This proposal presents a comparative study of the adsorption of three key chemical groups onto an important technological substrate, viz. fatty acid salt (Sodium hexanoate), phosphoric acid salt (Bis-(2-ethylhexyl) phosphate (Sodium-DEHP)) and sulphonic acid salt (Aerosol-OT (AOT)) onto aluminium oxide (sapphire) from water under well-controlled conditions (pHs and ionic strength). In particular, we seek the adsorption behaviour of these anionic species and particularly the competitive behaviour.