铁改性热处理凹凸棒颗粒对水体磷的去除效果

传统粉末态除磷材料颗粒过细，从而导致其难与水分离，这极大限制了其在实际工程中的应用。以热处理颗粒态凹凸棒黏土为载体（1~2 mm），采用氯化铁（FeCl₃）活性负载的方法制备颗粒态吸附磷材料，并详细研究了吸附材料除磷的最佳改性条件、反应时间、影响因素及其效率。结果表明:2 mol/L氯化铁溶液改性的凹凸棒达到最佳改性条件，且磷的吸附能较好地被朗格缪尔方程模拟，其最大吸附量为4.27 mg/g，是原状黏土固磷容量的2倍左右。铁改性凹凸棒土除磷效率受pH值的影响较大，当水体pH值从4提高到11，去除率下降了10%左右。吸附动力学表明，铁改性凹凸棒土对磷的吸附符合拟二级动力学方程，24 h内可以去除84.46%的磷。0.2 mol/L的盐酸对铁改性凹凸棒的再生效果最优，再生后吸附剂对磷的吸附效率下降40%左右。以上研究结果表明，铁改性凹凸棒土可以作为低浓度水体磷去除材料，具有较大的应用前景。

PHOSPHORUS REMOVAL BY THE IRON MODIFIED THERMALLY TREATED GRANULAR ATTAPULGITE CLAY

The traditional powder phosphorus removal materials were difficult to separate from water due to its small particle size, which greatly limited its application in practical engineering. In this paper, granular phosphorus removal materials were prepared by using heat treated attapulgite clay as carrier (1~2 mm) and iron chloride (FeCl₃) to active load. The optimum modification conditions, reaction time, influencing factors and phosphorus removal efficiency of the materials were studied in detail. The results showed that the maximum adsorption capacity of attapulgite clay modified by 2 mol/L iron chloride solution was 4.27 mg/g, which was about 2 times of the phosphorus fixation capacity of the original clay. The adsorption of phosphorus on iron modified attapulgite was greatly affected by pH value. The removal rate of phosphorus decreased by about 10%, as the pH value of water body increased from 4 to 11. The adsorption kinetics showed that the adsorption of phosphorus on Fe-modified attapulgite was in accordance with the quasi-second-order kinetic equation, and 84.46% of the phosphorus could be removed within 24 hours. Best effect on the regeneration of iron modified attapulgite was found using 0.2 mol/L hydrochloric acid, and then the phosphrous adsorption efficiency of the regenerated adsorbent decreased by about 40%. The above results showed that iron modified attapulgite can be used as absorbent on water bodies with low phosphrous concentration and has great application prospect.