Mixed matrix membranes for efficient adsorption of copper ions from aqueous solutions

Adsorption of Ca(II), Mg(II), Zn(II), and Cd(II) on Chitosan Membrane Blended with Rice Hull Ash Silica and Polyethylene Glycol

“…Among these methods, adsorption is one of the most effective, economical and widely used method for heavy metal ion removal in wastewater [1,[3][4][5]. Some studies focus on adsorptive membranes to remove heavy metal ions from aqueous solutions.…”

“…Some studies focus on adsorptive membranes to remove heavy metal ions from aqueous solutions. Heavy metal ions can be removed when the ions are in contact with the surface of the membrane, even when the pore sizes of the membrane are much larger than the dimensions of the metal ions [1][2][3][4][5][6][7][8].…”

Gold-recovery PVDF membrane functionalized with thiosemicarbazide

“…The adsorption materials vary, including active carbon, gels and natural biomass [5][6][7]. However, packed bed usually used for adsorption causes high pressure drops and sometimes low adsorption rates [8] because the majority of the binding sites are located inside the pores of the adsorbents, which results in long intra-particle diffusion path-length in additional to film diffusion. Meanwhile, the adsorbents, if not designed properly, may not have high selectivity for gold over base metals such as Fe 3+ , Cu 2+ and Zn 2+ which often coexist with Au in disproportionate amounts.…”

“…Unfortunately, the adsorption capacity of membranes is generally low due to their low surface area. Such a problem can be abated by using a mixed matrix membrane as the stationary phase [11] which typically consists of a porous or non-porous bead incorporated in a porous polymeric membrane. As an alternative, we can also functionalize a polymer resin with the right ligand chemistry and make a porous membrane consisting of small dispersed resin particles to elevate the internal surface area, and hence the amount of active adsorption sites, for more effective adsorption.…”

Poly-thiosemicarbazide membrane for gold recovery

“…Membrane technology can be used to reduce or even eliminate the pore diffusion limitation; when a solution is forced to pass through a porous membrane the molecules travel by convective flow through the membrane pores, eliminating the usually present long diffusion time that the molecules or ions take to reach the adsorption sites inside the pores [11]. Adsorption sites can be incorporated inside the membrane pores by different methods: (i) dispersion of adsorbent particles in the membrane matrix, known as mixed matrix membranes (MMMs) [12,13]; (ii) incorporation of a liquid carrier in the membrane matrix by either filling the pores of the membranes with the carrier, known as supported liquid membranes (SLMs), or by mixing the liquid carrier with the polymer solution before membrane casting, know as polymer inclusion membranes (PIMs) [14][15][16][17][18]; (iii) functionalization of polymeric membranes to incorporate chelate-forming groups, ion-exchange groups or affinity ligands [19][20][21][22][23]; (iv) fabrication of membranes from blends between membrane-forming polymers and polymers containing the appropriate functional groups for the adsorption process [24][25][26][27][28]; (v) fabrication of membranes from metal-complexing polymers [29][30][31]. The latter enables the highest concentration of adsorption sites per membrane volume, because each monomeric unit has at least one adsorption site.…”