Calcium-mediated polysaccharide gel formation and breakage: Impact on membrane foulant hydraulic properties

Effect of iron on membrane fouling by alginate in the absence and presence of calcium

“…Therefore, constant pressure filtration studies investigating the effects of calcium and alginate concentrations were conducted at 135 kPa in order to facilitate the accumulation of a large data set. As confirmed previously, determination of the material properties that describe how the cake behaves under various constant applied pressures demonstrated that results developed at 135 kPa are applicable and can be extended to lower pressures typical of plant operation [23]. The applicability of some data to lower operating pressures was also confirmed via a second set of constant pressure filtration studies conducted over a range of pressures at one alginate concentration and selected iron/calcium concentrations.…”

“…The final flux (J e ) at the cessation of filtration, following the attainment of steady state filtration, has been shown previously [7], and was shown on numerous filtration runs in this study, to be equal to the (constant) steady state flux (J ss ) that occurred when the remaining Fe-alginate solution was removed from above the gel layer and replaced with clean permeate and filtration recommenced [7,23]. Therefore, for all subsequent filtration runs the value of J e is substituted for J ss in the derivations of cake properties and filtration performance.…”

“…For example, how do the gel layer properties of Fe-alginate assemblages differ from those of Caalginate assemblages? Does Fe-alginate show similar biphasic fouling behavior to that recently observed for Ca-alginate [23]? Furthermore, how does the presence of calcium influence the Fe-alginate interaction and the associated fouling behavior?…”

“…While we have recently made progress in understanding the relationship between suspension properties of Ca-alginate assemblages and the corresponding membrane fouling behavior for different alginate and calcium concentrations [23], limited insight into the relationship between relative polysaccharide and iron content and membrane fouling is available. For example, how do the gel layer properties of Fe-alginate assemblages differ from those of Caalginate assemblages?…”

Absorption of calcium ions on oxidized graphene sheets and study its dynamic behavior by kinetic and isothermal models

“…16 Pseudo-second-order adsorption of calcium ion adsorption on graphene sheets adsorption occurs. Adsorption is assumed to take place at specific homogeneous sites within the adsorbent (Xin et al 2015). Once a sorbate molecule occupies a site, northern adsorption takes place at that site.…”