MICROENCAPSULATION OF TRIOCTYLAMINE IN POLYMERIC MATRICES FOR REMOVING Zn(II) AND Cu(II) FROM CHLORIDE AQUEOUS SOLUTIONS

Abstract

The microencapsulation of the non-specific basic extractant trioctylamine in polymeric matrices synthesized from styrene and divinylbenzene was studied. The microcapsules were prepared by adding the amine compound during in situ free radical suspension polymerization using benzoyl peroxide as the initiator and using variable proportions of both monomers. SEM analysis shows that the microcapsules have a spherical shape presenting an average surface area of 480 m 2 g -1 and a pore size around 0.5 to 1.8 nm. Synthesis of the microspheres was affected by the amount of extractant used and by the proportion of both monomers during their preparation.The obtained microcapsules were used for the sorptive removal of Zn(II) and Cu(II) ions from chloride aqueous solutions, reaching extraction extents near 90% under the best conditions, following an anion-exchange mechanism between the metallic ions and the extractant immobilized onto the microcapsules. Zn(II) and Cu(II) sorption kinetics experiments were performed and efficient uptake of both metals within a few minutes was measured. The experimental results were explained using a pseudo-second-order rate kinetics model, which fit the results of chemisorption of both metals onto the microcapsules well.

Adsorption of Pollutant Ions From Residual Aqueous Solutions Onto Nano-Structured Calcium Silicate

“…Cairns et al have proposed that the calcium silicate would contain 1.5 % of hydroxil groups meaning that approximately 8% of silicon atoms present are silanol groups allowing metallic ions like Cu(II) and Zn(II) to form the respective hydroxides on the surface of the silicates, which would act as nucleation site 33) . Measurements of porosimetry analysis using the N 2 sorptometer, indicated for the obtained nano-structured compounds an average surface area of 333.0 m 2 /g, value much higher than the surface area shown by other sorbents prepared in our laboratory 22,23,34) . The mean pore diameter varied between 15.8-23.6 nm and the pore volume between 0.7853-1.5441 cm 3 /g for calcium silicates synthesized at 6000 min -1 and 2000 min -1 , respectively.…”

Zn(II) Sorption From Aqueous Solutions Using Polymeric MicrocapsulesContaining 2-Ethylhexylphosphonic Acid Mono-2-Ethylhexyl Ester

“…In another communication, we reported the microencapsulation of trioctylamine in a polymeric matrix synthesised from styrene and divinylbenzene for the purpose of taking up Zn(II) and Cu(II) from chloride-containing aqueous solutions [21]. We also reported the quantitative uptake of Cr(VI) ions from aqueous solutions using microcapsules containing a long-chain quaternary ammonium salt-type ion-exchanger as the extractant [22].…”