ABSTRACTOrdered mesoporous silica (OMS) adsorbents were prepared by grafting amino, carboxylic and thiol-containing functional groups onto MCM-41 for the selective removal of dye and metal pollutants from wastewater. The amino containing OMS-NH2 adsorbent has a large adsorption capacity and a strong affinity for the Acid blue 25. It can selectively remove Acid blue 25 from a mixture of dyes (i.e., Acid blue 25 and Methylene blue). The OMS-COOH is a good adsorbent for Methylene blue displaying excellent adsorption capacity and selectivity for the dye. The chemically modified OMS adsorbents were also tested for the selective removal and recovery of metals (i.e., lead and copper). The OMS-SH adsorbent can selectively remove lead from solutions containing Pb2+ and Cu2+ ions, whereas the OMS-NH2 selectively adsorbed a large quantity of copper. The selectivity of the adsorbents for lead and copper is strongly influenced by pH. Indeed, by simply adjusting the pH, OMS-NH2 can adsorb mainly lead or copper from a mixture containing both metals.
Grafting and stabilization of ordered mesoporous silica COK-12 with graphene oxide for enhanced removal of methylene blue
