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

We report an anion exchange composite material based on a protonated amine-functionalized metal-organic framework, denoted Metal Organic Resin-1 (), and alginic acid (). 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 for Cr(vi) is shown to be the result of strong OCr···NH interactions. The composite sorbent can be successfully utilized in an ion-exchange column, in contrast to pristine which forms fine suspensions in water passing through the column. Remarkably, an ion exchange column with only 1% wt 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 /sand column and its high regeneration capability and reusability make it particularly attractive for application in the remediation of Cr(vi)-bearing industrial waste.