Removal of methyl orange from aqueous solutions by novel magnetic multi-walled carbon nanotube/iron oxide hybrids

摘要

Dyes are used extensively in the textile, leather, paper, plastic and other industries. Removal of dyes from colored wastewater is important for environmental remediation. Adsorption has been proved to be effective for dye removal in treating wastewater: it is low-cost, highly efficient, simple, easy to perform, and insensitive to toxic substances. In this regard, the high aspect ratio and the s mall diameter of carbon nanotubes (CNTs) makes them a promising candidate for water purification. Large surface area and high porosity of CNTs provide rich adsorption sites for harmful cations, anions and other organic and inorganic impurities present in natural sources of water. However, it is difficult to separate CNTs from aqueous solutions after treatment because of their small sizes. Traditional methods to separate CNTs from aqueous phases include ultracentrifugation and filtration. Centrifugation methods require very high rotational speeds and the traditional filtration method is prone to filter blockage. In recent years, the application of magnetic adsorbents has received considerable attention because of their easy separation after use . The magnetic absorbents can be separated and recovered from environmental applications using an external magnetic field.