Ultrafiltration Membranes Functionalized with Polydopamine with Enhanced Contaminant Removal by Adsorption

Abstract

The performance of polymeric ultrafiltration membranes functionalized with polydopamine to couple depth adsorption of contaminants with the typical surface rejection characteristics of the membrane is investigated. Two approaches are deployed to achieve this functionalization: in a two‐step method, the ultrafiltration membranes are initially fabricated by phase inversion, then followed by coating with polydopamine; in a more facile and advantageous one‐step method, the membranes are subjected to phase inversion in a water solution containing dopamine, so that polymer precipitation and polydopamine functionalization occur at the same time. Methylene blue is used as the representative target contaminant to study the enhancement of membrane adsorption behavior, and its removal is investigated both in batch and under filtration conditions. The sorption capacity increases with increasing polydopamine coating time and is higher for the membranes fabricated via the one‐step protocol. The amount of methylene blue adsorbed per unit of membrane mass is large (roughly 5–10 mg g−1) and the kinetics of adsorption is fast. These characteristics allow these materials to get operated effectively and for long times in membrane filtration processes before stopping the system for regeneration. The saturated membranes are completely regenerated and reused without loss of performance by cycling in acidic and alkaline solutions.

Polydopamine Nanoparticle-Coated Polysulfone Porous Granules as Adsorbents for Water Remediation

“…For example, it has been demonstrated that the PD deposition on polysulfone membranes increased the removal of a representative positively charged contaminant as methylene blue (MB) with increasing PD coating time. 23 The increased removal of heavy metals and metal cations (i.e., Cd(II) and Pb(II)) upon PD functionalization of graphene hydrogel was also reported. 24 A similar behavior was also observed for PD-functionalized zeolite that showed an adsorption capacity toward Cu(II) at pH = 5.5, about 40% higher than that of the pristine material.…”

Mussel‐Inspired Membrane Adsorber with Thiol Ligand for Patulin Removal: Adsorption and Regeneration Behaviors

“…Membrane‐based techniques have received much attention in the field of micropollutants removal due to their convenient and continuous operation . But the traditional membranes separated micropollutants mainly by means of the size exclusion effect or charge effect, and it may not work for some small molecular organic micropollutants with electric neutrality.…”

Fabrication of nanofiltration membranes via stepwise assembly of oligoamide on alumina supports: Effect of number of reaction cycles on membrane properties

“…The instrument is equipped with an ATR accessory containing a diamond crystal internal reflection element. The analysis was carried out with a resolution of 4 cm -1 and samples were scanned 32 times in the wavenumber range between 750 and 3750 cm -1 [29]. Thermogravimetric analyses (TGA) were performed with a Mettler TGA/SDTA 851 instrument between 20 and 650 °C at a heating rate of 10 °C min −1 in air.…”

“…The surface and cross-sectional morphology of the membranes was analyzed through field emission scanning electron microscopy (FESEM). The instrument is the MERLIN model by ZEISS, equipped with a state-of-the-art GEMINILIS column, to ensure accurate control of spot and current [29]. The operational voltage was 5kV, except for the samples fabricated following 6.5 reaction cycles, for which the voltage was adjusted to 7.5 kV.…”