Selective capture of hexavalent chromium from an anion-exchange column of metal organic resin-alginic acid composite

Sofia Rapti; Anastasia Pournara; Debajit Sarma; Ioannis T Papadas; Gerasimos S Armatas; Athanassios C Tsipis; Theodore Lazarides; Mercouri G Kanatzidis; Manolis J Manos

doi:10.1039/c5sc03732h

Selective capture of hexavalent chromium from an anion-exchange column of metal organic resin-alginic acid composite

Chem Sci. 2016 Mar 1;7(3):2427-2436. doi: 10.1039/c5sc03732h. Epub 2015 Nov 18.

Authors

Sofia Rapti¹, Anastasia Pournara¹, Debajit Sarma², Ioannis T Papadas³, Gerasimos S Armatas³, Athanassios C Tsipis¹, Theodore Lazarides⁴, Mercouri G Kanatzidis², Manolis J Manos¹

Affiliations

¹ Department of Chemistry , University of Ioannina , 45110 Ioannina , Greece . Email: emanos@cc.uoi.gr.
² Department of Chemistry , Northwestern University , Evanston , IL 60208 , USA.
³ Department of Materials Science and Technology , University of Crete , 71003 Heraklion , Greece.
⁴ Department of Chemistry , Aristotle University of Thessaloniki , 54124 Thessaloniki , Greece.

Abstract

We report an anion exchange composite material based on a protonated amine-functionalized metal-organic framework, denoted Metal Organic Resin-1 (MOR-1), and alginic acid (HA). MOR-1-HA material shows an exceptional capability to rapidly and selectively sorb Cr(vi) under a variety of conditions and in the presence of several competitive ions. The selectivity of MOR-1-HA for Cr(vi) is shown to be the result of strong O₃Cr^VI···NH₂ interactions. The composite sorbent can be successfully utilized in an ion-exchange column, in contrast to pristine MOR-1 which forms fine suspensions in water passing through the column. Remarkably, an ion exchange column with only 1% wt MOR-1-HA and 99% wt sand (an inert and inexpensive material) is capable of reducing moderate and trace Cr(vi) concentrations to well below the acceptable safety limits for water. The relatively low cost of MOR-1-HA/sand column and its high regeneration capability and reusability make it particularly attractive for application in the remediation of Cr(vi)-bearing industrial waste.