Influence of Micro- and Mesoporosity of Resorcinol-Formaldehyde Xerogels on Adsorption

Effects of micro- and mesoporosity of resorcinol-formaldehyde xerogels (RFXs) on the adsorptive properties of crystal violet (CV) were investigated. RFXs were synthesized at different pH values, and corresponding pore structures were examined. RFXs were characterized by thermal gravimetric analysis, scanning electron microscopy, and wide-angle X-ray diffraction. RFXs performed efficiently for removing CV from water, and were easily regenerated. RFXs synthesized at pHs of 5.5 and 7.0 exhibited relatively high surface areas and micropore volumes, whereas those synthesized at pH 2.5 exhibited relatively low surface areas and micropore volumes. Overall, surface areas of RFXs increased when increasing the pH of RF solutions, and this corresponded to higher CV adsorption capacities. This work is the first of its kind for studying the use of RFXs in the removal of such dyes from wastewater, and is anticipated to have a major impact on the treatment of wastewater generated by textiles industries.