Highly efficient capture of thorium ion by citric acid-modified chitosan gels from aqueous solution

A novel citric acid-modified chitosan gel(CSCA)was synthesized through a simple one-step process and was used to extract thorium ions from wastewater.The CSCA samples with varying chemical compositions were analyzed using SEM with mapping EDS,FT-IR,and static water contact angle measurements,and their adsorption behaviors were studied in detail.The results showed that the adsorption performance of CSCA improves with the increase of CA content in the sample.CSCA possesses an impressive capacity for thorium adsorption of 279.8 mg/g.Furthermore,it showed an ultra-fast adsorption rate and reached equilibrium within 30 min.In terms of recyclability,the CSCA still retained more than 86%of its initial adsorption capacity after 6 cycles of reuse.Density functional theory(DFT)analysis reveals that the good selectivity of this material towards thorium ions should be attributed to the high density of adsorption sites and strong interaction between carboxyl groups and thorium ions.This work could be beneficial in the design and synthesis of new polymer materials for extracting thorium.

Electrochemical deposition of uranium oxide with an electrocatalytically active electrode using double potential step technique

The development of effective uranium-removal techniques is of great significance to the environment and human health.In this work,a double potential step technique(DPST)was applied to remove U(VI)from uranium-containing wastewater using a carbon felt electrode modified by graphene oxide/phytic acid composite(GO-PA@CF).The application of DPST can inhibit water splitting and prevent GO-PA from adsorbing other interfering ions in wastewater.The GO-PA composite can effectively accelerate the electrochemical reduction rate of U(VI),which significantly improved the electrochemical deposition rate of uranium oxide.As a result,the maximum removal efficiency and maximum removal capacity of GOPA@CF electrode reached 98.7%and 1149.3 mg/g,respectively.The removal efficiency remained 97.2%after five cycles of reuse.Moreover,the removal efficiency of GO-PA@CF electrode can reach more than 70%in simulated wastewater.