was greatly enhanced by the surface modification of MgO.The additive method,amount of additives,and their effects on the LaFeO3 structure and gas response have been analyzed and discussed by temperature-programmed desorption(TPD)and X-ray photoelectron spectroscopic(XPS)analysis.
