The influence of particle size of TiO2 on the photocatalytic degradation of methylene blue (MB) in a suspended aqueous solution has been studied. The results suggested that the adsorption rate and adsorbability of MB on suspended TiO2 particles increased as the particle sizes of TiO2 decreased. Photocatalytic activity of TiO2 also increased as the particle size of TiO2 became smaller, especially when the particle size is less than 30 nm. The half-life (t 0.5) of the photocatalytic degradation of MB also decreased as the particle sizes of TiO2 decreased. The first-order reaction rate constant for photodegradation of MB increased as the particle size of TiO2 decreased. The initial degradation rate of MB in a suspended model was higher than that of a fixed-bed model. This will overcome the difficulty of preparation of ultrafine TiO2 catalyst particles. Once the problem of separation of fine TiO2 particles is solved, a TiO2 suspended photoreactor could be provided on an industrial basis.

Recent innovations highlight the great potential of two-dimensional graphene oxide (GO) films in water-related applications.However,undesirable water-induced effects,such as the redispersion and peeling of stacked GO laminates, greatly limit their performance and impact their practical application. It remains ag reat challenge to stabilizeG O membranes in water.Amolecular bridge strategy is reported in which an interlaminar short-chain molecular bridge generates ar obust GO laminate that resists the tendency to swell. Furthermore,a ni nterfacial long-chain molecular bridge adheres the GO laminate to ap orous substrate to increase the mechanical strength of the membrane.B yr ationally creating and tuning the molecular bridges,t he stabilized GO membranes can exhibit outstanding durability in harsh operating conditions,s uch as cross-flow, high-pressure,a nd longterm filtration. This general and scalable stabilizing approach for GO membranes provides new opportunities for reliable two-dimensional laminar films used in aqueous environments.

In this study, we report a promising rGO-CNT hybrid nanofiltration (NF) membrane that was fabricated by loading reduced graphene oxide that was intercalated with carbon nanotubes (rGO-CNTs) onto an anodic aluminum oxide (AAO) microfiltration membrane via a facile vacuum-assisted filtration process. To create this NF membrane, the CNTs were first dispersed using block copolymers (BCPs); the effects of the types and contents of BCPs used on the dispersion of CNTs have been investigated. The as-prepared rGO-CNT hybrid NF membranes were then used for drinking water purification to retain the nanoparticles, dyes, proteins, organophosphates, sugars, and particularly humic acid. Experimentally, it is shown that the rGO-CNT hybrid NF membranes have high retention efficiency, good permeability and good anti-fouling properties. The retention was above 97.3% even for methyl orange (327 Da); for other objects, the retention was above 99%. The membrane's permeability was found to be as high as 20-30 L m(-2) h(-1) bar(-1). Based on these results, we can conclude that (i) the use of BCPs as a surfactant can enhance steric repulsion and thus disperse CNTs effectively; (ii) placing well-dispersed 1D CNTs within 2D graphene sheets allows an uniform network to form, which can provide many mass transfer channels through the continuous 3D nanostructure, resulting in the high permeability and separation performance of the rGO-CNT hybrid NF membranes.

Developing advanced membranes with high separation performance and robust mechanical properties is critical to the current water crisis. Herein, a general and scalable fabrication of nanoparticles (NPs)@reduced graphene oxide (rGO) membranes with significantly expanded nanochannels meanwhile ordered laminar structures using in situ synthesized NPs@rGO nanosheets as building blocks is reported. Size‐ and density‐controllable NPs were uniformly grown on the regularly stacked rGO nanosheets through coordination, followed by filtration‐deposition on inner surface of porous ceramic tubes. The NPs bonded rGO building blocks enabled the as‐prepared membranes 1–2 orders of magnitudes higher water permeance than the counterparts while keeping excellent rejections for various organic matters and ions. Moreover, the industrially preferred GO‐based tubular membrane exhibited an extraordinary structural stability under high‐pressure and cross‐flow process of water purification, which is considered as a notable step toward realizing scalable GO‐based membranes. © 2017 American Institute of Chemical Engineers AIChE J, 2017