Acta Phys. -Chim. Sin. ›› 1989, Vol. 5 ›› Issue (02): 185-190.doi: 10.3866/PKU.WHXB19890211

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ADSORPTION OF POLYETHYLENE GLYCOLS, POLYPROPYLENE GLYCOL AND POLYOXYETHYLENE-POLYOXYPROPYLENE BLOCK COPOLYMERS ON SOLID/LIQUID INTERFACES Ⅰ .ACTIVE CARBON/WATER INTERFACE

Zhao Zhenguo; Gu Tiren   

  1. The Institute of physical Chemistry; Peking University
  • Received:1987-09-15 Revised:1988-02-10 Published:1989-04-15
  • Contact: Zhao Zhenguo

Abstract:

The adsorption isotherms of polyethylene glycols(PEG,molecular weights of 400,1000, 3350, 6000 and 20000), one polypropylene glycol(PPG) and polyoxyethylene -polyoxypropylene block co-polymers (L61, L64, and F68) from water onto the active carbon have been measured (at 25℃).The results show that all the isotherms are Lagmuir-type, and the limiting, or plateau adsorption is approached at relatively low concentration The limiting adsorption(g.g-1) of the polymers onto active carbon is constant apparently. For PEG series, the plot of molecular area at limiting adsorption (A) versus the number of ethylene oxide units in the polymer molecules (n_(EO)) is a straight line through the origin. For EO-PO co-polymer series the A-n_(EO) plot is also a straight line with same slop as that for PEG series, however, the straight line intercepts with area axis. The areas of EO and PO calculated from the slop and the intercept are 2.6 nm~2 and 2.9 nm~2, respectively. From these results, it is suggested that the adsorbed molecules lies flat on the active carbon surface.