Application Of Multiwalled Carbon Nanotubes In Trace Elements Separation And Preconcentration

With the development of technology, environment pollution becomes more serious along with human's standard of living improving, thus, it is necessary to monitor the environment exactly and timely. So, the analyzers who deal with environmental samples must try their best to improve the accuracy of analysis methods, shorten the analytical time, debase the detection limits, and set up more economical and effective detection methods.The very low concentration level of interesting substances and the complex matrix of many environmental samples make sample preparation necessary for a reliable determination of these compounds prior to their determination.Recently, solid-phase extraction (SPE) technique has become increasingly popular in trace elements separation or preconcentration due to its advantages of high enrichment factor, high recovery, rapid phase separation, low cost, low consumption of organic solvents and the ability of combination with different detection techniques in the form of on-line or off-line mode. Numerous substances have been proposed and applied as solid-phase extraction sorbent for the preconcentration of organic and inorganic compounds. And the choice of solid-phase adsorbents is the decisive factor that affects analytical sensitivity and selectivity. So, it has still been a heated research field to find new and effective adsorbents nowadays.Nanometer material has attracted the attention, imagination and close scrutiny of scientists and engineers in recent years. Nanomaterials are made up of nanoparticles; the size of a nanoparticle ranges from 1 nm to almost 100 nm, and thus falls between the classic fields of chemistry and solid-state physics. The size, surface structures, and interparticle interactions of nanomaterial are responsible for their unique properties and improved performance, and determine their potential applications in many areas. One of the specific properties of nanomaterials is that a high percentage of the atoms of a nanoparticle are at the surface. The surface atoms are unsaturated and can therefore bind with other atoms, and possess a high chemical activity. Nanoparticulate metal oxides exhibit intrinsic surface reactivity and large surface areas, and can strongly chemisorb many substances.