Preparation And Adsorption Experiment Of Phosphate Removal Ceramsite

In order to prepared a phosphate removal matrix for constructed wetland, amino-functionalized polymer materials were investigated to add to unburned ceramsite. The single experiment was determined to find the proper range of flyash, cement, calcined lime, gypsum, amino materials and NaOH. And Plackett-Burman design was used to choose the significant factors which were effective for phosphorus removal. Then Box-Behnken Design response surface method was used to investigate the interaction of those significant factors. Only after establishing the mathematical regression model that the amount of optimal materials was calculated, and the amino-functionalized unburned ceramsite was prepared. Compared with the normal unburned ceramsite, the effects of the removal of phosphate by amino-functionalized unburned ceramsite were investigated. The effects of some important factors, i.e., the effects of initial concentration of phosphate, adsorbing time, adsorbing temperature were intensively investigated.Mixture experimental results show that based on the optimum range of materials by single experiment, Plackett-Burman design found out the significant factors which were effective for phosphorus removal were flyash and gypsum, p values reached to 0.0030 and 0.0418, respectively. And the significant factors which influenced the strength of ceramsite were cement, calcined lime, gypsum, and NaOH, p values were< 0.0001, < 0.0001, 0.0120, < 0.0001, respectively. And the materials of fly ash, cement, calcined lime and NaOH were chose to optimize thier contents. Box-Behnken Design(BBD) response surface analysis that flyash and gypsum, flyash and NaOH have significant interaction effects on phosphorus removal, p values were 0.0108 and 0.0295, respectively. After establishing a mathematical regression model, the optimization of the mixture proportion were: flyash 60 g(54.5%), cement 15 g(13.6%), calcined lime 15 g(13.6%), gypsum 3 g(2.7%), amino-functionalized materials 2 g(1.8%), and NaOH 15 g(13.6%).Adsorption experimental results show that: the adsorption of amino-functionalized unburned ceramsite and normal unburned ceramsite on phosphorus were well correlated with Langmuir isotherm model. And the kinetic studies showed that the adsorption process on both ceramsite for phosphate fitted the pseudo-second-order rate equations well, the balance adsorption amount qe were 0.0561 mg/g and 0.0229 mg/g, respectively. As adsorption parameters of 0,,,showed that adsorption process is a spontaneous endothermic process of entropy increase. Paired sample t-value test was used to determine the differences between amino-functionalized unburned ceramsite and normal unburned ceramsite, result shows that the correlation coefficient between two detas were 0.998 and 0.937, respectively, and the differences both two ceramsite were significant, p values were 0.094 and 0.000, respectively.