Polysilicate aluminum ( PSA) ,polysilicate ferric ( PSF) ,polysilicate aluminum ferric ( PSAF) coagulants were prepared by copolymerization.The preparation conditions and dosage were investigated on the effect of flocculation performance and wastewater iron concentration. Flocculant structure and thermal stability were analyzed by Fourier transform infrared spectrometer ( FT?IR ) , X?ray diffraction ( XRD ) , thermogravimetric calorimeter.Results showed that PSAF had better flocculation performance than PSA, PSF,and a commercial PSAF.When the dosage was appropriate,there was no residual metal ions.On the contrary, there were residual metal ions. Among three kinds of flocculant, PSA had more residual aluminum ions,while PSF had more residual iron ions.FT?IR and XRD results showed that the hydrolysis of Al3+and Fe3+ polymer had complexation or adsorption with hydroxyl silicate. Thermogravimetric results showed that the stability of three coagulants was good at normal temperature.%采用共聚法制备聚硅酸铝(PSA)、聚硅酸铁(PSF)、聚硅酸铝铁(PSAF)3种絮凝剂,考察制备条件和投加量对絮凝剂的絮凝性能及废水中离子残留的影响.采用傅里叶红外光谱仪(FT-IR)、X线衍射仪(XRD)、热分析仪分别对絮凝剂的结构及热稳定性进行表征.结果表明:PSAF的絮凝性能优于PSA、PSF及市售PSAF;制备条件和投加适当时,离子不会残留,反之,出现离子残留;3种絮凝剂中,PSA的Al3+残留最严重,PSF的Fe3+残留最严重.FT-IR和XRD结果表明:Al3+和Fe3+的水解产物与硅酸的羟基发生配位或吸附作用;热分析结果表明:常温下,3种絮凝剂稳定性较好.
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