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As-made and calcined forms of large-pore (5.3 nm) mesostructured silica with a wormhole framework structure, denoted MSU-J, have been used to form rubbery epoxy mesocomposites containing 1.0-12% (w/w) silica. The tensile modulus, strength, toughness, and extension-at-break for the mesocomposites formed from as-made and calcined forms of MSU-J silica are systematically reinforced by up to 4.8, 5.7, 1.6, and 8.5 times, respectively, in comparison to the pure epoxy polymer. The composites represent the first examples wherein the reinforcement benefits provided by mesostructured silica particles are comparable to those provided by exfoliated organoclay nanolayers at equivalent loadings. Moreover, the reinforcement benefits are realized without the need for organic modification of the silica surface, and the increases in tensile properties occur with little or no sacrifice in optical transparency or thermal stability. The oxygen permeability of the mesocomposites prepared from as-made MSU-J silica increases dramatically at loadings g5.0% (w/w), whereas the compositions made from the calcined form of the mesostructure show no permeation dependence on silica loading. For instance, the oxygen permeability of the mesocomposites containing 12% (w/w) as-made MSU-J silica is 6-fold higher than that of the silica-free epoxy membrane. Positron annihilation lifetime spectroscopy established the absence of free volume in the mesocomposites, thus precluding the possibility of facile oxygen diffusion through the framework pores of the silica. The increase in oxygen permeability is correlated with the partitioning of curing agent between the as-made mesostructure and the liquid prepolymer, which leads to coronas of permeable polymer with reduced chain cross-linking in the vicinity of the silica particles. Mesocomposites made from calcined forms of the mesostructured silica do not allow for curing agent partitioning, and the oxygen permeability is not significantly influenced by the silica loading.

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Platform chemicals such as medium-chain carboxylic acids (MCCAs) can be produced from organic waste streams via chain elongation in anaerobic mixed-culture bioreactors. A product recovery system is needed to collect MCCAs from the bioreactor effluent. Membrane-based liquid−liquid extraction, the most commonly used product recovery approach, requires suspended solids removal from the bioreactor effluent to avoid membrane fouling. An anaerobic dynamic membrane bioreactor (AnDMBR) was developed to evaluate MCCA production from brewery and prefermented food waste and to produce a permeate with low suspended solids to facilitate downstream product recovery. The AnDMBR employed an inexpensive stainless-steel mesh as the support material for the development of a biofilm or dynamic membrane, which was responsible for solids−liquid separation. The AnDMBR produced a permeate quality with an average total suspended solids (TSS) concentration of 0.12 g L −1 , while the average bioreactor TSS concentration was two orders of magnitude higher (21.6 g L −1 ). A maximum solids removal efficiency of ≥99% was achieved and good permeate quality was sustained for over 200 days without fouling control or cleaning the support material. In addition to solids−liquid separation, the dynamic membrane was responsible for a substantial fraction of the biological activity of the AnDMBR. The relative activity of Clostridiales, as determined by 16S rRNA sequencing, correlated with MCCA production and was higher in the dynamic membrane (20.0 ± 4.9%) than in the suspended biomass (5.2 ± 2.7%) in the bioreactor. This observation was consistent with MCCA production data as the permeate MCCA concentrations were significantly (p = 8.2 × 10 −5 ) higher than that in the bioreactor, suggesting that the dynamic membrane biofilm contributed to chain elongation.