Abstract:
A solid phase extraction or chromatographic medium comprises a porous nonwoven fibrous matrix comprising at least one of polytetrafluoroethylene and blown microfibers, and sorptive or reactive hydrophobic siliceous molecular sieve particulates enmashed in said matrix, the ratio of molecular sieves to matrix being in the range of 40:1 to 1:40.
Abstract:
A sheet article for solid phase extraction or solid phase reaction comprises at least one sorptive polymer pulp, and optionally at least one of sorptive and reactive particulate. The article can be used in a method of separating an analyte from a fluid comprising the step of passing a fluid comprising an analyte through a sheet article comprising poly(p- or m-phenylenephthalamide) pulp, the pulp optionally having incorporated therein solid phase particulates, the sheet article being capable of isolating the analyte from the fluid.
Abstract:
An efficient method removes oxidants from fluids (gases and liquids, particularly air) by means of solid phase extraction or reaction. The solid phase extraction or reaction medium comprises a porous, preferably fibrous, polymeric, membrane or web in which are incorporated oxidant scavanger particulates. Typical oxidants removed in the method include ozone, oxides of nitrogen, halogen, and peroxides. The method of the invention protects organic analytes in analytical applications and removes oxidants in remediation applications by use of oxidant scavenger particles in porous membranes.
Abstract:
Composite articles are useful for separating mercury from fluids. The composite articles can be porous supports comprising an inert substrate having immobilized thereon finely divided gold optionally in combination with a tin salt coating. The porous support can be a particulate or porous fibrous web. Alternatively, the composite articles can comprise a porous fibrous membrane having enmeshed therein the aforementioned porous supports which can be in particulate or fibrous forms. The method for separating elemental, ionic, or organic mercury in fluids comprises the steps of contacting and passing a fluid containing mercury through a support comprising a porous, high surface area, inert substrate on which is immobilized finely divided elemental gold at a controlled rate for a time sufficient for the mercury to sorb to the elemental gold and to provide an immobilized gold-mercury amalgam on the support. If a tin salt also is immobilized on the inert substrate, mercury-tin salt can also be formed. In a further, and optional, step, elemental mercury can be removed from the support and optionally can be quantified.
Abstract:
A particle loaded, porous, fibrous compressed or fused article comprises a nonwoven fibrous polymeric web, which preferably is thermoplastic, melt-extrudable, and pressure-fusible blown microfibrous web, and sorptive particles enmeshed in said web, the particle loaded fibrous article has a Gurley number of at least two seconds, and the article is useful in separation science. A method of preparation of the article and method of use is also disclosed.
Abstract:
A functionalized macroporous poly(styrene divinylbenzene) particle comprises at least one ionic functional group covalently bonded thereto, the functionalized particle having sorptive capability towards an analyte, said functional group being present in the range of 0.1 to 2.5 milliequivalents per gram of poly(styrene divinylbenzene). The functionalized particles can be used in a packed column or enmeshed in a nonwoven web for utility in solid phase extraction applications.
Abstract:
A method and apparatus for performing solid-phase extraction (SPE) on a fluid that contains solubles and suspended solids. The method includes: (a) providing a volume of fluid that contains solubles and suspended solids, (b) processing the volume of fluid to extract solubles therefrom by the steps comprising: (i) passing a first portion of the volume of fluid in a first direction through a solid phase extraction medium; and then (ii) passing a second portion of the volume of fluid through the solid phase extraction medium in a second direction opposite to the first direction; and (c) repeating step (b) a plurality of times such that no substantial amount of the suspended solids is removed from the processed volume of fluid. The apparatus includes a conduit, an SPE medium located in the conduit, and a fluid flow direction altering mechanism or an SPE rotating mechanism.
Abstract:
A composite article comprising, in the unexpanded form, a fibrillated PTFE matrix and a combination of energy expandable hollow polymeric particles and sorptive particles, which composite, on applying energy such as steam, heat, or laser energy, provides an expanded article having increased void volume and decreased density. The expanded articles are porous and efficient articles for separation and purification applications. In flat or rolled form, the composite article can be used in separation devices.