Resin-Loaded Heterogeneous Polyether Sulfone Ion Exchange Membranes for Saline Groundwater Treatment

Abstract

Arid areas often contain brackish groundwater that has a salinity exceeding 500 mg/L. This poses several challenges to the users of the water such as a salty taste and damage to household appliances. Desalination can be one of the key solutions to significantly lower the salinity and solute content of the water. However, the technology requires high energy inputs as well as managing waste products. This paper presents the fabrication of ultrafiltration heterogeneous ion exchange membranes for brackish groundwater treatment. Scanning electron microscopy (SEM) images showed a relatively uniform resin particle distribution within the polymer matrix. The mean roughness of the cation exchange membrane (CEM) and anion exchange membrane (AEM) surfaces increased from 42.12 to 317.25 and 68.56 to 295.95 nm, respectively, when resin loading was increased from 1 to 3.5 wt %. Contact angle measures suggested a more hydrophilic surface (86.13 to 76.26° and 88.10 to 74.47° for CEM and AEM, respectively) was achieved with greater resin loading rates. The ion exchange capacity (IEC) of the prepared membranes was assessed using synthetic groundwater in a dead-end filtration system and removal efficiency of K+, Mg2+, and Ca2+ were 56.0, 93.5, and 85.4%, respectively, for CEM with the highest resin loading. Additionally, the anion, NO3− and SO42− removal efficiency was 84.2% and 52.4%, respectively, for the AEM with the highest resin loading. This work demonstrates that the prepared ultrafiltration heterogeneous ion exchange membranes have potential for selective removal for of ions by ion exchange, under filtration conditions at low pressure of 0.05 MPa.

Multifunctional Heterogeneous Ion-Exchange Membranes for Ion and Microbe Removal in Low-Salinity Water

“…Custom-made ultrafiltration heterogeneous ion-exchange membranes previously reported by Mudau et al (2022) [ 47 ] were used to fabricate metal nanocomposite membranes, and their properties are shown in Table 1 . Silver nitrate (AgNO 3 , ≥99%), copper sulfate (CuSO 4 , ≥99%), and sodium borohydride (NaBH 4 , ≥98%) purchased from Sigma Aldrich were used for the synthesis of metal nanocomposites.…”

“…Please note that the custom-made ultrafiltration heterogeneous ion-exchange membranes were chosen because of their ability to undergo an ion-exchange process under low-pressure filtration conditions. The ion-exchange resin loading was kept at 3.5 wt.% to achieve the desired structural integrity for ion removal and macromolecule retention application [ 47 ].…”

“…In this work, we developed novel Ag- and Cu-functionalized UF heterogeneous IEMs for surface water treatment under low-pressure filtration conditions. Custom-made UF heterogeneous IEMs reported in a previous study by Mudau et al (2022) were used to synthesize the novel metal nanocomposite IEMs [ 47 ]. The custom-made heterogeneous UF IEMs had dual functionality of the ion-exchange process and size exclusion but did not mitigate biofouling.…”

Poly(arylene ether)s-Based Polymeric Membranes Applied for Water Purification in Harsh Environment Conditions: A Mini-Review

“…PES membranes possess diverse applications such as adsorption of metal ions, salt resistance, removal of dyes, and potential as exchange membranes for selective removal of ions [60,61], making them suitable for treating textile wastewater, food industry wastewater, etc. For example, Giwa et al [62] utilized electrically enhanced membrane bioreactors (eMBR) to achieve a high-quality effluent at a lower cost compared to conventional methods [63,64].…”