Development of the Technique for Recovery and Purification of Lead and Arsenic in Water on Biomass Wastes.

采用褐藻酸和果胶酸作为吸附剂回收铅和砷。这些是交联的，不溶于碱性溶液。交联的方法有两种：一种是氯甲基氧环在碱性溶液中交联，另一种是甲醛在盐酸中交联。这些树脂对铅和铁有很高的选择性。特别是在pH低于1的条件下，铁仍能被吸附，说明铁/褐藻酸和铁/果胶酸交联可以作为砷的吸附剂。另一方面，我们合成了一种引入硫氨基基的壳聚糖衍生物来回收被归类为“软酸”的砷（III）。由于巯基被归类为“软碱”，这种壳聚糖衍生物有望作为砷（III）的选择性吸附剂。然而，这种壳聚糖衍生物不能吸附砷（III），尽管它可以选择性地吸附汞（II），而不是贱金属，如铁、镍、钴和锌。因此，我们决定使用铁/褐藻酸和铁/果胶酸作为砷的吸附剂。这些金属络合树脂被发现是砷的选择性和有效的吸附剂（III， IV）。

Alginic acid and pectinic acid are used as adsorbents for recovery of lead and arsenic. These were crosslinked not to dissolve in an alkaline solution. The crosslinking was carried out by two kinds of methods : one is the crosslinking by chloromethyl oxirane in an alkaline solution, and the other is the crosslinking by formaldehyde in hydrochloric acid. These resins were found to have a high selectivity for lead and ferric iron. Especially, ferric iron was adsorbed even at below pH 1, indicating that the crosslinked Fe/alginic acid and Fe/pectinic acid can be used as the adsorbents for arsenic. On the other hand, we synthesized a chitosan derivative introducing thiocarbamoyl groups to recover arsenic(III) being classified as "soft acid". Scince the thiocarbamoyl group is classified as "soft base", this chitosan derivative was expected as a selective adsorbent for arsenic(III). However, this chitosan derivative was not able to adsorbed arsenic(III) though this can selectively adsorbed mercury(II) over base metals such as ferric iron, nickel, cobalt, and zinc. Therefore, we determined to use the Fe/alginic acid and Fe/pectinic acid as adsorbents for arsenic. These metal-complex resins found to be a selective and effective adsorbent for arsenic(III, IV).