KGM-based magnetic carbon aerogels matrix for the uptake of methylene blue and methyl orange

In this study, the preparation of magnetic Fe and Mn oxides (Mag-FMBO) loaded carbon aerogels (CA) based on konjac glucomannan (KGM) and their performance for dyes adsorption were investigated. The prepared magnetic carbon aerogels (Mag-CA) materials were characterized by various methods, including BET surface area analysis, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and vibrating sample magnetometer (VSM). What's more, the Mag-CA materials were used as adsorbents to remove dyes [anionic methyl orange (MO) and cationic methylene blue (MB)] from aqueous solutions. The results showed that Mag-CA had an excellent adsorption performance towards MO and MB. The adsorption equilibrium data of both MO and MB can be well described by Langmuir model. The maximum MO and MB uptake capacity of Mag-CA reached 7.42mgg^-1 and 9.37mgg^-1 according to Langmuir isotherm at 303K, respectively. Thermodynamic parameters such as ΔG, ΔH and ΔS were estimated to understand the adsorption mechanism of MO and MB. The adsorption processes of MO and MB could be well described by the pseudo-second-order model. Moreover, Mag-CA with dyes (MO or MB) were successfully regenerated by ethanol and then easily separated from aqueous solution by applying magnetic field.

Solid-solid grinding/templating route to magnetically separable nitrogen-doped mesoporous carbon for the removal of Cu(2+) ions

N-doped ordered mesoporous carbon materials (NOMC) with 2D hexagonal symmetry structure were synthesized via a facile solid-solid grinding/templating route, in which the ionic liquids (ILs) of 1-cyanoethyl-3-methylimidazolium chloride and SBA-15 were employed as the precursor and hard template, respectively. The as-synthesized NOMC features with a uniform mesoporous size (3.5nm), ropes-like morphology (0.4-1μm in length) and high surface area (803m(2)/g). The quantitative analysis revealed the nitrogen content on the surface of NOMC is 5.5at%. Magnetic iron nanoparticles were successfully embedded into the carbon matrix by introducing iron chloride to the mixture of SBA-15 and ILs during the synthesis process. The NOMC-Fe composite possessed superior adsorption capacity of Cu(2+) ions (23.6mg/g). Kinetic and isothermal analysis demonstrated the strong interactions between Cu(2+) ion and the adsorbent. Furthermore, the composite was magnetically separable from solution under an external magnetic field and thus displayed a superior reusability in the recycling test.