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Removal of Cr (VI) from aqueous solution using MCM-41
Ist Teil von
Desalination and water treatment, 2011-12, Vol.36 (1-3), p.334-343
Ort / Verlag
L'Aquila: Desalination Publications
Erscheinungsjahr
2011
Link zum Volltext
Quelle
Taylor & Francis Current Content Access
Beschreibungen/Notizen
Mesoporous molecular sieves (MCM-41) was successfully synthesized using hydrothermal synthesis and characterized by X-ray diffraction and nitrogen adsorption-desorption. Characterization results show that synthesized MCM-41 is a good adsorption material of good crystallinity, large surface area (1,040 m super(2)/g) and uniform diameter (centered at 2.8 nm). Removal of Cr (VI) from aqueous solution using MCM-41 was carried out by UV-Vis spectrophotometry. The different parameters affecting the adsorption efficiency were investigated and obtained their optimal values (pH 4, temperature 35 degree C, initial Cr (VI) concentration < 10 mg/L, adsorption time 2 h, adsorbent concentration of 10 mg/L). It is very useful and important to deal with Cr (VI) from aqueous solution. The adsorption isotherm was also investigated. It is found that the adsorption isotherm follows the Langmuir model better. Whaf s more, b of 76.71 mg super(-1) and q of 904 mg/g were calculated from Langmuir linear fitting. The adsorption reaction is spontaneous and endoihermic as Delta G super(0) < 0 and Delta H super(0) > 0. Finally, we studied the adsorption kinetics and find that the adsorption of Cr (VI) ions onto MCM-41 is more suitable for pseudo-second-order kinetics. q sub(e) and k sub(2) were calculated. The detailed kinetic mechanism is that film diffusion is its mainly controlling step, but intra-particle diffusion is a considerable contribution to adsorption mechanism, which must be meaningful to accelerate adsorption rate.