Benchtop Approach Research Articles

Development of microbial desalination cells for the treatment of reverse osmosis reject water: A new benchtop approach

To address the growing global demand for usable water, there is an immediate necessity to enhance wastewater treatment systems. A continuous mode adaption of the conventional three-chamber microbial desalination cell (MDC) configuration was used, with gravity facilitating the flow of residential reject water for desalination. Initially, operating in batch mode with a 100 mL treatment volume, the single microbial desalination machine was expanded to 300 mL in continuous mode, capable of treating 5 L of home refuse water over 36 days. The batch mode MDC had a maximum current and power density of 3.81 µA/cm2 and 0.337 µW/cm2, resulting in 76 % desalination and 83.9 % COD eradication rates. Scaling up increased the MDC's performance, reaching a maximum of 0.45 µW/cm2 and 5.31 µA/cm2, which was 1.3 times greater than batch mode operation. The current work demonstrates the feasibility of microbial desalination cells and their novel approach for treating much higher quantities of reverse osmosis (R.O.) saline water in a comparable period of roughly 36 days. It emphasizes the actual limits when dealing with real-world wastewater samples, presenting a unique path for biotechnology by simultaneously generating bio-electricity and tackling future contaminants. Furthermore, incorporating desalination chambers with microbial fuel cells increases efficiency and opens up new options for enhanced wastewater treatment, resource recovery, and bioenergy generation. This pioneering strategy uses innovative membrane technologies and microbial optimization approaches to push the limits of desalination.

A Recipe for a Great Meal: A Benchtop Route from Elemental Se to Superior Thermoelectric β-Ag2Se.

The low-temperature modification of β-Ag2Se has proven to be useful as a near-room-temperature thermoelectric material. Over the past years, research has been devoted to interstitial, vacancy, and substitutional doping into the parent β-Ag2Se structure, aiming at tuning the material's charge and heat transport properties to enhance thermoelectric performance. The transformation of β-Ag2Se into α-Ag2Se at ∼134 °C and the low solubility of dopants are the main obstacles for the doping approach. Herein, we report a facile, safe, scalable, and cost-effective benchtop approach to successfully produce metal-doped β-Ag2Se. The doped materials display a remarkable enhancement of thermoelectric performance with a record-high peak zT of 1.30 at 120 °C and an average zT of ∼1.15 in the 25-120 °C range for 0.2 at. % Zn-doped Ag2Se. The enhancement in zT is attributed to point defects created by Zn doping into Ag vacancies/interstitials, which enhances the scattering of phonons and tunes the charge carrier properties, leading to the significant suppression of thermal conductivity. The simplicity of the synthetic method developed herein and the high performance of the final products provide an avenue to produce high-quality Ag2Se-based thermoelectric materials.

Electrochemical Deposition of N-Heterocyclic Carbene on Steels As a Corrosion Protective Layer

Steels play a vital role in every aspect of day-to-day life. They are major components in construction,transportation, medicine, and etc. Despite their larger usability, steels are suffering from inevitablecorrosion. Hence, finding a sustainable solution for corrosion has been a hot topic in the research field forcenturies. One extensively studied strategy is applying a protective layer on top of metals. The recentfindings show that N-heterocyclic carbene (NHC) has the potency to form a carbon-metal bond throughself-assembling1 or electrochemical deposition2 on different metals such as Au, Pt, Pd, and Ag. Herein, weare trying to coat NHC on mild steel (MS) through electrochemical deposition to act as a corrosionprotective layer. Deposition conditions will be optimized by varying the material concentrations, appliedvoltages, time durations, and substrate roughness. The NHC-coated surface is characterized by X-rayPhotoelectron Spectroscopy (XPS), Matrix-Assisted Laser Desorption/Ionization (MALDI), and AtomicForce Microscope-Infrared Spectroscopy (AFM-IR). In addition, the contact angle measurements can beattributed to visualizing the differences in coatings under different conditions. The corrosion studies areutilized to understand the corrosion-resistant properties of the NHC coating. Moreover, the NHC moietycan be modified to perform better to inhibit corrosion and improve the properties of mild steel on theirapplications. Ultimately, this benchtop approach will be utilized and tested on a large scale and industriallevel.(1) Crudden, C. M.; Horton, J. H.; Ebralidze, I. I.; Zenkina, O. V.; McLean, A. B.; Drevniok, B.; She, Z.; Kraatz,H.-B.; Mosey, N. J.; Seki, T. Ultra stable self-assembled monolayers of N-heterocyclic carbenes on gold. Nat. Chem. 2014, 6 (5), 409-414.(2) Amit, E.; Dery, L.; Dery, S.; Kim, S.; Roy, A.; Hu, Q.; Gutkin, V.; Eisenberg, H.; Stein, T.; Mandler, D.Electrochemical deposition of N-heterocyclic carbene monolayers on metal surfaces. Nat. Commun. 2020, 11 (1), 1-10.

Temperature-dependent complex dielectric permittivity: a simple measurement strategy for liquid-phase samples

Microwaves (MWs) are an emerging technology for intensified and electrified chemical manufacturing. MW heating is intimately linked to a material’s dielectric permittivity. These properties are highly dependent on temperature and pressure, but such datasets are not readily available due to the limited accessibility of the current methodologies to process-oriented laboratories. We introduce a simple, benchtop approach for producing these datasets near the 2.45 GHz industrial, medical, and scientific (ISM) frequency for liquid samples. By building upon a previously-demonstrated bireentrant microwave measurement cavity, we introduce larger pressure- and temperature-capable vials to deduce temperature-dependent permittivity quickly and accurately for vapor pressures up to 7 bar. Our methodology is validated using literature data, demonstrating broad applicability for materials with dielectric constant ε' ranging from 1 to 100. We provide new permittivity data for water, organic solvents, and hydrochloric acid solutions. Finally, we provide simple fits to our data for easy use.

Effects of salinity on the leaching of ionic species from hydrocarbon target formations during hydraulic fracturing

The combination of hydraulic fracturing with horizontal drilling has revolutionized oil and gas production. However, most of our understanding of the subsurface mechanisms and chemical interactions that occur during the process come from analyses of flowback and produced water (FPW). While the chemical composition of FPW can provide some information to understand water-rock interactions in the subsurface, the mechanisms by which dissolved species, including potentially toxic heavy metals (PTHM), are mobilized remain poorly constrained. In this study, we used stirred benchtop reactors to simulate the geochemical processes that occur when injected hydraulic fracturing fluid (HFF) interacts with reservoir rock formations of the Upper Devonian Duvernay Formation, a mudstone formation that is an important hydraulic fracturing target in west-central Alberta, Canada. Our aims were to: (1) assess whether our laboratory methods can be used to predict the inorganic chemistry of FPW, including concentrations of PTHM, and (2) to ascertain the reaction kinetics and mechanisms of the release of inorganic components from reservoir rocks. Our results indicate that elemental concentration data from reactor experiments coupled with saturation indices modelling can be used to predict the assemblage of solid phases that precipitates downhole, such as barite + celestine + gypsum. High salinity experiments (0.5 M NaCl), simulating FPW reuse, showed increased concentrations of many dissolved species with increasing salinity. Our findings were corroborated with geochemical modelling of FPW samples collected from operating unconventional wells in the Duvernay Formation. FPW from wells using a mixture of recycled produced water (RPW) and fresh source water to make up the injected HFF had higher concentrations of many elements, including the PTHM, Ba, Sr, and As. Our work illustrates the potential environmental risks of using RPW in hydraulic fracturing operations in the event of a spill and it provides a robust benchtop approach to predict the leaching of elements from the host rock during hydraulic fracturing.

Direct, Site-Selective and Redox-Neutral α-C-H Bond Functionalization of Tetrahydrofurans via Quantum Dots Photocatalysis.

As one of the most ubiquitous bulk reagents available, the intrinsic chemical inertness of tetrahydrofuran (THF) makes direct and site-selective C(sp3 )-H bond activation difficult, especially under redox neutral condition. Here, we demonstrate that semiconductor quantum dots (QDs) can activate α-C-H bond of THF via forming QDs/THF conjugates. Under visible light irradiation, the resultant alkoxyalkyl radical directly engages in radical cross-coupling with α-amino radical from amino C-H bonds or radical addition with alkene or phenylacetylene, respectively. In contrast to stoichiometric oxidant or hydrogen atom transfer reagents required in previous studies, the scalable benchtop approach can execute α-C-H bond activation of THF only by a QD photocatalyst under redox-neutral condition, thus providing a broad of value added chemicals starting from bulk THFs reagent.

Direct, Site‐Selective and Redox‐Neutral α‐C−H Bond Functionalization of Tetrahydrofurans via Quantum Dots Photocatalysis

AbstractAs one of the most ubiquitous bulk reagents available, the intrinsic chemical inertness of tetrahydrofuran (THF) makes direct and site‐selective C(sp3)−H bond activation difficult, especially under redox neutral condition. Here, we demonstrate that semiconductor quantum dots (QDs) can activate α‐C−H bond of THF via forming QDs/THF conjugates. Under visible light irradiation, the resultant alkoxyalkyl radical directly engages in radical cross‐coupling with α‐amino radical from amino C−H bonds or radical addition with alkene or phenylacetylene, respectively. In contrast to stoichiometric oxidant or hydrogen atom transfer reagents required in previous studies, the scalable benchtop approach can execute α‐C−H bond activation of THF only by a QD photocatalyst under redox‐neutral condition, thus providing a broad of value added chemicals starting from bulk THFs reagent.

Dual-excitation in-lab-made device based on a handy UV lamp and GQDs-modified PADs for simultaneous determination of acetaminophen and its endocrine disrupting impurity 4-nitrophenol

In this study, we first propose novel and intelligent strategies for simultaneous estimation of acetaminophen (AC) and its potential toxic impurity 4-nitrophenol (NP) using an in-lab-made device as well as a benchtop fluorometry technique. The developed approaches depend on the dual-excitation of fluorescent graphene quantum dots (GQDs) at 240 and 350 nm, and measurement of the characteristic emission at 440 nm. AC efficiently quenches the fluorescence of GQDs when excited at 240 nm, while NP quenches the fluorescence of GQDs when excited at 350 nm. The mechanism involved in the quenching has been established to be the inner filter effect via absorption of the incident excitation light by the quenchers. An in-lab-made device that integrates a dual-wavelength handy UV lamp and a GQDs modified paper-based analytical device (PAD) confined with a permanent ink marker has been developed. Imaging of the PAD was performed by a smartphone, and image processing permitted the selective estimation of AC and NP. This technique offers an affordable, easily fabricated, and widely accessible device for application in limited-resources laboratories. The benchtop approach permitted the determination of AC and NP over the range of 0.1–20 and 0.1–2.0 µg/mL, while the in-lab-made device approach allowed AC and NP determination within the ranges of 0.04–6.0 and 0.04–2.0 µg/detection zone, respectively. The two approaches have been successfully validated for the estimation of AC and NP in pharmaceutical preparations. The proposed strategies are the first to utilize a single nanomaterial for simultaneous analysis of two analytes adapting the dual excitation technique.

Benchtop One‐to‐One Nanocontact Replication Across Length Scales from 100 nm to 10 cm via Ambient Polycarbonate Molding

Herein, a benchtop technique to create one‐to‐one plastic replicas of nanostructured “masters” of various materials and dimensions via polycarbonate (PC) molding under ambient conditions is described. Instead of conventional thermal molding of PC under high temperature and pressure, it is explored to adapt solvent‐assisted method that has been traditionally unpopular due to the alteration of its morphology induced by swelling and recrystallization. A thorough study of how polymer spherulites (spherical domains of semicrystalline polymer chains) develop and whether their growth can be inhibited by nanocontact molding is conducted; it demonstrated not only how molding drastically limits crystallization but also how the crystallization can be controlled in the process of replicating micro/nanostructures. The efficacy of one‐to‐one replication across length scales from 100 nm to 1 mm over large areas (>5 cm2) has been confirmed with high‐resolution scanning electron microscopy and atomic force microscopy. The durable monolithic PC replicas can be used as templates for casting polydimethylsiloxane (PDMS) devices, allowing expensive lithographically designed masters to be preserved and accelerating production by multiplexing. The simplicity and low cost of this benchtop approach augment the feasibility of nanofabrication in resource‐limited settings with reduced costs and processing time.

Xurography-Enabled Thermally Transferred Carbon Nanomaterial-Based Electrochemical Sensors on Polyethylene Terephthalate-Ethylene Vinyl Acetate Films.

A novel benchtop approach to fabricate xurography-enabled thermally transferred (XTT) carbon nanomaterial-based electrochemical sensors is proposed. Filtered nanomaterial (NM) films were transferred from Teflon filters to polyethylene terephthalate-ethylene vinyl acetate (PET-EVA) substrates by a temperature-driven approach. Customized PET-EVA components were xurographically patterned by a cutting plotter. The smart design of PET-EVA films enabled us to selectively transfer the nanomaterial to the exposed EVA side of the substrate. Hence, the substrate played an active role in selectively controlling where nanomaterial transfer occurred allowing us to design different working electrode geometries. Counter and reference electrodes were integrated by a stencil-printing approach, and the whole device was assembled by thermal lamination. To prove the versatility of the technology, XTT materials were exclusively made of carbon black (XTT-CB), multiwalled carbon nanotubes (XTT-MWCNTs), and single-walled carbon nanotubes (XTT-SWCNTs). Their electrochemical behavior was carefully studied and was found to be highly dependent on the amount and type of NM employed. XTT-SWCNTs were demonstrated to be the best-performing sensors, and they were employed for the determination of l-tyrosine (l-Tyr) in human plasma from tyrosinemia-diagnosed patients. High analytical performance toward l-Tyr (linear range of 0.5-100 μM, LOD = 0.1 μM), interelectrode precision (RSD ip,a = 3%, n = 10; RSD calibration slope = 4%, n = 3), and accurate l-Tyr quantification in plasma samples with low relative errors (≤7%) compared to the clinical declared values were obtained. The proposed benchtop approach is cost-effective and straightforward, does not require sophisticated facilities, and can be potentially employed to develop pure or hybrid nanomaterial-based electrodes.

A Benchtop Approach to the Location Specific Blood Brain Barrier Opening using Focused Ultrasound in a Rat Model.

Stereotaxic surgery is the gold standard for localized drug and gene delivery to the rodent brain. This technique has many advantages over systemic delivery including precise localization to a target brain region and reduction of off target side effects. However, stereotaxic surgery is highly invasive which limits its translational efficacy, requires long recovery times, and provides challenges when targeting multiple brain regions. Focused ultrasound (FUS) can be used in combination with circulating microbubbles to transiently open the blood brain barrier (BBB) in millimeter sized regions. This allows intracranial localization of systemically delivered agents that cannot normally cross the BBB. This technique provides a noninvasive alternative to stereotaxic surgery. However, to date this technique has yet to be widely adopted in neuroscience laboratories due to the limited access to equipment and standardized methods. The overall goal of this protocol is to provide a benchtop approach to FUS BBB opening (BBBO) that is affordable and reproducible and can therefore be easily adopted by any laboratory.

A Benchtop Approach to the Location Specific Blood Brain Barrier Opening using Focused Ultrasound in a Rat Model

A Benchtop Approach to the Location Specific Blood Brain Barrier Opening using Focused Ultrasound in a Rat Model

Nylon-MOF Composites through Postsynthetic Polymerization.

Hybridization of metal-organic frameworks (MOFs) and polymers into composites yields materials that display the exceptional properties of MOFs with the robustness of polymers. However, the realization of MOF-polymer composites requires efficient dispersion and interactions of MOF particles with polymer matrices, which remains a significant challenge. Herein, we report a simple, scalable, bench-top approach to covalently tethered nylon-MOF polymer composite materials through an interfacial polymerization technique. The copolymerization of a modified UiO-66-NH2 MOF with a growing polyamide fiber (PA-66) during an interfacial polymerization gave hybrid materials with up to around 29 weight percent MOF. The covalent hybrid material demonstrated nearly an order of magnitude higher catalytic activity for the breakdown of a chemical warfare simulant (dimethyl-4-nitrophenyl phosphate, DMNP) compared to MOFs that are non-covalently, physically entrapped in nylon, thus highlighting the importance of MOF-polymer hybridization.

An automatic integrated microfluidic system for allergy microarray chips.

Billions of people suffer from allergies, though in many cases, the source allergen is unknown. If one knows which allergens to avoid, this would result in an improved quality of life. Since a rapid, high-throughput, automatic allergen detection method is of great need, an integrated system combining microfluidic techniques and microarray chips has been developed herein to automate the allergen detection process. The developed microfluidic system could automatically carry out the entire procedure such as reagent incubation, hybridization, transport, and washing without any intermediate step. The microarray chip could be easily detached from the microfluidic chip afterwards, enabling it to be read under a fluorescence scanner. The experimental results indicated that the developed microfluidic system can automatically perform all the incubation processes, including hybridization, reagent transportation, and washing. It is worth noting that active mixing has been applied in the present study which is different from our previous study using micro-channels for passive incubation. Comparable results to a conventional benchtop approach were obtained in ∼30% less time with ∼25% less samples/reagents. Similar results were also demonstrated while detecting immunoglobulin E samples. The developed system could therefore provide a rapid, reliable, and automated approach for detecting allergen-specific antibodies in human serum.

Liquid metal ‘does a solid’ for semiconductors

Growing high-quality semiconducting crystals isn’t easy. It typically takes high temperatures, highly reactive precursors, and extensive equipment. Electrochemical deposition could simplify the process, but attempts using conventional solvents yield “amorphous junk,” says Stephen Maldonado of the University of Michigan. Working with colleagues at Ohio State University, Maldonado’s team has found that a liquid metal can help electrochemistry conquer this shortcoming (J. Am. Chem. Soc. 2017, DOI: 10.1021/jacs.7b01968). The researchers started with an aqueous germanium oxide solution and introduced eutectic gallium-indium, or eGaIn. This liquid metal forms an intermediate layer between the solution and a solid silicon substrate. Germanium reduced in water can cross the interface into the eGaIn and migrate to the silicon. By tuning the thickness of the eGaIn layer, the researchers ensure that germanium accumulates into a high-quality, crystalline film. This low-cost, benchtop approach works at room temperatur...

Mild, Redox‐Neutral Formylation of Aryl Chlorides through the Photocatalytic Generation of Chlorine Radicals

AbstractWe report a redox‐neutral formylation of aryl chlorides that proceeds through selective 2‐functionalization of 1,3‐dioxolane through nickel and photoredox catalysis. This scalable benchtop approach provides a distinct advantage over traditional reductive carbonylation in that no carbon monoxide, pressurized gas, or stoichiometric reductant is employed. The mild conditions give unprecedented scope from abundant and complex aryl chloride starting materials.

Mild, Redox-Neutral Formylation of Aryl Chlorides through the Photocatalytic Generation of Chlorine Radicals.

We report a redox-neutral formylation of aryl chlorides that proceeds through selective 2-functionalization of 1,3-dioxolane through nickel and photoredox catalysis. This scalable benchtop approach provides a distinct advantage over traditional reductive carbonylation in that no carbon monoxide, pressurized gas, or stoichiometric reductant is employed. The mild conditions give unprecedented scope from abundant and complex aryl chloride starting materials.

Oxygen tolerant photopolymerization for ultralow volumes

A benchtop approach is developed for the synthesis of various polymeric architectures using an aqueous Reversible Addition–Fragmentation chain Transfer (RAFT) photopolymerization technique.

19F and 31P Solid-State NMR Characterization of a Pyridine Pentafluorophosphate-Derived Solid-Electrolyte Interphase

Solid-state NMR spectroscopy was used to characterize the solid-electrolyte interphase (SEI) formed on the graphite electrode surface from the electrolyte additive pyridine pentafluorophosphate (PPF). The PPF-derived SEI was prepared in a full Li(Ni0.4Mn0.4Co0.2)O2/graphite cell, rather than in a coin cell or using a bench-top synthesis approach. 19F and 19F→31P cross-polarization measurements provide direct evidence that F atoms and P–F bonds are present at the graphite surface. By comparing rinsed and unrinsed samples, an insoluble SEI component was differentiated from residual LiPF6 from the dried electrolyte. The SEI species contains F and P chemical environments that are similar to, but distinct from, the additive starting material and the lithium hexaflurophosphate (LiPF6) electrolyte salt used in this work. The results are consistent with the previously proposed formation of a dilithium 4,4’–bipyridine-N,N’–bis(pentafluorophosphate) salt. LiF was also observed and is attributed to decomposition of the PPF-derived surface layer and/or the LiPF6 electrolyte salt.

Benchtop Fluorination of Fluorescent Nanodiamonds on a Preparative Scale: Toward Unusually Hydrophilic Bright Particles

Fluorination of diamonds modulates their optical and electromagnetic properties and creates surfaces with increased hydrophobicity. In addition, fluorination of diamonds and nanodiamonds has been recently shown to stabilize fluorescent nitrogen‐vacancy centers, which can serve as extremely sensitive single atomic defects in a vast range of sensing applications from quantum physics to high‐resolution biological imaging. Traditionally, fluorination of carbon nanomaterials has been achieved using harsh and complex experimental conditions, creating hydrophobic interfaces with difficult dispersibility in aqueous environments. Here, a mild benchtop approach to nanodiamond fluorination is described using selective Ag+‐catalyzed radical substitution of surface carboxyls for fluorine. In contrast to other approaches, this high‐yielding procedure does not etch diamond carbons and produces a highly hydrophilic interface with mixed C−F and C−OH termination. This dual functionalization of nanodiamonds suppresses detrimental hydrophobic interactions that would lead to colloidal destabilization of nanodiamonds. It is also demonstrated that even a relatively low surface density of fluorine contributes to stabilization of negatively charged nitrogen‐vacancy centers and boosts their fluorescence. The simultaneous control of the surface hydrophilicity and the fluorescence of nitrogen‐vacancy centers is an important issue enabling direct application of fluorescent nanodiamonds as nanosensors for quantum optical and magnetometry measurements operated in biological environment.