Fouling mechanisms underlying the filtration behaviors of alginate solution caused by calcium addition were investigated by Terahertz time-domain spectroscopy (THz-TDS) and density functional theory (DFT) techniques. Filtration tests showed that specific filtration resistance (SFR) of alginate solution (0.75 g·L^-1) monotonously increased with calcium addition at a relatively low range of calcium concentration (0-1.0 mM), and SFR (2.61 × 10¹⁵ m·kg^-1) of alginate solution with 1.0 mM calcium addition was extremely high as compared with sludge suspension. Characterizations by X-ray photoelectric spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and Thermogravimetric analysis (TGA) showed that the composition of functional groups, elements and thermal stability of alginate was not apparently affected by calcium concentration. Howbeit, THz-TDS spectra showed that calcium addition caused structural variation of alginate polymer in solution. DTF calculation results showed that initial binding of alginate chains induced by calcium ions preferentially occurred in intermolecular other than intramolecular, and moreover, the two alginate chains bridged by a calcium atom tend to stretch in a tetrahedron structure (cross to each other) other than parallel to each other. According to these results, “chemical potential gap” depicted by Flory-Huggins theory was suggested to be responsible for the filtration behaviors of alginate solution caused by calcium addition. This study improved the mechanistic insights into membrane fouling.

通过太赫兹时域光谱法（THz-TDS）和密度泛函理论（DFT）技术研究了因添加钙引起的藻酸盐溶液过滤行为的结垢机理。过滤试验显示的藻酸盐溶液（0.75克·L该特定过滤阻力（SFR）^-1）在相对低的范围内的钙浓度（0-1.0毫摩尔）与钙添加单调增加，和SFR（2.61×10 ¹⁵男·千克^-1与污泥悬浮液相比，添加了1.0 mM钙的藻酸盐溶液的极高。通过X射线光电光谱（XPS），傅里叶变换红外光谱（FTIR）和热重分析（TGA）进行表征，结果表明，钙的浓度显然不会影响藻酸盐的官能团，元素和热稳定性。然而，THz-TDS光谱表明，钙的添加引起溶液中藻酸盐聚合物的结构变化。DTF计算结果表明，由钙离子诱导的藻酸盐链的初始结合优先发生在分子内而不是分子内，并且，由钙原子桥接的两个藻酸盐链倾向于以平行于四面体的结构延伸（彼此交叉）。对彼此。根据这些结果，Flory-Huggins理论所描绘的“化学势差”被认为是钙添加引起藻酸盐溶液过滤行为的原因。这项研究提高了对膜污染的机理认识。