Preparation of Engineered Carbon Nanorods from Garbage Leachate by Pyrolysis on the Sand Particles and Its Application for 4-Nonylphenol Removal from Surface Water

Silica sand filters are usually employed for water treatment. Their capacity for removal of 4-nonylphenol from the water streams is low. In addition, for using nano-adsorbents in the slurry mode, they should be removed at the end of the process. These problems in this study were solved by the immobilization of nanorods on silica particles. The acid-washed sand particles were mixed constantly with the garbage leachate on a heater so that they were covered completely with the garbage leachate. Then, the obtained particles were put in the furnace and pyrolyze (at varying temperatures in a range of 300 to 800 °C) for preparation of the nanocomposite. According to the scans from scanning electron microscopy and results of the Raman test, the nanotubes were formed on the silica surface. Furthermore, the EDS analysis results for carbon nanorods showed the existence of oxygen, silica, and a small amount of aluminium. The 4-Nonylphenol adsorption was examined using a new nanocomposite under various operating circumstances (initial concentration, contact time, temperature). The isotherm, kinetics, and thermodynamics of the adsorption process were also studied. Following a different regeneration process, data indicated that the novel developed material is an appropriate recyclable adsorbent that can be used in water treatment.

The selective adsorption performance and mechanism of multiwall magnetic carbon nanotubes for heavy metals in wastewater

The safe treatment of heavy metals in wastewater is directly related to human health and social development. In this paper, a new type of recyclable adsorbent is synthesized through the oxidation of enhancer and modification with magnetic nanoparticles. The new adsorbent not only inherits the advantages of multiwall carbon nanotubes (6O-MWCNTs), but also exhibits a new magnetic property and further improved adsorption capacity, which is conducive to the magnetic separation and recovery of heavy metals. The adsorption results indicate that multiwall magnetic carbon nanotubes (6O-MWCNTs@Fe3O4) have a good performance for Pb(II) selective adsorption, with a maximum adsorption capacity of 215.05 mg/g, much higher than the existing adsorption capacity of the same type of adsorbents. Under the action of an external magnetic field, 6O-MWCNTs@Fe3O4 that adsorbed metal ions can quickly achieve good separation from the solution. The joint characterization results of FTIR and XPS show that under the action of both coordination and electrostatic attraction, the C=O bond in the –COOH group is induced to open by the metal ions and transforms into an ionic bond, and the metal ions are stably adsorbed on the surface of 6O-MWCNTs@Fe3O4. Pb(II) has a stronger attraction than Cu(II) and Cd(II) to the lone pair of electrons in oxygen atoms to form complexes, due to the covalent index of Pb (6.41) is more larger than that of Cu (2.98) and Cd (2.71).These data provide a new type of recyclable adsorbent for the efficient treatment of heavy metal ions in wastewater and enrich relevant theoretical knowledge.