Contact Temperature Research Articles

Protein Adsorption on Solid Surfaces: Data Mining, Database, Molecular Surface-Derived Properties, and Semiempirical Relationships.

Protein adsorption on solid surfaces is a process relevant to biological, medical, industrial, and environmental applications. Despite this wide interest and advancement in measurement techniques, the complexity of protein adsorption has frustrated its accurate prediction. To address this challenge, here, data regarding protein adsorption reported in the last four decades was collected, checked for completeness and correctness, organized, and archived in an upgraded, freely accessible Biomolecular Adsorption Database, which is equivalent to a large-scale, ad hoc, crowd-sourced multifactorial experiment. The shape and physicochemical properties of the proteins present in the database were quantified on their molecular surfaces using an in-house program (ProMS) operating as an add-on to the PyMol software. Machine learning-based analysis indicated that protein adsorption on hydrophobic and hydrophilic surfaces is modulated by different sets of operational, structural, and molecular surface-based physicochemical parameters. Separately, the adsorption data regarding four "benchmark" proteins, i.e., lysozyme, albumin, IgG, and fibrinogen, was processed by piecewise linear regression with the protein monolayer acting as breakpoint, using the linearization of the Langmuir isotherm formalism, resulting in semiempirical relationships predicting protein adsorption. These relationships, derived separately for hydrophilic and hydrophobic surfaces, described well the protein concentration on the surface as a function of the protein concentration in solution, adsorbing surface contact angle, ionic strength, pH, and temperature of the carrying fluid, and the difference between pH and the isoelectric point of the protein. When applying the semiempirical relationships derived for benchmark proteins to two other "test" proteins with known PDB structure, i.e., β-lactoglobulin and α-lactalbumin, the errors of this extrapolation were found to be in a linear relationship with the dissimilarity between the benchmark and the test proteins. The work presented here can be used for the estimation of operational parameters modulating protein adsorption for various applications such as diagnostic devices, pharmaceuticals, biomaterials, or the food industry.

Constructing the synergistic effects of chitosan and ionic liquid on SPEEK polymer for efficient adsorption of crystal violet dye

In the study, a novel chitosan biopolymer and 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid (IL)-incorporated sulfonated poly (ether ether ketone) (SPEEK) composite (Ch-IL@SPEEK) was prepared for adsorption of cationic crystal violet (CV) dye. The proposed composite was well characterized by several techniques. CV adsorption performance was examined via batch studies by varying various variables involving adsorbent dosage, contact time pH and temperature. The isotherm results were demonstrated the adsorption characters of the processes were Langmuirian. The maximum adsorption capacity was determined as 77.66 mg g−1 for the composite which was significantly higher than SPEEK (qmax = 45.36 mg g−1). The determined equilibrium time of the operated system was 360 min and the kinetic model was assessed as Elovich. At low pHs the protonated surface groups repelled the positively charged CV and the adsorption rate increased with increasing pH. The process is spontaneous and favorable as it proceeds via endothermic interactions. Furthermore, even at the end of 5 successful adsorption cycles, 77.86 % CV removal was obtained. Remarkable efficiencies were also achieved in the removal performance of different organic pollutants. Based on the reported results, Ch-IL@SPEEK composite were exhibited as an impressive adsorbent material for adsorption processes.

Abnormal fretting wear behavior of Fe-based amorphous coating

To promote the application of Fe-based amorphous coating (AMC)-protected magnesium alloys in fretting wear conditions, a Fe-based AMC with a thickness of about 164 μm was deposited on AZ31B magnesium alloy substrate by detonation spraying. The microstructure and fretting wear behaviors against GCr15 counterpart ball in different frequencies of the Fe-based AMC were studied in detail. The results show that the Fe-based AMC has a substantially complete amorphous structure, the porosity and surface hardness are ≤1.2 vol %, and 764.7 ± 37.5 Hv0.1, respectively. Therefore, the Fe-based AMC presents excellent fretting wear resistance, and its wear rate is almost 1/10 of that of AZ31B magnesium alloy, and 1/5 of that of high-velocity oxygen-fuel sprayed 316L stainless steel coating on AZ31B magnesium alloy substrate. The fretting wear behavior of Fe-based AMC was found to be sensitive to the fretting frequency: as the frequency increases from 5 to 100 Hz, the average steady-state friction coefficient increases from 0.77 to 1.07, but the wear rate exhibits an anomalous phenomenon, decreasing from 5.26 × 10−5 mm3N−1m−1 to 3.47 × 10−5 mm3N−1m−1. The improvement in wear rate is mainly attributed to the formation of an oxygen-rich river-like friction layer on the worn surface as the transient contact temperature increases with frequency, effectively suppressing delamination wear. Additionally, the occurrence of high transient frictional temperatures at high frequencies leads to evident crystallization within the coating, accompanied by the formation of nanocrystals, oxide films, and a large area river-like friction layer consisting of debris-compacted layers, which strengthens the Fe-based AMC. Consequently, the wear mechanism changes from delamination wear and abrasive wear at low frequencies to oxidative wear and adhesive wear at high frequencies, resulting in superior fretting wear resistance of the Fe-based AMC at high frequencies.

Preparation of low‐rolling resistance natural rubber composites from pyrolysis carbon black by plasma treatment

AbstractIn this study, the surface of pyrolysis carbon black (CBp) is modified by integrating the ball milling process with plasma treatment. High‐energy mechanical ball milling enabled more uniform contact and sufficient reaction temperature for the silane coupling agent and CBp. In addition, the impact of plasma activated the ash and surface deposits of CBp, reducing its inertness. Herein, the filler dispersion grade, Payne effect, vulcanization characteristics, and mechanical and dynamic mechanical properties are investigated by considering modified CBp/natural rubber (NR) composites. The ball milling plasma process can reduce the polarity of CBp. Compared with untreated CBp/NR composites, the plasma‐treated SCA‐CBp/NR composites exhibited increased CBp dispersion grades, higher processing safety, better processing fluidity, and improved mechanical properties. The reduced Payne effect ensured more filler‐rubber network structure, resulting in a reduction in rolling resistance.HighlightsThe coupling agent and CBp are treated by low‐temperature plasma and ball milling.The process promotes the formation of the filler‐rubber network.The dispersion grade of composites increased by 26.29%.The tensile strength increased by 5.57%, and the rolling resistance decreased by 19.44%.

A quantitative method of calculating transient nonlinear heat partition coefficient between clutch friction discs with deep learning

In the current clutch temperature field study, the generally used constant heat partition coefficient tends to overestimate the separator disc temperature and underestimate the friction disc temperature. Although some researchers have found the characteristics of the time-varying heat partition coefficient, a suitable method is still needed to apply it to temperature calculations. This study provides a quantitative method for the application of the transient nonlinear heat partition coefficient to temperature calculations. The finite difference method is adopted to figure out the time-varying curve of the heat partition coefficient by coupling the contact temperature of the friction components. The numerical results show that the heat partition coefficient is independent of rotation speed with three stages: initial value, rapid time-varying, and steady-state. Different from the analytical method, we apply a deep learning method to train the quantisation function to characterise these three stages, avoiding complex formula derivation. As a result, the quantitative function can characterise the time-varying heat partition coefficient accurately, with an average error of 0.19%, 3.05% and 0.62% for the inert, time-varying, and steady-state stages, respectively. In addition, the accuracy of applying the quantisation function in temperature simulation is verified by friction experiments, and the error is less than 8%. This is superior to the results of solving the temperature field by a constant heat partition coefficient.

Glycogen-assisted biosynthesis of MnO2 for adsorptive elimination of methylene blue from water

A novel biosynthesis of manganese dioxide (MnO2) NPs was achieved by oxidizing glycogen with KMnO4 in an alkaline medium. X-ray powder diffraction, Fourier-transform infrared spectroscopy, N2 sorption, and transmission electron microscope (TEM) techniques were utilized to assess the physicochemical characteristics of the prepared MnO2. The impacts of different adsorption parameters, including contact time, pH, concentration, temperature, and adsorbent dose, on methylene blue (MB) elimination utilizing the prepared MnO2 NPs, were investigated. It was found that the Langmuir model well describes how the dye molecules arrange themselves on the MnO2 surface compared to other models. This proposes a single layer of dye forms, with each molecule attaching to a specific site on the MnO2. Additionally, the results were well-matched with a pseudo-2nd-order model, demonstrating that chemical reactions had a significant role in the adsorption experiment. Under specific conditions (RT, natural pH of the dye solution, and 30-minute contact time), the MnO2 could hold up to 40.85 mg of dye per gram of MnO2 (mg/g). Further analysis reflected that the adsorption procedure was spontaneous, which means it happened favorably without needing extra energy input. This suggests that biosynthesized MnO2 has great potential as an eco-friendly material for cleaning up MB dye contamination in water.

A study on the performance, structure, composition, and release behavior changes of polybutylene adipate terephthalic acid (PBAT) film during food contact

Polybutylene adipate terephthalic acid (PBAT) is an emerging biodegradable material in food packaging. However, concerns have been raised regarding the potential hazards it could pose to food safety. In this study, the changes of PBAT films during food contact and the release of small molecules were inestigated by a multiscale approach. On a macro-scale, the surface roughness of the films increased with the reduction in the concentration of food simulants and the increase in contact temperatures, especially after immersion in acidic food environments. On a micro-scale, the crystallinity (Xc) and degradation indexes (DI) of the films increased by 5.7–61.2% and 7.8–48.6%, respectively, which led to a decrease in thermal stability. On a scale approaching the molecular level, 2,4-di-tert-butylphenol (2,4-DTBP) was detected by gas chromatography-mass spectrometry (GC-MS/MS) with the highest migration content, and the release behavior of 2,4-DTBP was further investigated by migration kinetics. In addition, terephthalic acid (TPA), a hydrolysis product of PBAT, was detected in acidic food environments by liquid chromatography-mass spectrometry (LC-MS/MS). The results of this study could provide practical guidance and assistance to promote sustainable development in the field of food packaging.

The Effectiveness of Carbonized Neem Leaves Adsorbent for the Removal of Phenol from Synthesized Effluent Using the Batch Process Method

The adsorption of phenol in aqueous solution was investigated using carbonized neem leaves adsorbents. The effect of various factors such as contact time, phenol concentration, pH, temperature, and amount of adsorbent on the adsorption capacity of the adsorbents was determined. The results show that maximum adsorption was obtained at a contact time of 150 minutes, at a phenol concentration of 50 mg/L, optimum adsorption temperature of 45⁰C, pH of 2 and adsorbent dosage of 3 g/L. The equilibrium data was well described by the Freundlich isotherm equation (R2= 0.955 ). This shows a heterogenous adsorption process. The kinetics of the process were explained by the intra-particle diffusion models (R2>0.9). This fitted data indicates a degree of boundary layer control and is not limited to intra-particle diffusion.

Wastewater treatment from a typical multisystem hospital using chemically modified banana peels: Taguchi parametric optimization and characterization

The study aims to develop an eco-friendly solution for addressing contaminants in hospital wastewater. To achieve this, banana peel, a cost-effective and easily available agricultural waste, was chemically modified using sulfuric acid and sodium hydroxide. The hospital wastewater was analyzed using an Atomic Absorption Spectrometer to identify the presence of heavy metals. The physicochemical properties were measured and compared against the standards set by the World Health Organization (WHO). Scanning electron microscopy and Fourier-transform infrared spectroscopy were used to characterize the chemically modified banana peel. Batch adsorption was conducted with the wastewater using the prepared adsorbent. The effect of contact time, mixing rate, temperature, and adsorbent dosage was examined to know the removal efficiency of the adsorbent. The experimental design incorporates Taguchi OA design to optimize the process. The total heavy metals discovered in the wastewater were As, Cd, Fe, Cu, Ni, Cr, Pb, Mn and Zn. The percentage of Cd, Fe, Cu, Ni, Cr and Pb removed were 79.5%, 87.9%, 56.9%, 89.0%, 88.5% and 93.5%, respectively, at temperature, adsorbent dosage, mixing rate and contact time of 30 °C, 3 g, 700 rpm and 60 min, respectively. The physicochemical properties remain within the acceptable WHO range except the turbidity. At optimum point, the percentage removal of Cd, Fe, Cu, Ni, Cr, Pb and Zn were 64.3%, 80.5%, 51.4%, 82.3%, 72.4%, 86.6% and 72.1%, respectively; while, the conductivity, pH, TDS, and turbidity value were, respectively, 20.57 mS/cm, 6.8, 10.16 mg/l, and 86.31 NTU. Characterization revealed the existence of active functional groups on the adsorbent surface enhancing the hospital wastewater treatment and change in its morphological structure after the treatment was noticed. In conclusion, the modified banana peel was effective for the treatment of hospital wastewater.

Multi-objective design optimization of polymer spur gears using a hybrid approach

Polymer gears are used in applications requiring small to moderate loads to effectively transmit power and use the limited place available as possible. Various commercial standards have been provided designers with the rating criteria and acquaintance of different polymer material properties for the process of design. However, the result was unsatisfactory in terms of economy, time, and the optimality of the product. Thus, classic and stochastic algorithms have been embraced to reach the best design of polymer gears. Taking advantage of the former and latter algorithm’ methods, optimal design of gears could be attained with an increased gear life span and decreased failure modes. In this study, polyoxymethylene (POM) spur gear set has been optimized combining the mathematical model from plastic standards and hybrid optimization approach of multi-objective genetic algorithm (MOGA) and sequential quadratic programming (SQP). Weight and power loss were the objective functions. Five design variables were optimized with the satisfaction of bending and contact stresses, temperature, wear, and deformation as constraints. Solutions of the problem were formulated as Pareto optimal set. The results of multi-objective were compared with previously published single-objective optimization. The results favored multi-objective optimization (82.67%, 31.39% reduction in weight and power loss respectively) as it gave the best applicable solution fitting in real life situations. The results also went hand in hand with literature confirming the efficiency of the proposed algorithm. With the variation of operating parameters, various optimal designs could be obtained where the designers can choose the design that is suitable for a particular application.

An investigation into the thermal surface contact resistance, fin width and temperature on negative bias temperature instability during self-heating

This work investigates the impacts of the thermal surface contact resistance (SR), fin width and temperature on the negative bias temperature instability (NBTI) during self-heating based on 14 nm p-FinFET through technology computer-aided design (TCAD) tool. In order to promote the accuracy of simulation, the experimental data are used to calibrate the TCAD results. The simulation results reveal that as SR increases, the lattice temperature rises by 20.07 %, which leads to a 15.84 % decrease of the carrier mobility and finally a reduction of the saturation current by 5.07 %. Moreover, as WFin decreases from 8 nm to 2 nm, the device threshold voltage increases by 15.41 %, resulting in that the saturation current reduces by 19.06 %. Besides, with an increase of the ambient temperature from 300 K to 500 K, the lattice temperature and trapped charge rise by 60.48 % and 12.53 %, respectively, which eventually leads to an 18.13 % decrease of the saturation current.

Temperature field reconstruction based on femtosecond laser prepared of multiwavelength fibre bragg grating array

Temperature field measurements are of great significance in industrial production, scientific research, and other fields. Contact temperature measurements usually achieve high spatial resolution by increasing the layout density of the sensors. However, in practical applications, achieving high-density sensor placement is often difficult. Therefore, when the number of sensors is limited, it is necessary to perform function fitting or interpolation of the temperature of the sampling points to reconstruct the temperature field distribution. This study proposed a temperature field reconstruction method based on femtosecond laser prepared multiwavelength fibre Bragg grating (FBG) array. A multiwavelength FBG array was prepared using the femtosecond laser phase mask method combined with stress stretching, and applied for measuring the temperature field distribution in a tubular high-temperature furnace. Cubic spline interpolation and backpropagation (BP) neural networks were used to construct two-dimensional temperature field models for the temperature field distribution data measured by the FBGs, and the prediction accuracies of the two models were compared. The test results show that the root mean square error of the temperature field distribution constructed using the BP neural network is 0.7333 °C, which is approximately 23.18% of the predicted results of the cubic spline interpolation model, indicating that it is a high-precision temperature field reconstruction method.

Invasive lignocellulose-based plants bio-sorbents for the elimination of nitrites of emerging concern from water

The regulation of nitrite levels in potable water is primarily motivated by the potential for excessive amounts to induce methemoglobinemia, which is also referred to as blue baby syndrome. Human and industrial activities generate and release nitrite-containing wastewater into water bodies, thereby endangering ecosystem health and contaminating water sources. Biosorption is an alternative and environmentally beneficial method of wastewater treatment. These methods have several advantages over conventional methods, including their cost-effectiveness, accessibility, and reusability. This study investigates the viability of utilizing guava leaf, neem leaf, orange peel, banana peel, and custard apple leaf as bio-sorbents for the removal of nitrite from contaminated water. One hundred percent removal efficiency is the result of this endeavor. Following an examination of all six bio-sorbents, it was observed that the guava leaf bio-sorbents exhibited the most effective performance in the removal of nitrite from water. Additionally, the impacts of various parameters including contact duration, agitation speed, adsorbent dosage, pH, and temperature are also investigated. Additionally, prior to utilization, the biomass may undergo physical and chemical modifications. To enhance the analysis of each bio-sorbent, a range of characterization techniques are utilized, including XRD, SEM-EDX, FTIR, and BET analysis. Economic feasibility can be achieved by regenerating and reprocessing the bio-sorbent subsequent to the nitrites removal process.

Biosorption of arsenic (III) from aqueous solution using calcium alginate immobilized dead biomass of Acinetobacter sp. strain Sp2b

This study presents a novel biosorbent developed by immobilizing dead Sp2b bacterial biomass into calcium alginate (CASp2b) to efficiently remove arsenic (AsIII) from contaminated water. The bacterium Sp2b was isolated from arsenic-contaminated industrial soil of Punjab, a state in India. The strain was designated Acinetobacter sp. strain Sp2b as per the 16S rDNA sequencing, GenBank accession number -OP010048.The CASp2b was used for the biosorption studies after an initial screening for the biosorption capacity of Sp2b biomass with immobilized biomass in both live and dead states. The optimum biosorption conditions were examined in batch experimentations with contact time, pH, biomass, temperature, and AsIII concentration variables. The maximum biosorption capacity (qmax = 20.1 ± 0.76 mg/g of CA Sp2b) was obtained at pH9, 35 ̊ C, 20 min contact time, and 120 rpm agitation speed. The isotherm, kinetic and thermodynamic modeling of the experimental data favored Freundlich isotherm (R2 = 0.941) and pseudo-2nd-order kinetics (R2 = 0.968) with endothermic nature (ΔH° = 27.42) and high randomness (ΔS° = 58.1).The scanning electron microscopy with energy dispersive X-ray (SEM–EDX) analysis indicated the As surface binding. The reusability study revealed the reasonable usage of beads up to 5 cycles. In conclusion, CASp2b is a promising, efficient, eco-friendly biosorbent for AsIII removal from contaminated water.

Finite element investigations for chip scraping during orthogonal cutting process with micro-textured tools

Compared with the conventional tool (CT), the micro-textured tool (MTT) has the advantages of reducing cutting forces, lowering cutting temperatures and inhibiting tool wear. However, the chip scraping phenomenon generated in the cutting process has negative effects and degrades cutting performance when using the MTT with grooves perpendicular to the cutting edge. Due to the difficulty in observing and characterizing chip scraping in situ by experiments, its mechanism and influence on specific cutting forces and tool wear are not fully understood. To this end, finite element (FE) method is employed for simulating the cutting process with MTT. The simulation model is validated by comparing the predicted and measured specific cutting forces. The average prediction error of specific cutting and feed forces is 12.4 % and 18.8 %, respectively. The simulation results indicate that chip scraping mainly results from the discontinuity, non-uniformity and high contact stress state of the tool-chip interface. The minimum specific cutting force is achieved when the advantages of micro-texture and the chip scraping effects are balanced. The MTT rake face wear is subdivided into a severe and a sliding wear zone. This partition characteristic is closely associated with normal contact stress and temperature distributions. The work in this paper contributes to improving the understanding of chip scraping, optimizing micro-texture and cutting parameters, and promoting MTT applications in the manufacturing industry.

Oxidation behaviour of NiSi–NiCr thin film thermocouples and antioxidation effect of SiNxOy film

NiSi–NiCr thin film thermocouples (TFTCs) have significant application value as contact temperature sensors in cutting temperature measurements owing to their fast response and negligible volume. However, due to the relatively high chemical activity of Ni-based alloys, high-temperature oxidation strongly affects the operational reliability of NiSi–NiCr TFTCs. In this respect, depositing an anti-oxidation coating onto the surface of NiSi–NiCr TFTCs is considered an effective way to protect them in high-temperature environments. In this study, NiSi and NiCr films were deposited on cemented carbides and annealed at 200 °C–600 °C in air. Scanning electron microscope, X-ray diffraction spectroscopy, X-ray photoelectron spectroscopy, and four-probe resistivity tests were used to characterize the microstructure and resistivity of NiSi and NiCr film. Then SiNxOy films were deposited onto the NiSi and NiCr films and compared with uncoated samples after annealing at 600 °C. The effect of SiNxOy films on the thermal stability and thermoelectric output of NiSi–NiCr TFTCs was investigated. The results show that the NiSi film was partially oxidized at 200 °C and entirely oxidized when the temperature exceeded 400 °C. The completely oxidized NiSi films had evident defects and cracks, and the resistivity increased by a factor of over 1000. The NiCr film could not be completely oxidized at 600 °C, which is attributed to the formation of Cr2O3 as an external oxide barrier layer. Below 600 °C, SiNxOy films could effectively protect NiSi and NiCr films from oxidation. Thus, the addition of SiNxOy film increases the maximum temperature at which NiSi–NiCr TFTCs can be used.

Shaping of thermal protective properties of basalt fabric-based composites by direct surface modification using magnetron sputtering technique

Abstract A direct modification of the surface of the basalt fabric was carried out by using magnetron sputtering to obtain composites intended for effective protection against contact and radiant heat. One-layer composite with a coating of aluminum (Al) and zirconium dioxide (ZrO2), two-layer composite with a coating of Al/ZrO2, and two-layer composite with a coating of Al/(ZrO2 + titanium dioxide [TiO2]) were deposited on the fabric surface. Scanning electron microscopy with energy-dispersive X-ray spectroscopy analysis was used to assess the coating on basalt fabrics and determine their chemical composition. Parameters such as thermal conductivity coefficient, resistance to radiant heat, and resistance to contact heat for a contact temperature of 250°C were determined for assessment of the composites from the point of view of protective properties. The similarity analysis of composites was performed to state the impact of coating components’ content and coating thickness on chosen parameters. It was found that a two-layer composite in which the outer layer is Al and the inner layer is a mixture of ZrO2 and TiO2 provides good thermal insulation properties. The composites capable of protecting against contact heat at the first efficiency level and against radiant heat at the second efficiency level were obtained.

Numerical modeling of the heat flow component of the composite developed on the basis of basalt fabric

Abstract Numerical simulation basic steps are making a model and recreating the course of the examined process. The article presents numerical modeling of the component of heat flow through a composite developed on the basis of basalt fabric. The composite consisted of the following components: basalt fabric, modified with a composite coating consisting of 1 µm thick aluminum with a mixture of 1 µm zirconia and titanium dioxide, silicone, and Mylar® film modified with the same coating as the basalt fabric. Numerical modeling was performed using the ANSYS 2022 R1 program. The performed numerical simulations of the temperature gradient represented the contact heat resistance test for the contact temperature of 250°C for the basalt fabric and the composite. The proposed model reproduced the exact course and results of the actual study. Each of the layers making up the composite had a thickness and was mapped in accordance with the physical model.

Bioremoval of lead ion from the aquatic environment using lignocellulosic (Zea mays), thermodynamics modeling, and MC simulation

AbstractLead (Pb+2) ions considered a crucial neurotoxic heavy metal result in serious troubles in the live biological environment including poisoning, and liver and kidney shortage, in addition to anemia, hepatitis, encephalopathy, and renal syndrome. In the current study, the biomass of Zea mays (ZMS) was prepared as a biosorbent for the elimination of Pb+2 ions from the aquatic environment in batch mode relevant to contact time, pH solution, biosorbent dose, and temperature. The Zea mays biomass was characterized using an SEM microscope coupled with EDX, FTIR, XRD, and BET surface area analysis to investigate the modification of chemical structure for the biosorption system. According to the biosorption experiments, the supreme biosorbent capability of ZMS approaches 16.9 mg/g for 180 min at pH = 5.5. The evaluation of kinetics analysis reveals that the (Pb+2) biosorption by ZMS was better described with pseudo-second-order kinetics. In addition, the nonlinear regression of Freundlich, Langmuir, Temkin, and Elovich isothermal models was modeled to the equilibrium data, and it was deduced that the Langmuir isotherm provides a better fit than Langmuir based on the correlation coefficient values. The thermodynamic factors were calculated for this biosorption process in which the lead ions are sequestered by the ZMS. According to these factors, it was elucidated that the (Pb+2) ions biosorption onto the Zeamays sponge is exothermic and spontaneous. In addition, Monte Carlo (MC) simulations were conducted to screen the adsorption competence of pigments and ligands in Zea mays for Pb+2 ions adsorption. The outputs of experimental and simulation studies proved the potentiality of Zea mays sponge (ZMS) as a promising biosorbent for eliminating heavy metallic elements from aqueous media.

Synthesis of reusable graphene oxide based nickel-iron superparamagnetic nanoadsorbent from electronic waste for the removal of doxycycline in aqueous media

Graphene oxide-based nickel-iron superparamagnetic nanoadsorbent (GO/Ni-Fe) was synthesized from electronic waste to effectively remove doxycycline (DXC) in aqueous media. The GO/Ni-Fe nanoadsorbent has been characterized using a number of instrumental techniques, including X-ray diffractometer, Zeta potential, Fourier transform infrared spectroscopy, elemental analyzer, vibrating sample magnetometer, transmission electron microscopy, energy dispersive x-ray, and X-ray photoelectron spectroscopy. These techniques showed that nickel-iron (Ni-Fe) nanoparticles with an average size of 4.26 nm were successfully fabricated on GO surfaces. The batch experiments were conducted under different conditions, including contact time, adsorption dosage, pH, concentration, and temperature, to determine the optimal conditions of the adsorption process. The maximum adsorption (90% removal) was established within 20 min, while the adsorbent dose was only 0.1 g/L at pH 5. The adsorption process was best fitted with the pseudo-second-order model, which suggests the interaction of doxycycline with the GO/Ni-Fe nanoadsorbent is mainly controlled by the chemisorption process. This may be due to hydrogen bonding as well as electrostatic interaction and π-π interaction between adsorbates and adsorbents. The isotherm data of the adsorption process was best fitted with Langmuir isotherm model with a maximum adsorption capacity of 13.02 mg g−1 at 25 °C, indicating that the adsorption is a monolayer adsorption to heterogeneous surfaces with electrostatic interaction. The superparamagnetic properties of GO/Ni-Fe nanoadsorbent can be easily separated by external magnetic field and regenerated with methanol washing. The findings unambiguously demonstrated that magnetically separable GO/Ni-Fe nanoadsorbent could be a good choice to remove DXC from wastewater sources.