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Surface modification

About: Surface modification is a research topic. Over the lifetime, 35544 publications have been published within this topic receiving 859567 citations.


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Journal ArticleDOI
15 May 2015
TL;DR: An ultrasonic surface modified chitin (USM-chitin) was prepared and used for Methylene Blue adsorption and its surface was modified by an ultrasound-assisted treatment, presenting surface area 25 times higher than raw Chitin.
Abstract: Hypothesis Chitin is a biopolymer which can be used as a low-cost and eco-friendly material for dyes adsorption. The use of chitin for dyes removal is little investigated, due its low surface area, porosity and high crystallinity. So, an ultrasonic surface modified chitin (USM-chitin) was prepared and used for Methylene Blue (MB) adsorption. Experiments Chitin was obtained from shrimp wastes and its surface was modified by an ultrasound-assisted treatment. USM-chitin was characterized by N2 adsorption/desorption isotherms (BET surface area, total pore volume), infrared spectroscopy, X-ray diffraction and scanning electron microscopy. The adsorption of MB on USM-chitin was studied by kinetic, equilibrium, thermodynamic, interactions analysis, desorption and mass transfer aspects. Findings USM-chitin presented surface area 25 times higher than raw chitin. The porosity was increased and the crystallinity was decreased. The general order model was suitable to represent the adsorption kinetics and the Langmuir model was adequate for the equilibrium. The maximum adsorption capacity was 26.69 mg g−1. The adsorption was spontaneous, favorable and exothermic. USM-chitin can be used seven times maintaining the same adsorption capacity.

211 citations

Journal ArticleDOI
TL;DR: In this article, a new nanostructured catalyst, made of small uniform gold nanoparticles (AuNPs) and ceria nanotubes (CeO2NTs), is presented.
Abstract: We report the preparation and catalytic properties of a new nanostructured catalyst, made of small (∼5 nm in diameter) and uniform gold nanoparticles (AuNPs) and ceria nanotubes (CeO2 NTs). “Surfactant-free” AuNPs fabricated by pulsed laser ablation in liquid (PLAL) on a bulk Au target are efficiently assembled onto the surface of CeO2 NTs without performing any surface functionalization of either component to promote their coupling, thanks to the presence of OH on the PLAL-AuNPs. The reduction reaction of 4-nitrophenol into 4-aminophenol catalyzed by our PLAL-AuNP/CeO2-NT catalyst exhibits remarkably higher reaction rate in comparison to that catalyzed by similar catalysts composed of chemically prepared AuNPs (Chem-AuNPs) as an active phase and/or commercially available CeO2 powder as support. Their superior catalytic activity is found to be due to the unique, relatively “bare” surface of the PLAL-AuNPs as well as oxidized Au species induced by the strong interaction between the “barrier-free” surface of PLAL-AuNPs and surface defects (oxygen vacancies) of CeO2 NTs. The important role of unique surface chemistry of PLAL-AuNPs in catalysis was further demonstrated in CO oxidation reaction in gas phase. Our results suggest that the use of PLAL-AuNPs enables easy and efficient attachment of AuNPs onto the surface of the CeO2 NTs and their unique combination leads to the development of highly efficient catalysts. Our design and fabrication of the nanocatalysts take full advantage of the unique features of the PLAL-AuNPs and potentially constitute a general and efficient route to prepare other metal-NP/metal-oxide-support catalysts, which can therefore largely expand the applications of PLAL-noble metal NPs in catalysis.

211 citations

Journal ArticleDOI
TL;DR: In this paper, a number of monomers with a variety of functional groups have been successfully grafted from the surface of selected substrates, and the grafting efficiency determined using X-ray photoemission spectroscopy.
Abstract: Photografting has been used for the surface modification of a wide range of commercial commodity polymers such as poly- styrene, poly(methyl methacrylate), poly(dimethyl siloxane), polycarbonate, Parylene C, polypropylene, cyclic olefin copolymer, and hydrogenated polystyrene that are useful substrate materials for the fabrication of microfluidic chips. Since the chain propagation is initiated after UV light-activated abstraction of a hydrogen atom from the surface of channels within the materials, their permeability for UV light was tested and polyolefins were found to be the best candidates. A number of monomers with a variety of functional groups such as perfluorinated, hydrophobic, hydrophilic, reactive, acidic, basic, and zwitterionic have been successfully grafted from the surface of selected substrates, and the grafting efficiency determined using X-ray photoemission spectroscopy. Layered surface structures were prepared by consecutive grafting of different monomers. Our approach also enables photolithographic patterning of surfaces and specific functionalization of confined areas within the microchannel.

210 citations

Journal ArticleDOI
TL;DR: In this article, the 3-glycidoxypropyl trimethoxylsilane (GPS) was grafted onto the surface of silica gel, P2 glass beads and TiO2 oxide particles.
Abstract: The silane coupling agent 3-glycidoxypropyl trimethoxylsilane (GPS) was grafted onto the surface of silica gel, P2 glass beads and TiO2 oxide particles. FT-IR, thermogravimetric and elemental analysis were used to characterize the modified particles. The effects of various factors on the GPS grafting efficiency such as catalyst, GPS concentration, reaction temperature and time were studied. After modification with GPS, the xanthene dye rhodamine B and azo dyes 4-phenylazophenol and 4-phenylazoaniline, respectively, were grafted on to the particles, which were then used as pigment fillers. The colors of the pigments were adjusted by changing the kind of dyes, the concentration, the pH and the reaction solvents. Copyright © 2001 John Wiley & Sons, Ltd.

210 citations

Journal ArticleDOI
TL;DR: In this article, the effect of liquid-phase oxidation on the Pb2+ adsorption capacities of activated carbon was investigated, and two series of functionalized samples were prepared by means of oxidation of a commercially available activated carbon with either HNO3 or H2O2.

210 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20232,530
20225,209
20211,961
20202,217
20192,313
20182,263