The influence of Mn(Ⅱ)adsorbed by kaolinite on the reduction of Cr(Ⅵ)by oxalic,citric and tartaric acids is investigated through batch experiments.The results show that Mn(Ⅱ)adsorbed by kaolinite accelerates the reduction of Cr(Ⅵ)by the three organic acids,and the catalysis is in the order:oxalic acid,citric acid,tartaric acid.When the concentration of tartaric acid is lower than 2.0 mmol·L-1,the catalysis of adsorbed Mn(Ⅱ)is not obviously observed,but it becomes manifest with a higher concentration.The tem...