Abstract: The effect of the  pH of adsorption medium,  the urea and the salts on the adsorption property of sodium lignosulphonate(SL) on the surface of the ferric oxide particles was studied. The results showed that the sodium citrate with strongest complexing power maked  the adsorption amount of SL on ferric oxide reduce to almost zero. The sodium sulfite with weak complexing power causes the adsorption amount of SL a certain reduction. The sodium sulfate with no complexing power causes the adsorption amount of SL a certain increase instead. It is concluded that the complex adsorption driving force between the carboxyl groups of SL and the ferric oxide plays a leading role in the adsorption process and the sulfonic groups of SL have very weak influence on the adsorption on the ferric oxide. The lithium chloride was used to mask most carboxyl groups of SL,  and the adsorption amount of the masked SL on ferric oxide was reduced evidently. The results further proved that the complex force between the carboxyl groups of SL and the ferric oxide played the leading role in the adsorption process. In addition,  the results showed that the electrostatic and hydrogen bond interaction between SL and ferric oxide had little influence on the adsorption.

Key words: Sodium lignosulphonate, Carboxyl group, Adsorption driving force, Complexing adsorption, Ferric oxide