Rational design of nanomaterials for water treatment

Li, Renyuan; Zhang, Lianbin; Wang, Peng

doi:10.1039/c5nr04870b

Cited by 184 publications

(134 citation statements)

References 395 publications

(864 reference statements)

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“…ETAS is expected to show higher energy efficiencies and incur lower environmental costs than established methods for separation of neutral organics from water such as distillation, stripping, extraction, adsorption and filtration. [11][12][13] It operates at ambient temperature and pressure, requires no need for 21 -responsive systems that exhibit only two levels of hydrophobicity (i.e., merely ''on/off'' bimodal control), ETAS can achieve multiple levels of hydrophobicity and thus affinity towards organics since the electrical signal (i.e., potential) can be tuned with high precision, permitting a systematic adjustment of the ratio between the hydrophobic and hydrophilic moieties. Such flexible modulation of affinity for target pollutants is key to achieving a balance between the separation degree and the energetic efficiency, as discussed later.…”

Section: Introductionmentioning

confidence: 99%

“…[7][8][9][10] High separation efficiencies for the removal of organics from water have been achieved using conventional processes such as adsorption, stripping, distillation, and solvent extraction, as well as more recent technologies such as advanced oxidation treatment and membrane separation. [11][12][13] However, the overall separation processes inherently associated with these methods usually involve energy-intensive steps (e.g. requirement for high temperature or pressure) and/or environmentally unfriendly processes (e.g., use of organic solvents and additives, generation of secondary pollutants).…”

Section: Introductionmentioning

confidence: 99%

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Energetically efficient electrochemically tunable affinity separation using multicomponent polymeric nanostructures for water treatment

Mao

Tian

Ren

et al. 2018

Energy Environ. Sci.

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We describe a water treatment strategy, electrochemically tunable affinity separation (ETAS), which, unlike other previously developed electrochemical processes, targets uncharged organic pollutants in water. Key to achieving ETAS resides in the development of multicomponent polymeric nanostructures that simultaneously exhibit the following characteristics: an oxidation-state dependent affinity towards neutral organics, high porosity for sufficient adsorption capacity, and high conductivity to permit electrical manipulation. A prototype ETAS adsorbent composed of nanostructured binary polymeric surfaces that can undergo an electrically-induced hydrophilic-hydrophobic transition can provide programmable control of capture and release of neutral organics in a cyclic fashion. A quantitative energetic analysis of ETAS offers insights into the tradeoff between energy cost and separation extent through manipulation of electrical swing conditions. We also introduce a generalizable materials design approach to improve the separation degree and energetic efficiency simultaneously, and identify the critical factors responsible for such enhancement via redox electrode simulations and theoretical calculations of electron transfer kinetics. The effect of operation mode and multistage configuration on ETAS performance is examined, highlighting the practicality of ETAS and providing useful guidelines for its operation at large scale. The ETAS approach is energetically efficient, environmentally friendly, broadly applicable to a wide range of organic contaminants of various molecular structures, hydrophobicity and functionality, and opens up new avenues for addressing the urgent, global challenge of water purification and wastewater management. Broader contextSeparation processes are of paramount importance in the chemical and environmental industries, accounting for 10-25% of the world's energy consumption, and about a third of total capital and operation costs in industrial plants. The development of separation technologies for water treatment with high energy efficiency and low environmental impact has become a primary engineering challenge for the 21st century due to the worldwide occurrence of water contamination and its associated negative impacts on the environment and human health. Electrochemically controlled processes, such as capacitive deionization, have emerged as promising candidates for wastewater management and water desalination. However, since these previously developed electrochemical methods rely primarily on the electrostatic interaction between the electrode and the target pollutant, they only work for charged species (e.g., anions, cations), and are not applicable to uncharged organic pollutants, which constitute the majority of industrial and municipal water contaminants, including many dyes, pesticides, pharmaceuticals and carcinogenic aromatics. This study investigates a conceptually novel separation strategy that enables sensitive, programmable electrochemical control over the release and capture of u...

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Energetically efficient electrochemically tunable affinity separation using multicomponent polymeric nanostructures for water treatment

Mao

Tian

Ren

et al. 2018

Energy Environ. Sci.

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“…Recently, increasing water demands have forced research into membranes with a superior water flux. With this progress in water flux enhancement, research into membrane antifouling has become more and more pressing as membrane fouling worsens along with increasing water flux [9,10]. Fouled membranes have substantially shorter lifespan and lessened filtration efficiency.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Nanostructured Polyamic Acid Membranes for Antimicrobially Enhanced Water Purification

Kimotho

Noah

Nawiri

et al. 2020

Advances in Polymer Technology

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Water scarcity and quality challenges facing the world can be alleviated by Point-of-Use filtration devices (POU). e use of filtration membranes in POU devices has been limited largely because of membrane fouling, which occurs when suspended solids, microbes, and organic materials are deposited on the surface of filtration membranes significantly decreasing the membrane lifespan, thereby increasing operation costs. ere is need therefore to develop filtration membranes that are devoid of these challenges. In this work, nanotechnology was used to fabricate nanostructured polyamic acid (nPAA) membranes, which can be used for microbial decontamination of water. e PAA was used as support and reducing agent to introduce silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) with antimicrobial properties. e nPAA membranes were fabricated via thermal and wet phase inversion technique and then tested against Escherichia coli and Staphylococcus aureus following standard tests. e resulting nanoparticles exhibited excellent dispersibility and stability as indicated by the color change of the solution and increments of optical density at 415 nm for AgNPs and 520 nm for AuNPs. e wet phase inversion process used produced highly porous, strong, and flexible nPAA membranes, which showed well-dispersed spherical AuNPs and AgNPs whose rough average size was found to be 35 nm and 25 nm, respectively. e AgNPs demonstrated inhibition for both gram positive E. coli and gram negative S. aureus, with a better inhibitory activity against S. aureus. A synergistic enhancement of AgNPs antimicrobial activity upon AuNPs addition was demonstrated. e nPAA membranes can thus be used to remove microbials from water and can hence be used in water purification.

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“…4 However, traditional nanoporous adsorbents, such as activated carbon, are incompatible with micrometer-sized droplets. [4][5][6] polyurethane sponge coated with decyl capped nanocrystalline silicon. The surface chemistry, surface charge, roughness, and surface energy were characterized using X-ray photoelectron spectroscopy, microscopy, electrokinetic analysis, and inverse chromatographic techniques.…”

Section: Introductionmentioning

confidence: 99%

Adsorptive Recovery of Crude Oil Microdroplets from Wastewater Using Surface Engineered Sponges

Cherukupally¹,

Sun²,

Wong³

et al. 2019

Preprint

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In the US, the oil industry produces over 15 billion barrels of wastewater contaminated with crude oil microdroplets annually. Current technologies are unable to remove these microdroplets at different pH conditions. Herein, an innovative surface engineered sponge (SEnS) was designed by combining surface chemistry, surface charge, roughness, and surface energy. Under all pH conditions, the SEnS rapidly adsorbed oil microdroplets with 95-99% removal efficiency predominantly by Lifshitz-van der Waals forces. Furthermore, at the best pH value, 92% of the oil was adsorbed within 10 min due to synergistic Lifshitz-van der Waals and acid-base (electrostatic attractive interactions and hydrogen bond) forces. The adsorbed crude oil was recovered at ambient conditions while the cleaned SEnS was reused up to five times for crude oil adsorption. Due to the process efficacy, sponge reuse, and oil recovery, this adsorptive-recovery method using SEnS demonstrates great potential for the industrial recovery of oil from wastewater.Recently, surface engineered sponges (SEnS) have emerged as promising adsorbents for oil microdroplets. 7-9 Due to their low cost, ease of fabrication, and high uptake capacity, sponges have great potential as industrial-scale sorbents. 10 To date, most sponge surfaces have been tailored to adsorb surfactant-stabilized pure hydrocarbon emulsions, which exhibit monotonous wetting at different pH values. 7,8 In contrast, crude oil is a complex mixture of ionic, polar, and non-polar components. 11,12 As a result, depending on pH, these complex chemical mixtures can exhibit large variability in physicochemical properties 13,14 leading to a broad range of contact angles at a solid surface. 9 Furthermore, the fundamental mechanisms governing variation in crude oil wetting behaviour with pH, which are important for material design, are not well understood.This work develops new sponges that are robust to the variable pH-responsive wetting behaviour of crude oil. Desirable sponge surface properties for microdroplets adsorption over broad pH conditions were hypothesized. To complement crude oil composition variability, the sponge surface is predicted to need organic, acid and base sites for effective oil adsorption (Figure 1a).Along with tailored surface chemistry, 15-17 the surface charge, [17][18][19] and roughness 20-22 may also invoke favorable wetting behavior 23-26 at the sponge surface (Figure 1b), enabling adsorption of oil droplets over a broad pH range. Based on these properties, the crude oil adsorption process efficacy can be predicted and validated experimentally.Herein, the aforementioned approach was applied to develop SEnS for adsorptive recovery of crude oil microdroplets for variable pH conditions. The SEnS consists of an acid-base polyester Affiliations

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Rational design of nanomaterials for water treatment

Cited by 184 publications

References 395 publications

Energetically efficient electrochemically tunable affinity separation using multicomponent polymeric nanostructures for water treatment

Energetically efficient electrochemically tunable affinity separation using multicomponent polymeric nanostructures for water treatment

Fabrication of Nanostructured Polyamic Acid Membranes for Antimicrobially Enhanced Water Purification

Adsorptive Recovery of Crude Oil Microdroplets from Wastewater Using Surface Engineered Sponges

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