High‐performance composite photocatalytic membrane based on titanium dioxide nanowire/graphene oxide for water treatment

Abstract

In this study, a novel dopamine-modified TiO 2 nanowire (NW)-intercalated graphene-oxide-based photocatalytic (NWC) membrane was prepared by vacuum-assisted filtration using a commercial cellulose acetate membrane as a support layer. At the same time, compared with the synthesized reduced graphene-oxide/polydopamine/TiO 2 nanoparticle composite (NPC) membrane, it was found that the NWC membrane has high water flux (273 L m −2 h −1 ) and removal rate (above 98%) on the dye-oil emulsion. After 5 cycles of experiments, the NWC membrane maintained a relatively stable permeation flux and removal rate, which was significantly better than the NPC membrane. The results showed that the NWC membrane had a more uniform distribution of TiO 2 NW, and had better antifouling ability, recyclability, and photocatalytic performance than NPC membrane. In summary, the NWC photocatalytic membrane of this study shows excellent water purification potential and provides a new path for photocatalytic water treatment.

Surface Functionalization of Metal Oxide Semiconductors with Catechol Ligands for Enhancing Their Photoactivity

“…[ 19,33,38,63,64 ] Catecholates, such as dopamine, have also been reported to form polymers. [ 46,65 ] Catechol ligands can bind onto metal oxide surfaces through two adjacent phenolic –OH groups to form bonds based on bidentate chelating, bidentate inner sphere bridging or bidentate outer sphere bridging. [ 36,58,66,67 ]…”

“…[ 80 ] Catecholate molecules with hydrocarbon chains terminating with –COOH or –NH 2 functional groups are able to dissociate or absorb protons to form a charged surface, providing electric charge and reducing agglomeration through electrostatic repulsion. [ 33,81 ] Catechol ligands can also act as versatile molecular linkers between metal oxide surfaces and many different types of materials [ 33,38,58 ] binding to carbon nanostructures, [ 65 ] other metal oxides nanostructures, [ 40 ] dyes, [ 82 ] polymers, [ 38 ] nucleic acids, [ 33 ] and peptides. [ 83 ] Catechol ligands with hydrocarbon chains containing –COH end groups bind to –NH 2 groups of other material through Schiff base reactions forming an imine bond.…”

“…[ 33,43,44 ] Molecular linking through Schiff base reactions can also be achieved if the catechol molecule contains an –NH 2 group, whereas the other material contains –COH/–COOH, as the Schiff base reaction and carboxamide binding happens regardless of the location of the functional groups. [ 65,82,83 ] Burger et al. demonstrated this using dopamine, an –NH 2 ‐containing catecholate molecules to establish linking between ZnO nanorods and –COOH‐containing porphyrins, which are macrocyclic organic molecules commonly used as photoactive sensitizers (Figure 3D).…”

2D Nanocomposite Membranes: Water Purification and Fouling Mitigation

“…Due to the increase in surface area, the adsorption and resultant photocatalytic removal of pollutants was better for NW than for NP. Additionally, the hydrophilicity and flux were enhanced with intercalated 1D nanostructures [ 230 ]. Shi et al [ 224 ] reported that self-cleaning membranes with photocatalytic properties reduce irreversible fouling.…”

A Fuzzy Analytic Hierarchy Model to Appraise Water Absorption Process Parameters in Cocoa Pod Husk Composite

“…In marine-oriented composites, water absorption tests are used to analyze the integrity of the composites regarding their mechanical, wear and corrosive properties before full-scale manufacturing (Karthick et al, 2018;Saxena and Gupta, 2018;Aydemir et al, 2019;Kusmono et al, 2020). Knowledge on the performance of composites in water media provides ideas to design engineers and fabricators on structural (re)design and computations concerning composite parameters (Daramola et al, 2019;Yu et al, 2020). Hence, their service capability is enhanced as well as their maintenance costs.…”