Poly-NIPAM/Fe3O4/multiwalled carbon nanotube nanocomposites for kerosene removal from water.

Multiwalled carbon nanotubes (MWCNTs) were oxidized using a mixture of H2SO4 and HNO3, and the oxidized MWCNTS were decorated with magnetite (Fe3O4). Finally, poly-N-isopropyl acrylamide-co-butyl acrylate (P-NIPAM) was added to obtain P-NIPAM/Fe/MWCNT nanocomposites. The nanosorbents were characterized by various techniques, including X-ray diffraction, transmission electron microscopy, scanning electron microscopy, thermogravimetric analysis, and Brunauer-Emmett-Teller analysis. The P-NIPAM/Fe/MWCNT nanocomposites exhibited increased surface hydrophobicity. Owing to their higher adsorption capacity, their kerosene removal efficiency was 95%; by contrast, the as-prepared, oxidized, and magnetite-decorated MWCNTs had removal efficiencies of 45%, 55%, and 68%, respectively. The P-NIPAM/Fe/MWCNT nanocomposites exhibited a sorbent capacity of 8.1 g/g for kerosene removal from water. The highest kerosene removal efficiency from water was obtained at a process time of 45 min, sorbent dose of 0.005 g, solution temperature of 40 °C, and pH 3.5. The P-NIPAM/Fe/MWCNTs showed excellent stability after four cycles of kerosene removal from water followed by regeneration. The reason may be the increase in the positive charge of the polymer at pH 3.5 and the increased adsorption affinity of the adsorbent toward the kerosene contaminant. The pseudo second-order model was found to be the most suitable model for studying the kinetics of the adsorption reaction.

Polyethylene over magnetite-multiwalled carbon nanotubes for kerosene removal from water.

In this study, a nano-adsorbent was prepared for kerosene removal from water. Multiwalled carbon nanotubes (MWCNTs) were functionalized with concentrated HNO3 (nitric acid). Subsequently, Fe3O4 (magnetite) nanoparticles were deposited on the MWCNTs to prepare a magnetite/MWCNTs (Fe-MWCNTs) nanocomposite. Then, polyethylene was added to the Fe-MWCNTs to fabricate a polyethylene/magnetite/MWCNTs (PE/Fe-MWCNTs) novel nanocomposite. The nano-adsorbent was characterized using BET, FTIR, Raman, XRD, TEM, and SEM. A kerosene-water model mixture was used for adsorption tests. Several parameters: adsorption time, adsorbent dose, solution pH, solution temperature, and kerosene concentration in the kerosene-water model mixture, were analyzed during adsorption experiments. After each batch experiment, kerosene concentration was determined using high-performance liquid chromatography (HPLC). Magnetic field was used to remove the adsorbent after each experiment. The kerosene adsorption capacity and removal efficiency of the PE/Fe-MWCNTs nanocomposite (3560 mg/g and 71.2 %, respectively) were higher than those of Fe-MWCNTs, ox-MWCNTs, and fresh MWCNTs (3154 mg/g and 63.1 %, 2204 mg/g and 44.0 %, and 2092 mg/g and 41.8 %, respectively). Kerosene adsorption followed a pseudo-second-order kinetic model (R2 = 0.999) and the Langmuir isotherm model, suggesting that adsorption was uniform and homogenous process.