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Multifunctional heteroatom zeolites: construction and applications

《化学科学与工程前沿（英文）》 2021年 第15卷 第6期   页码 1462-1486 doi: 10.1007/s11705-021-2099-x

摘要： Multifunctional heteroatom zeolites have drawn broad attentions due to the possible synergistic effects in the catalytic reactions. Remarkable achievements have been made on the synthesis, characterization and catalytic applications of multifunctional heteroatom zeolite, while a review on this important topic is still missing. Herein, current research status of multifunctional heteroatom zeolites is briefly summarized, aiming to boost further researches. First, the synthesis strategies toward heteroatom zeolites are introduced, including the direct synthesis and postsynthesis routes; then, the spectroscopic techniques to identify the existing states of heteroatom sites and the corresponding physiochemical properties are shown and compared; finally, the catalytic applications of multifunctional heteroatom zeolites in various chemical reactions, especially in one-step tandem reactions, are discussed.

关键词： zeolite     multifunctional active sites     heteroatom     characterization     catalysis    

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New approaches to water purification for resource-constrained settings: Production of activated biochar by chemical activation with diammonium hydrogenphosphate

Mohit Nahata, Chang Y. Seo, Pradeep Krishnakumar, Johannes Schwank

《化学科学与工程前沿（英文）》 2018年 第12卷 第1期   页码 194-208 doi: 10.1007/s11705-017-1647-x

摘要： A significant portion of the world’s population does not have access to safe drinking water. This problem is most acute in remote, resource-constrained rural settings in developing countries. Water filtration using activated carbon is one of the important steps in treating contaminated water. Lignocellulosic biomass is generally available in abundance in such locations, such as the African rain forests. Our work is focused on developing a simple method to synthesize activated biochar from locally available materials. The preparation of activated biochar with diammonium hydrogenphosphate (DAP) as the activating agent is explored under N flow and air. The study, carried out with cellulose as a model biomass, provides some insight into the interaction between DAP and biomass, as well as the char forming mechanism. Various characterization techniques such as N physisorption, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and Raman spectroscopy are utilized to compare the properties between biochar formed under nitrogen and partial oxidative conditions. At a temperature of 450 °C, the loading of DAP over cellulose is systematically varied, and its effect on activation is examined. The activated biochar samples are predominantly microporous in the range of concentrations studied. The interaction of DAP with cellulose is investigated and the nature of bonding of the heteroatoms to the carbonaceous matrix is elucidated. The results indicate that the quality of biochar prepared under partial oxidation condition is comparable to that of biochar prepared under nitrogen, leading to the possibility of an activated biochar production scheme on a small scale in resource-constrained settings.

关键词： cellulose     DAP     activation     heteroatom     microporous    

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标题 作者 时间 类型 操作

Multifunctional heteroatom zeolites: construction and applications

期刊论文

New approaches to water purification for resource-constrained settings: Production of activated biochar by chemical activation with diammonium hydrogenphosphate

Mohit Nahata, Chang Y. Seo, Pradeep Krishnakumar, Johannes Schwank

期刊论文