Influence of particle type and concentration on the ultrafiltration behavior of nanoparticle stabilized Pickering emulsions and suspensions

Organic Solvent Nanofiltration of Water-in-Oil Pickering Emulsions—What Influences Permeability?

“…For all emulsions, deionized water was used as the aqueous phase. Based on our previous work [13][14][15]17,18], 1-dodecene was used as the "standard" organic solvent (VWR International GmbH, Dresden, Germany), as it constitutes a representative long-chain olefin suited for, e.g., hydroformylation reactions (e.g., [18]). Additionally, dodecane (Fisher Scientific GmbH, Schwerte, Germany), decene (Sigma-Aldrich Chemie GmbH, Taufkirchen, Germany), octene (Fisher Scientific GmbH, Schwerte, Germany) and heptane (Th.…”

“…[g mol −1 ] [kg m −3 Different types of silica nanoparticles were used (Table 2). Commercially available fumed fractal-like particles of varying hydrophobicity and specific particle surface area by Wacker Chemie AG (as published in our previous works [14,15]) and spherical inhouse particles differing in charge or size (as published in our previous work [18]) were investigated. The particles will be referred to by the short names given in Table 2 in the following.…”

“…The catalyst could be immobilized within the dispersed aqueous phase droplets, while the product containing organic phase was continuously filtered through the membrane. Since then, some studies on the ultrafiltration of w/o PEs were published [5,[11][12][13][14]. However, the ultrafiltration membranes used in these studies (molecular weight cut-off (MWCO) ranging from 1 to 10 kDa) were originally designed for aqueous applications and showed-in some cases-an unexpected disproportionate increase of flux with pressure and strong fluctuations in pure organic solvent flux [10,11,13,14].…”

“…Since then, some studies on the ultrafiltration of w/o PEs were published [5,[11][12][13][14]. However, the ultrafiltration membranes used in these studies (molecular weight cut-off (MWCO) ranging from 1 to 10 kDa) were originally designed for aqueous applications and showed-in some cases-an unexpected disproportionate increase of flux with pressure and strong fluctuations in pure organic solvent flux [10,11,13,14]. Therefore, an organic solvent nanofiltration membrane with a relatively high MWCO of 900 Da was tested for w/o PE filtration for the first time in [13,15].…”

“…Therefore, an organic solvent nanofiltration membrane with a relatively high MWCO of 900 Da was tested for w/o PE filtration for the first time in [13,15]. Since the droplets are expected to be in the µmrange [14] and possibly freely suspended particle aggregates have a size of approximately 150 nm [16], membranes with a smaller MWCO were not necessarily needed. Despite the low applied pressures (1-4 bar, based on the first investigations using ultrafiltration Furthermore, the validity of the proposed mathematical model to describe the filtration of w/o PEs developed in [15] was tested for different organic solvents and was adapted to include properties of the solvents.…”