10 results found
Yang Y, Hillmann R, Qi Y, et al., 2020, Ultrahigh ionic exclusion through carbon nanomembranes, Advanced Materials, Vol: 32, Pages: 1-5, ISSN: 0935-9648
The collective “single‐file” motion of water molecules through natural and artificial nanoconduits inspires the development of high‐performance membranes for water separation. However, a material that contains a large number of pores combining rapid water flow with superior ion rejection is still highly desirable. Here, a 1.2 nm thick carbon nanomembrane (CNM) made from cross‐linking of terphenylthiol (TPT) self‐assembled monolayers is reported to possess these properties. Utilizing their extremely high pore density of 1 sub‐nm channel nm−2, TPT CNMs let water molecules rapidly pass, while the translocation of ions, including protons, is efficiently hindered. Their membrane resistance reaches ≈104 Ω cm2 in 1 m Cl− solutions, comparable to lipid bilayers of a cell membrane. Consequently, a single CNM channel yields an ≈108 higher resistance than pores in lipid membrane channels and carbon nanotubes. The ultrahigh ionic exclusion by CNMs is likely dominated by a steric hindrance mechanism, coupled with electrostatic repulsion and entrance effects. The operation of TPT CNM membrane composites in forward osmosis is also demonstrated. These observations highlight the potential of utilizing CNMs for water purification and opens up a simple avenue to creating 2D membranes through molecular self‐assembly for highly selective and fast separations.
Ultrathin nanostructured membranes are widely pursued to apply into different processes ranging from air separation to seawater desalination. Here, freestanding carbon nanomembranes (CNMs) are employed to dehydrate vaporous alcohols at room temperature. The structure of the microporous material is addressed by measuring permeation rates of homologous n-alkanols. To examine the separation performance, we introduce a model heavy water/n-propanol azeotrope. While ordinary nanomembranes show moderate selectivity of around 300, complete rejection of organic molecules is achieved upon stacking two CNM layers. Furthermore, the mixture experiments with the stacks demonstrate a 10-fold slowdown in the transmembrane diffusion of water as compared to both the single-layer material and pure vapor. We discuss the observed effect as a “molecular jam” in the interlayer spacing, which effectively disrupts the collective flow of liquefied water. Our work sheds light on molecular transport under nanoconfinement.
Li X, Qing W, Wu Y, et al., 2019, Omniphobic Nanofibrous Membrane with Pine-Needle-Like Hierarchical Nanostructures: Toward Enhanced Performance for Membrane Distillation, ACS APPLIED MATERIALS & INTERFACES, Vol: 11, Pages: 47963-47971, ISSN: 1944-8244
Yang Y, Dementyev P, Biere N, et al., 2018, Rapid Water Permeation Through Carbon Nanomembranes with Sub-Nanometer Channels, ACS NANO, Vol: 12, Pages: 4695-4701, ISSN: 1936-0851
Li X, Wang H, Yang Y, et al., 2016, Electrocatalytic membrane reactor for industrial wastewater treatment: Sustainability and prospects, Green Technologies for Sustainable Water Management, Pages: 651-678, ISBN: 9780784414422
Industrial wastewater has become a global issue because of its high concentration of pollutants, especially refractory organic compounds. This chapter focuses on the application of the electrocatalytic membrane reactor (ECMR) in wastewater treatment. It explains the concept and types of electrocatalytic membrane materials applied in wastewater treatment. The chapter discusses design optimization of ECMR for wastewater treatments, such as oil water treatment, phenolic wastewater, and dyeing wastewater treatment. It explores the mechanism of ECMR for wastewater treatment. Refractory wastewater is mainly discharged from coking plants, pharmaceutical factories, refineries, and dye factories, among others, and is of a high density of pollutants, poor biodegradability, and high toxicity. The mechanism of ECMR for wastewater treatment suggests that the organic pollutants in wastewater would be decomposed into CO2 and H2O or biodegradable products through the generation of physically adsorbed active oxygen.
Chen X, Wang H, Yang Y, et al., 2013, The surface modification of coal-based carbon membranes by different acids, DESALINATION AND WATER TREATMENT, Vol: 51, Pages: 5855-5862, ISSN: 1944-3994
Li J, Li J, Wang H, et al., 2013, Electrocatalytic oxidation of n-propanol to produce propionic acid using an electrocatalytic membrane reactor, CHEMICAL COMMUNICATIONS, Vol: 49, Pages: 4501-4503, ISSN: 1359-7345
Chen XP, Wang H, Yang Y, et al., 2012, Controlled generation of oxygen functionalities on the surface of coal-based carbon membrane by HNO <inf>3</inf> oxidation, Journal of Tianjin Polytechnic University, Vol: 31, Pages: 1-5, ISSN: 1671-024X
HNO 3 oxidation is used to modify coal-based carbon membrane and finely adjust the amount of oxygenated surface groups on it to a desired degree through investigating the oxidate process and controlling reaction condition. XPS and TGA are used to determine the nature and the content of different surface oxygen groups. The results indicate that the degree of surface oxygen functionalization is correlated with the concentration of nitric acid and reactant temperatures. The functionalization follows a progressive pathway starting with the creation of C-O groups and C=O groups on the surface of membrane, and then they are further oxidated to COO groups. The first step can take place easily. While the second step should be carried out under rigorous conditions like high reactant temperature and HNO 3 concentration.
Yang Y, Wang H, Li J, et al., 2012, Novel Functionalized Nano-TiO2 Loading Electrocatalytic Membrane for Oily Wastewater Treatment, ENVIRONMENTAL SCIENCE & TECHNOLOGY, Vol: 46, Pages: 6815-6821, ISSN: 0013-936X
Yang Y, Li J, Wang H, et al., 2011, An Electrocatalytic Membrane Reactor with Self-Cleaning Function for Industrial Wastewater Treatment, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, Vol: 50, Pages: 2148-2150, ISSN: 1433-7851
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