Edta型キレート繊緎による銅，ニッケル及びコバルトの固相抽出

摘要

エチレンジアミン四酢酸（EDTA）型キレート繊維（以下EDTA-Cellと略）を合成し，水溶液中のCu，rnNi，Coの吸着挙動をバッチ法及びカラム法で調べた．本吸着材の構造は，EDTAの4つのカルボキシル基rnのうち1つが，セルロース繊維に直接結合し，残りの3つが金属とキレートを形成していると考えられる．rnpH＞2.9で，3金属とも定量的に吸着され，この吸着材は他の類似の吸着材と比較してより強く金属を吸着rnすると考えている．流量の影響を調べたところ少なくとも26mL/minまでは影響がなかった．吸着した金rn属は1M硝酸10mLで脱着することができた．濃縮率について検討したところ3金属とも96%以上の回収rn率で200倍濃縮が可能であると言うことが分かった．吸着等温線を作成し，ラングミュア式から吸着容量rnはCuで0.25mmol/g，Niでは0.29mmol/g，Coでは0.30mmol/gであることが明らかとなった．%EDTA-type chelating cellulose (abbr. : EDTA-Cell) has been synthesized and studied for its adsorption properties with respect to Cu, Ni and Co from aqueous solutions in both batch and column experiments. This adsorbent has a structure such that one of the carboxyl groups of EDTA directly binds with cellulose fiber, and it is considered that the remaining three carboxyl groups form a chelate with metal ions. This structure is suggested to be favorable to adsorb metals more strongly as compared to other analogous adsorbents. The above-mentioned three metal ions were quantitatively retained on the adsorbent at pH > 2.9. No effect of the flow rate on the adsorption performance was observed for at least by a rate of 26 mL/min. The retained metal ions could easily be desorbed with 10 mL of 1 M nitric acid. The recovery values were greater than 96% and the preconcantration factor was 200 for all analyte ions. The adsorption isotherm of an element when it adsorbs by a monolayer from a diluted aqueous solution can be understood by the Langmuir method. The maximum sorption capacities were found to be 0.25 mmol/g for Cu, 0.30 mmol/g for Co and 0.29 mmol/g for Ni, respectively.