Cleanability of titanium and stainless steel particles in relation to surface charge aspects
Cleanability of titanium and stainless steel particles in relation to surface charge aspects
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DOI：
10.4265/bio.13.9
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发表时间：
2008-03-01
影响因子：
1.2
通讯作者：
Fukuzaki, Satoshi
中科院分区：
文献类型：
--
作者：
Takahashi, Kazuhiro;Fukuzaki, Satoshi
根据钛和 316L 不锈钢颗粒的表观表面电荷密度 (sigma(app)) 研究其清洁性。牛血清白蛋白（BSA）用作模型污垢剂。钛和不锈钢颗粒的 sigma(app) 曲线显示表观零电荷点 (pzc(app)) 分别为 4.6 和 8.5。与不锈钢的 sigma(app) 曲线相比，钛的 sigma(app) 值具有正值小、负值大的特点。 BSA 的吸附等温线以及 BSA 在钛和不锈钢上的饱和吸附量在很大程度上取决于 BSA 的固有性质。在用 0.05M NaOH 溶液进料的活塞流柱中进行连续清洗时，发现 BSA 从钛上解吸的速度比从不锈钢上更快，并且在 120 分钟清洗后在钛上观察到残留的 BSA 量较少。动力学分析表明，钛的两个一级解吸速率常数（反映清洗初期和后期BSA解吸速率）分别是不锈钢的1.7倍和1.3倍。可以认为，钛较好的可清洁性可能是由于BSA在带轻微负电荷的钛表面上的结合强度较小以及在碱性清洁条件下其负sigma(app)值较大。
The cleanability of titanium and 316L stainless steel particles was studied in terms of their apparent surface charge density (sigma(app)). Bovine serum albumin (BSA) was used as the model fouling agent. Curves for the sigma(app) of titanium and stainless steel particles showed the apparent points of zero charge (pzc(app)) of 4.6 and 8.5, respectively. Compared with the curve for the sigma(app) of stainless steel, that of titanium was characterized by small positive and large negative sigma(app) values. The isotherms for BSA adsorption and the saturation amount of BSA adsorbed on titanium and stainless steel depended largely on the intrinsic properties of BSA. In continuous cleaning in a plug-flow column fed by a 0.05M NaOH solution, BSA was found to be faster desorbed from titanium than from stainless steel, and smaller amounts of BSA remaining after 120-min cleaning were observed on titanium. Kinetic analysis showed that the two first-order desorption rate constants, reflecting the rate of BSA desorption in the initial and later stages of cleaning, for titanium were respectively 1.7-fold and 1.3-fold higher than those values for stainless steel. It could be suggested that the better cleanability of titanium was probably due to the small binding strength of BSA on slightly negatively-charged titanium surfaces and due to their large negative sigma(app) values under alkaline cleaning conditions.