Membrane-based technologies for lithium recovery from water lithium resources: A review

The nucleation of crystals in liquids is one of nature's most ubiquitous phenomena, playing an important role in areas such as climate change and the production of drugs. As the early stages of nucleation involve exceedingly small time and length scales, atomistic computer simulations can provide unique insight into the microscopic aspects of crystallization. In this review, we take stock of the numerous molecular dynamics simulations that in the last few decades have unraveled crucial aspects of crystal nucleation in liquids. We put into context the theoretical framework of classical nucleation theory and the state of the art computational methods, by reviewing simulations of e.g. ice nucleation or crystallization of molecules in solutions. We shall see that molecular dynamics simulations have provided key insight into diverse nucleation scenarios, ranging from colloidal particles to natural gas hydrates, and that in doing so the general applicability of classical nucleation theory has been repeatedly called into question. We have attempted to identify the most pressing open questions in the field. We believe that by improving (i.) existing interatomic potentials; and (ii.) currently available enhanced sampling methods, the community can move towards accurate investigations of realistic systems of practical interest, thus bringing simulations a step closer to experiments.

Crystal Nucleation in Liquids: Open Questions and Future Challenges in Molecular Dynamics Simulations

Omniphobic membranes for direct contact membrane distillation: Effective deposition of zinc oxide nanoparticles

Engineering antifouling reverse osmosis membranes: A review

Process development of flue gas desulphurization wastewater treatment in coal-fired power plants towards zero liquid discharge: Energetic, economic and environmental analyses

The environmental impacts of brine disposal from seawater desalination plants and wastewater treatment plants represent a subject of growing concern; thus, determining the potential applicability of zero liquid discharge (ZLD) for water treatment is crucial. Membrane-based technologies are a potentially attractive strategy that can be used to reach this goal. Recent studies have highlighted that integrating a series of membrane processes is a viable approach to achieving ZLD for industrial use. However, a relatively limited number of reports have been published on the challenging problems encountered with ZLD approaches. Here, we provide a review of membrane processes that may be used in ZLD approaches and describe their problems as well as potential solutions and innovative technologies for improving their performance. Furthermore, the energy consumption of the different approaches is calculated and analyzed because it represents a major contributor to the total cost, and investments in innovative technologies are discussed. Finally, the prospects for membrane-based ZLD and further research are highlighted.

Membrane-based zero liquid discharge: Myth or reality?

Designing and optimization of continuous direct contact membrane distillation process

Membrane-assisted crystallization, aiming to induce supersaturation in a solution, has been successfully tested in the crystallization of ionic salts, low molecular organic acids, and proteins. Membrane crystallization is an emerging membrane process with the capability to simultaneously extract fresh water and valuable components from various streams. Successful application of crystallization for produced water treatment, seawater desalination, and salt recovery has been demonstrated. Recently, membrane crystallization has been developed to recover valuable minerals from highly concentrated solutions, since the recovery of high-quality minerals is expected to impact agriculture, pharmaceuticals, and household activities. In this work, molecular dynamics simulations were used to study the crystal nucleation and growth of sodium chloride in bulk and with hydrophobic polymer surfaces of polyvinylidene fluoride (PVDF) and polypropylene (PP) at a supersaturated concentration of salt. In parallel, membrane crystallization experiments were performed utilizing the same polymeric membranes in order to compare the experimental results with the computational ones. Moreover, the comparison in terms of nucleation time between the crystallization of sodium chloride (NaCl) using the traditional evaporation process and the membrane-assisted crystallization process was performed. Here, with an integrated experimental–computational approach, we demonstrate that the PVDF and PP membranes assist the crystal growth for NaCl, speeding up crystal nucleation in comparison to the bulk solution and leading to smaller and regularly structured face-centered cubic lattice NaCl crystals. This results in a mutual validation between theoretical data and experimental findings and provides the stimuli to investigate other mono and bivalent crystals with a new class of materials in advanced membrane separations.

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Membrane-assisted crystallization: A molecular view of NaCl nucleation and growth

Cleaning is an important unit operation in food processing for removal of fouling deposits to ensure not only optimal operability of process equipment but also product safety and quality. In modern large-scale processing plants, cleaning is commonly achieved by cleaning-in-place (CIP) operation, which, however, consumes large amounts of water, energy, and chemicals. Because of their unique interfacial physicochemical properties, this study incorporated microbubbles (MBs) into water as a novel cleaning agent for the prerinse step of CIP operation, aiming to enhance its cleaning efficiency. MB-infused water (MB water) was introduced into bench-top spinning disc apparatus to clean milk deposits fouled on a stainless-steel surface. A computational fluid dynamics model was built to predict the contact frequency of MBs with deposits under swirl flow and further identify the cleaning conditions that provided maximum MB–deposit contact. MB–deposit attachment was visualized by microscopic imaging. A series of cleaning experiments were conducted at 25–55 °C and a Reynolds number (Re) of 3380–5403, and incorporation of MBs into water with 1431 bubbles/mL proved effective in increasing the cleaning efficiency at 25 °C and a Re of 4392 and 5403 by 27 and 31%, respectively. However, increasing water temperature and decreasing Re and bubble density were found to make the effect of MBs on cleaning insignificant. The findings of this study can serve as the groundwork for developing an MB-assisted CIP system to improve the environmental performance of food manufacturing. 

Jheng-Han Tsai

Papers

Membrane-based zero liquid discharge: Myth or reality?

Designing and optimization of continuous direct contact membrane distillation process

Membrane-assisted crystallization: A molecular view of NaCl nucleation and growth

Microbubble-Assisted Cleaning To Enhance the Removal of Milk Deposits from the Heat Transfer Surface

Multipass hollow fiber membrane modules for membrane distillation