污泥对分散剂的吸附及其对污泥水煤浆成浆特性的影响

采制城市污泥样品和煤样,采用傅里叶变换红外光谱和扫描电子显微镜表征污泥样品的组成特征和微观形貌,测定污泥颗粒和煤颗粒对聚羧酸型分散剂SAF的吸附等温线、研究吸附动力学。此外,制备了污泥水煤浆并考察污泥掺加量与分散剂用量对水煤浆浓度的影响。结果表明,污泥中存在极强的分子间氢键缔合羟基,并含有大量由丝状微生物等形成的絮凝体结构;污泥颗粒对分散剂的饱和吸附量为7.98 mg/g,大于煤颗粒对分散剂的饱和吸附量4.91 mg/g;污泥颗粒对分散剂的吸附基本符合一级动力学方程,而煤颗粒对分散剂的吸附符合二级动力学方程,且分散剂在污泥颗粒形成的空隙中的扩散是决定吸附过程的主要因素;随污泥掺加量的增大,污泥水煤浆的定黏浓度降低、成浆性变差。污泥的组成、结构特征造成了成浆体系中污泥和煤对分散剂的竞争吸附,是影响污泥水煤浆成浆特性的重要因素,可以通过增加分散剂的用量来改善污泥水煤浆的成浆性。

Adsorption of dispersant onto sludge and its effect on preparation of coal sludge slurry

The municipal sludge (sludge) and coal samples were collected and prepared in this study.The constituent characteristics and microstructures of sludge were tested by Fourier transform infrared spectroscopy and scanning electron microscope.The isothermal adsorption of the dispersant (sulfonated acetone-formaldehyde dispersant (SAF)) onto sludge and coal surface were studied，respectively.Furthermore，the adsorption kinetics were also researched.Additionally，the coal sludge slurries (CSSs) were prepared to study the influences of sludge additive amount and dispersant quantity.The results showed that there were strongly polar hydroxyl functional groups in sludge，associating by intermolecular hydrogen bonds.A plenty of flocs composed by filamentous microorganism were discovered in sludge.The extent of saturated adsorption of SAF by sludge particles was 7.98 mg/g，greater than the value of 4.91 mg/g for the saturated adsorption of SAF by coal particles.The adsorption kinetics of sludge adsorbing SAF closely fitted the first-order kinetics model.However，the pattern of coal adsorbing SAF trended toward the second-order kinetics model.The research also indicated that the determinant factor of sludge adsorbing SAF was the diffusion of SAF in a porous structure built by sludge particles.With the increases of sludge additive amount，the fixed-viscosity concentrations and the slurryabilities of CSSs decreased.The constituents and microstructures of sludge were the main reasons for the competition between sludge and coal to adsorb SAF，and it also deeply influenced the slurryability of CSSs which could be improved by adding dispersant amount.