Membrane fouling, critically determined by the interplay of interfacial interaction between foulant and membrane, is a critical impediment that limits application extension of electrodialysis (ED) process. In this study, the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) model and molecular simulation were performed to quantify the interaction energy barrier for revealing anion exchange membranes (AEMs) fouling mechanisms of calcium ions coexisted with natural organic matter (NOM) (sodium alginate, humic acid, and bovine serum albumin). The insight gained from DMol module was also utilized to interpret the adhesion process of NOM at the molecular level.
View Article and Find Full Text PDFMulti-walled carbon nanotubes (MWCNTs) were modified on the tips and inner walls by 12-chloro-12-oxododecanedioic acid-methyl ester groups and then added to the polyamide composite membranes to prepare MWCNT-CHOCOCHO membranes for desalination. The characterization results of transmission electron microscopy, Fourier transform, infrared transform, and thermogravimetric analysis showed that the 12-chloro-12-oxododecanedioic acid-methyl ester group was successfully grafted to the entrances and inner walls of the MWCNTs. The performance of the MWCNTs' composite membranes was evaluated by scanning electron microscopy, contact angle, and filtration test.
View Article and Find Full Text PDFIn the present work, a novel mixed matrix cation exchange membrane composed of sulfonated polyether sulfone (SPES), N-phthaloyl chitosan (NPHCs) and MIL-101(Fe) was synthesized using response surface methodology (RSM). The electrochemical and physical properties of the membrane, such as ion exchange capacity, water content, morphology, contact angle, fixed ion concentration and thermal stability were investigated. The RSM based on the Box-Behnken design (BBD) model was employed to simulate and evaluate the influence of preparation conditions on the properties of CEMs.
View Article and Find Full Text PDFThe fouling mechanism of the anion exchange membrane (AEM) induced by natural organic matter (NOM) in the absence and presence of calcium ions was systematically investigated via the extended Derjaguin-Landau-Verwey-Overbeek (xDLVO) approach. Sodium alginate (SA), humic acid (HA), and bovine serum albumin (BSA) were utilized as model NOM fractions. The results indicated that the presence of calcium ions tremendously aggravated the NOM fouling on the anion exchange membrane because of Ca-NOM complex formation.
View Article and Find Full Text PDFMar Pollut Bull
September 2019
The sorption behavior of phosphorus onto sediment was investigated with the addition of BC derived from incomplete biomass combustion (PC). The sorption kinetic curves of phosphorus onto PC and sediment could be described by a two-compartment first order equation, and the sorption isotherms fit the Freundlich model well. With increasing amounts of PC added, the sorption capacity increased while the HI did not change much.
View Article and Find Full Text PDFBiofouling is a critical issue in the membrane separation process as it can increase the operational cost by lower down membrane permeability. Covalent binding of an antibacterial agent on the membrane surface to kill microorganisms to hinder biofouling formation process draws great attention. In this study, we used three kinds of capsaicin derivatives, MBHBA, HMBA, and HMOBA, to fabricate antibiofouling membrane via UV-assisted photo grafting method.
View Article and Find Full Text PDFDuring an oceanographic campaign in the western Pacific Ocean from 12 August to 3 October 2014, the concentrations of five non-methane hydrocarbons (NMHCs) were measured in marine atmosphere and seawater. The average mixing ratios of ethane, ethylene, propane, propylene, and isoprene were 1.109 ± 0.
View Article and Find Full Text PDFHexavalent chromium is one of the main heavy metal pollutants. As the environmental legislation becomes increasingly strict, seeking new technology to treat wastewater containing hexavalent chromium is becoming more and more important. In this research, a novel modified ultrafiltration membrane that could be applied to adsorb and purify water containing hexavalent chromium, was prepared by polyvinylidene fluoride (PVDF) blending with 2-aminobenzothiazole via phase inversion.
View Article and Find Full Text PDFThis study aimed to investigate the effect of temperature variation on membrane fouling and microbial community in a membrane bioreactor (MBRs). The results indicated that extracellular polymer substances (EPS) and soluble microbial products (SMPs) increased due to decreasing temperature, which triggered membrane fouling as evidenced by the trans-membrane pressure (TMP) increase rate. Moreover, fluorescent intensity variations in the excitation-emission matrix (EEM) fluorescence spectroscopy of SMPs were closely related to rapid increase in TMP, suggesting that they might be used to monitor SMPs variations and indicate membrane performance.
View Article and Find Full Text PDFJ Chromatogr B Analyt Technol Biomed Life Sci
August 2011
Two types of amorphous, silica nanoparticles have been produced and used as surface assisting agents during laser desorption/ionisation time-of flight-mass spectrometry (SALDI-TOF-MS). The first is hydrophilic possessing surface aminopropyl groups and the second hydrophobic containing surface phenyl groups. Each particle type acts as a solid phase adsorbent, adsorbing analytes according to their charge and hydrophobicity.
View Article and Find Full Text PDFCopper phthalocyanine can assemble along PPE backbones into molecular arrays and 2D assemblies with structural parameters different from its intrinsic 2D crystal. The template effect depends on the match between the size of phthalocyanine and the repeating period of the PPE backbone.
View Article and Find Full Text PDFThis article examines the use of doped amorphous silica nanoparticles for surface-assisted laser desorption/ionisation-time of flight-mass spectrometry (SALDI-TOF-MS) of hydrophilic and hydrophobic compounds. A range of particles with surface aliphatic carboxylic, aminophenyl, phenyl or aminopropyl groups have been produced and these have been doped with carbon black, polyaniline or graphite. The effects of surface groups and dopants on the laser desorption/ionisation process were studied.
View Article and Find Full Text PDFBuilding and networking: Ternary supramolecular networks have been formed by coadsorption of dissimilar ternary building units at the liquid-solid interface. The structural characteristics of the networks undergo distinctive transformations as the building units change from binary to ternary components (see graphic).
View Article and Find Full Text PDFA novel alternant amphiphilic polymer poly[1,4-bis(phenylethynyl)-2,5-bis(hexyloxy)benzene-alt-tetra(ethylene oxide)] was prepared. Atom force microscope (AFM) images showed that the molecular self-assembly morphologies changed from molecular nanowires to twist fibrillar architectures with the increase of the solution concentrations. Short and thin wires formed in dilute solution, while large bundles developed in relatively concentrated ones, shown by fluorescence microscope images.
View Article and Find Full Text PDFA series of star-shaped oligofluorenes end-capped with carboxylic acid groups were synthesized. Different numbers of carboxyl groups that can form hydrogen bonds, and long alkane chains that have stabilizing effects, were intentionally introduced. The resulting molecular architectures of the so-prepared star-shaped oligofluorenes at the liquid-solid interface were investigated by scanning tunneling microscopy.
View Article and Find Full Text PDFTwo conjugated polymers (CPs), poly(9,9-dioctylfluorene) (PF) and poly(3-octylthiophene) (PT) were analyzed by direct laser desorption/ionization time-of-flight mass spectrometry (LDI-ToF MS). Because of their strong absorption near the wavelength of the laser (337 nm), easy and transient energy transfer properties and sufficient thermal stability, CPs can be desorbed and ionized directly without a matrix. For comparison, these two polymers were also analyzed using matrix-assisted laser desorption/ionization (MALDI)-ToF MS in the positive reflectron mode.
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