Study on removal of salt from iron artifacts that came out of underground at histrical places by using alkaline solutions containing fluorinated oligomers

以人工压制的生锈铁片为材料，研究了在碱性溶液中加入含氟低聚物对脱盐的影响。结果发现，在KOH溶液中加入氟化低聚物，与实际应用的倍半碳酸氢盐溶液相比，脱盐效果更好。此外，我们发现甜菜碱型低聚物适合于脱盐。为了找出哪种类型的甜菜碱适合这一目的，我们实验研究了氟化低聚物对脱盐的影响。含有亲水基团和长链氟化基团的甜菜碱型低聚物SK-6的KOH水溶液的盐去除率是倍半碳酸氢盐溶液的3.7倍。另一方面，发现具有疏水性基团的寡聚物SK-15可以防止铁盘生锈。接下来，我们研究了低聚物对含有甜菜碱型氟化低聚物的碱性溶液处理过的铁制品的长期保存的影响。我们使用的测试件已经在我们的房间里保存了14到18个月。然后，将试样悬浮在底部有水的100ml瓶子中，瓶子保持在空气中，以防止与水接触。之后，测量体重的变化。从结果来看，我们发现与不含低聚物的KOH溶液相比，倍半碳酸氢盐的试样干重增量为5.9倍，SK-15为2.5倍，SK-2为2.2倍，SK-6为1.3倍。重锈引起的重量增量随着除盐量的增加而减小。因此，我们发现，在含氟低聚物的碱性溶液中去除盐后，短时间内的再锈蚀受到甜菜碱型低聚物中的疏水性基团的抑制，而长期保存的再锈蚀将取决于铁制品中残留的盐的数量。因此，SK-6被认为是足够的添加剂，以去除碱性溶液中的盐，因为在我们的实验中，SK-6的添加最改善了盐的去除。少

Using rusted iron disks pressed artificially, effects of fluorinated oligomers added to alkaline solutions on removal of salt were investigated. As a result, addition of fluorinated oligomer to KOH solution was found to bring improvement on removal of salt compared with the sesquicarbonate solution that have been applied in practice. Also, we found that betaine-type oligomers are adapted for removal of salt. To find which type of betaine is adequate for this purpose, we investigated the effects of fluorinated oligomers on removal of salt experimetally.Amount of salt removed for KOH aqueous solution containing SK-6, betaine-type oligomer with hydrophilic group and long chains of fluorinated group, increased 3.7 times as much as that for the sesquicarbonate solution. On the other hand, an oligomer, SK-15, with hydrophobic group was found to prevent the iron disk from rusting.Next, we investigated the effects of the oligomers on long-term conservation of iron artifacts treated by alkaline … More solutions containing betaine-type fluorinated oligomers. We used test pieces which had been kept in our romm for 14 to 18 months. Then, the test piece was suspended in a 100 mL bottle with water on the bottom, which was kept in air to prevent from contacting with water. After that, change in weight was measured. From the results, we found that increments of dry weight of the test pieces were 5.9 times for sesquicarbonate, 2.5 times for SK-15, 2.2 times for SK-2, 1.3 times for SK-6 compared to that for KOH solution without oligomers. The increment in weight due to re-rusting decreased with increasing the amount of salt removed.Consequently, we found that re-rusting in a short period after removal treatment of salt by alkaline solution containing fluorinated oligomer was suppressed by the hydrophobic group in the betaine-type oligomer, and re-rusting in long-term conservation will depend on the amount of salt remainted in the iron artifacts. Hence, the SK-6 is considered to be adequate as an additive to alkaline solution for removal of salt, because in our experiment addition of the SK-6 most improved the removal of salt. Less