Uranium sorption on activated carbon prepared from rice straw: Competition with humic acids

What is it about?

Adsorptive competition between uranium (VI) and humic acids (HAs) was investigated using Rice Straw activated carbon U(VI) showed a decreased adsorbability when it coexisted with HA from the start (Simultaneous) compared with the case when U(VI) was added after equilibrium adsorption of HA on activated carbon (sequential). The interactions between uranium ions and HA caused the formation of U–HA complexes that changed the surface interactions of both uranium ions and HA with carbon surface. Adsorption isotherms for multi-component systems were studied; the experimental results showed that the equilibrium data fit well Langmuir equation. Multi-component adsorption can be significantly affected by adsorbate interactions and the understanding of these interactions needs great attention in adsorption study in the future. It could be concluded that, humic acid was a strong inhibitor of uranium binding, thus limits the wastewater treatment by this sorbent. Therefore, humic substance should be removed from waste solution before treatment to remove uranium.

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Why is it important?

Sorptive competition of uranium(VI) with humic acid, in multi-component system, was investigated using activated carbon prepared from rice straw by steam pyrolysis method, then modified by KOH to prevent environmental pollution. The prepared material is low cost material and characterized by high adsorption capacity for U(IV) ions compared to other low-cost adsorbents as compared to the state of the art in the literature. The studies illustrated that our prepared material can be considered as a promising material for removing of U(IV) ions form waste water.