Sorbents based on crown ethers: preparation and application for the sorption of strontium

High strontium adsorption performance of layered zirconium phosphate intercalated with a crown ether

“…As a result, the ZrP/18C6 composite provides more room between the layers for adsorbate. As the 18-crown-ether-6 has been known as a highly selective adsorbent for Sr 2+ , 34,40 the ZrP/ 18C6 composite could be prospective for an Sr 2+ adsorbent with high adsorption capacity.…”

“…Moreover, 18-crown-ether-6 is known as an adsorbent with a special affinity for Sr 2+ . 34,37 Therefore, the ZrP/18C6 composite is expected to be a strong adsorbent for the removal of Sr isotopes from nuclear wastes.…”

“…This is attributed to the special affinity of the 18-crown-ether-6 to Sr 2+ . 19,34 3.3.7 Desorption studies. How strongly the ions adsorbed on a material is important in evaluating its stability and applicability.…”

“…32,33 As the diameter of Sr 2+ (0.23 nm) is close to the size of the cavity in 18-crown-ether-6 (18C6) and its derivatives, which is in the range of 0.26-0.32 nm, Sr 2+ can enter the cavity to interact with O atoms in 18C6 to form stable complexes. 19,34 As a result, the 18C6 has become the most studied extractant in the removal of Sr-90 from highly radioactive waste streams. 7,[35][36][37][38] However, as an organic material, posttreatment of the crown ether aer nuclear waste adsorption poses a challenge.…”

Highly efficient removal of Sr2+ from aqueous solutions using a polyacrylic acid/crown-ether/graphene oxide hydrogel composite

“…28,29 It was found that 18-crown-ether-6 and its derivatives are the most effective adsorbents in removing Sr 2+ as their pore size is in the range 0.26–0.32 nm that is suited to ingress of strontium ion. 27,30 Therefore, dibenzo-18-crown-ether-6 (DB18C6) has been used as a filler in the polymer composite to enhance its selectivity for Sr 2+ . 31 Meanwhile graphite oxide (GO) has been reported as an efficient adsorbent due to its high content of oxygen-containing functional groups, including carboxyl, hydroxyl and epoxy groups.…”