Effect of combination dope composition and evaporation time on the separation performance of cellulose acetate membrane for demak brackish water treatment

Abstract

Abstract. The coastal areas in Indonesia often have a problem of clean water lack, because the water is classified as brackish water. Therefore, this research investigated the fabrication of CA membranes using phase inversion method for brackish water treatment. Investigation was conducted to study the effect of combination dope composition and evaporation time on separation performance and morphology of the memrbane. Membrane was fabricated by dry-wet phase inversion technique with variation of polymer concentration 17, 18 and 20 wt% in the total solid and evaporation time of 5, 10 and 15 seconds, respectively. The asymmetric membranes were characterized by permeability test through rejection and flux measurements using brackish water as feed. The experimental results from SEM images analysis showed that all the membranes have a thin small porous layer and thicker sub-structure of larger porous layer formed asymmetric membrane. Moreover, the greater polymer concentration is resulting smaller pore size and smaller membrane porosity. The longer evaporation time was also resulted in denser membrane active layer. The best membrane performance was observed at the composition of 20 wt% CA polymer, 1 wt % polyethylene glycol with the solvent evaporation time of 15 seconds.

Characteristics and Performances of Blended Polyethersulfone and Carbon‐Based Nanomaterial Membranes: Effect of Nanomaterial Types and Air Exposure

“…The evaporation of air has an impact on the surface skin of the membrane in which delayed evaporation time resulted in smaller, denser, and smoother pore formation of the upper skin. These findings are in accordance to the study conducted by Kusworo et al [32].…”

Influence of Polymer Blending of Cellulose Acetate Butyrate for CO2/N2 Separation

“…Moreover, the increment in the polymer concentration increased the solvent diffusivity, which caused more solvent to evaporate from the cast polymer solution resulting in reduced membrane thickness. 21 Besides that, the membrane thickness of M3 increased from 6.96 ± 0.10 µm to 7.57 ± 0.07 µm, as demonstrated in Figure 1(f and h). This was due to the strong interaction between solvent and polymer, which accelerated the aggregation of polymer molecules and formed a thicker membrane.…”

Porous polyether sulfone for direct methanol fuel cell applications: Structural analysis

“…As concern, the relationship between viscosity and concentration are likewise. Nevertheless, the increase in concentration also will affect the formation of thicker upper layer with lower porosity and pore inter‐connectivity of membranes 37 . From Table 5, it is clearly recorded that the thickness of PES‐NMP type membranes is 13% higher than PES‐DMAc type membranes.…”

“…However, at 2 minutes SET, the formation of membrane was merely stable due to the balanced effect of solvent evaporation and water absorption. 37 Larger pores were observed on PES-DMAc 2MIN rather than PES-NMP 2MIN due to the faster solvent evaporation DMAc than NMP. Therefore, it is worth noting that the narrowed ionic channel of porous PES membrane does increase the methanol permeability which is unexpected to occur.…”

“…As the SET higher than 2 minutes, the structure become unstable because of water absorption which resulted in larger pore size in membranes matrix. 37 Worth to note that, the ionic channels in dense membrane plays an important role in determining the performance of PEM for fuel cell applications. These affects mainly happened at low operating condition towards ion conductivity and water transport properties.…”