Liquid Contact Research Articles

Coating polyurethane sponge with Dy-MOF for efficient oil–water separation in complex environments

Leakage of industrial oil and organic solvents seriously harms environment and ecology yet demanding highly efficient and durable materials for oil–water separations. In this work, ultra-light and highly flexible polyurethane (PU) sponges were engineered to 3D oil–water separators by coating the dysprosium metal organic framework (Dy-MOF) onto the surfaces of the PU frames. Through a facile impregnation, the Dy-MOF was attached to the full frames of the sponges. Consequently, liquid contact surfaces were extended from these on top layers to the whole rack. Superhydrophobicity with water contact angles up to 152.08° and lipophilicity enable continuous separations of dichloromethane from water through the resulted Dy-MOF@PU sponges in a continuous mode. The modified sponges own high gravimetric absorption capacities for oil and organic solvents, and high resistances to temperature variations, corrosive solutions, and mechanical abrasions, thanks to the well-connected and stable superhydrophobic/supportive interfaces. An efficient separation was successfully piloted for oily wastewater consisting of water-in-oil emulsions stabilized by surfactants, demonstrating the potential of practical water treatment of Dy-MOF@PU in complex environments. Mechanism leading to superior oil–water separation capability was studied and inferred as the combined effects of the physical and chemical properties arisen from the stable Dy-MOF and flexible but porous matrix.

Study on robust absorption performance of hydrophilic membrane contactor for direct air capture

Increased atmospheric carbon dioxide (CO2) concentration constitutes a growing environmental and health concern. The absorption of CO2 from air requires a large gas–liquid contact area due to low driving force. Here, the membrane absorption was proposed to the removal of atmospheric CO2 using a ceramic membrane contactor, while NaOH serves as absorbent, performance of ceramic membrane absorption was study. In hydrophilic membrane, NaOH concentration of 2 mol⋅L−1 has the best absorption performance, which serves as initial concentration in absorption cyclic process, and when NaOH utilization reaches 75 %, it still has great absorption performance. In addition, suitable gas and liquid operating parameters of this work were also confirmed as 1000 mL⋅min−1 and 1 mL⋅min−1, respectively, corresponding mass transfer coefficient and CO2 absorption flux is 2.6 mm⋅s−1 and 0.096 mol⋅m−2⋅h−1, respectively. The great absorption stability shows the huge potential of ceramic membrane contactor application for direct air capture.

Inhibitory effect of (E)-2-heptenal on Aspergillus flavus growth revealed by metabolomics and biochemical analyses

The prevention of fungal proliferation in postharvest grains is critical for maintaining grain quality and reducing mycotoxin contamination. Fumigation with natural gaseous fungicides is a promising and sustainable approach to protect grains from fungal spoilage. In this study, the antifungal activities of (E)-2-alkenals (C5-C10) on Aspergillus flavus were tested in the vapor phase, and (E)-2-heptenal showed the highest antifungal activity against A. flavus. (E)-2-Heptenal completely inhibited A. flavus growth at 0.0125 µL/mL and 0.2 µL/mL in the vapor phase and liquid contact, respectively. (E)-2-Heptenal can disrupt the plasma membrane integrity of A. flavus via leakage of intracellular electrolytes. Scanning electron microscopy indicated that the mycelial morphology of A. flavus was remarkably affected by (E)-2-heptenal. Metabolomic analyses indicated that 49 metabolites were significantly differentially expressed in A. flavus mycelia exposed to 0.2 µL/mL (E)-2-heptenal; these metabolites were mainly involved in galactose metabolism, starch and sucrose metabolism, the phosphotransferase system, and ATP-binding cassette transporters. ATP production was reduced in (E)-2-heptenal-treated A. flavus, and Janus Green B staining showed reduced cytochrome c oxidase activity. (E)-2-Heptenal treatment induced oxidative stress in A. flavus mycelia with an accumulation of superoxide anions and hydrogen peroxide and increased activities of superoxide dismutase and catalase. Simulated storage experiments showed that fumigation with 400 µL/L of (E)-2-heptenal vapor could completely inhibit A. flavus growth in wheat grains with 20% moisture; this demonstrates its potential use in preventing grain spoilage. This study provides valuable insights into understanding the antifungal effects of (E)-2-heptenal on A. flavus. KEY POINTS : • (E)-2-Heptenal vapor showed the highest antifungal activity against A. flavus among (C5-C10) (E)-2-alkenals. • The antifungal effects of (E)-2-heptenal against A. flavus were determined. • The antifungal actions of (E)-2-heptenal on A. flavus were revealed by metabolomics and biochemical analyses.

A numerical study of the droplet impact dynamics on a two-dimensional random rough surface

Considerable efforts had been devoted to investigating numerically the droplet impact dynamics on a superhydrophobic surface, whereas most of these numerical simulations were restricted to the two-dimensional (2D) axisymmetric coordinate system with the one-dimensional (1D) substrate surface. In this work, a three-dimensional (3D) computational fluid dynamics (CFD) model, which intergrew a 2D random rough surface, was proposed to investigate the droplet impact dynamics, and the multi-phase flow issue was solved by the Navier–Stokes equations. It is remarkable that the 3D CFD model revealed several significant dynamic details that were not easily captured in a 2D axisymmetric coordinate system or practical experiments. For instance, the 3D CFD model provided a unique perspective to understand the varying dynamic behaviors of impinged droplet in terms of the velocity streamline and dynamic viscosity analyses. Herein, the dynamic viscosity diagram revealed that the sprawl droplet on the 2D random rough surface was classified as the Cassie state, while as the Wenzel state for the smooth surface, which also explained the better bouncing behaviors of the droplet from the random rough surface. Accordingly, we suggested a visual way to evaluate the solid–liquid contact area surrounded by the triple-phase contact line. The effects of finger protrusion and central cavity growth from the sprawl droplet on the vortex generation were further analyzed on the ground of the velocity amplitude distribution and streamline data. The present work can provide early guidance to inquire into the impact dynamics of droplets on the random rough surface.

Two fabricated carbon paste electrodes for novel potentiometric determination of probenecid in dosage form and human plasma

Solid contact ion selective electrodes are extensively utilized owing to their marvelous performance over traditional liquid contact ones. The main drawback of those solid contact electrodes is aqueous layer formation which affects their constancy. Herein and to overcome this common drawback, a carbon paste electrode containing poly(3,4-ethylenedioxythiophene) was constructed and used for determination of probenecid at variant pH values. This modification decreased the potential drift down to 0.8 mV/h and improved its stability over 30 days. A Nernstian slope of − 57.8 mV/decade associated with a linear range of 1.0 × 10−6–1.0 × 10−2 mol/L was obtained. The modified carbon paste electrode successfully detected up to 8.0 × 10−7 mol/L probenecid. Results of this modified carbon paste electrode were also compared to unmodified one.

Efficient carbon capture using sub-textured polymer packing surfaces via 3D printing

Gas absorption is a common unit operation whose performance deeply relies on the gas liquid contact behavior. Here we report a solid polymeric surface feature containing microscale striation to improve the solid-liquid and gas-liquid contact and facilitate mass transfer. As a proof of concept, the surface feature is adopted for CO2 capture absorber packing via 3D printing. Besides traditional embossing texture, an additional laminar striation is applied to the packing surface as a sub-texture. The packing shows notable CO2 mass transfer increase without interfering with other key operating characteristics including pressure drop and liquid holdup. The improvement is based on the synergy of favorable wettability, thin liquid film and increased liquid mixing from rougher surface. In the demonstration test, the packing height could decrease by 33 % using the advanced packing with same CO2 removal, leading to a significant decrease in equipment size and capital expense for commercial CO2 capture systems.

Study of Wear, Stress and Vibration Characteristics of Silicon Carbide Tool Inserts and Nano Multi-Layered Titanium Nitride-Coated Cutting Tool Inserts in Turning of SS304 Steels.

Cutting tool characterization plays a crucial role in understanding the behavior of machining operations. The selection of a suitable cutting material, the operating conditions for the work piece, is necessary to yield good cutting-tool life. Several pieces of research have been carried out in cutting-tool characteristics for turning operation. Only a few pieces of research have focused on correlating the vibrations and stress with wear characteristics. This research article deals with stress induced in silicon carbide tool inserts and coated tool inserts while machining SS304 steel. Since this material is much less resistant to corrosion and oxidation it is widely used in engineering applications such as cryogenics, the food industry and liquid contact surfaces. Moreover, these materials have much lower magnetic permeability so they are used as nonmagnetic engineering components which are very hard. This article focuses on the machining of SS304 by carbide tool inserts and then, the cutting forces were observed with a tool dynamometer. Using observed cutting forces, the induced stress in the lathe tool insert was determined by FEA investigation. This research also formulates an idea to predict the tool wear due to vibration. Apparently, the worn-out tool vibrates more than new tools. Using the results, the relation between stress, strain and feed rate, depth of cut and speed was found and mathematically modeled using MINI TAB. It was observed that carbide tool inserts with coating withstand better than uncoated tools while machining SS304. The results were anticipated and correlation between the machining parameters furnished the prediction of tool life and obtaining the best machining outcomes by using coated tool inserts.

Pore‐network modelling of combined molecular diffusion and gravity drainage mechanisms in a porous matrix block: The competitive role of driving forces

AbstractA large part of the world's hydrocarbon resources are located in fractured reservoirs, and mass transfer phenomena play a crucial role in enhanced hydrocarbon recovery from these reservoirs. Pore‐network models have been widely used to study kinetic and pore‐scale micro‐mechanisms. Molecular diffusion involves mass transfer and liquid–vapour phase change and can be simulated by a modified invasion percolation model. Despite the existence of separate pore‐scale studies on molecular diffusion and gravity drainage, no articles have been published that evaluate the combined effect of both mechanisms. This study investigates the competitive roles of the two phenomena and the effective factors controlling each mechanism with the aid of pore‐network models. According to the results obtained, gravity drainage and molecular diffusion would have a synergic effect when they are simultaneously active. Although for a single‐component liquid system, there would be a capillary holdup residual saturation in the pure gravity drainage process (between 11% and 14% for the evaluated cases) and a slow and lengthy evaporation in pure molecular diffusion (between 47% and 57% longer for the cases under study), our investigation revealed that when the two mechanisms coexist, a faster process with no residual liquid is expected. Our findings clarify that when the system is strongly gravity dominated, the liquid body remains integrated, gas–liquid contact recedes in a piston‐like manner, and three‐stage liquid desaturation is observed. Furthermore, highly clustered liquid saturation is observed in strongly capillary‐dominated systems, and the liquid desaturation curve in a capillary‐dominated model has two distinguishable stages. The competitive contribution of gravity drainage and molecular diffusion as the main driving forces of liquid extraction from a single‐block model is quantified for the entire period of desaturation. Depending on the dominance of the production mechanisms, the process is either gravity‐assisted molecular diffusion or diffusion‐assisted gravity drainage.

Simulation Assessment of Inlet Parameters and Membrane-Surface-Structure Effects on CO2 Absorption Flux in Membrane Contactors

The management of global carbon dioxide (CO2) emissions is considered one of the main environmental problems facing the modern world. One of the potential techniques for CO2 capture is absorption, using membrane contactor modules. Most of the previous research that dealt with membrane contactor simulations considered the whole membrane surface as the active reaction surface. However, in this paper, a more realistic model of the membrane-contactor module is presented, taking into account the effects of the pore size and surface porosity. CO2 absorption into the monoethanolamine (MEA) solution in hollow fiber membrane-contactor modules was numerically investigated. A computational fluid dynamics simulation was established using essential basic fluid dynamics and mass transfer equations in reactive mode. An algorithmic function was used to present the relations between the CO2 absorption flux and the hollow fiber length, membrane surface pore size, and porosity. The simulation results were compared to previously obtained experimental results without using any fitting parameters, and a good agreement was found with an average error of 8.5%. The validated simulation was then used to predict the effects of the MEA inlet velocity and concentration, the membrane surface pore size, and porosity on the total CO2 absorption flux. A maximum absorption flux of about 1.8 mol/m2·s was achieved at an MEA concentration of 4 M with a pore size of 0.2 microns, a surface porosity of 1%, and an inlet velocity of 0.25 m/s. The extrapolation technique was then used to predict the values of the absorption flux at longer fiber lengths. The concentration profiles around the pores at the gas–liquid contact surface of the membrane were obtained and presented. The proposed model exhibited excellent potential to evaluate the effective reaction surface in hollow fiber membrane contactors. This model could be considered the first step to obtaining accurate predictions of the membrane contactor gas absorption performance based on its surface structure.

Study on the mass transfer of SO2 in ammonia-based desulfurization process

The coal hydrogen production process requires high-temperature steam as a reactant. Coal-fired boilers are usually used to provide high-temperature steam. The ammonia-based desulphurization process is an effective technology to remove SO2 in the coal-fired flue gas. However, the mass transfer coefficient of SO2 in such an engineered process is not readily available in the literature. In this paper, experiments were carried out to investigate the mass transfer process of SO2 absorption. Combing calculating the air and liquid contact area of the droplet and liquid membrane on the tower wall, the mass transfer coefficient contain parameters pH, gas flue rate and liquid to gas ratio was proposed. The comparison results show that the calculated SO2 mass transfer rate agrees well with the measured data. The relative error of the calculated and experimental values was less than ±20%. This proposed mass transfer coefficient appears to be beneficial for the design and operation of ammonia-based desulfurization FGD system.

Effect of resistance internal on hydrodynamic behaviours and bubble characteristics in a laboratory‐scale bubble column

AbstractA novel resistance internal is proposed to optimize the flow field and improve the gas–liquid contact in a co‐hydrogenation reactor of coal and vacuum residuum. Local gas holdup, local liquid velocity, and characteristics of the bubble were investigated in a scaled‐down laboratory model. The quantitative results showed that the resistance internals could reduce the thickness of the liquid reflux layer by a percentage up to 32% and reduce the difference in the local gas holdup at cross‐sections of up to 44%. The Sauter mean diameter of the bubble decreased from 20.30 to 16.00 mm, which aroused the increase in bubble surface area by a percentage of up to 71.9%. The resistance internal promoted the breakup of the bubble with multiple mechanisms and provided diversion to fluid. In this work, improvement at multiple scales was realized, and the technical support for industrial application was provided.

Three-dimensional printed liquid diodes with tunable velocity: Design guidelines and applications for liquid collection and transport

Directional and self-propelled flow in open channels has a variety of applications, including microfluidic and medical devices, industrial filtration processes, fog-harvesting, and condensing apparatuses. Here, we present versatile three-dimensional-printed liquid diodes that enable spontaneous unidirectional flow over long distances for a wide range of liquid contact angles (CAs). Typically, we can achieve average flow velocities of several millimeters per second over a distance of tens to hundreds millimeters. The diodes have two key design principles. First, a sudden widening in the channels' width, in combination with a small bump, the pitch, ensure pinning of the liquid in the backward direction. Second, an adjustable reservoir with differing expansion angles, the bulga, is introduced to manipulate the liquid velocity. Using a combination of experiments and lattice Boltzmann simulations, we provide a comprehensive analysis of the flow behavior and speed within the channels depending on CAs, pitch heights, and bulga angles. This provides guidelines for the fabrication of bespoke liquid diodes with optimal design for their potential applications. As a feasibility investigation, we test our design for condensation of water from fog and subsequent transport uphill.

Robust air cavity generation on sacrificial microstructures for sustainable underwater drag reduction

Reducing fluid frictional drag at the solid–liquid interface is a promising strategy for improving the hydrodynamic properties of the structure in water, though so far it has remained unattainable without robust air cavities. Herein, we report a durable generation strategy of robust air cavity on the rough microstructured surface, which could achieve stable drag reduction even after 2000th water entry test. It is worth noting that the generation strategy is almost independent of the wear of surface microstructure, as the worn microstructures still keep a rough morphology and would alter the capillary driving force and prevent the spreading of the liquid film along the structure body. Therefore, the triple contact line is pinned at the solid–liquid interface and induces the generation of a complete air cavity. Comprehensive evaluation, including the mechanical and chemical stability tests, confirm that the microstructured spheres could produce robust cavities even after harsh destruction, and they also reduce the hydrodynamic drag by more than 70.8% at a higher Reynolds number of ∼4.9 × 104. Finally, the boundary slip at the solid–liquid interface of the microstructured surface is simulated, which concludes that the decrease in the contact angle at air–liquid interface and fraction of solid–liquid contact area on the wall would enhance the slip length of fluid, thus resulting in an obvious decreasing of frictional resistance at the solid–liquid interface. We believe that the present work provides a perspective on the sustainable construction of the robust cavity which may have important potential application value in the field of drag reduction.

Improving the Corrosion Resistance of Aluminum Alloy by Creating a Superhydrophobic Surface Structure through a Two-Step Process of Etching Followed by Polymer Modification.

A multifunctional aviation aluminum alloy with good superhydrophobicity and corrosion resistance was prepared by a two-step process of etching followed by polymer modification. Meanwhile, micro- and nanostructures formed on the processed sample. Compared with bare sample, the static liquid contact angle on the as-prepared sample was increased by 100.8°. Further polarization tests showed that the corrosion potential of such a sample increased, and the corrosion current density decreased obviously, thus suggesting that the corrosion resistance of the modified sample was significantly improved. The same conclusion was confirmed by subsequent impedance testing. The work is of great economic value and practical significance to enhance the corrosion resistance of aviation actuator materials and also lays a foundation for future hydrophobic application research in aeronautical engineering.

Falling-Film Absorption Model Considering Surface Wave and Vibration Effects Based on Lattice Boltzmann Method

As one of the effective solutions to recover waste heat, absorption refrigeration systems are used in various industrial or refrigeration places. Flat-plate falling-film absorption is one of the newer types, and the lattice Boltzmann method (LBM) has certain advantages compared with the traditional numerical simulation method. In this work, an LBM is used to analyze flat-plate falling-film absorption. Using the additional calculation of the pressure by the pseudo-force model, a lithium bromide–water working fluid–heat and mass transfer model driven by steam partial pressure is realized. The results show that the turbulence generated in the surface wave has a favorable effect on the absorption process; the degree of turbulence gradually decreases with the increase in the Reynolds number, which weakens the increasing effect of the surface wave on the absorption. When the Reynolds number is moderate, the solitary wave flows forward relative to the front thin liquid film, which promotes concentration and temperature diffusion inside the liquid film and inside the solitary wave. The model of falling-film flow under vibration environment is realized by using the characteristic of imposing inertial force in the model by pseudo-force method. The results show that vibration has a favorable effect on liquid film absorption, increasing the amplitude can increase the gas–liquid contact area and obtain a lower average film thickness, while increasing the vibration frequency can promote the internal diffusion of the solution.

High shear mixer works as a heat exchanger enhancing the liquid–liquid direct contact heat transfer

As an indispensable unit equipment in industrial production, the design of efficient heat exchangers is of great significance to improve energy utilization rate. In this paper, the in-line high shear mixer (HSM) was investigated as a heat exchanger for the first time by experiments and assisted with CFD simulations, and the heat transfer performance was measured using kerosene and thermal water as the heat transfer fluids. Effects of operational parameters, including rotor speed, fluids temperature and flow rate, as well as the structural parameters, involving the rotor teeth number, teeth height, and the shear gap, were studied on the volume heat transfer coefficient and the heat transfer efficiency of such inline HSM. The results indicated that the volume heat transfer coefficient can be significantly improved by increasing the rotor speed and the flow rate of the heat transfer fluids, but reducing the heat transfer temperature difference, whereas increasing the thermal fluid flow rate deteriorates heat transfer efficiency. Furthermore, the structural parameters including rotor teeth number and teeth height, the shear gap within the stator and rotor were optimized to enhance the heat transfer of HSM. The optimal HSM possesses a shear gap of 0.5 mm, a teeth height of 10 mm and a teeth number of 6, which can generate larger turbulent energy dissipation rate and higher shear rate, meanwhile make more fluids jet out of the shear gap and stator hole. The maximum volume heat transfer coefficient and heat transfer efficiency can be up to 2522.8 kW·m−3·°C−1 and 92.4% with the optimal structure. Finally, the dimensionless correlations of heat transfer performance were established to guide the operating mode and structural design of high-efficiency high shear mixer.

Liquid–Liquid Triboelectric Nanogenerator for Harvesting Distributed Energy

AbstractAs one of the most widely distributed water resources, rainwater contains tremendous energy that cannot be effectively utilized by the conventional electromagnetic generators. Triboelectric nanogenerators (TENGs) represent a distributed method to convert trivial mechanical energy into electricity based on contact electrification. Benefiting from the large and replenishable contact interfaces in liquid–liquid systems, liquid–liquid TENG further promises efficient charge transfer. However, the limited understanding of liquid–liquid contact electrification has restricted its development. In this study, the mechanisms of contact electrification in various liquid–liquid systems is comprehensively investigated and thus a liquid–liquid TENG with optimized materials and structures to harvest energy from rainwater is demonstrated. The proposed liquid–liquid TENG generates a high charge density (3.63 µC L−1) with high output stability (crest factor ≈1.1) and long effective contact electrification time. Based on the direct current characteristics, energy harvested from rainwater can be fed directly to electronic devices and a self‐powered rainfall sensor can also be implemented. This study highlights the promise of all‐liquid systems in distributed green energy and passive sensors, offering a new perspective on self‐powered devices.

A novel method based on hydrodynamic cavitation to effectively remove NO2

Marine ships’ exhaust causes serious air pollution, among which NO is the most difficult to control. However, when a wet scrubber is used to oxidize and remove NO, a large amount of NO2 is produced, which makes it difficult to improve the NOx removal efficiency. We propose a new method for NO2 removal based on hydrodynamic cavitation (HC). Compared with the bubbling method, the HC method could be used to improve mass transfer by increasing the gas–liquid contact area and generating microjets, thereby improving NO2 removal efficiency. A 12-h long continuous experiment was conducted which revealed that HC could delay but not prevent NO production. Experiments using HCl, NaOH, and HNO3 to adjust the pH of the solution showed that the change in pH or the accumulation of NO3- had little effect on the formation of NO. The results obtained using ion chromatography analysis further revealed that the accumulation and decomposition of HNO2 were the primary causes of NO formation. Following this, we carried out experiments to investigate possible enhancement of NO2 removal efficiency by H2O2, Na2S2O8, NaClO2, and ClO2 under conditions of HC. The results showed that ClO2, H2O2, and Na2S2O8 increased the NO2 removal efficiency by only 2.29%–4.79% compared to water. However, the NO2 removal efficiency of NaClO2 was 0.54% lower than that of water, and it gradually decreased. The results of this study provide new ideas for improving NO removal efficiency using oxidants.

(Digital Presentation) Fuel Cell Electrode Design - Using a Specially-Modified Force Tensiometer for Gas Bubble Adhesive Force Measurements on Nanostructured Copper Electrodes Submerged in a Liquid

Direct liquid-feed fuel cells (DLFCs) have gained attention because of their low-cost, high power densities and clean energy. They have a bright future for both mobile andstationary applications. DLFCs directly convert chemical energy into electrical energy by the oxidization of liquid fuels. Numerous nanostructured catalysts on the electrodes have been explored to improve the energy conversion efficiency. However, the behavior of the gas products (such as N2 and CO2) on the electrode surfaces received very little attention, which is critical to achieve better performance of the DLFCs especially at high reaction rates. The reason for this is that gas bubbles that accumulate on the surface will not only block the catalyst sites but also cause high pressure in the liquid flow area limiting the fuel crossover. It has been reported that the surface architecture can significantly affect the gas bubble adhesion behavior.In this work, adhesive forces of the gas bubbles on planar and nanostructured films were measured. Using a force tensiometer outfitted with a video camera and software, adhesion force of the gas bubble on a flat Cu foil was measured. Adhesive forces and submerged liquid contact angle measurements of gas bubbles on planar and nanostructured Cu films are possible. Adhesive forces of liquids in air phase or of gas bubbles under liquid phase can also be analyzed. The special force tensiometer system with video upgrade combines a force measurement to determine the force of adhesion and an optical system to determine the area of contact between the liquid/gas and solid phase for each force that is measured. In such a way, force per area can be determined. The measurement procedure involves a liquid or gas bubble being pushed onto a solid substrate under air or liquid and then pulled off.

Green potentiometric electrode for determination of salbutamol in biological samples

Clinical drug analyses and identification of pharmaceuticals in biological samples are highly crucial for therapeutic drug monitoring, pharmacokinetic studies, and screening of illicit drugs. Various analytical tools, such as potentiometric electrodes, are used to conduct these investigations. These potentiometric electrodes are superior to other techniques in terms of greenness and cost efficacy, and thus present a good alternative for researchers. In this study, we develop an advanced electrode for the in-situ monitoring of salbutamol in plasma, this electrode was synthesized using multiwalled carbon nanotubes (MWCNT) as hydrophobic conductive substance and copper oxide nanoparticle (CuO NP) as a surface modifier, the developed electrode was compared to traditional liquid contact electrode as well as solid contact electrode and proved its superiority. The use of MWCNT improved the stability of the electrode via preventing the formation of this water layer and the CuO NP improved the sensitivity due to its high surface area and rich electronic properties. CuO NP modified electrode was used for the determination of salbutamol with a Nernstian slope of 57.4 over a linearity range of range 1.0 × 10−7- 1.0 × 10−2 M, and a detection limit of 4.0 × 10−7 M. The proposed electrode was effectively applied for the determination of the cited drug in rat plasma without interference and compared with chromatographic reported method. The proposed method is economic as it has a low sample analysis cost, time saving and needs fewer manipulation steps and a simple convenient device. It also proved to be a greener method when compared with chromatographic methods using an eco-scale metric system.