Water scarcity and waste mismanagement are global crises that threaten the health of populations worldwide and a sustainable future. In order to help mitigate both these issues, a solar desalination device composed entirely of fallen leaves and guar – both natural materials – has been developed and demonstrated herein. This sustainable desalinator realizes an evaporation rate of 2.53 kg m −2 h −1 under 1 sun irradiance, and achieves consistent performance over an extended exposure period. Furthermore, it functions efficiently under a variety of solar intensities and in high salinity environments, and can produce water at salinities well within the acceptable levels for human consumption. Such strong performance in a large variety of environmental conditions is made possible by its excellent solar absorption, superb and rapid water absorption, low thermal conductivity, and considerable salt rejection abilities. Composed primarily of biowaste material and boasting a simple fabrication process, this leaf-guar desalinator provides a low-cost and sustainable avenue for alleviating water scarcity and supporting a green path forward.
Turning dead leaves into an active multifunctional material as evaporator, photocatalyst, and bioplastic
Large numbers of leaves fall on the earth each autumn. The current treatments of dead leaves mainly involve completely destroying the biocomponents, which causes considerable energy consumption and environmental issues. It remains a challenge to convert waste leaves into useful materials without breaking down their biocomponents. Here, we turn red maple dead leaves into an active three-component multifunctional material by exploiting the role of whewellite biomineral for binding lignin and cellulose. Owing to its intense optical absorption spanning the full solar spectrum and the heterogeneous architecture for effective charge separation, films of this material show high performance in solar water evaporation, photocatalytic hydrogen production, and photocatalytic degradation of antibiotics. Furthermore, it also acts as a bioplastic with high mechanical strength, high-temperature tolerance, and biodegradable features. These findings pave the way for the efficient utilization of waste biomass and innovations of advanced materials.
- Publication Date:
- NSF-PAR ID:
- 10399895
- Journal Name:
- Nature Communications
- Volume:
- 14
- Issue:
- 1
- ISSN:
- 2041-1723
- Publisher:
- Nature Publishing Group
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Li−O2 batteries with carbon electrodes made from three commercial carbons and carbon made from waste tea leaves are investigated in this study. The waste tea leaves are recycled from household tea leaves and activated using KOH. The carbon materials have various specific surface areas, and porous structures are characterized by the N2 adsorption/desorption. Vulcan XC 72 carbon shows a higher specific surface area (264.1 m2/g) than the acetylene black (76.5 m2/g) and Super P (60.9 m2/g). The activated tea leaves have an extremely high specific surface area of 2868.4 m2/g. First, we find that the commercial carbons achieve similar discharge capacities of ∼2.50 Ah/g at 0.5 mA/cm2. The micropores in carbon materials result in a high specific surface area but cannot help to achieve higher discharge capacity because it cannot accommodate the solid discharge product (Li2O2). Mixing the acetylene black and the Vulcan XC 72 improves the discharge capacity due to the optimized porous structure. The discharge capacity increases by 42% (from 2.73 ± 0.46 to 3.88 ± 0.22 Ah/g) at 0.5 mA/cm2 when the mass fraction of Vulcan XC 72 changes from 0 to 0.3. Second, the electrode made from activated tea leaves is demonstrated for the first timemore »
-
The recalcitrance of some emerging organic contaminants through conventional water treatment systems may necessitate advanced technologies that use highly reactive, non-specific hydroxyl radicals. Here, polyacrylonitrile (PAN) nanofibers with embedded titanium dioxide (TiO 2 ) nanoparticles were synthesized via electrospinning and subsequently carbonized to produce mechanically stable carbon/TiO 2 (C/TiO 2 ) nanofiber composite filters. Nanofiber composites were optimized for reactivity in flow through treatment systems by varying their mass loading of TiO 2 , adding phthalic acid (PTA) as a dispersing agent for nanoparticles in electrospinning sol gels, comparing different types of commercially available TiO 2 nanoparticles (Aeroxide® P25 and 5 nm anatase nanoparticles) and through functionalization with gold (Au/TiO 2 ) as a co-catalyst. High bulk and surface TiO 2 concentrations correspond with enhanced nanofiber reactivity, while PTA as a dispersant makes it possible to fabricate materials at very high P25 loadings (∼80% wt%). The optimal composite formulation (50 wt% P25 with 2.5 wt% PTA) combining high reactivity and material stability was then tested across a range of variables relevant to filtration applications including filter thickness (300–1800 μm), permeate flux (from 540–2700 L m −2 h), incident light energy (UV-254 and simulated sunlight), flow configuration (dead-end and cross-flow filtration),more »
-
Abstract Abstract Options for recycling fiber composite polymer (FCP) materials are scarce, as these materials cannot be normally recycled and are toxic when improperly disposed. Additionally, reducing water usage is an increasing concern, as the concrete industry currently uses 10% of the world’s industrial water. Therefore, building upon our previous work, this research explores the use of polymer hybrid carbon and glass composite waste products as reinforcements in high-pressure compacted cement. Our material used nearly 70% less water during manufacturing and exhibited improved durability and salt corrosion resistance. Compression strength tests were performed on high-pressure compacted materials containing 6.0 wt% recycled admixtures before and after saltwater aging, and the results showed that the material retained 90% of its original compression strength after aging, as it contained fewer pores and cavities. Our experimental work was supplemented by molecular dynamics. Simulations, which indicated that the synergetic effects of compaction and FCP admixture addition slowed the diffusion of corrosive salt ions by an average of 84%. Thus, our high-pressure compacted cement material may be suitable for extended use in marine environments, while also reducing the amount of commercial fiber composite polymer waste material that is sent to the landfill.
<bold>Article Highlights</bold> Fiber composite wastemore »
High-pressure compacted cement samples containing 6% recycled admixtures retained 90% of their compression strength after salt aging.
The high-pressure compaction method utilized 70% less water during specimen fabrication.
-
Abstract Over 50% of the energy from power plants, vehicles, oil refining, and steel or glass making process is released to the atmosphere as waste heat. As an attempt to deal with the growing energy crisis, the solid-state thermoelectric generator (TEG), which converts the waste heat into electricity using Seebeck phenomenon, has gained increasing popularity. Since the figures of merit of the thermoelectric materials are temperature dependent, it is not feasible to achieve high efficiency of the thermoelectric conversion using only one single thermoelectric material in a wide temperature range. To address this challenge, this paper proposes a method based on topology optimization to optimize the layouts of functional graded TEGs consisting of multiple materials. The objective of the optimization problem is to maximize the output power and conversion efficiency as well. The proposed method is implemented using the Solid Isotropic Material with Penalization (SIMP) method. The proposed method can make the most of the potential of different thermoelectric materials by distributing each material into its optimal working temperature interval. Instead of dummy materials, both the P and N-type electric conductors are optimally distributed with two different practical thermoelectric materials, namely Bi2Te3 & PbTe for P-type, and Bi2Te3 & CoSb3more »
