Mixed matrix PVDF membranes with in-situ synthesized PAMAM dendrimer- like particles: A new class of sorbents for Cu(II) recovery from aqueous solutions by ultrafiltration

A one-pot method for the preparation of a new family of mixed matrix polyvinylidene fluoride (PVDF) membranes with in-situ synthesized poly(amidoamine) [PAMAM] particles is described. The key feature of this membrane preparation method is the in-situ synthesis of PAMAM dendrimer-like particles in the dope solutions prior to membrane casting using low-generation dendrimers with terminal primary amine groups (G0 and G1-NH2) as precursors and epichlorohydrin (ECH) as cross-linker. By using a combined thermally induced phase separation (TIPS) and non-solvent induced phase separation (NIPS) casting process, a new family of asymmetric PVDF ultrafiltration membranes with (i) neutral and hydrophilic surface layers of average pore diameters of 22−45 nm, (ii) high loadings (∼48 wt %) of dendrimer-like PAMAM particles with average diameters of ∼1.3−2.4 μm, and (iii) matrices with sponge-like microstructures characteristic of membranes with strong mechanical integrity were successfully prepared. Preliminary experiments show that these new mixed matrix PVDF membranes can serve as reusable high capacity sorbents for Cu(II) recovery from aqueous solutions by ultrafiltration

Next generation of multifunctional membranes for resource recovery

Polymeric membranes have become the crit. components of a broad range of sustainability and resource recovery applications including 1) energy generation and storage, 2) water desalination and reuse and 3) biopharmaceutical sepns. and purifications. During the last two decades, substantial research efforts have been devoted to the development of mixed matrix membranes with embedded functional particles and nanomaterials. Such membranes are being designed to carry out multiple functions (e.g. retention, sorption and catalysis) with improved properties and performance including higher permselectivity and flux, greater mech. strength and lower fouling propensity. Polymeric particles could provide greater flexibility for the prepn. of mixed matrix membranes with improved particle- matrix compatibility, particle loading, flux and selectivity. Polymeric particles can be prepd. with different sizes, shapes and morphologies. Their chem. can be tuned to produce functional particles that can serve as org. sorbents, ion exchange media and affinity/chelating media making them particularly attractive as building blocks for multifunctional membranes for the recovery of crit. materials and resources from solns. and impaired water including saline water and wastewater. In this presentation, we will describe a facile and simple route to the prepn. of mixed matrix membranes with embedded functional polymeric particles. The crit. step of our novel methodol. is the in-situ synthesis and functionalization of polymeric nano/microparticles in a dope soln. prior to membrane casting. We highlight two applications of our new mixed matrix membranes with in- situ synthesized polymeric particles: 1) weak- base membrane absorbers for protein sepns. by ion exchange membrane chromatog. and 2) high flux and fouling resistant ultrafiltration membranes for microalgae recovery and harvesting from wastewater and culture media

Mining Critical Metals and Elements from Seawater: Opportunities and Challenges

The availability and sustainable supply of technology metals and valuable elements is critical to the global economy. There is a growing realization that the development and deployment of the clean energy technologies and sustainable products and manufacturing industries of the 21st century will require large amounts of critical metals and valuable elements including rare-earth elements (REEs), platinum group metals (PGMs), lithium, copper, cobalt, silver, and gold. Advances in industrial ecology, water purification, and resource recovery have established that seawater is an important and largely untapped source of technology metals and valuable elements. This feature article discusses the opportunities and challenges of mining critical metals and elements from seawater. We highlight recent advances and provide an outlook of the future of metal mining and resource recovery from seawater

A facile route to the preparation of mixed matrix polyvinylidene fluoride membranes with in-situ generated polyethyleneimine particles

The development of mixed matrix polymeric membranes with embedded functional particles/nanomaterials has been an active area of research during the last two decades. Such membranes are being designed to carry out multiple functions (e.g. retention, sorption and catalysis) with improved properties and performance over those of commercial membranes. Polymeric particles could provide greater flexibility for the preparation of mixed matrix membranes with improved particle–matrix compatibility, particle loading, flux and permselectivity. In this article, we describe a facile and simple route to the preparation of mixed matrix polyvinylidene fluoride (PVDF) membranes embedded with branched polyethylenimine (PEI) particles. The critical step of our novel methodology is the in-situ generation of crosslinked PEI micro/nanoparticles (with diameters ranging from 400 nm to 3 μm) in the membrane casting solution using epichlorohydrin as crosslinker. This eliminates the need to utilize inverse emulsion polymerization techniques to synthesize PEI particles prior to the membrane casting. Using non-solvent induced phase separation (NIPS), we successfully prepared mixed matrix PVDF membranes with uniform particle distribution and PEI particle loadings ranging from 27 to 48 wt%. Our novel membrane preparation route exhibits many advantages including simplicity, scalability and versatility. Preliminary experiments show that our new mixed matrix PVDF membranes with embedded PEI particles can serve as weak-base membrane absorbers for proteins such as bovine serum albumin