Abstract: Oxalic acid-modified manganese ore and natural manganese ore were used as adsorbents for Ni²⁺removal from water. The effect of pH value, adsorption time and adsorbent dosage on the Ni²⁺removal rate was investigated and the saturated adsorption amount was measured. The results show that Ni²⁺adsoption-pH curve is of S type and the Ni²⁺adsoption rate is increased with the increase of the adsorption time and the addition of the modified manganese ore. Under the conditions of 25 ℃, pH=0.7 and a adsorbent concentration of 0.2 g/L, modified and natural manganese ores have a saturated adsorption amount for Ni²⁺ of 32.3 and 11.6 mg［Ni²⁺］ respectively, with the former's adsorption amount being 2.8 times that of the latter. Therefore, modified manganese ore is expected to become a new adsorptive material for treating water containing Ni²⁺.

Key words: Oxalic acid-modified manganese ore, Natural manganese ore, Ni²⁺ adsorption