Diethanolamine functionalized rice husk for highly efficient recovery of gallium(III) from solution and a mechanism study.

Diethanolamine functionalized cellulose based on rice husk (DEA-EPI-RH) was prepared to separate gallium ions from As(III) or/and Ge(IV) mixtures. The contents of hydroxyl functional group in the DEA-EPI-RH were up to 1.48 mmol g, and the maximum adsorption capacity for Ga(III) achieved to 130.44 mg g. The adsorption mechanism depended on the ion exchange of Ga(OH), Ga(OH), or Ga with trihydroxy hydrogen on the surface of the DEA-EPI-RH. The DEA-EPI-RH showed superior selectivity with high adsorption capacity towards gallium as compared to As(III) or/and Ge(IV) with several times higher than concentration of Ga(III). Furthermore, the excellent reusability of the DEA-EPI-RH were confirmed by the desorption and regeneration experiments. The studied adsorbent was deemed to be promising, environment-friendly and low-cost materials to recovery of gallium from aqueous solution containing As(III) or/and Ge(IV).