Fe(Ⅱ)协同过硫酸钾改善河道底泥的脱水性能

Dehydration property of river sediment with combined conditioning using Fe(Ⅱ)-potassium persulfate

含水率是影响河道底泥后续处置效果与成本的重要因素,采用响应曲面法(RSM)和中心复合设计法(CCD)对Fe(Ⅱ)-过硫酸钾(K_2S_2O_8)优化河道底泥脱水性能进行研究。结果表明,K_2S_2O_8投加量为22.26 mg·g^(-1)TSS、Fe(Ⅱ)投加量为43.63 mg·g^(-1)TSS(K_2S_2O_8和Fe(Ⅱ)投加摩尔比为1∶1.9),初始pH为5.95时,其脱水效果最佳,CST削减率在10 min内能够达到86.16%,与优化响应器拟合的最佳CST削减率86.44%基本一致。基于RSM建立CST削减率预测模型,模型的相关系数R^2和R_(adj)~2分别为0.905 8和0.821 1,拟合度良好。经回归模型方差分析(ANOVA),底泥脱水效率受Fe(Ⅱ)投加量影响最大(P<0.001),其次是初始pH(P=0.023),最后是K_2S_2O_8投加量。与市场上常用聚合硫酸铁(PFS)和聚丙烯酰胺(PAM)相比,具有优越的经济性和良好的脱水效果。

The moisture of river sediment significantly influenced its dehydration and the disposal cost. Re- sponse surface method （RSM） and central composite design （CCD） were applied to optimize the effectiveness of combined oxidation conditioning process using Fe （ Ⅱ ） and potassium persulfate （K2S20s）. The results indica- ted that the optimum values for K2S2O8, Fe（ Ⅱ） , and initial pH were found to be 22.26 mg· g-1 TSS, 43.63 mg· g-1 TSS（n（K2S2O8） ：n（Fe（Ⅱ）） =1：1.9）, pH =5.95, respectively. CST reduction was decreased to 86. 16% in 10 min, in agreement with the predicted value of 86.44%. R2 and R21aj of predicted model was 0. 905 8 and 0. 821 1, respectively, which showed that RSM could explain the dehydration process with combined oxidation conditioning. ANOVA analysis confirmed that Fe （ Ⅱ ） （P 〈 0. 001 ） had the largest effect on CST reduction, followed by initial pH （P = 0. 023） and then K2S208. Compared with polymeric ferric sulfate （PFS） and polyacrylamide （PAM） , the combined oxidation conditioning has good performance in economy and dehydration property.