A Novel Reverse Osmosis Carbon Nanotube Composite Membranes: Preparation and Characterization

Since Iijima was invented in 1991 [1], CNT has become an important material in many aspects due to its unique structure, mechanical, electrical and physicochemical properties [2]. Currently, CNT-containing materials are developed and evaluated for various applications such as sensors, electronic devices, actuators, drug delivery vehicles, new composite materials, etc. [3] Unfortunately, as strong van der Waals interactions cause packing and entanglement, CNTs usually exist in the form of ropes or bundles with diameters of 10-30 nm; these phenomena slow down the application of carbon nanotubes 4-4.

Carbon nanotubes have useful absorption, photoluminescence (fluorescence) and Raman spectroscopic properties. Spectroscopic methods provide the possibility of rapid, non-destructive characterization of a relatively large number of carbon nanotubes. From an industrial point of view, there is a strong need for such characterization: many parameters of nanotube synthesis can be changed intentionally or unintentionally to change the quality of the nanotubes. As shown below, light absorption, photoluminescence, and Raman spectroscopy can rapidly and reliably determine such "nanotube mass" with respect to non-tubular carbon content, resulting nanotube structure (chirality) and structural defects Can be characterized. These features determine almost all other characteristics, such as optical, mechanical and electrical properties.

New chemical, electrical and mechanical properties not found in other materials were found in carbon nanotubes. Raw carbon nanotubes are inert to most chemicals and require grafting with surface functional groups to enhance their chemical reactivity and add new properties. In the case of SWNT, the conductivity depends on the chiral vector and is independent of the length determined by quantum mechanics. Consider a chiral vector whose index is (n, m). This is metallic when n = m or (n - m) = 3 i (i is an integer), otherwise it is semiconductor. Along the longitude direction, the carbon nanotubes show excellent mechanical strength and have the best known tensile strength and elastic modulus among the known materials.