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Room-temperature hydrogenation of halogenated nitrobenzenes over metal–organic-framework-derived ultra-dispersed

《化学科学与工程前沿（英文）》 2022年第16卷第12期页码 1782-1792 doi: 10.1007/s11705-022-2220-9

摘要： Ultra-dispersed Ni nanoparticles (7.5 nm) on nitrogen-doped carbon nanoneedles (Ni@NCNs) were prepared by simple pyrolysis of Ni-based metal–organic-framework for selective hydrogenation of halogenated nitrobenzenes to corresponding anilines. Two different crystallization methods (stirring and static) were compared and the optimal pyrolysis temperature was explored. Ni@NCNs were systematically characterized by wide analytical techniques. In the hydrogenation of p-chloronitrobenzene, Ni@NCNs-600 (pyrolyzed at 600 °C) exhibited extraordinarily high performance with 77.9 h^–1 catalytic productivity and > 99% p-chloroaniline selectivity at full p-chloronitrobenzene conversion under mild conditions (90 °C, 1.5 MPa H₂), showing obvious superiority compared with reported Ni-based catalysts. Notably, the reaction smoothly proceeded at room temperature with full conversion and > 99% selectivity. Moreover, Ni@NCNs-600 afforded good tolerance to various nitroarenes substituted by sensitive groups (halogen, nitrile, keto, carboxylic, etc.), and could be easily recycled by magnetic separation and reused for 5 times without deactivation. The adsorption tests showed that the preferential adsorption of –NO₂ on the catalyst can restrain the dehalogenation of p-chloronitrobenzene, thus achieving high p-chloroaniline selectivity. While the high activity can be attributed to high Ni dispersion, special morphology, and rich pore structure of the catalyst.

关键词： halogenated nitrobenzenes room-temperature hydrogenation Ni nanoparticles nitrogen-doped carbon nanoneedles metal–organic-framework

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Whole pictures of halogenated disinfection byproducts in tap water from China’s cities

Yang PAN,Xiangru ZHANG,Jianping ZHAI

《环境科学与工程前沿（英文）》 2015年第9卷第1期页码 121-130 doi: 10.1007/s11783-014-0727-0

摘要： When bromide/iodide is present in source water, hypobromous acid/hypoiodous acid will be formed with addition of chlorine, chloramine, or other disinfectants. Hypobromous acid/hypoiodous acid undergoes reactions with natural organic matter in source water to form numerous brominated/iodinated disinfection byproducts (DBPs). In this study, tap water samples were collected from eight cities in China. With the aid of electrospray ionization-triple quadrupole mass spectrometry by setting precursor ion scans of 35, 81, and 126.9, whole pictures of polar chlorinated, brominated, and iodinated DBPs in the tap water samples were revealed for the first time. Numerous polar halogenated DBPs were detected, including haloacetic acids, newly identified halogenated phenols, and many new/unknown halogenated compounds. Total organic chlorine, total organic bromine, and total organic iodine were also measured to indicate the total levels of all chlorinated, brominated, and iodinated DBPs in the tap water samples. The total organic chlorine concentrations ranged from 26.8 to 194.0 μg·L as Cl, with an average of 109.2 μg·L as Cl; the total organic bromine concentrations ranged from below detection limit to 113.3 μg·L as Br, with an average of 34.7 μg·L as Br; the total organic iodine concentrations ranged from below detection limit to 16.4 μg·L as I, with an average of 9.1 μg·L as I; the total organic halogen concentrations ranged from 31.3 to 220.4 μg·L as Cl, with an average of 127.2 μg·L as Cl.

关键词： Disinfection byproducts (DBPs) total organic halogen tap water in China

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Catalytic reduction for water treatment

Maocong Hu, Yin Liu, Zhenhua Yao, Liping Ma, Xianqin Wang

《环境科学与工程前沿（英文）》 2018年第12卷第1期 doi: 10.1007/s11783-017-0972-0

摘要： Treating water contaminants via heterogeneously catalyzed reduction reaction is a subject of growing interest due to its good activity and superior selectivity compared to conventional technology, yielding products that are non-toxic or substantially less toxic. This article reviews the application of catalytic reduction as a progressive approach to treat different types of contaminants in water, which covers hydrodehalogenation for wastewater treatment and hydrogenation of nitrate/nitrite for groundwater remediation. For hydrodehalogenation, an overview of the existing treatment technologies is provided with an assessment of the advantages of catalytic reduction over the conventional methodologies. Catalyst design for feasible catalytic reactions is considered with a critical analysis of the pertinent literature. For hydrogenation, hydrogenation of nitrate/nitrite contaminants in water is mainly focused. Several important nitrate reduction catalysts are discussed relating to their preparation method and catalytic performance. In addition, novel approach of catalytic reduction using in situ synthesized H evolved from water splitting reaction is illustrated. Finally, the challenges and perspective for the extensive application of catalytic reduction technology in water treatment are discussed. This review provides key information to our community to apply catalytic reduction approach for water treatment.

关键词： Halogenated compounds Nitrate/nitrite contaminants Hydrodechloriantion Hydrogenation Wastewater treatment Groundwater remediation