铝污泥吸附水中磷的影响因素及响应面法优化

为提高铝污泥的利用效率,将其更好地应用于富营养化水体的修复之中,以给水厂脱水铝污泥为吸附材料对水中的磷进行吸附,考察铝污泥投加量、铝污泥颗粒粒径、体系pH、水样磷浓度对吸附效果的影响。拟合了等温吸附方程,并借助响应面分析中的BBD(Box-Behnken Design)模型确定吸附时间、pH和铝污泥投加量这3种因素对吸附反应影响的显著性及交互作用的强弱,同时利用此模型对实验条件进行优化。结果表明:①上述4种因素均对吸附过程有所影响,Langmuir等温吸附方程拟合效果较好,铝污泥对磷的理论饱和吸附量为1.487 mg/g(温度298 K)。②铝污泥投加量对吸附的影响最为显著,pH和反应时间产生的交互作用最强。③当水体中磷浓度为10 mg/L时,其最佳工艺条件为铝污泥投加量12 g/L、pH=4.5及反应时间48 h,最大去除率为92.38%。

Influential factors on adsorption of phosphorus in water by aluminum sludge and experiment optimization by response surface methodology

In order to improve the utilization efficiency of Aluminum sludge and make it better used in the remediation of eutrophic water body, we carried out a series of phosphorus adsorption experiments in water by dewatered Aluminum sludge (DAS) from water supply plant as adsorptive material. The influence of DAS dosage and particle size, pH and phosphorus concentration in water samples on the absorption process were studied. The Langmuir and Freundlich isothermal adsorption equation model were used to fit the absorption process. Box-Behnken Design（BBD）model in response surface methodology (RSM) was used to evaluate the influence significance of several variables, including adsorption time, pH and DAS dosage and their interaction effects. In addition, we have optimized the experimental conditions by the BBD model. The results showed that the four factors mentioned above all have some influence on the adsorption process. The fitting effect of Langmuir isotherm adsorption equation was better. The theoretical saturated adsorption capacity of phosphorus by aluminum sludge is 1.487mg/g (at 298K). The response surface analysis results showed that the amount of aluminum sludge had the most significant effect on the adsorption, and the interaction effects between pH and reaction time were the strongest. When the phosphorus concentration in the water is 10mg/L, the optimum technological conditions are as follows: the aluminum sludge dosage is 12 g / L, pH is 4.5 and reaction time is 48 h, and the corresponding maximum removal rate is 92.38%.