Abstract:This research investigated the effects of temperature and solution/soil ratio on the adsorption of oxalic, citric, tartaric and malic acids in red soil by a batch equilibrium method. The results indicated that the adsorption capacity, the maximum adsorption capacity (Sm) and adsorption affinity constant (K) all increased with the increase of temperature, but decreased with the increase of solution/soil ratio. The effects depended on the kinds of organic acids, and the influencing extent was negative to adsorption affinity constant (K). The adsorption capacities of oxalic, citric, tartaric and malic acids at 45℃ was 1.19, 1.22, 1.24 and 1.28 times higher than those at 25℃, respectively. The adsorption capacities of oxalic, citric, tartaric and malic acids at 100:1 solution/soil reduced by 48.3%, 54.9%, 63.5% and 76.1% compared to those at 10:1 solution/soil, respectively.