Strategic Growth Area: Economical and Sustainable Materials (ESM)

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Bioelectrochemical production of hydrogen in an innovative pressure-retarded osmosis/microbial electrolysis cell system: experiments and modeling
Yuan, Heyang; Lu, Yaobin; Abu-Reesh, Ibrahim M.; He, Zhen (Biomed Central, 2015-08-14)
Background While microbial electrolysis cells (MECs) can simultaneously produce bioelectrochemical hydrogen and treat wastewater, they consume considerable energy to overcome the unfavorable thermodynamics, which is not sustainable and economically feasible in practical applications. This study presents a proof-of-concept system in which hydrogen can be produced in an MEC powered by theoretically predicated energy from pressure-retarded osmosis (PRO). The system consists of a PRO unit that extracts high-quality water and generates electricity from water osmosis, and an MEC for organic removal and hydrogen production. The feasibility of the system was demonstrated using simulated PRO performance (in terms of energy production and effluent quality) and experimental MEC results (e.g., hydrogen production and organic removal). Results The PRO and MEC models were proven to be valid. The model predicted that the PRO unit could produce 485 mL of clean water and 579 J of energy with 600 mL of draw solution (0.8 M of NaCl). The amount of the predicated energy was applied to the MEC by a power supply, which drove the MEC to remove 93.7 % of the organic compounds and produce 32.8 mL of H2 experimentally. Increasing the PRO influent volume and draw concentration could produce more energy for the MEC operation, and correspondingly increase the MEC hydraulic retention time (HRT) and total hydrogen production. The models predicted that at an external voltage of 0.9 V, the MEC energy consumption reached the maximum PRO energy production. With a higher external voltage, the MEC energy consumption would exceed the PRO energy production, leading to negative effects on both organic removal and hydrogen production. Conclusions The PRO-MEC system holds great promise in addressing water-energy nexus through organic removal, hydrogen production, and water recovery: (1) the PRO unit can reduce the volume of wastewater and extract clean water; (2) the PRO effluents can be further treated by the MEC; and (3) the osmotic energy harvested from the PRO unit can be applied to the MEC for sustainable bioelectrochemical hydrogen production.
Characterization of Particle Emissions and Fate of Nanomaterials During Incineration
Vejerano, Eric P.; Leon, Elena C.; Holder, Amara L.; Marr, Linsey C. (The Royal Society of Chemistry, 2014-01-24)
As the use of nanotechnology in consumer products continues to grow, it is inevitable that some nanomaterials will end up in the waste stream and will be incinerated. Through laboratory-scale incineration of paper and plastic wastes containing nanomaterials, we assessed their effect on emissions of particulate matter (PM) and the effect of incineration on the nanomaterials themselves. The presence of nanomaterials did not significantly influence the particle number emission factor. The PM size distribution was not affected except at very high mass loadings (10 wt%) of the nanomaterial, in which case the PM shifted toward smaller sizes; such loadings are not expected to be present in many consumer products. Metal oxide nanomaterials reduced emissions of particle-bound polycyclic aromatic hydrocarbons. Most of the nanomaterials that remained in the bottom ash retained their original size and morphology but formed large aggregates. Only small amounts of the nanomaterials (0.023–180 mg g−1 of nanomaterial) partitioned into PM, and the emission factors of nanomaterials from an incinerator equipped with an electrostatic precipitator are expected to be low. However, a sustainable disposal method for nanomaterials in the bottom ash is needed, as a majority of them partitioned into this fraction and may thus end up in landfills upon disposal of the ash.
Effect of Curing on Mechanical Properties of Cement-Stabilized Coral Sand in Marine Environment
Chen, Mingyuan; Geng, Jiuguang; Xiong, Haocheng; Shang, Tao; Xue, Cheng; Abbas, Montasir M. (Hindawi, 2020-07-22)
The use of coral sand prepared from cement-stabilized materials can significantly reduce the cost, construction period, and damage to the environment caused by stone mining. The choice of water in mixing and curing the cement-stabilized materials on islands should be considered. Cement-stabilized coral sand was tested in three different preparation and maintenance systems in the marine environment. The compressive strength, weight change, and chloride ion concentration change in cement-stabilized coral sand with different cement content were measured after 7 d, 28 d, 60 d, and 90 d, respectively. The microstructure of specimens was observed by XRD and SEM. Results show that the compressive strength of specimens in the seawater mixing and seawater curing system developed 0.9 MPa faster than that in the fresh water mixing and curing system at an early stage. But the compressive strength of specimens in seawater mixing and seawater curing shrank later, being 0.5 MPa lower than that in fresh water mixing and curing. The cement content was positively correlated with the free chloride ion reaction and mass growth rate. For road construction on islands, the mixing and curing of cement-stabilized coral sand with seawater should be given priority in the early stage.
Environmental science and engineering applications of nanocellulose-based nanocomposites
Wei, Haoran; Rodriguez, Katia; Renneckar, Scott; Vikesland, Peter J. (The Royal Society of Chemistry, 2014-06-26)
Compared with cellulose, the primary component of the paper we use every day, nanocellulose has a much smaller diameter (typically <10 nm) that renders it many unique properties. Amongst many others, these properties include high mechanical strength, large surface area and low visual light scattering. Nanocellulose can be obtained by disintegration of plant cellulose pulp or by the action of specific types of bacteria. Once produced, nanocellulose can be used to make transparent films, fibers, hydrogels, or aerogels that exhibit extraordinary mechanical, thermal, and optical properties. Each of these substrates is a suitable template or carrier for inorganic nanoparticles (NPs), thus enabling production of nanocomposites that possess properties of the two constituents. In this review, we focus on the preparation of nanocellulose, nanocellulose films, and nanocellulose papers, and introduce nanocellulose-based nanocomposites and their environmental applications.
Exceptional capacitive deionization rate and capacity by block copolymer–based porous carbon fibers
Liu, Tianyu; Serrano, Joel; Elliott, John; Yang, Xiaozhou; Cathcart, William; Wang, Zixuan; He, Zhen; Liu, Guoliang (American Association for the Advancement of Science, 2020-04-17)
Capacitive deionization (CDI) is energetically favorable for desalinating low-salinity water. The bottlenecks of current carbon-based CDI materials are their limited desalination capacities and time-consuming cycles, caused by insufficient ion-accessible surfaces and retarded electron/ion transport. Here, we demonstrate porous carbon fibers (PCFs) derived from microphase-separated poly(methyl methacrylate)-block-polyacrylonitrile (PMMA-b-PAN) as an effective CDI material. PCF has abundant and uniform mesopores that are interconnected with micropores. This hierarchical porous structure renders PCF a large ion-accessible surface area and a high desalination capacity. In addition, the continuous carbon fibers and interconnected porous network enable fast electron/ion transport, and hence a high desalination rate. PCF shows desalination capacity of 30 mgNaCl g⁻¹ PCF and maximal time-average desalination rate of 38.0 mgNaCl g⁻¹ PCF min⁻¹, which are about 3 and 40 times, respectively, those of typical porous carbons. Our work underlines the promise of block copolymer–based PCF for mutually high-capacity and high-rate CDI.
Experimental Investigation of Sound Transmission Loss in Concrete Containing Recycled Rubber Crumbs
Chalangaran, Navid; Farzampour, Alireza; Paslar, Nima; Fatemi, Hadi (Technopress, 2021-05-15)
This study represents procedures and material to improve sound transmission loss through concrete without having any significant effects on mechanical properties. To prevent noise pollution damaging effects, and for reducing the transmission of the noises from streets to residential buildings, sound absorbing materials could be effectively produced. For this purpose, a number of several mixture designs have been investigated in this study to reduce the sound transmission through concrete, including control sample and three mixtures with recycled rubber with sizes of from 1mm up to 3 mm to limit the sound transmission. The rubber is used as a replacement of 5, 10, and 15 percent of sand aggregates. First, 7, 14 and 28-day strengths of the concrete have been measured. Subsequently, the sound transmission losses through the samples have been measured at the range of 63 Hz up to 6300 Hz by using impedance tube and the transfer function. The results show specimens containing 15% fine-grained crumbs, the loss of sound transmission were up to 190%, and for samples with 15% coarse-grained rubber, the loss of sound transmission were up to 228%, respectively. It is shown that concrete with recycled rubber crumbs could effectively improve environmental noise absorption.
Importance of Graphene in the Electro-Fenton Process
Divyapriya, Govindaraj; Nidheesh, Puthiya Veetil (2020-03-17)
Graphene-based nanomaterials have attracted researchers from various fields due to their extraordinary physical, chemical, and electrochemical properties. An emerging class of graphene-based nanostructures and nanocomposites is considered to be a promising solution to various types of environmental pollution. The electro-Fenton process is one of the easy and effective approaches to treating a wide range of organic pollutants in a liquid medium. The usage of graphene-based electrodes in the electro-Fenton process is considered to be a promising and cleaner way to produce reactive oxygen species to mineralize organic contaminants rapidly. Graphene derivatives are used to immobilize various heterogeneous Fenton catalysts for improved catalytic activity, stability, and reusability. In this review, the importance of graphene-based materials in improving the performance efficiency in the electro-Fenton process is presented along with an enhancement mechanism through the following discussions: (i) the significance of oxygen functional groups and nitrogen doping on graphene layers to enhance the two-electron oxygen reduction reactions; (ii) the advantages of iron-loaded graphene-based materials as catalysts and composite electrodes for the enhanced production of reactive oxygen species; (iii) a summary of various forms of graphene-based materials, modifications in their chemical structure, properties, and applications in the electro-Fenton process to remove organic contaminants.
Mechanical Performance of Yellow-Poplar Cross Laminated Timber
Mohamadzadeh, Milad; Hindman, Daniel (2015-12-03)
Cross-laminated timber (CLT) is a structural wood composite material consisting of multi-layers of lumber orthogonal to each other creating massive wood panels. Development of CLT introduced a new concept of using wood in low to midrise buildings as an alternative for concrete and steel. Speed and ease of construction, seismic performance and carbon sequestration are advantages of CLT material. Softwood species have been traditionally used as wood structural materials while hardwood species have not. The purpose of this paper was to examine whether CLT made from fast growing hardwood species can provide sufficient mechanical performance need to be used in structural engineering applications. Yellow-poplar CLT was tested experimentally for stiffness and strength in five-point bending and four-point bending tests, respectively as well as resistance to shear by compression lading and resistance to delamination and the results were compared with American National Standard Institute/APA-The Engineered Wood Association (ANSI/APA) PRG 320-Standard for Performance Rated Cross-Laminated Timber and previous research. Bending stiffness, bending strength and resistance to delamination exceeded the required value in the standard, while wood failure in resistance to shear by compression loading was less than the required value. Shear strength of the yellow-poplar CLT was also greater than CLT produced from softwood species tested in previous research. Acceptable mechanical performance of yellow-poplar CLT confirmed in this research, could be a start point of using hardwood species in CLT structural design.
Mitigation of bidirectional solute flux in forward osmosis via membrane surface coating of zwitterion functionalized carbon nanotubes
Zou, Shiqiang; Smith, Ethan D.; Lin, Shihong; Martin, Stephen M.; He, Zhen (Elsevier, 2019-07-08)
Forward osmosis (FO) has emerged as a promising membrane technology to yield high-quality reusable water from various water sources. A key challenge to be solved is the bidirectional solute flux (BSF), including reverse solute flux (RSF) and forward solute flux (FSF). Herein, zwitterion functionalized carbon nanotubes (Z-CNTs) have been coated onto a commercial thin film composite (TFC) membrane, resulting in BSF mitigation via both electrostatic repulsion forces induced by zwitterionic functional groups and steric interactions with CNTs. At a coating density of 0.97 gm⁻², a significantly reduced specific RSF was observed for multiple draw solutes, including NaCl (55.5% reduction), NH₄H₂PO₄(83.8%), (NH₄)₂HPO₄ (74.5%), NH₄Cl (70.8%), and NH₄HCO₃ (61.9%). When a synthetic wastewater was applied as the feed to investigate membrane rejection, FSF was notably reduced by using the coated membrane with fewer pollutants leaked to the draw solution, including NH₄⁺-N (46.3% reduction), NO₂⁻₋N (37.0%), NO₂⁻₋N (30.3%), K⁺ (56.1%), PO₄³⁻₋P (100%), and Mg²⁺ (100%). When fed with real wastewater, a consistent water flux was achieved during semi-continuous operation with enhanced fouling resistance. This study is among the earliest efforts to address BSF control via membrane modification, and the results will encourage further exploration of effective strategies to reduce BSF.
Nano Silica and Metakaolin Effects on the Behavior of Concrete Containing Rubber Crumbs
Chalangaran, Navid; Farzampour, Alireza; Paslar, Nima (MDPI, 2020-11-08)
The excessive production of worn tires remaining from the transportation system and the lack of proper procedures to recycle or reuse these materials have caused critical environmental issues. Due to the rubber’s toughness, this material could be implemented to increase concrete toughness, and by crushing the tires concrete aggregates can be replaced proportionally with rubber crumbs and large quantities of scrapped rubber. However, this substitution decreases the concrete strength. In this study, crushed rubber with sizes from 1 to 3 mm and 3 to 6 mm were replaced by 5%, 10%, and 15% sand; the combination of two additives of nano silica and metakaolin additives with optimum values was used to compensate the degradation of the strength and improve the workability of the concrete. Moreover, the compressive strength, tensile behavior, and modulus of elasticity were measured and compared. The results indicate that the optimum use of nano silica and metakaolin additives could compensate the negative effects of the rubber material implementation in the concrete mixture while improving the overall workability and flowability of the concrete mixture.
Nanomaterial enabled sensors for environmental contaminants
Willner, Marjorie R.; Vikesland, Peter J. (2018-11-22)
The need and desire to understand the environment, especially the quality of one’s local water and air, has continued to expand with the emergence of the digital age. The bottleneck in understanding the environment has switched from being able to store all of the data collected to collecting enough data on a broad range of contaminants of environmental concern. Nanomaterial enabled sensors represent a suite of technologies developed over the last 15 years for the highly specific and sensitive detection of environmental contaminants. With the promise of facile, low cost, field-deployable technology, the ability to quantitatively understand nature in a systematic way will soon be a reality. In this review, we first introduce nanosensor design before exploring the application of nanosensors for the detection of three classes of environmental contaminants: pesticides, heavy metals, and pathogens.
Numerical Analysis of Signal Response Characteristic of Piezoelectric Energy Harvesters Embedded in Pavement
Yang, Hailu; Zhao, Qian; Guo, Xueli; Zhang, Weidong; Liu, Pengfei; Wang, Linbing (MDPI, 2020-06-18)
Piezoelectric pavement energy harvesting is a technological approach to transform mechanical energy into electrical energy. When a piezoelectric energy harvester (PEH) is embedded in asphalt pavements or concrete pavements, it is subjected to traffic loads and generates electricity. The wander of the tire load and the positioning of the PEH affect the power generation; however, they were seldom comprehensively investigated until now. In this paper, a numerical study on the influence of embedding depth of the PEH and the horizontal distance between a tire load and the PEH on piezoelectric power generation is presented. The result shows that the relative position between the PEH and the load influences the voltage magnitude, and different modes of stress state change voltage polarity. Two mathematic correlations between the embedding depth, the horizontal distance, and the generated voltage were fitted based on the computational results. This study can be used to estimate the power generation efficiency, and thus offer basic information for further development to improve the practical design of PEHs in an asphalt pavement.
The State of the Art: Application of Green Technology in Sustainable Pavement
Sun, Wenjuan; Lu, Guoyang; Ye, Cheng; Chen, Shiwu; Hou, Yue; Wang, Dawei; Wang, Linbing; Oeser, Markus (Hindawi, 2018-06-03)
A wide range of literature on predominant green technologies for sustainable pavements is summarized in this paper. It covers two major aspects: energy harvesting technologies and permeable pavement systems. Fundamental mechanics of energy harvesting techniques and possible designs of energy harvesters are described, with the evaluation of energy conversion efficiency, and advantages and disadvantages. In addition, the designs of permeable pavement systems are discussed, along with their advantages and disadvantages. The latest technical innovations are highlighted. It is found that green technologies are promising for developing more sustainable pavements. Application issues are also pointed out, including construction challenges, durability, and life-cycle cost-benefit assessment. Future research directions are suggested to address practical challenges, such as efficient design, construction challenge, timely maintenance, and life-cycle performance assessment.
Toxicity of Particulate Matter from Incineration of Nanowaste
Vejerano, Eric P.; Ma, Yanjun; Holder, Amara L.; Pruden, Amy; Elankumaran, Subbiah; Marr, Linsey C. (The Royal Society of Chemistry, 2015-01-13)
Disposal of some nanomaterial-containing waste by incineration and the subsequent formation of particulate matter (PM) along with hazardous combustion by-products are inevitable. The effect of nanomaterials on the toxicity of the PM is unknown. We assessed the oxidative potential (OP) and toxicity of PM resulting from the incineration of pure nanomaterials and of paper and plastic wastes containing Ag, NiO, TiO2, ceria, C60, Fe2O3, or CdSe/ZnS quantum dots (CdSe QD) at mass loadings ranging from 0.1 wt% to 10 wt%. We measured reactive oxygen species (ROS) using the dichlorofluorescein assay, and we also measured consumption of ascorbic acid, dithiothreitol (DTT), glutathione (GSH), or uric acid antioxidants from raw and solvent-extracted PM, denoted “cleaned PM”. We determined cytotoxicity and genotoxicity of PM to A549 human lung epithelial cells with the WST-1 cell viability and histone immunofluorescence assays, respectively. In most cases, the presence of nanomaterials in the waste did not significantly affect the OP of PM; however, PM derived from waste containing Ag, TiO2, and C60 had elevated ROS response in the GSH and DTT assays. The ratio of reduced to oxidized glutathione was significantly higher for cleaned PM compared to raw PM for almost all nanomaterials at almost all concentrations, indicating that combustion by-products adsorbed on raw PM play an important role in determining OP. The presence of nanomaterials did not significantly modify the cytotoxicity or genotoxicity of the PM. Different antioxidants used to assess OP had varying sensitivity towards organic compounds v. metals in PM. The presence of these seven nanomaterials at low concentrations in the waste stream is not expected to exacerbate the hazard posed by PM that is produced by incineration.
Waste not want not: life cycle implications of gold recovery and recycling from nanowaste
Pati, Paramjeet; McGinnis, Sean; Vikesland, Peter J. (Royal Society of Chemistry, 2016-08-24)
Commercial-scale applications of nanotechnology are rapidly increasing. Enhanced production of nanomaterials and nano-enabled products and their resultant disposal lead to concomitant increases in the volume of nanomaterial wastes (i.e., nanowaste). Many nanotechnologies employ resource-limited materials, such as precious metals and rare earth elements that ultimately end up as nanowaste. To make nanotechnology more sustainable it is essential to develop strategies to recover these high-value, resource-limited materials. To address this complex issue, we developed laboratory-scale methods to recover nanowaste gold. To this end, α-cyclodextrin facilitated host–guest inclusion complex formation involving second-sphere coordination of [AuBr4]− and [K(OH2)6]+ was used for gold recovery and the recovered gold was then used to produce new nanoparticles. To quantify the environmental impacts of this gold recycling process we then produced life cycle assessments to compare nanoparticulate gold production scenarios with and without recycling. The LCA results indicate that recovery and recycling of nanowaste gold can significantly reduce the environmental impacts of gold nanoparticle synthesis.

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