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

采用海藻酸和果胶酸作为吸附剂回收铅和砷。这些都是交联的，不会在碱性溶液中溶解。交联法有两种：一种是氯甲基环氧乙烷在碱性溶液中的交联，另一种是甲醛在盐酸中的交联。研究发现，这些树脂对铅和铁有很高的选择性。尤其是Fe/褐藻酸和Fe/果胶酸交联铁在pH 1以下仍能吸附砷，表明Fe/褐藻酸和Fe/果胶酸交联铁可以作为砷的吸附剂。另一方面，我们合成了一种引入硫代氨基甲酰基的壳聚糖衍生物来回收属于软酸的砷(III)。由于硫代氨基甲酰基被归类为“软碱”，这种壳聚糖衍生物有望成为砷(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贱金属如铁、镍、钴和锌上的汞(II)。因此，我们决定使用铁/海藻酸和铁/果胶酸作为砷的吸附剂。这些金属络合树脂是一种选择性和有效的砷(III，IV)的吸附剂。

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).