Evaluation of reusable organic-inorganic nafion/layered double hydroxide nanohybrids for highly efficient uptake of mercury ions from aqueous solution

摘要

In this study, we introduced a new strategy for efficient uptake of toxic mercury ions (Hg2+) from aqueous solutions using hybrid organic-inorganic nafion intercalated layered double hydroxide (Naf-LDH) with the molecular formula [Zn0.77Cr0.23(OH)(2)] (NO3)(0.02) (nafion)(0.21)(nH(2)O). The resulting Naf-LDH exhibited both high uptake affinity (K-d = 6.0 x 10(7) mL g(-1)) and remarkable uptake capacity (302.14 mg g(-1)) for Hg2+ uptake from water, clearly demonstrating that Naf-LDH could act as a useful and effective adsorbent for removing Hg2+ from contaminated water. The uptake kinetic curves for Hg2+ fitted well with the pseudo-second order- model, suggesting a chemical uptake mechanism via SO3-center dot center dot center dot Hg2+ and C-F center dot center dot center dot Hg2+ bonding. For the highly toxic Hg2+ (at similar to 30 ppm concentration), the uptake was exceptionally rapid, showing a 77.6% uptake within 25 min, 92.7% uptake within 40 min, and 98.5% uptake within 1 h. The sorption isotherm for Hg2+ agrees with the Langmuir model, suggesting a monolayer uptake. Finally, application of Naf-LDH for the extraction and pre-concentration of trace amounts of Hg2+ provided satisfactory results in terms of sensitivity, linearity, and reproducibility, representing its high capability for use in the analysis of trace amounts of Hg2+.