3D printed membrane‐integrated spacers for enhanced antifouling in ultrafiltration

Abstract

Feed spacers are an important component of membrane‐based filtration systems as they promote turbulence and mass transfer during the filtration process—thereby, reducing the membrane fouling and improving the flux. Whereas spacers are used as a separate component in conjunction with membranes, herein, we demonstrate that membrane‐integrated spacers offer superior fouling resistance and hence an improved output flux during filtration. The integrated spacers were fabricated by 3D printing a composite slurry of UV curable resin and polyvinylidene fluoride on the Polyethersulfone‐based ultrafiltration (UF) membrane. After curing under the UV light, the 3D printed spacers showed excellent flexibility and mechanical integrity along with permanent adhesion to the UF membrane. When tested for filtration using humic acid as foulant, the integrated spacer offered significantly reduced fouling and an increased flux as compared with the commercial spacer. Moreover, it was found that the geometry of the integrated spacers plays an important role in their performance. Among different geometries, the “gyroid” geometry, with an optimal infill density, provided the highest fouling resistance while improving the flux by nearly 150% as compared with the commercial spacer. When tested as stand‐alone spacers, the 3D spacers with identical geometries resulted in an increased fouling and lower flux which confirmed the superior performance of membrane integrated spacers.

Bovine Serum Albumin Rejection by an Open Ultrafiltration Membrane: Characterization and Modeling

“…Common approaches to improve the performance of the separation include the development of new membrane materials and modification of the system configuration. Modification of the membrane surface can be performed to reduce the fouling of the membrane [ 32 , 33 ], and spacer design may help in the reduction in concentration polarization [ 34 , 35 ], or by using an extension to the UF system such as sonication, which induces strong local turbulence and enhances the effect of the crossflow [ 36 ]. For these systems, the estimation of mass transfer coefficients cannot be performed with Sherwood relations that are based on the conventional crossflow and system geometry.…”

“…Harriot-Hamilton equation [16] 1.97 × 10 −6 −2.65 Turbulent flow in pipe [31] Sh = 0.0096Re 0.91 Sc 0. 35 Bandini and Morelli [26] 3.15 × 10 −4 0.03 Spiral wound 1812 NF dextrose Sh = 0.016Re 0.8 Sc 1/3 Shi et al [27] 2.67 × 10 −6 0.12 Spiral wound 1812 organic solvent NF Sh = 0.075Re 0.61 Sc 0. 33 The model for the advection-dominated rejection equation (Equation ( 9)) only requires two fitting parameters (both k dbl and σ i ) or just one with only σ i fitted, with k dbl values obtained from Table 4; the parameter values from both strategies are given in Appendix B, Table A2.…”

Modified Electrospun Membranes Using Different Nanomaterials for Membrane Distillation

“…Detailed failure mechanisms due to multiple fouling or scaling phenomena have to be explored with the help of experimental investigation and computational fluid dynamics. Membrane-integrated 3D spacers could be another area to be explored to mitigate membrane fouling and scaling propensity [ 157 , 158 ].…”