基于小角度激光光散射的聚硅酸铁絮体特性研究

Flocs Characteristics of Poly-silicic-ferric Coagulant Based on Small-angle Laser Light Scattering

以腈纶废水生化出水为原水,采用小角度激光散射技术分析了聚硅酸铁(PSF)的絮凝特性,并考察了PSF投加量、p H值对絮体的生长、破碎与再凝聚过程中絮体平均粒径的影响。结果表明,在絮体生长过程中,絮体粒径随着PSF投加量的增加先增大后减小;反应体系p H值接近中性时,粒径最大。当PSF投加量为1.5 g/L、反应体系p H值为7.6时,平均粒径最大(890μm)。在破碎和再凝聚过程中,当反应体系p H值为7.6时,絮体强度随着PSF投加量的增加而增大,随着剪切强度的增大而减小。当PSF投加量为2.0 g/L、转速为75 r/min时,絮体破碎因子为2.78%。当PSF投加量为1.5 g/L时,反应体系p H值越低,絮体强度越大,在p H值为4.5时,絮体破碎因子为55.43%。在PSF投加量为1.5 g/L、p H值为7.6条件下,破碎时间越短,絮体恢复能力越强,以200 r/min转速对其进行1 min的破碎试验,絮体恢复因子为26.06%。

The biochemical treatment effluent of acrylic wastewater was targeted, and the flocs characteristics of poly-silicic-ferric （PSF） coagulant were studied using the small-angle laser light scattering （SALLS） technique. The impacts of PSF dosages and pH values on the variation of d0.5 of the flocs during the formation, breakup and regrowth processes were investigated. The results indicated that the size of flocs expanded and then shrunk with the increase of the PSF dosage. The flocs were largest when the pH value was close to 7. Under 1.5 g/L of PSF and 7.6 of pH value, the maximum do. 5 of the flocs was 890 μm. In addition, during the process of breakup and regrowth with a pH value of 7.6, the flocs was strengthened as the PSF dosage increased, but weakened with the increasing of shearing strength. When the dosage of PSF was at 2.0 g/L and the stirring speed was 75 r/rain, the breakage factor （Bf） was 2.78%. When the dosage of PSF was 1.5 g/L, the Bf of the flocs increased when the shearing strength was enhanced. The Bf increased as the pH in raw water decreased. The Bf was 55.43% when the pH value was 4.5. When the dosage of PSF was 1.5 g/L and the pH was 7.6, the recovery factor （Rf） of the flocs rose when the shearing time was shortened. When a crushing test was conducted at the stirring speed of 200 r/rain for one minute, the Rf was 26.06%.