value cited in the abstract as weighted average log K, in text and table value obvious exchanged with log K (NO3-), log K (0.001 M NaNO3)= -0.207, log K (0.01 M)= -0.148, and log K(0.1 M)=-0.453 , data sets of all ionic strength were taken together in calculation: log K=-0.396 not correct equation in the paper: »Al-OH 1/2- + Na+ = »Al-OH2-Na 1/2+