Display omitted
•Nanotechnology is a promising alternative to traditional water treatment methods.•Nanotechnology is more effective for removing emerging contaminants.•Treatment cost of some ...nanotechnology is comparable to that of conventional methods.•Risk assessment of nanotechnology is needed in order to advance the technology.
The application of nanotechnology in drinking water treatment and pollution cleanup is promising, as demonstrated by a number of field-based (pilot and full scale) and bench scale studies. A number of reviews exist for these nanotechnology-based applications; but to better illustrate its importance and guide its development, a direct comparison between traditional treatment technologies and emerging approaches using nanotechnology is needed. In this review, the performances of traditional technologies and nanotechnology for water treatment and environmental remediation were compared with the goal of providing an up-to-date reference on the state of treatment techniques for researchers, industry, and policy makers. Pollutants were categorized into broad classes, and the most cost-effective techniques (traditional and nanotechnology-based) in each category reported in the literature were compared. Where information was available, cost and environmental implications of both technologies were also compared. Case studies were also provided where traditional technologies were directly compared with nanotechnology-based technologies for the similar pollutants. Although nanotechnology-based methods are generally believed to be more expensive, we found instances where they offer cheaper and more effective alternatives to conventional techniques. In addition, nano-based techniques may become extremely important in meeting increasingly stringent water quality standards, especially for removal of emerging pollutants and low levels of contaminants. We also discuss challenges facing environmental application of nanotechnology and offer potential solutions.
Sediment and soil contamination with toxic heavy metals, including cadmium (Cd.sup.2+) and lead (Pb.sup.2+ ), represents a major long-term remediation challenge. Resuspension of contaminated ...sediments into the water column, or the uptake of toxic metals from top soil, can lead to exposure of aquatic or terrestrial organisms, followed by bioconcentration, bioaccumulation and biomagnification, which may pose a threat to public health. We have developed a novel nanoscale engineered material, namely ligand-coated dense nanoparticles (Ligand DNPs), which contain a dense WO.sub.3 nanoparticle core and a shell functionalized with a metal-binding organic ligand (EDTA), to effectively sequester heavy metal ions deeper into the soil and sediments. We demonstrate that one application of Ligand DNPs can remove from 60% to almost 80% of the Cd and Pb in two different soil matrices, driving these metal ions deeper into the sediment or soil column via gravity, and making them less bioavailable. Ligand DNPs can provide a relatively fast, convenient, and efficient in-situ approach for the remediation of sediments and soils contaminated with heavy metals.
To better understand the mechanisms of hydrogen peroxide (H
2
O
2
)’s decomposition and reactive oxygen species (ROS)’s formation on the catalyst’s surface is always a critical issue for the ...environmental application of Fenton/Fenton-like reaction. We here report a new approach to activate H
2
O
2
in a co-catalytic Fenton system with oxygen incorporated MoS
2
, namely MoS
2−
x
O
x
nanosheets. The MoS
2−
x
O
x
nanosheets assisted co-catalytic Fenton system exhibited superior degradation activity of emerging antibiotic contaminants (e.g., sulfamethoxazole). Combining density functional theory (DFT) calculation and experimental investigation, we demonstrated that oxygen incorporation could improve the intrinsic conductivity of MoS
2−
x
O
x
nanosheets and accelerate surface/interfacial charge transfer, which further leads to the efficacious activation of H
2
O
2
. Moreover, by tuning the oxygen proportion in MoS
2−
x
O
x
nanosheets, we are able to modulate the generation of ROS and further direct the oriented-conversion of H
2
O
2
to surface-bounded superoxide radical (·O
2 surface
−
). It sheds light on the generation and transformation of ROS in the engineered system (e.g., Fenton, Fenton-like reaction) for efficient degradation of persistent pollutants.
There has been an increasing influx of nanopesticides into agriculture in recent years. Understanding the interaction between nanopesticides and edible plants is crucial in evaluating the potential ...impact of nanotechnology on the environment and agriculture. Here we exposed lettuce plants to Cu(OH)2 nanopesticides (1050–2100 mg/L) through foliar spray for one month. Inductively coupled plasma-mass spectrometry (ICP-MS) results indicate that 97–99% (1353–2501 mg/kg) of copper was sequestered in the leaves and only a small percentage (1–3%) (17.5–56.9 mg/kg) was translocated to root tissues through phloem loading. Gas chromatography-time-of-flight mass spectrometry (GC-TOF-MS) based metabolomics combined with partial least squares-discriminant analysis (PLS-DA) multivariate analysis revealed that Cu(OH)2 nanopesticides altered metabolite levels of lettuce leaves. Tricarboxylic (TCA) cycle and a number of amino acid-related biological pathways were disturbed. Some antioxidant levels (cis-caffeic acid, chlorogenic acid, 3,4-dihydroxycinnamic acid, dehydroascorbic acid) were significantly decreased compared to the control, indicating that oxidative stress and a defense response occurred. Nicotianamine, a copper chelator, increased by 12–27 fold compared to the control, which may represent a detoxification mechanism. The up-regulation of polyamines (spermidine and putrescine) and potassium may mitigate oxidative stress and enhance tolerance. The data presented here provide a molecular-scale perspective on the response of plants to copper nanopesticides.
Nanoscale zerovalent iron (nZVI) has demonstrated high efficacy for treating nitrate or cadmium (Cd) contamination, but its efficiency for simultaneous removal of nitrate and Cd has not been ...investigated. This study evaluated the reactivity of nZVI to the co-contaminants and by-product formation, employed different catalysts to reduce nitrite yield from nitrate, and examined the transformation of nZVI after reaction. Nitrate reduction resulted in high solution pH, negatively charged surface of nZVI, formation of Fe3O4 (a stable transformation of nZVI), and no release of ionic iron. Increased pH and negative charge contributed to significant increase in Cd(II) removal capacity (from 40 mg/g to 188 mg/g) with nitrate present. In addition, nitrate reduction by nZVI could be catalyzed by Cd(II): while 30% of nitrate was reduced by nZVI within 2 h in the absence of Cd(II), complete nitrate reduction was observed in the presence of 40 mg-Cd/L due to the formation of Cd islands (Cd(0) and CdO) on the nZVI particles. While nitrate was reduced mostly to ammonium when Cd(II) was not present or at Cd(II) concentrations ≥ 40 mg/L, up to 20% of the initial nitrate was reduced to nitrite at Cd(II) concentrations < 40 mg/L. Among nZVI particles doped with 1 wt. % Cu, Ag, or Au, nZVI deposited with 1 wt. % Au reduced nitrite yield to less than 3% of the initial nitrate, while maintaining a high Cd(II) removal capacity.
Display omitted
•Nitrate enhanced the Cd removal capacity of nZVI from 40 mg/g to 188 mg/g.•The presence of Cd improved nitrate removal efficiency by nZVI from 30% to 100%.•Low level of Cd caused nitrite accumulation in system.•Au doped nZVI successfully reduced nitrite yield ratio from 20% to 3%.•Au doped nZVI can be used to treat nitrate and Cd contaminated groundwater.
Distributed energy resources (DERs) provide flexible load restoration strategies, which can effectively enhance the resilience of active distribution systems (ADSs). Whereas, the widespread DERs in ...ADSs complicates the supply‐demand relationship and make the system resilience difficult to access. Therefore, this paper proposes a simulation‐based resilience assessment algorithm of ADSs considering the microgrid formation based on grid‐edge DERs. Microgrid formation is used to depict the resilience gain of grid‐edge DERs on ADSs. Specifically, a resilience assessment framework for ADSs is firstly proposed, where the uncertainty of component state and supply‐demand is modelled based on probability statistics. Then the mixed integer linear programming is used to search for optimal load restoration strategies with microgrid formation. On this basis, a set of resilience indices are defined to quantitatively analyse the resilience of ADSs, and a resilience assessment algorithm with uncertainty scenario generation is proposed to obtain these indices. Furthermore, extensive numerical results based on a modified IEEE 123‐bus feeder validate the effectiveness of the proposed method.
A simulation‐based resilience assessment algorithm for active distribution systems considering the microgrid formation based on grid‐edge DERs is proposed here, which is helpful to solve the problems brought by the integration of DERs on the resilience assessment of distribution systems, for example, uncertain power flow and flexible load restoration strategies.
Microplastics(MPs) have been one of the most concerned environmental issues since the 21st century. MPs are plastic particles with diameters less than 5 mm, which are widely sourced in the aquatic ...environment. After being released into the aquatic environment, MPs would experience complicated physical, chemical and biological aging processes driven by mechanical forces, photooxidation, and biological degradation, which would result in changes in MPs’ physicochemical properties, such as the particle size, specific surface area, hydrophobicity, crystallinity, etc. In this review, we have illustrated the current study status on MPs’ environmental aging processes and pointed out the knowledge gaps. MPs’ aging processes would consequentially influence MPs’ interaction with the co-existing organic and inorganic pollutants in the aquatic environment as well as lead to the leaching of chemical additives involved in plastic production, including plasticizers and flame retardants, which can trigger high ecotoxicity to the aquatic environment. Furthermore, aged MPs would cause ecotoxicity to aquatic organisms
via
bioaccumulation, biomagnification, and indirect carrier pathways. The review would provide an in-depth overview of MPs’ environmental aging processes and consequential ecotoxicity implications, as well as propose future research needs.
Emerging technologies have driven the rise of many water-related startups and created new opportunities in water markets. The global water crisis could be mitigated by applying innovative ...technologies, sound water management decisions, and successful business models, and it is essential to better understand the status and future trends of emerging water markets. This study aims to discover shifts in the entrepreneurial landscape and evaluate water startups' development performance for the sustainable development of emerging water markets. We collected and analyzed data including the founding date, service area, service provided, details of funding raised, revenues, and consumer responses on 132 water startups founded between 2008 and 2018 in California, USA. Our results indicated that municipal area dominated the emerging water startup market compared to agricultural and industrial areas, and that many of the services provided shifted from conventional technologies to digital technologies. Though digital water startups' current revenues were relatively low, digital techniques applied in the water industry exhibited the good potential to promote public health and water saving. The development trends and performance of water startups enlighten the technological and commercial revolutions in the emerging water market, and provide guidelines for the decision-making in relevant stakeholders in the scientific, governmental, and industrial communities.
Distribution system (DS) communication failures following extreme events often degrade monitoring and control functions, thus preventing the acquisition of complete global DS component state ...information, on which existing post‐disaster DS restoration methods are based. This paper proposes methods of inferring the states of DS components in the case of incomplete component state information. By using the known DS information, the operating states of unobservable DS branches and buses can be inferred, providing complete information for DS performance restoration before full communication recovery.
Distribution system (DS) communication failures following extreme events often degrade monitoring and control functions, thus preventing the acquisition of complete global DS component state information, on which existing post‐disaster DS restoration methods are based. This letter proposes novel methods of inferring the states of DS components in the case of incomplete component state information. By using the known DS information, the operating states of unobservable DS branches and buses can be inferred, providing complete information for DS performance restoration before full communication recovery.
An increasing number of inorganic ultraviolet filters (UVFs), such as nanosized zinc oxide (nZnO) and titanium dioxide (nTiO
), are formulated in sunscreens because of their broad UV spectrum ...sunlight protection and because they limit skin damage. However, sunscreen-derived inorganic UVFs are considered to be emerging contaminants; in particular, nZnO and nTiO
UVFs have been shown to undergo absorption and bioaccumulation, release metal ions, and generate reactive oxygen species, which cause negative effects on aquatic organisms. We comprehensively reviewed the current study status of the environmental sources, occurrences, behaviors, and impacts of sunscreen-derived inorganic UVFs in aquatic environments. We find that the associated primary nanoparticle characteristics and coating materials significantly affect the environmental behavior and fate of inorganic UVFs. The consequential ecotoxicological risks and underlying mechanisms are discussed at the individual and trophic transfer levels. Due to their persistence and bioaccumulation, more attention and efforts should be redirected to investigating the sources, fate, and trophic transfer of inorganic UVFs in ecosystems.
PDF
