Irreversible exchange of potassium with thallium in coordination polymer nanostructures upon solid-state Mechanochemical process

Highly-efficient and easy separation of hexahedral sodium dodecyl sulfonate/δ-FeOOH colloidal particles for enhanced removal of aqueous thallium and uranium ions: Synergistic effect and mechanism study

Thallium (Tl) and uranium (U) contaminants pose serious threats to the ecological environment and human health. In this research, a cost-effective feroxyhite (δ-FeOOH) dispersed with sodium dodecyl sulfonate (SDS) was prepared and a series of experiments were optimized to explore the removal mechanism of Tl⁺ and UO₂²⁺ from the effluent. The SDS/δ-FeOOH exhibited highly dispersed colloidal particles and showed significantly enhanced adsorption performance on the removal of Tl and U in the presence of H₂O₂ and pH of 7.0. Equilibrium uptakes of 99.5% and 99.7% were rapidly achieved for Tl⁺ and UO₂²⁺ within 10 min, respectively. The Freundlich isotherm model fitted well with the adsorption data of Tl and U. The maximum isotherm sorption capacity of SDS/δ-FeOOH for Tl⁺ and UO₂²⁺ was 182.9 and 359.6 mg/g, respectively. The sorption of Tl followed the pseudo-second-order kinetic model, whereas the sorption of U followed the pseudo-first-order kinetic model. The uptake of Tl and U by SDS/δ-FeOOH was notably inhibited at Na⁺, K⁺ concentrations over 5.0 mM, and a high content of dissolved organic matter (over 0.5 mg/L). The mechanistic study revealed that ion exchange, precipitation, and surface complexation were main mechanisms for the removal of Tl and U. The findings of this study indicate that stabilizer dispersion may serve as an effective strategy to facilitate the treatment of wastewater containing Tl and U by using δ-FeOOH.

Extensive removal of thallium by graphene oxide functionalized with aza-crown ether

Thallium (Tl) is a highly toxic heavy metal, and its pollution and remediation in aquatic environments has attracted considerable attention. To reduce or remove Tl pollution in the environment, various strategies have been applied. Graphene oxide (GO) has abundant oxygen-containing functional groups, indicating its high application potential for pollution remediation via methods involving binding to metal ions or positively charged organic molecules or electrostatic interaction and coordination. However, the adsorption of Tl to GO occurs via physical adsorption, for which the adsorption efficiency is low. Therefore, herein, we report a new method to effectively remove Tl pollution in water. We combined GO with aza-crown ether, which enhanced the electronegativity and ability to bind metal ions. The functionalized graphene oxide (FGO) demonstrated high efficiency through a wide pH gradient of 5-10, with a dominant Tl(i) adsorption capacity (112.21 mg g-1) based on the Langmuir model (pH 9.0, adsorbent concentration of 0.8 g L-1). The adsorption of Tl(i) during removal fit a pseudo-second-order kinetic model well. The mechanisms of Tl removal involve physical and chemical adsorption. In summary, our study provides a new method for the detection and treatment of Tl-containing wastewater by using FGO.