Isotherm Patterns Research Articles

Thermally radiative nanofluid heat transfer analysis inside a closed chamber with gyrotactic microorganisms

PurposeThis paper aims to numerically examine the impact of gyrotactic microorganisms and radiation on heat transport features of magnetic nanoliquid within a closed cavity. Thermophoresis, chemical reaction and Brownian motion are also considered in flow geometry for the moment of nanoparticles.Design/methodology/approachFinite element method (FEM) was depleted to numerically approximate the temperature, momentum, concentration and microorganisms concentration of the nanoliquid. The present simulation was unsteady state, and the resulting transformed equations are simulated by FEM-based Mathematica algorithm.FindingsIt has been found that isotherm patterns get larger with increasing values of the magnetic field parameter. Additionally, numerical codes for rate of heat transport impedance inside the cavity with an increasing Brownian motion parameter values.Originality/valueTo the best of the authors’ knowledge, the research work carried out in this paper is new, and no part is copied from others’ works.

Multiplex competitive annealing mediated isothermal amplification with high fidelity DNA polymerase (HiFi-CAMP)

Various isothermal amplification methods have been developed for point-of-care testing (POCT) of various infectious diseases. Here, we proposed a novel isothermal amplification method, named as 5′-half complementary primers mediated isothermal amplification (HCPA). Because of the similarity of our method to the previous method competitive annealing mediated isothermal amplification (CAMP) in primer design, we also use the name CAMP for our method. We demonstrated that CAMP is mediated by both a linear isothermal amplification pattern and a loop-mediated isothermal amplification pattern. To improve the specificity and enable multiplex detection, we further developed HiFi-CAMP method that uses a small amount of high-fidelity DNA polymerase to cut HFman probe to release fluorescent signal. The HiFi-CAMP method was demonstrated to have a good specificity and sensitivity, and fast amplification speed in detection of three human respiratory viruses, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), respiratory syncytial virus A (RSV-A) and influenza A viruses (IAV). When compared with gold standard RT-qPCR assays, the HiFi-CAMP assays showed sensitivities of 90.0 %, 71.4 % and 78.1 %, specificities of 100 %, 100 % and 95.5 %, and consistencies of 93.0 %, 93.3 % and 88.2 % for SARS-CoV-2, RSV-A and IAV, respectively. Furthermore, a duplex HiFi-CAMP assay was also developed to simultaneously detect RSV-A and SARS-CoV-2. The HiFi-CAMP will provide a promising candidate for POCT diagnosis in resource-limited settings.

Mercury Adsorption Test on Several Large Groups of Soils in West Sumbawa Regency, Indonesia

Mercury is one of the heavy metals that has the highest toxicity in the global environment. Mercury can cause environmental damage and if it enters the food chain it can have negative impacts on human health. In overcoming the problem of mercury entering the food chain, it is very important to study the mobility and distribution of mercury in the soil. The presence of mercury (Hg2+) in soil is largely controlled by adsorption reactions with certain specific adsorption patterns. Therefore, it is very important to study mercury adsorption on several different types of soil in order to get an idea of ​​how adsorption occurs in West Sumbawa Regency. The aim of this research is to determine the pattern and capacity of mercury adsorption on various large groups of soil in West Sumbawa Regency and the relationship between soil properties and mercury adsorption. The results of the research show that the adsorption isotherm pattern in the great soil groups Endoaquepts, Ustipsamments, and Udorthents more closely follows the Langmuir adsorption model, while the great soil groups Haplustepts, Hapludolls, Eutrudepts and Ustifluvents follow the Freundlich adsorption model. The major soil group that has the highest maximum mercury adsorption capacity in West Sumbawa Regency is Endoaquepts at 4,604 mg/g.

Entropy generation due to mixed convective transport from a rotating porous cylinder inside a shear-driven cavity

The mixed convective transport in a vertically shear-driven square cavity with a rotating circular porous cylinder is investigated numerically in two dimensions. This study aims to enhance the understanding of heat distribution within a closed environment containing intricate electronic systems and heat exchangers by employing a porous media modeling approach. The vertical walls of the enclosure are kept isothermal, while both the horizontal walls are assumed to be adiabatic. Upward progress is being made by the left wall at a constant translational speed. The porous circular cylinder is inserted within the square cavity concentrically, which is then rotated both clockwise and counter-clockwise. While the Reynolds number based on the motion of the lid is maintained constant at Re = 100, the porosity of the cylinder fluctuates in accordance with the Darcy number range 10−6 ≤ Da ≤ 10−2 The streamline and the isotherm patterns for a range of controlling factors, including the Richardson number (0.5 ≤ Ri ≤ 10) and the dimensionless rotational speed ( − 5 ≤ Ω ≤ 5 ) are used to show how the flow and the thermal fields within the enclosure evolve. Additionally, the entropy generation is calculated and compared for the above mentioned parameters. The irreversibility generation as well as the flow and the heat transfer phenomena are observed to be significantly influenced by the rotation and the porosity of the cylinder.

Influence of periodicity on natural convection in a square porous cavity due to non-uniform heat under LTNE state

In this article, the influence of the local thermal non-equilibrium (LTNE) state on free convection in a square cavity filled with fluid-saturated porous medium is investigated numerically. The steady-state flow is induced due to sinusoidal heat distributed on the side walls of the cavity and insulated of the horizontal walls. The coupled flow governing equations are solved numerically by using the finite volume method (FVM) consisting of the SIMPLER (Semi-Implicit Method for Pressure Linked Equation Revised) Algorithm. The numerical simulations of temperature and stream-function contours are carried out for the non-Darcy model. The developed code is validated with existing numerical and present computed results for the case of a square enclosure associated with non-uniform heat source. Then, the present numerical results are analyzed over a range of physical parameters, like periodicity parameter ( N ≥ 1 ), interface heat transfer coefficient ( 10 − 2 ≤ H ≤ 10 2 ), porosity scaled thermal conductivity ratio ( 10 − 2 ≤ γ ≤ 10 2 ), with a fixed Rayleigh number ( Ra = 10 6 ), Darcy number ( Da = 10 − 4 ), Prandtl number (Pr = 0.71), and porosity ( ε = 0.8 ). To study the impacts of these key parameters on the fluid flow behavior and isotherm patterns of fluid as well as solid phase in the porous-square enclosure. From present numerical experiments that the structure of flow is controlled by multicellular structure with rotating clockwise and anticlockwise directions in the entire results. The flow dynamics are highly affected by the periodicity parameter (N) under LTNE circumstances. The characteristics of the local Nusselt number have the point of inflection and the maximum magnitude of it increases with N. The significant effect of H is found on the heat transfer rate of fluid phase but it is negligible on the heat transfer rate of solid phase. However, the influence of γ is found reverse in nature on the heat transfer rate of fluid as well as solid phase when as compared to the effect of H.

Heat transfer investigation of nano – Encapsulated phase change materials (NEPCMs) in a thermal energy storage device

Phase change natural convection heat transport and flow features of a variety and new types of hybrid nanoliquids, suspension of Nano – encapsulated phase change materials (NEPCMs), within a square cavity is inspected theoretically in this analysis. The capsules are arranged with a shell and a PCM as a core. The shell of this NEPCM prevents the phase change material from the direct interaction of hot fluid and from the leakage. The heat capacity of the suspension contains latent heat generated at the time of phase change. The modeled equations are numerically scrutinized with Finite element method. Variable thermal conductivity parameter 1≤Nc≤5, variable viscosity parameter 1≤Nv≤5, radiation number 0.5≥R≥0.1, Rayleigh parameter 102≤Ra≤103, volume fraction of NEPCMs1%≤ϕ≤5% and fusion temperature (0.2≤θf≤1.0) impact on the patterns of heat capacity ratio, isotherms and velocity lines are examined in detail. The results indicates that, as the volume fraction values of NEPCMs amplifies from 1% to 5% the rates of heat transfer of the nanoliquid magnifies 42% compared to the host fluid. Non – dimensional rates of heat transport magnifies with growing (Ste) values.

Free convective heat flow from cold and heated conical shape bodies in Newtonian liquids

Investigation on the simulation effects of free convection flow from a cold and heated cone with a downward pointing tip in various stagnant fluids is presented in this study. Examining the steady-state isotherm patterns around the cone to determine heat transfer characteristics. Results are presented for friction factor and Nusselt number distributions Over the surface of the cone for distinct dimensionless quantities like Pr and Gr to deliver an extensive class of dimensionless numbers. The commercial program ANSYS CFX 16.0 was used to solve the regulating equations which governs the motion vis., momentum mass and energy were computed. The temperature as well as flow fields are coupled using the Boussinesq approximation in order to simplify the governing equations and capture natural convection. Heat transmission has a rather minimal influence on the local Nusselt number for low Grashof and Prandtl values, according to the findings. It gains strength as the Grashof and Prandtl numbers grow, because of the extreme curvature of the isotherms, the maximum value of the local Nusselt number may be found around the corner of the vertical cone in both cones. The current simulations closely match the numerical values provided in the printed matter.

Unsteady, two-dimensional magnetohydrodynamic (MHD) analysis of Casson fluid flow in a porous cavity with heated cylindrical obstacles

This research presents an analysis of entropy generation during natural convection in a porous medium using triangular heated cylindrical obstacles with equal spacing. The study consists of three cylindrical obstacles arranged in a triangular pattern. Each cylinder is uniformly spaced from its neighboring cylinders, creating equilateral triangles throughout the arrangement. All of these cylindrical obstacles are heated. The triangular arrangement guarantees an even distribution of obstacles across the experimental space. The governing equations, with entropy, are numerically solved using the finite element method. The study aims to investigate the interactions between several key elements in fluid dynamics: Casson fluid, magnetohydrodynamics, the Darcy–Forchheimer model, entropy, and natural convection. The goal is to gain insights into the individual behaviors of these elements and their interactions in combined systems. The results indicate that the Casson fluid parameter has an impact on the flow and heat transfer characteristics, while the Hartmann and Nusselt numbers exhibit control mechanisms for the intensity of natural convection and affect the patterns of isotherms, streamlines, and entropy.

Removal of 2,4-Dichlorophenoxyacetic Acid from Aqueous Solutions Using Al2O3/Graphene Oxide Granules Prepared by Spray-Drying Method

Within this study, aluminum oxide granules with 0.25%vol. of graphene oxide were prepared by a spray-drying method to make an adsorbent for the 2,4-Dichlorophenoxyacetic acid (2,4-D) herbicide removal from aqueous solutions. The obtained adsorbent was studied using infrared spectroscopy, scanning electron microscopy and Raman spectroscopy. The presence of graphene in the spray-dried powder was confirmed. The adsorption removal of 2,4-D using the obtained material was performed at an ambient temperature by varying the process parameters such as pH and adsorption time. The adsorption of 2,4-D was a monolayer chemisorption according to the Langmuir isotherm pattern and a pseudo-second-order kinetic model. The maximum Langmuir adsorption capacity of the monolayer was 35.181 mg/g. The results show that the Al2O3-0.25%vol. GO powder obtained by spray drying is suitable for the production of adsorbents for toxic herbicides.

Water desorption isotherms and thermodynamic properties of Ora-pro-nóbis (Pereskia aculeata Miller)

Desorption isotherms of ora-pro-nóbis leaves were determined at storage (5 °C, 10 °C, 20 °C, 30 °C, and 40 °C) and drying (40 °C, 50 °C, 60 °C, 70 °C, and 80 °C) temperatures by the gravimetric static method using saturated saline solutions to obtain relative humidities ranging from 5.20% to 98.48%. The net isosteric heat of desorption and thermodynamic properties such as differential enthalpy, differential entropy, and Gibbs free energy were also estimated. The GAB model presented the best parameters of fitting and the lowest Akaike and Bayesian information criteria values. The desorption isotherm patterns presented a sigmoid shape and were categorized as BET Type II sigmoid shape. The monolayer moisture content was estimated in 0.06 kg of water/kg of dry matter using the GAB model, and it remained constant at all temperatures. The leaves presented an optimal water activity equal to 0.35 at storage temperatures. The net isosteric heat of desorption decreased with increasing Xeq, and differential entropy increased with rising equilibrium moisture content (Xeq > 0.07). The enthalpy-entropy compensation was evaluated, and the desorption process is revealed to be entropy-driven and non-spontaneous.

ANALYSIS OF FLUID-FLOW CHARACTERISTICS AND HEAT-TRANSFER PATTERNS AROUND A SQUARE BLUFF BODY

In this study, we investigate a numerical simulation of the flow and heat transfer characteristics around a single square cylinder subjected to incidence in a two-dimensional plane. The Reynolds and Prandtl numbers are set at <i>Re</i> = 100 and <i>Pr</i> = 0.71, respectively. The cylinder's surface is subjected to pressure and viscous forces due to the passing flow, with the magnitude of these forces influenced by the cross-sectional shape of the bluff body, the angle of attack, and flow velocity. The angle of orientation for the square cylinder varies from 0° to 45° in 5° increments. The study begins with comprehensively examining the governing equations, simulation procedures, and grid generation, employing an efficient and robust in-house finite volume code. Subsequently, we present and discuss the instantaneous streamlines, velocity components, vorticity, and isotherm patterns for different angles of attack. Additionally, global quantities such as viscous, pressure, total lift, drag coefficients, their root-mean-square, Strouhal, and Nusselt numbers are analyzed for various angles of attack. It is observed that the frequency of vortex shedding decreases with an increasing angle of attack. Furthermore, the values of global quantities and flow and temperature patterns remain relatively constant for angles of attack in the range of θ = 30°-45°. The numerical results show good agreement with experimental and numerical data in the existing literature.

Adsorption equilibrium of activated carbon amid fluctuating benzene concentration in indoor environments

Adsorption is commonly employed to remove volatile organic compounds (VOCs) from indoor air. However, the reversibility of this process has been rarely explored in prior research. Meanwhile, some previous research indicated partial reversibility in adsorption and desorption processes, which has not been described in traditional adsorption equilibrium models. In this study, we measured benzene adsorption and desorption isotherms on 6 activated carbons within two concentration ranges: 0–3 ppm and 0–6 ppm. The results showed that the adsorption process was partially reversible and the desorption isotherm was hysteretic for all the samples. Different carbons exhibited distinct isotherm patterns, yet the desorption isotherms in the experimental concentration range can be calculated from the adsorption isotherms using the same empirical equation. In addition, we measured the breakthrough curves using the oscillating benzene concentration (6 ppm to background) on the test columns. Reversible adsorption was observed at low degrees of saturation of the test column. Especially for microporous activated carbon, desorption could be sustained for several hours with purging even at the breakthrough rate of about 10%. An adsorption equilibrium model incorporating partially reversible adsorption and hysteretic desorption isotherm was developed based on the experimental data, which allows a preliminary interpretation of the measured breakthrough curves at fluctuating inlet concentrations.

Analysis of natural convection and the generation of entropy within an enclosure filled with nanofluid-packed structured pebble beds subjected to an external magnetic field and thermal radiation

The efficient heat transfer and energy storage during periods of excess energy production, like peak solar or wind power generation, is facilitated by the compact design and closely packed pebble bed thermal energy storage system. This study focuses on analyzing natural convection and entropy generation in a closed chamber filled with water/Al2O3-water nanofluid containing eight spherical pebbles arranged in a structured manner, referred to as packed beds while considering the presence of an external magnetic field and surface thermal radiation. The single-phase and two-phase models for nanofluid equations are solved using Ansys Fluent, employing a non-dimensional approach for the calculations and presenting the results. Two cases with two-dimensional cavities in the presence of a magnetic field and conductive solid blocks are considered for validating the numerical method. Besides two-dimensional cases, another three-dimensional case is considered to evaluate heat transfer for the air-filled cubic cavity. The active parameters are the Hartmann number, Rayleigh number, and solid-to-liquid thermal conductivity ratio. The findings are displayed for different parameters, encompassing the mean Nusselt number, generation of entropy, mean Bejan number, patterns of isotherms, velocity distribution, and localized entropy generation. The averaged Nusselt number decreases by approximately 2 % when applying a magnetic field. However, thermal radiation partially compensates for the negative effect of the strong magnetic field. At a Rayleigh number (Ra) of 106, entropy generation increases by 18 % due to radiation and by 78 % because of the magnetic field. The average Bejan number increases from approximately 0.02 to 0.36 while the Hartmann number increases from 0 to 100 for a single-phase nanofluid without radiation effect.

Isotherm and Kinetic Adsorption of Cadmium (Cd) onto Biosorbent Made from Kepok Banana Peel (Musa Acuminata balbisian): the Effect of Activator Type and Biosorbent Dosage

The present study determined the isotherm and kinetics model of the cadmium adsorption process onto a biosorbent made from kepok banana peel (Musa Acuminata balbisian). The experiments were carried out in batch process, laboratories scale, room temperature, pH of Cadmium of 4, volume of Cd solution of 20 ml, and biosorbent size particle of 60 mesh—the biosorbent produced using chemical activation method onto dry banana peel. The variation in this research was the type of activator (H3PO4 and H2SO4) and the biosorbent dosage (1, 1.5, and 2 g). The experimental data was used to calculate the Langmuir and Freundlich isotherm—Kinetics analysis based on pseudo-first-order and second-order kinetics models. The best condition of the cadmium removal occurred at 90 minutes of contact time and 2 g dosage for H2SO4 and H3PO4 activators. Cadmium biosorption was in accordance with the Langmuir isotherm and pseudo-second-order kinetic model. The linear equation obtained is positive, with the maximum adsorption capacity and the affinity constant. Cadmium adsorption onto banana peel biosorbents followed the Langmuir adsorption isotherm pattern, so chemical adsorption occurred in this study. Cadmium adsorption kinetics onto biosorbent that activated with an acid activator of H3PO4 and H2SO4 followed the pseudo-second-order kinetic model. The best condition of the cadmium removal occurred at 90 minutes of contact time and 2 g dosage for H2SO4 and H3PO4 activators. Cadmium biosorption in this study was in accordance with the Langmuir isotherm and pseudo-second-order

Subcritical CO2 adsorption on geomaterials of coal-bearing strata in the context of geological carbon sequestration

This paper explores the adsorption behaviour of geomaterials in the framework of CO2 sequestration in shallow level coal seams. Manometric adsorption experiments were carried out on two anthracite coal samples, two rock samples from East Irish Sea, MX80-bentonite, Speswhite kaolinite, dry, wet and biofilm-laden (Bascillus mojavensis-laden) sand at subcritical pressure range (up to 6.4 MPa) of isothermal condition at 298.15 K. The experiments were aimed to investigate the influence of the biogeological conditions of coal and caprock constitutions on CO2 adsorption. At lower pressures, the moisture had an influence on the CO2 adsorption on coal resulted in reduced adsorption capacity. At elevated pressures, the volume expulsion behaviour and coal-water interaction had an influence on the adsorption capacities of moist coal sample and resulted in comparable adsorption capacities to dry sample. The disparity in the adsorption capacities between the wet powdered and wet intact core samples showed that the results obtained with powder samples may not reflect the field conditions. Wet conditions and Bascillus mojavensis bacteria influenced the adsorption capacity of sand and showed CO2 chemisorption capacity. The desorption isotherm pattern of wet and biofilm sand showed that the CO2 was continuously adsorbed independent of the gas phase pressure. Among the clay minerals, bentonite had greater affinity towards CO2. Despite the fact that the adsorption capacity of the cap rock is smaller than that of the coal samples, the experimental investigation with constituents of the cap rock provides insights into the effect of biogeological conditions of coal and rock sample constituents on CO2 storage in coal seams.

Free convection flow from a heated cone with a downward tip submerged in Newtonian fluids employing a finite volume technique

Computational fluid dynamics technique have been employed to capture the plain convective flow past from a heated cone with a tip downward in various stagnant Newtonian fluids. Using detailed isotherm patterns around the cone under steady-state conditions examine the heat transfer characteristics that have been reported. The findings illustrate the distribution of the friction factor, average Nusselt number and local Nusselt number around the cone surface over a wide range of dimensionless values such as Grashof and Prandtl numbers. The guiding PDEs such as conservation of mass, momentum and energy are solved by finite volume method using commercial software of ANSYSCFX16.0. To simplify the governing equations while capturing the natural convection, Boussinesq approximation has been adopted to coupling the flow and temperature fields.This study reveals the contribution of various angles (φ = 15°,300and45°), diverse Prandtl numbers (Pr = 0.71,5,10,20,50) and distinct Grashof numbers (GrL = 104, 105, 106) for the efficacy of them over the slant surface of the cone. The heat transmission and parametric features of these processes have been discussed for how heat can be transferred from a heated cone when it is submerged in a liquid. Visualization of the effects of different parameters for different cone apex angles was done by displaying the results graphically. The present simulations are in a near match to the numeric values appeared in the literature.

The effect of homogenisation pressure on the microstructure of milk during evaporation and drying: particle-size distribution, electronic scanning microscopy, water activity and isotherm.

Homogenisation is a widely used technique in manufacturing powdered milk with a direct impact on product solubility, and the homogenisation pressure is a central attribute of this process. We aimed to understand the effect of increasing homogenisation pressures (0/0, 15/5, and 75/5 MPa, 1st/2nd stages) on particle-size distribution during homogenised whole milk powder manufacture and rehydration of the final product. The fluid milk was thermally treated, homogenised, concentrated by rotary evaporation, and then dried using a spray dryer. Particle size (Dv90) was monitored at all stages of the manufacturing process. The final product (milk powder) was analysed using particle-size distribution, electronic scanning microscopy, water activity, and isotherms. The results demonstrated that increasing the homogenisation pressure leads to milk powder with smaller particle size when rehydrated (Dv90 values: 6.08, 1.48 and 0.64 μm for 0, 20 and 80 MPa, respectively). Furthermore, the volume (%) of the particles in the 'sub-micro' region (smaller than 1.0 μm) presented an inversely proportional profile to the homogenisation pressure (homogenised fluid milk: 86.1, 29.3 and 2.4%; concentrated milk: 86.1, 26.5 and 5.7%, and reconstituted milk powder: 84.2, 31.8 and 10.9%). Surprisingly, this pattern was not observed in the SPAN value (which corresponds to the width or range of the size distribution based on the volume). Additionally, the increase in the homogenisation pressure did not affect the sorption isotherm pattern. These results demonstrate that increasing the homogenisation pressure decreases the particle size of the reconstituted powdered milk, indicating the potential for future studies on how this phenomenon affects its physicochemical and final product properties.

Magnetic field impact on double diffusive mixed convective hybrid-nanofluid flow and irreversibility in porous cavity with vertical wavy walls and rotating solid cylinder

Mixed convective heat transfer due to rotating surface has sustainable importance in improving cooling efficiency of thermal engineering equipment. In this investigation, hydromagnetic double diffusive mixed convection in a wavy porous cavity filled with hybrid nanofluid having rotating heat source is numerically studied. A solid cylindrical rotating heat source is positioned at the center of the wavy cavity. The fluid domain inside the cavity is heated from the rotating heat source and partially heated bottom wall. The governing partial differential equations are simulated using finite element method. The computational technique is validated performing rational comparisons. The results indicate that the pattern of streamlines circulation, isotherms and local entropy generation are significantly influenced with the rotating heat source. The flow velocity is observed increasing rapidly with cylinder rotation speed which is maximized with increasing cavity porosity and permeability but minimized with magnetic field impact and amalgamating hybrid nanoparticles. Heat transfer enhancement is found increasing by 682.07% with rotating heat source for varying Darcy number (Da = 10−4 to 10−1) in absence of magnetic field (Ha = 0) which reduces to 504.02% in presence of magnetic field (Ha = 100). Moreover, 45.62% heat transfer enhancement is achieved for varying of cavity porosity (ε = 0.3 to 0.9) which declines to 22.83% in presence of magnetic field (Ha = 100). In addition, 90.04% more heat transfer enhancement is estimated in hybrid nanofluid of 5% volume fraction than base fluid water. The entropy generations components are affected significantly with higher values of physical parameters. The Bejan number is found declining for all influential parameters studied. Accordingly, the study has significant impact on the controlling and optimizing of fluid flow and heat transfer in hybrid nanofluid filled improved designing and is applicable in improving the performance of thermal equipment such as high-performance heat exchangers, electronic device cooling, energy storage systems, thermal mixing, space thermal management, crystal growth, float glass production, solidifications, solar technologies, and reactor safety devices, etc.

Insight into corrosion inhibition mechanism of carbon steel by an algal extract as an eco‐friendly corrosion inhibitor in 0.5 M H2SO4: Experimental and molecular dynamics study

AbstractTo explore the potential of new ecological corrosion inhibitors, we investigated the mechanism of corrosion inhibition in carbon steel using Halopitys incurvus, an algal extract available in both crude and chromatographic fractions, in a 0.5 M H2SO4 medium. Various methods were employed, including gravimetry, electrochemical impedance spectroscopy, polarization curves, scanning electron microscopy (SEM) techniques, and molecular dynamics. The crude extract exhibited a high corrosion‐inhibiting potential, with a maximum inhibitory efficiency of 85.30% at 600 mg/L. The electrochemical results indicated mixed behavior of the crude extract. Furthermore, we found that the adsorption of the crude extract onto the metal surface followed the Langmuir isotherm pattern. The SEM study confirmed our proposition that extract molecules were adsorbed onto the carbon steel surface. Using the chromatographic fractionation protocol, we were able to distinguish four main fractions, and the most effective fractions reached an inhibitory efficiency value of 96.00% at 100 mg/L. The molecular dynamics simulation confirmed the experimental results.

Characterization of solid and liquid carbonization products of polyvinyl chloride (PVC) and investigation of the PVC-derived adsorbent for the removal of organic compounds from water

The transformation of plastic wastes into value-added carbon materials is a promising strategy for the recycling of plastics. Commonly used polyvinyl chloride (PVC) plastics are converted into microporous carbonaceous materials using KOH as an activator via simultaneous carbonization and activation for the first time. The optimized spongy microporous carbon material has a surface area of 2093 m2 g−1 and a total pore volume of 1.12 cm3 g−1, and aliphatic hydrocarbons and alcohols are yielded as the carbonization by-products. The PVC-derived carbon materials exhibit outstanding adsorption performance for removing tetracycline from water, and the maximum adsorption capacity reaches 1480 mg g−1. The kinetic and isotherm patterns for tetracycline adsorption follow the pseudo-second-order and Freundlich models, respectively. Adsorption mechanism investigation indicates that pore filling and hydrogen bond interaction are mainly responsible for the adsorption. This study provides a facile and environmentally friendly approach for valorizing PVC into adsorbents for wastewater treatment.