Separation of Lead with a Novel Ion Separating Agent Prepared by Clothing a Chitin Whisker on a Potassium Tetratitanate Whisker

Separation of Pb(2+) from Cu(2+)-Pb(2+) mixed solution by a newly-developed ion separating agent was examined, which was obtained by clothing chitin whiskers (ChW) on the surface of potassium tetratitanate whiskers (PTW). The separation capability and mechanism of the ion separating agent (ChW-PTW) was determined, based on the difference of the adsorption isotherm pattern and the adsorption kinetics model between ChW and PTW on Cu(2+) and Pb(2+), respectively. The results showed that the adsorption process of ChW could be described by Freundlish isotherm. The adsorption affinity of Cu(2+) (k(F) = 0.085·g(−1)) on ChW was greater than Pb(2+) (k(F) = 0.077 g(−1)). The adsorption pattern of PTW was inclined to the Langmuir isotherm, and Pb(2+) (k(L) = 310.59 L·mmol(−1)) could be obviously more easily adsorbed on PTW than Cu(2+) (k(L) = 25.85 L·mmol(−1)). The experimental data both fitted well with the pseudo-second order kinetics. The reaction rate of Pb(2+) (k(2) = 4.442 for ChW and k(2) = 0.846 for PTW) was greater than that of Cu(2+) on both ChW and PTW, while the diffusion rate of intra-particles of PTW was much higher than ChW. The adsorption model of ChW and PTW could illustrate well the separation mechanism of ChW-PTW and allowed for relevant results.