The behavior of the sulfate anions SO4 -2adsorbed on the external surface of H-Capped (8, 0) AlN and BN zigzag Single-walled nanotubes was studied by using density functional calculations. Geometry optimizations were carried out at the B3LYP/6-31G* level of theory using the Gaussian 03 suite of programs. We present the nature of the SO4 -2 interaction in selected sites of the nanotubes. Our results show the BN nanotubes cannot significantly detect SO4 -2. The calculated binding energy of the AlN (8, 0) single-walled AlN nanotubes indicated that SO4 -2can be adsorbed significantly on the Al sites and these nanotubes can therefore be used for SO4 -2storage. Binding energies corresponding to adsorption of SO4 -2on the Al site in the (8,0) single-walled AlN nanotubes was calculated as (- 299.04hartree or -187650.11k.cal/mol or -8137.46ev).The calculated was binding energies for SO4 -2 in o-down orientation on surface Al N nanotubes higher than that adsorption on surface BN nanotubes. We also report the effects of SO4 -2 adsorption on electronics properties of the nanotubes.