Search | Engineering

Subscribe Submit

Home Journals Focus Achievement Fronts About Us 中文版

Resource Type

Journal Article 2

Year

2023 1

2022 1

Keywords

Adsorption 1

Inner-sphere complex 1

Nanoconfinement 1

Nanoscale effect 1

Regeneration 1

catalytic membrane reactor 1

catalytic ozonation 1

nanoconfinement 1

two-dimensional manganese oxide 1

open ︾

Search scope:

排序： Display mode:

Interlayer-confined two-dimensional manganese oxide-carbon nanotube catalytic ozonation membrane for efficient water purification

Frontiers of Chemical Science and Engineering 2022, Volume 16, Issue 5, Pages 731-744 doi: 10.1007/s11705-021-2110-6

Abstract: Catalytic ozonation technology has attracted copious attention in water purification owing to its favorable oxidative degradation of pollutants and mitigation of membrane fouling capacity. However, its extensive industrial application has been restricted by the low ozone utilization and limited mass transfer of the short-lived radical species. Interlayer space-confined catalysis has been theoretically proven to be a viable strategy for achieving high catalytic efficiency. Here, a two-dimensional MnO₂-incorporated ceramic membrane with tunable interspacing, which was obtained via the intercalation of a carbon nanotube, was designed as a catalytic ozonation membrane reactor for degrading methylene blue. Benefiting from the abundant catalytic active sites on the surface of two-dimensional MnO₂ as well as the ultralow mass transfer resistance of fluids due to the nanolayer confinement, an excellent mineralization effect, i.e., 1.2 mg O_3(aq) mg^–1 TOC removal (a total organic carbon removal rate of 71.5%), was achieved within a hydraulic retention time of 0.045 s of pollutant degradation. Further, the effects of hydraulic retention time and interlayer spacing on methylene blue removal were investigated. Moreover, the mechanism of the catalytic ozonation employing catalytic ozonation membrane was proposed based on the contribution of the Mn(III/IV) redox pair to electron transfer to generate the reactive oxygen species. This innovative two-dimensional confinement catalytic ozonation membrane could act as a nanoreactor and separator to efficiently oxidize organic pollutants and enhance the control of membrane fouling during water purification.

Keywords： catalytic membrane reactor catalytic ozonation nanoconfinement two-dimensional manganese oxide

HTML PDF Collect

Commercial Gel-Type Ion Exchange Resin Enables Large-Scale Production of Ultrasmall Nanoparticles for Highly Efficient Water Decontamination Article

Sikai Cheng, Jieshu Qian, Xiaolin Zhang, Zhenda Lu, Bingcai Pan

Engineering 2023, Volume 23, Issue 4, Pages 149-156 doi: 10.1016/j.eng.2021.09.010

Abstract:

Nanotechnology presents innovative solutions in advanced water treatment; however, its application is limited by the challenging large-scale production of ultrasmall (< 5 nm) nanoparticles (NPs) with extraordinary decontamination reactivity and the difficulty of handling such tiny NPs in engineering. To address these challenges, we propose a straightforward route for synthesizing ultrasmall NPs using the commercial gel-type anion exchange resin N201 as the host. N201 is a millimeter-scale poly(styrene-co-divinylbenzene) bead modified with quaternary ammonium groups. Nanoparticles of hydrated ferric oxide (HFO), hydrated manganese oxide (HMO), cadmium sulfide (CdS), and zero-valent iron (ZVI) were obtained through simple impregnation-precipitation in N201, and all of the NPs possessed an ultrasmall size of sub-5 nm. A pilot-scale production assay indicated that the synthetic system could be enlarged proportionally to prepare massive sub-5 nm HFO. Regarding the underlying mechanism, each N201 bead contained a continuous water phase, allowing the rapid diffusion of the reactants (7 s for diffusion from the bead surface to the center), resulting in burst nucleation to produce ultrasmall NPs with a narrow size distribution. Moreover, the crosslinked polymer chains provided a confined space (< 5 nm diameter) to prevent the excessive growth of the formed NPs. Owing to the millimetric N201 host, the resultant nanocomposite can be applied in flow-through systems. The batch and column adsorption assays demonstrate the dramatically enhanced adsorption performance of the ultrasmall HFO toward As(III/V) than the ∼17 nm analogs. This study can advance the widespread use of nanotechnology in practical water treatment.

Keywords： Nanoscale effect Nanoconfinement Adsorption Inner-sphere complex Regeneration