• Energy Research

There have been tremendous advances in membrane distillation (MD) since the concept was introduced in 1961: new membrane designs and process configurations have emerged, and its commercial viability has been evaluated in several pilot-scale studies. However, its high energy consumption has hindered its commercialization. One of the most promising ways to overcome this obstacle is to develop more energy-efficient membrane modules. The MD research community has therefore developed diverse new module configurations for hollow fiber and flat sheet membranes that increase the thermal energy efficiency of MD by minimizing thermal polarization, increasing mass transfer across the membrane, and improving heat recovery from the condensed vapor. This review summarizes the progress made in the design of hollow fiber and flat sheet membrane modules for MD applications. It begins with a brief introduction to MD and its configurations before describing developments in module fabrication and highlighting key areas where further research is needed.

Deep eutectic solvents (DES) have recently emerged as a new class of inexpensive biodegradable solvents and additives with diverse applications. In this study, a new family of non-ionic deep eutectic solvents (NIDES) is proposed for the first time for membrane preparation. Three types of NIDES, N-methylacetamide-acetamide (DES-1), N-methyl acetamide-N-methyl urea (DES-2), and N-methyl acetamide-N,N & PRIME;-dimethyl urea (DES-3) were synthesized and used to dissolve polyvinylidene fluoride (PVDF) polymer. The effects of the additive polyvinylpyrrolidone (PVP) and the type of NIDES on the PVDF membrane characteristics, water permeability and bovine serum albumin (BSA) separation were studied. The membranes prepared with DES-1 and 2 wt% PVP exhibited a good water permeate flux (96.82 L/m(2).h) and a high BSA separation factor (96.32%). High performance PVDF membranes can thus be efficiently prepared using biodegradable inexpensive NIDES.

AbstractThe lithium hexafluorophosphate (LiPF6) in spent lithium‐ion batteries (LIBs) is a potentially valuable resource and a significant environmental pollutant. Unfortunately, most of the LiPF6 in a spent LIB is difficult to extract because the electrolyte is strongly adsorbed by the cathode, anode, and separator. Storing extracted electrolyte is also challenging because it contains LiPF6, which promotes the decomposition of the solvent. Here we show that electrolytes in spent LIBs can be collected by a less polar solvent dimethyl carbonate (DMC) wash, and LiPF6 can be concentrated by simple aqueous extraction by lowering ethylene carbonate (EC) content in the recycled electrolyte. Due to the similar dielectric constant of EC and water, reducing the content of EC in LIB electrolytes, or even eliminating it, facilitates the separation of water and electrolyte, thus enabling the lithium salts in the electrolyte to be separated from the organic solvent. The lithium salt extracting efficiency achieved in this way can be as high as 99.8%, and fluorine and phosphorus of LiPF6 can be fixed in the form of stable metal fluoride and phosphate by hydrothermal method. The same strategy can be used in industrial waste electrolyte recycling by diluting the waste with DMC and extracting the resulting solution with water. This work thus reveals a new route for waste electrolyte treatment and will also support the development of advanced EC‐free electrolytes for high‐performance, safe, and easily recyclable LIBs.

This paper presents assessment of natural and anthropogenic sources of blue energy within Swedish territory to identify suitable spots for implementing new projects. The natural energy potential of salinity gradients was found to be higher in southwest Sweden, and a national energy resource potential of 2610.6 MW from seawater/river water mixing will be reduced to a technical potential ranging from 1044.3 MW to 1825.4 MW considering technical and environmental constraints. It has been found that the theoretical extractable energy potential in Sweden is equivalent to 13% of the total electricity consumption and 6.2% of the total final energy consumption by energy commodities. Anthropogenic water sources were also highlighted as promising low and high-concentration solutions for SGE extraction. Gotland was identified as an attractive location for generating salinity gradient power. The total salinity gradient power obtainable by mixing municipal wastewater with seawater in Sweden was estimated to be 11.8 MW. The most promising site for this process was determined to be Gryaab AB Ryaverket in Gothenburg, which accounted for 45.8% of the total national potential from anthropogenic sources.

AbstractIt is challenging to efficiently and economically recycle many lithium‐ion batteries (LIBs) because of the low valuation of commodity metals and materials, such as LiFePO4. There are millions of tons of spent LIBs where the barrier to recycling is economical, and to make recycling more feasible, it is required that the value of the processed recycled material exceeds the value of raw commodity materials. The presented research illustrates improved profitability and economics for recycling spent LIBs by utilizing the surplus energy in lithiated graphite to drive the preparation of organolithiums to add value to the recycled lithium materials. This study methodology demonstrates that the surplus energy of lithiated graphite obtained from spent LIBs can be utilized to prepare high‐value organolithiums, thereby significantly improving the economic profitability of LIB recycling. Organolithiums (R–O–Li and R–Li) were prepared using alkyl alcohol (R–OH) and alkyl bromide (R–Br) as substrates, where R includes varying hindered alkyl hydrocarbons. The organolithiums extracted from per kilogram of recycled LIBs can increase the economic value between $29.5 and $226.5 kg−1 cell. The value of the organolithiums is at least 5.4 times the total theoretical value of spent materials, improving the profitability of recycling LIBs over traditional pyrometallurgical ($0.86 kg−1 cell), hydrometallurgical ($1.00 kg−1 cell), and physical direct recycling methods ($5.40 kg−1 cell).

Abstract Polymeric membranes are important in advanced separation technologies because of their high efficiency and low environmental impact. However, procedures for membrane production are far from sustainable and environmentally friendly. This work presents a life cycle assessment of the environmental impact of fabricating 1000 m2 of hollow fiber polymeric membranes. Membrane materials considered include the most popular fossil- and bio-based polymers in current use, i.e., polysulfones, polyvinylidene fluoride, and cellulose acetate. Solvents considered for use in polymer dope solution included polar aprotic solvents (N-Methyl-2-pyrrolidone, N, N-dimethylacetamide, and dimethylformamide) that are widely used in industry and an alternative green solvent (ethylene carbonate). The impacts of membrane production on global warming, marine ecotoxicity, human carcinogenic and non-carcinogenic toxicity, land use potential, and fossil resource scarcity were analyzed. Additionally, the impact on the sustainability and environmental cost of membrane production resulting from replacing fossil-based polymers with bio-based polymers or substituting toxic solvents with a green alternative was investigated. Hot spots in the membrane production process were identified, and measures to reduce the environmental impact of membrane production were proposed.

Abstract Efficient and reliable energy storage systems are crucial for our modern society. Lithium-ion batteries (LIBs) with excellent performance are widely used in portable electronics and electric vehicles (EVs), but frequent fires and explosions limit their further and more widespread applications. This review summarizes aspects of LIB safety and discusses the related issues, strategies, and testing standards. Specifically, it begins with a brief introduction to LIB working principles and cell structures, and then provides an overview of the notorious thermal runaway, with an emphasis on the effects of mechanical, electrical, and thermal abuse. The following sections examine strategies for improving cell safety, including approaches through cell chemistry, cooling, and balancing, afterwards describing current safety standards and corresponding tests. The review concludes with insights into potential future developments and the prospects for safer LIBs.