Application of Nanomaterials and Nanotechnology in Water Treatment

A special issue of Nanomaterials (ISSN 2079-4991). This special issue belongs to the section "Environmental Nanoscience and Nanotechnology".

Deadline for manuscript submissions: closed (30 June 2022) | Viewed by 16023

Special Issue Editor

School of Energy & Power Engineering, Dalian University of Technology, Dalian 116024, China
Interests: low dimensional materials; carbon nanomaterials; water treatment; energy storage
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Clean water has become an increasingly precious resource. Most manufacturing and living activities consume large volumes of water and generate large volumes of polluted wastewater. Providing sufficiently safe and clean water is critical for peoples’ daily life and society’s development. Therefore, various technologies have been developed for water treatment aiming at sustainable development. The use of nanomaterials and nanotechnology holds the promise of producing potable water and treating polluted wastewater.

The large surface areas and tunable surface chemistry allow the used nanomaterials to increase and control the solid–water interface, directly removing or destroying the undesired species such as salts and contaminants. Additionally, nanomaterials provide ideal tools for the development of novel water treatment processes and devices.

This Special Issue of Nanomaterials will attempt to cover a wide range of water treatment where nanomaterials and nanotechnology play critical roles. The topics include, but are not limited to, nanomaterials, their composites, nanofabrication, process and device design, in the forms of communications, reviews, and regular research papers.

Prof. Dr. Zheng Ling
Guest Editor

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Keywords

  • nanomaterials
  • low dimensional materials
  • water treatment
  • desalination
  • phase change
  • interface

Published Papers (7 papers)

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Research

12 pages, 2259 KiB  
Article
Recovery of Ammonium Sulfate Solution by Regeneration of Loaded Clinoptilolite
by Stephan Wasielewski, Eduard Rott, Ralf Minke and Heidrun Steinmetz
Nanomaterials 2022, 12(3), 525; https://doi.org/10.3390/nano12030525 - 02 Feb 2022
Cited by 1 | Viewed by 1468
Abstract
The zeolite clinoptilolite (CLI) is known to be a very good ion exchanger, as it consists of a three-dimensional structure formed of AlO4 and SiO4 tetrahedral, which are connected by a common oxygen atom. The micropores formed by this structure [...] Read more.
The zeolite clinoptilolite (CLI) is known to be a very good ion exchanger, as it consists of a three-dimensional structure formed of AlO4 and SiO4 tetrahedral, which are connected by a common oxygen atom. The micropores formed by this structure (with free diameters in the range of 0.40 nm and 0.72 nm) are fine enough to allow cations and water molecules to enter and be exchanged. CLI is a suitable, inexpensive, and globally available material for removing ammonium from highly-concentrated wastewater and is proven to be selective in ammonium uptake and regeneration since no effect of the provenance of the ammonium (matrix-free NH4Cl solution or sludge water) could be found. However, regeneration of the clinoptilolite is necessary to recover the adsorbed ammonium for further use and restore its capability for ion exchange. Within this work, the method by which clinoptilolite, loaded with ammonium (q = 8.1–16.6 mg/g) from different sludge waters and ammonium chloride solution, can be regenerated to yield a stoichiometric ammonium sulfate solution (ASS), that could be used, e.g., as a fertilizer, was investigated. A regeneration solution containing Na2SO4 (0.25 n(Na2SO4)/n(NH4+ads)) with a varying NaOH ratio (0–2.14 n(NaOH)/n(NH4+ads)) was tested. To obtain a high ammonium concentration in the eluate, a large mass fraction ω of 284 g/kg of CLI in the regeneration solution was applied. The effects of different ammonium loads, different origins of the ammonium, and residual moisture on the necessary components of the regeneration solution, in which an ASS is obtained within a contact time of 10 min at 22 °C, were studied. A stoichiometric ASS from CLI loaded up to a maximum of 13.5 mg/g was obtained with a mixture of 0.25 n(Na2SO4)/n(NH4+ads) together with 0.8–1.0 n(NaOH)/n(NH4+ads) for dry CLI, and 0.75 n(NaOH)/n(NH4+ads) for CLI with residual moisture. Full article
(This article belongs to the Special Issue Application of Nanomaterials and Nanotechnology in Water Treatment)
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22 pages, 3302 KiB  
Article
As(III, V) Uptake from Nanostructured Iron Oxides and Oxyhydroxides: The Complex Interplay between Sorbent Surface Chemistry and Arsenic Equilibria
by Marco Sanna Angotzi, Valentina Mameli, Alessandra Fantasia, Claudio Cara, Fausto Secci, Stefano Enzo, Marianna Gerina and Carla Cannas
Nanomaterials 2022, 12(3), 326; https://doi.org/10.3390/nano12030326 - 20 Jan 2022
Cited by 8 | Viewed by 1684
Abstract
Iron oxides/oxyhydroxides, namely maghemite, iron oxide-silica composite, akaganeite, and ferrihydrite, are studied for AsV and AsIII removal from water in the pH range 2–8. All sorbents were characterized for their structural, morphological, textural, and surface charge properties. The same experimental conditions [...] Read more.
Iron oxides/oxyhydroxides, namely maghemite, iron oxide-silica composite, akaganeite, and ferrihydrite, are studied for AsV and AsIII removal from water in the pH range 2–8. All sorbents were characterized for their structural, morphological, textural, and surface charge properties. The same experimental conditions for the batch tests permitted a direct comparison among the sorbents, particularly between the oxyhydroxides, known to be among the most promising As-removers but hardly compared in the literature. The tests revealed akaganeite to perform better in the whole pH range for AsV (max 89 mg g−1 at pH0 3) but to be also efficient toward AsIII (max 91 mg g−1 at pH0 3–8), for which the best sorbent was ferrihydrite (max 144 mg g−1 at pH0 8). Moreover, the study of the sorbents’ surface chemistry under contact with arsenic and arsenic-free solutions allowed the understanding of its role in the arsenic uptake through electrophoretic light scattering and pH measurements. Indeed, the sorbent’s ability to modify the starting pH was a crucial step in determining the removal of performances. The AsV initial concentration, contact time, ionic strength, and presence of competitors were also studied for akaganeite, the most promising remover, at pH0 3 and 8 to deepen the uptake mechanism. Full article
(This article belongs to the Special Issue Application of Nanomaterials and Nanotechnology in Water Treatment)
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17 pages, 9634 KiB  
Article
Photocatalytic Activity of Titanium Dioxide Nanotubes Following Long-Term Aging
by Stephen Abela, Clayton Farrugia, Ryan Xuereb, Frederick Lia, Edwin Zammit, Alex Rizzo, Paul Refalo and Maurice Grech
Nanomaterials 2021, 11(11), 2823; https://doi.org/10.3390/nano11112823 - 24 Oct 2021
Cited by 5 | Viewed by 1915
Abstract
Anodic titanium dioxide (TiO2) nanotubes were found to be active photocatalysts. These photocatalysts possess a high surface area, even when supported, rendering them potential candidates for water treatment. In this work, photocatalytic surfaces were produced by anodizing commercially pure Ti plates [...] Read more.
Anodic titanium dioxide (TiO2) nanotubes were found to be active photocatalysts. These photocatalysts possess a high surface area, even when supported, rendering them potential candidates for water treatment. In this work, photocatalytic surfaces were produced by anodizing commercially pure Ti plates using two different electrolyte compositions and correspondingly diverse process parameters. Changes in the physical and chemical stability as well as photocatalytic activity were studied over a fifty-two-week aging process. During this period, the nanotubular surfaces were exposed to flowing synthetic greywater, solar irradiation, and the natural environment. The physical and phase stability of the materials anodized using the organic electrolyte were found to be outstanding and no degradation or change in crystalline structure was observed. On the other hand, materials anodized in the aqueous electrolyte proved to suffer from light-induced phase transition from anatase to rutile. Surfaces synthesized in the organic electrolyte were more resistant to fouling and showed a better tendency to recover photocatalytic activity upon cleaning. In conclusion, the nanotubes produced in the organic electrolyte proved to be stable, rendering them potentially suitable for real-life applications. Full article
(This article belongs to the Special Issue Application of Nanomaterials and Nanotechnology in Water Treatment)
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15 pages, 3360 KiB  
Article
Highly Efficient Iron Oxide Nanoparticles Immobilized on Cellulose Nanofibril Aerogels for Arsenic Removal from Water
by Md Musfiqur Rahman, Islam Hafez, Mehdi Tajvidi and Aria Amirbahman
Nanomaterials 2021, 11(11), 2818; https://doi.org/10.3390/nano11112818 - 23 Oct 2021
Cited by 11 | Viewed by 2971
Abstract
The application and optimal operation of nanoparticle adsorbents in fixed-bed columns or industrial-scale water treatment applications are limited. This limitation is generally due to the tendency of nanoparticles to aggregate, the use of non-sustainable and inefficient polymeric resins as supporting materials in fixed-bed [...] Read more.
The application and optimal operation of nanoparticle adsorbents in fixed-bed columns or industrial-scale water treatment applications are limited. This limitation is generally due to the tendency of nanoparticles to aggregate, the use of non-sustainable and inefficient polymeric resins as supporting materials in fixed-bed columns, or low adsorption capacity. In this study, magnesium-doped amorphous iron oxide nanoparticles (IONPs) were synthesized and immobilized on the surface of cellulose nanofibrils (CNFs) within a lightweight porous aerogel for arsenic removal from water. The IONPs had a specific surface area of 165 m2 g−1. The IONP-containing CNF aerogels were stable in water and under constant agitation due to the induced crosslinking using an epichlorohydrin crosslinker. The adsorption kinetics showed that both As(III) and As(V) adsorption followed a pseudo second-order kinetic model, and the equilibrium adsorption isotherm was best fitted using the Langmuir model. The maximum adsorption capacities of CNF-IONP aerogel for As(III) and As(V) were 48 and 91 mg As g-IONP−1, respectively. The optimum IONP concentration in the aerogel was 12.5 wt.%, which resulted in a maximum arsenic removal, minimal mass loss, and negligible leaching of iron into water. Full article
(This article belongs to the Special Issue Application of Nanomaterials and Nanotechnology in Water Treatment)
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14 pages, 2222 KiB  
Article
Efficient Hydrogen Generation and Total Nitrogen Removal for Urine Treatment in a Neutral Solution Based on a Self-Driving Nano Photoelectrocatalytic System
by Pengbo Wang, Jinhua Li, Yang Xu, Changhui Zhou, Yan Zhang, Lina Zha, Bo Zhang, Jing Bai and Baoxue Zhou
Nanomaterials 2021, 11(11), 2777; https://doi.org/10.3390/nano11112777 - 20 Oct 2021
Cited by 5 | Viewed by 1971
Abstract
Urine is the main source of nitrogen pollution, while urea is a hydrogen-enriched carrier that has been ignored. Decomposition of urea to H2 and N2 is of great significance. Unfortunately, direct urea oxidation suffers from sluggish kinetics, and needs strong alkaline [...] Read more.
Urine is the main source of nitrogen pollution, while urea is a hydrogen-enriched carrier that has been ignored. Decomposition of urea to H2 and N2 is of great significance. Unfortunately, direct urea oxidation suffers from sluggish kinetics, and needs strong alkaline condition. Herein, we developed a self-driving nano photoelectrocatalytic (PEC) system to efficiently produce hydrogen and remove total nitrogen (TN) for urine treatment under neutral pH conditions. TiO2/WO3 nanosheets were used as photoanode to generate chlorine radicals (Cl•) to convert urea-nitrogen to N2, which can promote hydrogen generation, due to the kinetic advantage of Cl/Cl• cyclic catalysis. Copper nanowire electrodes (Cu NWs/CF) were employed as the cathode to produce hydrogen and simultaneously eliminate the over-oxidized nitrate-nitrogen. The self-driving was achieved based on a self-bias photoanode, consisting of confronted TiO2/WO3 nanosheets and a rear Si photovoltaic cell (Si PVC). The experiment results showed that hydrogen generation with Cl• is 2.03 times higher than in urine treatment without Cl•, generating hydrogen at 66.71 μmol h−1. At the same time, this system achieved a decomposition rate of 98.33% for urea in 2 h, with a reaction rate constant of 0.0359 min−1. The removal rate of total nitrogen and total organic carbon (TOC) reached 75.3% and 48.4% in 2 h, respectively. This study proposes an efficient and potential urine treatment and energy recovery method in neutral solution. Full article
(This article belongs to the Special Issue Application of Nanomaterials and Nanotechnology in Water Treatment)
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13 pages, 3045 KiB  
Article
Incorporation of Biomass-Based Carbon Nanoparticles into Polysulfone Ultrafiltration Membranes for Enhanced Separation and Anti-Fouling Performance
by Zhiyu Zheng, Jingwen Chen, Jiamin Wu, Min Feng, Lei Xu, Nina Yan and Hongde Xie
Nanomaterials 2021, 11(9), 2303; https://doi.org/10.3390/nano11092303 - 04 Sep 2021
Cited by 6 | Viewed by 1990
Abstract
Functionalized carbon nanomaterials are considered to be an efficient modifier for ultrafiltration membranes with enhanced performance. However, most of the reported carbon nanomaterials are derived from unsustainable fossil fuels, while an extra modification is often essential before incorporating the nanomaterials in membranes, thus [...] Read more.
Functionalized carbon nanomaterials are considered to be an efficient modifier for ultrafiltration membranes with enhanced performance. However, most of the reported carbon nanomaterials are derived from unsustainable fossil fuels, while an extra modification is often essential before incorporating the nanomaterials in membranes, thus inevitably increasing the cost and complexity. In this work, novel functionalized biomass-based carbon nanoparticles were prepared successfully from agricultural wastes of corn stalks through simple one-step acid oxidation method. The obtained particles with the size of ~45 nm have excellent dispersibility in both aqueous and dimethyl formamide solutions with abundant oxygen-containing groups and negative potentials, which can endow the polysulfone ultrafiltration membranes with enhanced surface hydrophilicity, larger pore size, more finger-like pores, and lower surface roughness. Therefore, the separation and anti-fouling performance of membranes are improved simultaneously. Meanwhile, the addition of 0.4 wt% nanoparticles was proved to be the best condition for membrane preparation as excess modifiers may lead to particle aggregation and performance recession. It is expected that these biomass-based carbon nanoparticles are potential modifying materials for improving the separation performance and anti-fouling property of the membranes with great simplicity and renewability, which pave a new avenue for membrane modification and agricultural waste utilization. Full article
(This article belongs to the Special Issue Application of Nanomaterials and Nanotechnology in Water Treatment)
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18 pages, 3593 KiB  
Article
Enhanced Removal of Sulfonated Lignite from Oil Wastewater with Multidimensional MgAl-LDH Nanoparticles
by Ling Zhou, Michal Slaný, Bingbing Bai, Weichao Du, Chengtun Qu, Jie Zhang and Ying Tang
Nanomaterials 2021, 11(4), 861; https://doi.org/10.3390/nano11040861 - 28 Mar 2021
Cited by 29 | Viewed by 2857
Abstract
In this study, hierarchical MgAl-LDH (layered double hydroxide) nanoparticles with a flower-like morphology were prepared under a hydrothermal condition by employing worm-like micelles formed by cetyltrimethylammonium bromide (CTAB) and salicylic acid (SA) as templates. The morphology and structure of the materials were characterized [...] Read more.
In this study, hierarchical MgAl-LDH (layered double hydroxide) nanoparticles with a flower-like morphology were prepared under a hydrothermal condition by employing worm-like micelles formed by cetyltrimethylammonium bromide (CTAB) and salicylic acid (SA) as templates. The morphology and structure of the materials were characterized by Brunauer–Emmett–Teller (BET), SEM, and XRD analyses. The performance for the adsorption of sulfonated lignite (SL) was also investigated in detail. FTIR was used to detect the presence of active functional groups and determine whether they play important roles in adsorption. The results showed that the hierarchical MgAl-LDH nanoparticles with a specific surface area of 126.31 m2/g possessed a flower-like morphology and meso–macroporous structures. The adsorption capacity was high—its value was 1014.20 mg/g at a temperature of 298 K and an initial pH = 7, which was higher than traditional MgAl-LDH (86 mg/g). The adsorption process of sulfonated lignite followed the pseudo-second-order kinetics model and conformed to Freundlich isotherm model with a spontaneous exothermic nature. In addition, the hierarchical MgAl-LDH could be regenerated and used, and the adsorption was high after three adsorption cycles. The main adsorption mechanisms were electrostatic attraction and ion exchange between the hierarchical MgAl-LDH and sulfonated lignite. Full article
(This article belongs to the Special Issue Application of Nanomaterials and Nanotechnology in Water Treatment)
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