Wiśniewska M, Chibowski S, Urban T
Department of Radiochemistry and Colloids Chemistry, Faculty of Chemistry, Maria Curie Sklodowska University, M. Curie Sklodowska Sq. 3, 20-031 Lublin, Poland.
J Colloid Interface Sci. 2009 Jun 15;334(2):146-52. doi: 10.1016/j.jcis.2009.03.006. Epub 2009 Mar 28.
Free energies of polyacrylic acid (PAA) adsorption (DeltaG( composite function)) on an alumina (Al(2)O(3)) surface in the temperature range 15-35 degrees C were estimated on the basis of adsorption-desorption measurements of the inorganic radioactive ions (36)Cl, (45)Ca, and (55)Fe. Adsorbing polymer macromolecules caused the desorption process of previously adsorbed radioactive ions. The free energy of Ca-PAA surface complex formation (DeltaG(o)) was estimated to be close to the free energy of Ca(2+) ions adsorption (polymer causes about 50% desorption of these ions). Moreover, a free energy of polymer molecule adsorption increase with the increasing temperature was observed. The obtained values of DeltaG(o) were compared with those calculated from the adsorption data. Additionally, the amount of polymer adsorbed and the thicknesses of polymer adsorption layers were determined in the temperature range 15-35 degrees C. The changes of polymer chain conformation with the temperature increase are responsible for the increase of PAA adsorption as well as thickness of polymer adsorption layers in the studied temperature range.
基于无机放射性离子（³⁶Cl、⁴⁵Ca和⁵⁵Fe）的吸附 - 解吸测量，估算了15 - 35℃温度范围内聚丙烯酸（PAA）在氧化铝（Al₂O₃）表面的吸附自由能（ΔG（复合函数））。吸附的聚合物大分子导致先前吸附的放射性离子的解吸过程。钙 - PAA表面络合物形成的自由能（ΔG⁰）估计接近Ca²⁺离子吸附的自由能（聚合物导致这些离子约50%的解吸）。此外，观察到聚合物分子吸附自由能随温度升高而增加。将获得的ΔG⁰值与根据吸附数据计算的值进行了比较。另外，在15 - 35℃温度范围内测定了聚合物的吸附量和聚合物吸附层的厚度。在所研究的温度范围内，聚合物链构象随温度升高的变化是PAA吸附增加以及聚合物吸附层厚度增加的原因。
