Adsorption of methyl ethyl ketone onto poly(vinyl alcohol) (PVA)/peat/organoclay composite beads in aqueous solution

摘要

A new type of poly(vinyl alcohol)(PVA)/peat/ organoclay composite beads was prepared. This composite bead was a porous spherical particle with a diameter of 3.0- 5.0 mm and a porosity of about 50%. The oragnoclay is prepared by hexadecyl trimethyl ammonium bromide (HDTMA) exchanged clay. The dynamic adsorption behavior between methyl ethyl ketone (MEK) and this composite bead was investigated. The adsorption process occurs in two stages with external mass transport occurring in the early stage and intraparticle diffusion occurring in the later stage. The rate of MEK diffusion in the external mass transport process and the intraparticle diffusion process in the adsorptiontemperature 20-35 °C was 3.28-76.98×10 ~(?8) cm ~2/s and 1.62-3.17×10 ~(?7) cm ~2/s, respectively. The rate of MEK diffusion in both processes was concentration independent, and it increased with increasing the adsorption temperature. Langmuir isotherm adsorption model was more suitable for describing the adsorption equilibrium of MEK. The calculated Q values in the adsorption temperature 20-35 deg;C were 5.90-22.78 mg/g composite bead. The adsorption capacity of this composite bead increased with increasing theadsorption temperature. The adsorption process was physical adsorption, endothermic and non-spontaneous process.