Calixresorcin[4]arene-Mediated Transport of Pb(II) Ions through Polymer Inclusion Membrane

Abstract

A facilitated transport of Pb(II) through polymer inclusion membrane (PIM) containing 1,8,15,22-tetra(1-heptyl)-calixresorcin[4]arene and its tetra- and octasubstituted derivatives containing phosphoryl, thiophosphoryl or ester groups as an ion carrier was investigated. The efficiency of Pb(II) removal from aqueous nitrate solutions was considered as a function of the composition of membrane (effect of polymer, plasticizer, and carrier), feed (effect of initial metal concentration and presence of other metal ions) and stripping phases, and temperature of the process conducting. Two kinetic models were applied for the transport description. The highest Pb(II) ions removal efficiency was obtained for the membrane with tetrathiophosphorylated heptyl-calixresorcin[4]arene as an ion carrier. The activation energy value, found from Eyring plot to be equal 38.7 ± 1.3 kJ/mol, suggests that the transport process is controllable both by diffusion and chemical reaction. The competitive transport of Pb(II) over Zn(II), Cd(II), and Cr(III) ions across PIMs under the optimal conditions was also performed. It was found that the Cr(III) ions’ presence in the feed phase disturb effective re-extraction of Pb(II) ions from membrane to stripping phase. Better stability of PIM-type than SLM-type membrane was found.

Separation of Mercury(II) from Industrial Wastewater through Polymer Inclusion Membranes with Calix[4]pyrrole Derivative

“…Crystalline structures of deposits observed in the membrane after the transport process are most probably the result of Hg(II)-calix[4]pyrrole-Cl − adducts or the metal–carrier complex formation. Evident changes in the membrane appearance after transport can be the effect of metal ion accumulation in the membrane phase [ 34 ]. The SEM images indicate the formation of deposits, which clog the membrane pores.…”

Comparison of Kinetic Models Applied for Transport Description in Polymer Inclusion Membranes

“…This model was also successfully applied for the description of Pb(II) ion transport through PIMs containing calixresorcin [ 4 ] arene derivatives as carriers [ 20 ].…”

Removal of Copper (II), Zinc (II), Cobalt (II), and Nickel (II) Ions by PIMs Doped 2-Alkylimidazoles

“…The advantage of using them is that the separation process is carried out in one step (unit process) and no toxic organic solvents are used because in PIMs both the extraction and back extraction processes occur simultaneously. For example, PIMs are successfully used in the recovery and separation of such metals as Cu [8,9], Co [10,11], Ni [10,12,13], Zn [12,[14][15][16], Pb [12,17,18], Cd [10,12,19], Hg [20,21], Cr(III) [12,22], Cr(VI) [23], Mn [12], As [12,24], Fe [12], U [12,25], Ag [26,27], Au [28], as well as platinum group metals [29,30], lanthanides, and actinides [12,31,32].…”