Modification of graphene oxide and graphene oxide–TiO2 solutions by pulsed laser irradiation for dye removal from water

Highly effective and reusable sulfonated pentablock copolymer nanocomposites for water purification applications

“…MB is a cationic, thiazine dye, with an absorbance band centered at 664 nm (n-n*) (monomer) with a shoulder at 610 nm related to the MB dimer. 20,21 Fig . 6 shows the residual methylene blue concentration (calculated by the variation of the dye monomer peak) for the solutions where the s-PBC membrane and the composites were immersed for three hours in dark (blue bars) or under irradiation (cyan bars).…”

“…The MB higher aggregates can be clearly evidenced by the appearance of a peak at 577 nm. 20,21 Fig. 8a shows an example of deconvolution of the MB UV-vis absorbance spectrum in the aforementioned main components.…”

“…18,19 In particular, among carbon nanomaterials, graphene oxide (GO) has been widely investigated as high capacity and selective adsorbent for water contaminants such as organic dyes directly dispersed in water. 20,21 Indeed the release of organic colorants in the ecosystem causes several deleterious effects, such as eutrophication and perturbations in the aquatic life.…”

“…22 The possibility to increase the adsorption ability and selectivity of GO has been investigated by varying the quantity and quality of oxygen functional groups by other kinds of functionalization, 21,23 by thermal reduction or laser irradiation. 20,24 For example, sulfonated GO powder obtained by organic functionalization showed an increased ability to adsorb methylene blue (MB) with respect to GO powder. 21 The laser treated GO was also tested for antibacterial activity.…”

“…24 Furthermore, GO in combination with TiO 2 nanoparticles (NPs) was used to enhance the photocatalytic activity of the inorganic nanomaterial. 20 In the case of photocatalytic nanomaterials directly dispersed in water for purication purposes, their removal from water aer the use is required, otherwise they could cause further pollution in the environment. To get rid of this problem, the coupling of nanomaterials with membrane technology seems promising, also in view of reusing the same photocatalyst several times.…”