Transport of mercury(II) ion through a supported liquid membrane containing a triisobutylphosphine sulfide (Cyanex 471X) as a mobile carrier

Abstract

Carrier-facilitated transport of mercury(II) against its concentration gradient from aqueous 0.1 mol dm À3 hydrochloric acid solution across a¯at-sheet supported liquid membrane (SLM) containing triisobutylphosphine sul®de (Cyanex 471X) as the mobile carrier in kerosene as diluent has been investigated. Dilute sodium thiocyanate solution (0.11 mol dm À3 ) was the most ef®cient stripping agent among several aqueous reagents tested. Various parameters such as stirring rate, concentration of HCl in the feed solution, concentration of NaSCN in the strippant, concentration of Cyanex 471X in the membrane, and contact time were investigated. Under optimum conditions the transport of Hg(II) across the liquid membrane is about 100% after 6 h. The carrier, Cyanex 471X, selectively and ef®-ciently transported Hg(II) ions in the presence of other associated metal ions. The method has been demonstrated to recover selectively mercury from waste samples and mercurochrome solution.

Mercury(II) removal using polymer inclusion membranes containing Cyanex 471X

“…27 Additionally, a practically constant retention of mercury within the PIM is observed. It is also interesting to point out that the permeability values observed compare favorably to those reported for similar SLM systems employing Cyanex 471X as carrier (0.05-0.29 cm min −1 ), 23 and are higher than those reported for SLMs using benzoylthiourea derivatives (0.041-0.096 cm min −1 ) 19 and calix [4]arene nitrile derivatives (0.8 × 10 −4 to 8 × 10 −4 cm min −1 ) 17 as carriers. Transport rates are also higher than those reported for activated composite membranes (ACM) using DTPA as carrier (≈54% in strip after 180 min).…”

“…Changing the nature of the strip phase using different complexing agents does not show any improvement in Hg(II) transport with respect to the 0.2 mol dm −3 NaCl phase (Table 1). In this form one advantage of the system is that it employs a nonhazardous easy-to-dispose strip solution in comparison with other membrane systems that employ thiocyanate, 15,23 thiourea, 19,20 thiourea in sulfuric acid, 37 thiosulfate, 20 iodide in sulfuric acid, 21 or EDTA. 13,16 In addition, although mercury retention is observed in the membrane with all the tested strip solutions, which is associated with a higher rate of extraction than back-extraction probably due to kinetics factors, it diminished when using the optimized strip solution.…”

“…Some examples include derivatives of calixarenes and crown ethers in bulk and supported liquid membranes (BLMs and SLMs), 13 -17 amines in emulsion liquid membranes (ELM), 18 benzoylthiourea derivatives in SLMs and hollow-fibre supported liquid membranes (HFSLMs), 19 bis(di(2-ethylhexyloxy)thiophosphoryl) disulfide in SLMs, 20 methyl red in BLMs, 21 di(2-ethylhexyl)dithiophosphoric www.soci.org FE Mercader-Trejo, E Rodríguez de San Miguel, J de Gyves acid (DTPA) in gelled-supported liquid membrane (G-SLM), 22 and tri-isobutylphosphine sulphide (Cyanex 471X) in SLMs. 23 From a practical point of view the application of BLMs is restricted to fundamental studies, while for SLMs their stability has been a matter of concern during recent decades. 24 -26 In this context polymer inclusion membranes (PIMs), a type of supported membrane in which a carrier is entrapped in a polymeric matrix in the presence of a plasticizer, have gained attention recently.…”

Kinetic Study of Mercury(II) Transport through a Bulk Liquid Membrane Using Cyanex 301 as Carrier

“…[17][18][19][20][21] A limited number of reports is available on transport studies of Hg 2+ ions through the membrane. [22][23][24][25][26][27][28] The development of novel membrane carrier for selective removal of mercury from an aqueous mixture is still a challenge. 28 Moreover, due to wide industrial application of mercury [29][30][31][32] the development of new transport systems for selective removal of Hg 2+ ion is of interest.…”

Selective Transport of Bismuth Ions through Supported Liquid Membrane

“…The SLM has been employed for the separation of Pt ions with trioctylamine [22], LIX 26 [23] and bis(2-ethylhexyl)-phosphoric acid [24] as carriers. The transport of U ions through SLM can be facilitated by using LIX63 [25], Kelex100 [26], bis(2-ethylhexyl) phosphate [27], bis(2,4,4-trimethylpentyl)phosphinic acid [28], Cyanex 272 [28], and dicyclohexan-18-crown-6 [29].…”