## Nanomaterial-Based Membrane
### Polymer Nanocomposites Membranes for the Treatment of Wastewater
Accordingly, the upsurge of silver-nanoparticle/polymer ratio has a tendency to upsurge water permeability in polysulfone, whereas it was reduced by respectively employing polyethersulfone and cellulose acetate polymers. [PERSON] et al. [57] presented the immobilization of silver-nanoparticles on polyethersulfone membranes through the introduction of amino groups, which aid the formation of aminated polyethersulfone (NH\({}_{2}\)- polysulfone, APES) [57]. The antibacterial activity was assessed alongside Escherichia coli. The annex of silver-nanoparticles on the surface of aminated polysulfone improved the bacterial/silver contact. Silver nanoparticles basically revealed a maximum disinfection ability through the reduction of the colony count of zero. [PERSON] and [PERSON] presented a report on the modification of the surface of polysulfone membranes by using silver-nanoparticles [58]. Polyethersulfone membranes were sulfonated by employing concentrated sulfuric acid for the generation of \(-\)SO\({}_{3}\)H groups on the membrane surface; it dissociates to provide SO\({}^{3-}\) and H\({}^{+}\) ions. Adding AgNO\({}_{3}\) resulted in the replacement of H\({}^{+}\) ions via Ag\({}^{+}\) ions, and the silver-nanoparticles-polyethersulfone membranes demonstrated a constant permeate flow rate (3.45 Lh\({}^{-1}\)) as a result of total _Escherichia coli_ cell-killing. Hence, the integration of silver-nanoparticles on membrane surfaces led to the improvement in antibacterial effect [58]. Titanium dioxide (TiO\({}_{2}\)) is a photocatalytic material with three diverse forms of crystals: anatase, rutile, and brookite. To a reasonably extent, TiO\({}_{2}\) materials are not expensive when likened to the cost of other nanomaterials. TiO\({}_{2}\) materials exhibit excellent thermal and chemical stability [59]. Furthermore, titanium dioxide, as a nano-material, enhances the penetrability, temperature resistance, and antifouling properties of membranes [60]. [PERSON] et al. found that polyvinylidene difluoride and poly (amide-imide) membranescombined with TiO\({}_{2}\) as inorganic particle enhanced the resistance of temperature and permeability [61]. [PERSON] et al. used polyacrylic acid and TiO\({}_{2}\) nanoparticles to increase the antifouling property of polyvinylidene fluoride membrane [62]. The study shows that there was a notable improved fouling resistance on the account of the extraordinary yield resulted from and reduced TiO\({}_{2}\) agglomeration [62]. [PERSON] et al. [63] synthesized a hybrid composite membrane through the means of self-assembly of TiO\({}_{2}\) nanoparticles. The membrane accorded substantial photo-bactericidal impact on Escherichia coli under ultraviolet light illumination. [PERSON] et al. [64] used three different types of TiO\({}_{2}\) nanoparticles (P25, PC105, and PC500) with different sizes for the synthesis of mixed matrix polyethersulfone nanofiltration membranes [64]. The influence of forms and sizes of the nanoparticle on the structure, performance, and control of fouling was investigated. The higher the content of PC105 and PC500 TiO\({}_{2}\) nanoparticles in the casting solution, the lesser the performance of the membrane, with P25 demonstrating better dispersibility; this is because of the agglomeration of these nanoparticles in polymer matrix. Mechanisms of Polymer Nanocomposites Membranes for Water Treatment  
It is known that adsorption is the initial phase in the mechanism of water transportation and in other instances transportation of solutes through the membrane in the solution-diffusion model. This mechanism is affected by the membrane and charge of the molecules. This could boost the attraction or repulsion of forces between the membrane and molecules' charges. Adsorption contributes to high retention; however, lower retention is usually noticed in the course of the gradual saturation of membrane [65].