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The adsorption process has been successfully used as a technique for water and wastewater treatment over the past 40–50 years, but it is not without drawbacks as the treatment method for heavy metal removals. One of the main issues of the process is the posttreatment requirement to separate nanoparticles from the water sources. This chapter provides a review on the development of adsorptive ultrafiltration (UF) membranes composed of organic polymer and inorganic nanomaterial for elimination of heavy metal ions in a relatively simple way. The roles of different types of nanomaterials embedded in the membranes, including metal oxides (e.g., zirconium oxide, iron oxide, and titanium dioxide), carbon-based nanomaterials (e.g., carbon nanotubes and graphene oxide) and other nanomaterials (e.g., natural clays and waste) are assessed for their selectivity toward heavy metal ion adsorption. In most of the published research work, the adsorptive membranes exhibited promising results with respect to adsorption capacity and water permeability. However, more research is needed to address the possible leaching of nanomaterials from the membrane during operation and the potential of membrane degradation upon exposure to strong acid/alkali solutions during the desorption process.

An overview of the development of nanocomposite ultrafiltration (UF) membranes that are composed of organic polymer and inorganic nanomaterials for water treatment applications is provided in this chapter. Particular focus is placed on the roles of carbon-based nanomaterials embedded within the microporous membranes made via phase inversion technique for antifouling improvement and heavy metal removal. Compared to pristine membranes, the use of nanomaterials such as carbon nanotubes (CNTs) and graphene oxide (GO) to modify the surface morphology and chemistry of UF membranes was reported to have minimum adsorption and/or deposition of foulants, mainly due to the enhanced surface hydrophilicity coupled with greater charge properties that reduce the interaction between foulants and membrane surface. Such nanocomposite membranes also showed potential to be applied for heavy metal removal that is not possible to be achieved with pristine membranes. Compatibility between polymer and nanomaterials is not the main issue as most carbon-based nanomaterials are reported to distribute quite uniformly within the polymeric membranes, provided the loading used is at the appropriate range. This updated information is of great importance to provide good insights into the design and fabrication of advanced nanocomposite membranes for UF processes.

Millions of people in the world are exposed to arsenic-contaminated drinking water, causing them to have serious health problems. Compared to the conventional treatment method that uses nanoparticles to eliminate arsenic from water, emerging membrane technology, i.e., adsorptive mixed matrix membrane (MMM) offers unique features including one-step treatment, high reusability and effective even for extremely low concentration of contaminant. In the present study, hybrid nanomaterial namely graphene oxide-manganese ferrite (GMF) was self-synthesized followed by incorporation into polymeric membrane matrix to produce MMM for arsenate (As(V)) ion removal via adsorption-filtration method. The synthesized nanomaterial was characterized using Brunauer, Emmett and Teller (BET) analyzer, Fourier transform Infrared (FTIR) spectroscope, X-ray diffraction (XRD) analyser and transmission electron microscope (TEM), while the developed MMMs were characterized using scanning electron microscope (SEM) equipped with energy dispersive X-ray (EDX) spectroscope and contact angle goniometer before being used in adsorption-filtration process. The maximum adsorption capacity (qmax), adsorption isotherm and kinetic properties of the MMMs were determined by batch adsorption studies, while the adsorption-filtration experiment was conducted to evaluate the MMMs ability with respect to As(V) removal in cross-flow system and regeneration capability. The best performing MMM could achieve maximum adsorption capacity of 75.5 mg/g at pH 4 and uphold permeates level below the drinking water standard for up to 4 h in a cross-flow filtration process. These findings indicated that the newly developed MMMs are potential to be used as single-treatment method for As(V) ion removal.