Non-homogeneous Surface Research Articles

Benzonquanmine-based hypercrosslinked polymers for high-efficiency and reversible iodine capture

Designing and preparing of materials for highly efficient and reversible iodine adsorption remains a challenging task. In this study, a series of benzonquanmine-based hypercrosslinked polymers (BHCPs) with nitrogen-rich were designed and synthesized via Friedel-Crafts reaction. The obtained BHCPs showed the high specific surface and high thermal stability. Moreover, the BHCP-3 of BHCPs exhibits excellent iodine capture performance, including ultrahigh iodine vapor adsorption capacity of 619 wt%, the breakthrough iodine experiment of the adsorption capacity reached 2.29 g/g, which is the highest published capacity of HCP adsorbent. And the removal rate of iodine in aqueous solution also reached 92.5 %, and reached 87.4 % the first 10 min, demonstrating rapid adsorption effects. Additionally, the iodine adsorption process of BHCPs conformed to the pseudo-second-order kinetic models, and which were a multi-layer adsorption on non-homogeneous surfaces. Furthermore, the three adsorbents maintained more than 85 % of their iodine capture capacity after five cycles, demonstrating their good recyclability and potential for practical applications.

Transfer Efficiency and Organization in Turbulent Transport over Alpine Tundra

The exchange of momentum, heat and trace gases between atmosphere and surface is mainly controlled by turbulent fluxes. Turbulent mixing is usually parametrized using Monin–Obukhov similarity theory (MOST), which was derived for steady turbulence over homogeneous and flat surfaces, but is nevertheless routinely applied to unsteady turbulence over non-homogeneous surfaces. We study four years of eddy-covariance measurements at a highly heterogeneous alpine valley site in Finse, Norway, to gain insights into the validity of MOST, the turbulent transport mechanisms and the contributing coherent structures. The site exhibits a bimodal topography-following flux footprint, with the two dominant wind sectors characterized by organized and strongly negative momentum flux, but different anisotropy and contributions of submeso-scale motions, leading to a failure of eddy-diffusivity closures and different transfer efficiencies for different scalars. The quadrant analysis of the momentum flux reveals that under stable conditions sweeps transport more momentum than the more frequently occurring ejections, while the opposite is observed under unstable stratification. From quadrant analysis, we derive the ratio of the amount of disorganized to organized structures, that we refer to as organization ratio (OR). We find an invertible relation between transfer efficiency and corresponding organization ratio with an algebraic sigmoid function. The organization ratio further explains the scatter around scaling functions used in MOST and thus indicates that coherent structures modify MOST. Our results highlight the critical role of coherent structures in turbulent transport in heterogeneous tundra environments and may help to find new parametrizations for numerical weather prediction or climate models.

Adsorption-desorption behavior of malachite green on aged microplastics in seawater environment

The role of microplastics (MPs) as carriers of contaminants in the water environment is an emerging concern, significantly impacting migration and transformation. This study aims to compare the adsorption behavior of MPs with Malachite green (MG) dye before and after simulated short-term seawater aging (especially during the initial phase of the aging process) and to analyze in-depth the mechanism by which the aging process influences adsorption behavior. Results showed that after aging, the adsorption capacities of Polypropylene (PP), Polyethylene terephthalate (PET), and Polyethylene (PE) for MG were 2.58, 2.43, and 1.59 mg g−1, respectively. The adsorption capacity of other MPs for MG increased significantly, except for PE, which remained nearly unchanged. Calcium chloride (CaCl2) plays a significant role in the seawater aging process, and increasing the concentration of CaCl2 leads to a decrease in the adsorption amount of MG. Additionally, the adsorption capacity for MG varies significantly across different particle sizes and types of MPs, as well as the adsorption capacity of PP for different dyes. The Langmuir and Freundlich models indicate that the adsorption aligns more with the Freundlich model, which suggests that adsorption primarily occurs as multi-layer adsorption on a non-homogeneous surface. These results provide a scientific foundation for evaluating the ecological and environmental risks when MPs and organic dyes coexist. We also propose a novel approach of “treating waste dye with MPs” to mitigate their pollution in the aquatic environment.

Study of ignition and combustion of aluminum/ethanol nanofluid based on reactive molecular dynamics simulation

Aluminum/ethanol nanofluid fuel offers high energy density, high combustion efficiency, and low pollutant emissions, making it highly promising for aerospace applications. In recent years, the fundamental combustion characteristics for aluminum/ethanol nanofluid fuel have been extensively studied. However, current experimental techniques are still difficult to reveal the micro-mechanisms ignition and combustion of aluminum/ethanol nanofluid fuel. Hence, the ignition and combustion mechanisms of aluminum/ethanol nanofluid fuel were investigated from a microscopic point of view through reactive molecular dynamics simulation. The simulation results show that the mechanisms of enhanced ethanol combustion by aluminum nanoparticles mainly consists of micro-explosion at high temperature and small particle size, chain reaction at low temperature and large particle size, melt-dispersion in the mild oxidation state and diffusive oxidation in the moderate and heavy oxidation states. In addition, the initial stage of the combustion of aluminum nanoparticles with core-shell structure in ethanol is mainly a non-homogeneous surface reaction. This work reveals the combustion characteristics and mechanisms of aluminum/ethanol nanofluid fuel from an atomic perspective, which is expected to provide insights for the exploration and application of ethanol-based nanofluid fuel in the future.

Surface characteristics and adsorption properties of polypropylene microplastics by ultraviolet irradiation and natural aging

The vast application and deep integration of plastic commodity with our human lives raise a great concern about the ubiquitous microplastics (MPs) in nature, yet the environmental behavior of MPs remain unclear. As a main type and candidate of MPs, pristine polypropylene MPs (PP-MP-Pris), as well as the influence of ultraviolet (UV) irradiation on the degree of aging and surface characteristics, were characterized quantitatively by Fourier infrared spectroscopy, scanning electron microscopy, contact angle meter, automatic specific surface area and pore analyzer and laser particle analyzer, with natural aged PP-MPs (PP-MP-Age) as comparison. The carbonyl index (CI) of UV aged PP-MPs (PP-MP-U) was increased with extension of exposure time, while biofilm with abundant functional groups and the maximum CI value were the characteristics of PP-MP-Age. Moreover, the adsorption capacity of PP-MP-U for crystal violet (CV) was increased and reached the maximum after 30 days, while that of PP-MP-Age was weakened, probably due to the enhanced hydrophilicity and the shedding of calcium carbonate (CaCO3) during the natural aging process, which was demonstrated by hydrochloric acid treatment, indicating the vital involvement of CaCO3. Moreover, the better fitting to PSO kinetics and Freundlich isotherm models indicated that the multilayered and non-homogeneous surface adsorption was acted as the rate-controlling step. Furthermore, the positive values of ΔGθ, ΔHθ and ΔSθ indicated that the adsorption was a non-spontaneous, endothermic process with increased degree of the freedom on the interface of PP-MPs and CV solution. The presence of divalent salts inhibited CV adsorption, demonstrating that electrostatic attraction played a major role in CV capture. The hydrophobic interaction, micropore filling, hydrogen bonding, and π - π conjugation were possible involved. This study is of great significance for better understanding the complex pollution of MPs and its potential environmental risks in the future.

Eco-friendly, compact, and cost-efficient triboelectric nanogenerator for renewable energy harvesting and smart motion sensing

In recent years, the growth of Internet of Things devices has increased the use of sustainable energy sources. An alternative technology is offered by triboelectric nanogenerators (TENGs) that can harvest green energy and convert it into electrical energy. Herein, we assessed three different nopal powder types that were used as triboelectric layers of eco-friendly and sustainable TENGs for renewable energy harvesting from environmental vibrations and powering electronic devices. These nanogenerators were fabricated using waste and recycled materials with a compact design for easy transportation and collocation on non-homogeneous surfaces of different vibration or motion sources. In addition, these TENGs have advantages such as high output performance, stable output voltage, lightweight, low-cost materials, and a simple fabrication process. These nanogenerators use the contact-separation mode between two triboelectric layers to convert the vibration energy into electrical energy. TENG with the best output performance is based on dehydrated nopal powder, generating an output power density of 2.145 mWm−2 with a load resistance of 39.97 MΩ under 3g acceleration and 25 Hz operating frequency. The proposed TENGs have stable output voltages during 22500 operating cycles. These nanogenerators can light 116 ultra-bright blue commercial LEDs and power a digital calculator. Also, the TENGs can be used as a chess clock connected to a mobile phone app for smart motion sensing. These nanogenerators can harvest renewable vibration energy and power electronic devices, sensors, and smart motion sensing.

Optical properties of synthesized PVA/Cellulose phosphate composite films doped with Zn2+ ions for optical device applications

In this work, composite films of polyvinyl alcohol/cellulose phosphate doped with Zn2+ (PVA/CP/Zn2+) were prepared through a film casting procedure. The prepared films were analyzed using XRD, FTIR, TGA, and SEM. The XRD revealed a decrease in the semi-crystalline nature as Zn2+ concentrations increased. The TGA showed enhanced thermal stability for the composite films, where the SEM images illustrated the formation of a non-homogeneous surface morphology. The transmittance-absorption spectroscopic measurements showed a noticeable decrease in both the indirect energy gap (Eig) and the direct energy gap (Eg). Eig was decreased from 5.05 to 4.77 eV and Eg decreased from 5.51 eV to 5.12 eV with increasing Zn2+ concentration from zero to 14 wt%. Moreover, the transition strength (Ed), oscillator wavelength (λo), and the excitation energy (Es) were found to increase as Zn2+ content increased. These findings not only shed light on the physicochemical attributes of the prepared films but also emphasize their promising potential utilization in optical components.

Acid Treatments of Ti-Based Metallic Glasses for Improving Corrosion Resistance in Implant Applications

Ti-based bulk metallic glasses are promising materials for metallic bone implants, mainly due to their mechanical biofunctionality. A major drawback is their limited corrosion resistance, with high sensitivity to pitting. Thus, effective surface treatments for these alloys must be developed. This work investigates the electrochemical treatment feasibility of nitric acid (HNO3) solution for two bulk glass-forming alloys. The surface states obtained at different anodic potentials are characterized with electron microscopy and Auger electron spectroscopy. The corrosion behavior of the treated glassy alloys is analyzed via comparison to non-treated states in phosphate-buffered saline solution (PBS) at 37 °C. For the glassy Ti47Zr7.5Cu38Fe2.5Sn2Si1Ag2 alloy, the pre-treatment causes pseudo-dealloying, with a transformation from naturally passivated surfaces to Ti- and Zr-oxide nanoporous layers and Cu-species removal from the near-surface regions. This results in effective suppression of chloride-induced pitting in PBS. The glassy Ti40Zr10Cu34Pd14Sn2 alloy shows lower free corrosion activity in HNO3 and PBS due to Pd stabilizing its strong passivity. However, this alloy undergoes pitting under anodic conditions. Surface pre-treatment results in Cu depletion but causes enrichment of Pd species and non-homogeneous surface oxidation. Therefore, for this glassy alloy, pitting cannot be completely inhibited in PBS. Concluding, anodic treatments in HNO3 are more suitable for Pd-free glassy Ti-based alloys.

3D-printed electrodes using graphite/carbon nitride/polylactic acid composite material: A greener platform for detection of amaranth dye in food samples

The production of sustainable materials with properties aimed at the additive manufacturing of electrochemical sensors has gained prestige in the scientific scenario. Here, a novel lab-made composite material using graphite (G) and carbon nitride (C3N4) embedded into polylactic acid (PLA) biopolymer is proposed to produce 3D-printed electrodes. PLA offers printability and mechanical stability in this composition, while G and C3N4 provide electrical properties and electrocatalytic sites, respectively. Characterizations by Raman and infrared spectroscopies and Energy Dispersive X-rays indicated that the G/C3N4/PLA composite was successfully obtained, while electron microscopy images revealed non-homogeneous rough surfaces. Better electrochemical properties were achieved when the G/C3N4/PLA proportion (35:5:60) was used. As a proof of concept, amaranth (AMR), a synthetic dye, was selected as an analyte, and a fast method using square wave voltammetry was developed. Utilizing the 3D-printed G/C3N4/PLA electrode, a more comprehensive linear range (0.2 to 4.2 μmol/L), a 5-fold increase in sensitivity (9.83 μmol−1 L μA), and better limits of detection (LOD = 0.06 μmol/L) and quantification (LOQ = 0.18 μmol/L) were achieved compared to the G/PLA electrode. Samples of jelly, popsicles, isotonic drinks, and food flavoring samples were analyzed, and similar results to those obtained by UV–vis spectrometry confirmed the method's reliability. Therefore, the described sensor is a simple, cost-effective alternative for assessing AMR in routine food analysis.

Elastometry of Complex Fluid Pendant Capsules.

Oil/water interfaces are ubiquitous in nature. Opposing polarities at these interfaces attract surface-active molecules, which can seed complex viscoelastic or even solid interfacial structure. Biorelevant proteins such as hydrophobin, polymers such as PNIPAM, and the asphaltenes in crude oil (CRO) are examples of some systems where such layers can occur. When a pendant drop of CRO is aged in brine, it can form an interfacial elastic membrane of asphaltenes so stiff that it wrinkles and crumples upon retraction. Most of the work studying CRO/brine interfaces focuses on the viscoelastic liquid regime, leaving a wide range of fully solidified, elastic interfaces largely unexplored. In this work, we quantitatively measure elasticity in all phases of drop retraction. In early retraction, the interface shows a fluid viscoelasticity measurable using a Gibbs isotherm or dilatational rheology. Further retraction causes a phase transition to a 2D elastic solid with nonisotropic, nonhomogeneous surface stresses. In this regime, we use new techniques in the elastic membrane theory to fit for the elasticities of these solid capsules. These elastic measurements can help us develop a deeper understanding not only of CRO interfaces but also of the myriad fluid systems with solid interfacial layers.

Biomimetic approach for an articular cartilage patch: Combination of decellularized cartilage matrix and silk-elastin-like-protein (SELP) hydrogel

Articular cartilage degradation due to injury, disease and aging is a common clinical issue as current regenerative therapies are unable to fully replicate the complex microenvironment of the native tissue which, being avascular, is featured by very low ability to self-regenerate. The extracellular matrix (ECM), constituting almost 90% of the entire tissue, plays a critical role in its function and resistance to compressive forces. In this context, the current tissue engineering strategies are only partially effective in restoring the biology and function of the native tissue. A main issue in tissue regeneration is treatment failure due to scarce integration of the engineered construct, often following a gradual detachment of the graft. In this scenario, we aimed to create an adhesive patch able to adequately support cartilage regeneration as a promising tool for the treatment of cartilage injuries and diseases. For this, we produced an engineered construct composed of decellularized ECM (dECM) obtained from horse joint cartilage, to support tissue regeneration, coupled with a Silk-Elastin-Like Proteins (SELP) hydrogel, which acts as a biological glue, to guarantee an adequate adherence to the host tissue. Following the production of the two biomaterials we characterized them by assessing: 1) dECM morphological, chemical, and ultrastructural features along with its capability to support chondrocyte proliferation, specific marker expression and ECM synthesis; 2) SELP microarchitecture, cytocompatibility and mechanical properties. Our results demonstrated that both materials hold unique properties suitable to be exploited to produce a tailored microenvironment to support cell growth and differentiation providing a proof of concept concerning the in vitro biological and mechanical efficacy of the construct. The SELP hydrogel displayed a very interesting physical behavior due to its high degree of resistance to mechanical stress, which is generally associated with physiological mechanical load during locomotion. Intriguingly, the shear-thinning behavior of the hydrogel may also make it suitable to be applied and spread over non-homogeneous surfaces, therefore, we hypothesize that the hybrid biomaterial proposed may be a real asset in the treatment of cartilage defects and injuries.

Kinetic and thermodynamic studies of H2S adsorption by lignin-based composite membranes

Abstract Two lignin-based composite films were prepared by solution casting, which were named Cu-CLA/PVA and CuO-LA/PVA/CNF, respectively. The kinetic and thermodynamic analyses of the deodorization process of the composite membranes were performed by using adsorption models. The results showed that both membranes had good adsorption performance for H2S with the adsorption amounts of 36.39 mg g−1 and 35.69 mg g−1, respectively. The adsorption processes were mainly following the pseudo-secondary kinetic model, intraparticle diffusion model, and Freundlich isothermal adsorption model, indicating that the intraparticle diffusion resistance controlled the H2S adsorption rate and H2S was adsorbed on the non-homogeneous surface of the membranes through multiple layers. The adsorption of H2S by Cu-CLA/PVA is an exothermic process, while the adsorption of H2S by CuO-LA/PVA/CNF is a heat-absorbing process, indicating that Cu-CLA/PVA is more suitable for H2S adsorption at low temperatures, but CuO-LA/PVA/CNF, at higher temperatures, is favorable for H2S adsorption reactions. △G is negative of both Cu-CLA/PVA and CuO-LA/PVA/CNF, indicating that both Cu-CLA/PVA and CuO-LA/PVA/CNF are spontaneous for H2S adsorption.

Biopolymer Kappa Carrageenan with Ammonium Chloride as Electrolyte for Potential Application in Organic Battery

Carrageenan is a generic name for a family of natural, water-soluble, sulphated galactans isolated from red seaweeds and exploited commercially. The biopolymer of kappa carrageenan has been known to be used as electrolyte in electrochemical device since it shows good ionic conductivity characteristic. In this study, we attempt to study the chemical, morphology, and electric properties of biopolymer kappa carrageenan. We developed a free-standing film of kappa carrageenan with addition of ammonium chloride as an electrolyte for an organic battery prototype. We prepared the solution by mixing kappa carrageenan, ammonium chloride and water to form a gel with a particular concentration. Then, the gel was coated on the substrate and cured at 50°C for 4 hours. The final free-standing film product reveals a thickness about 100-200 mm as captured by SEM image in cross-section view. The morphology of kappa carrageenan with or without ammonium chloride clearly shows a non-homogeneous surface that attributed to the nature characteristics of kappa carrageenan immiscible. The addition of ammonium chloride into kappa carrageenan forms a smoother surface that show good mixture of kappa carrageenan. FTIR spectra of the samples show the interaction of ammonium chloride to the host polymer of kappa carrageenan as indicated by the shifted of the O-H peak from 3448 to 3446 cm-1 and from 3288 to 3207 cm-1 while the peak of 2924 cm-1 is disappeared after addition of the ammonium chloride. The implementation of this film in an organic C_Zn battery prototype shows that battery’s voltage reached 2.1 Volt by charging. Then, the battery can be used to emit an LED with 20 µA electrical current for about 1 hour in discharging process.

Modeling of monolayer water adsorption on surface of cement minerals by molecule simulation and adsorption isotherm

The performance of water on the pore surface governs the mechanical properties and durability of cementitious materials and structures. As a fundamental mechanism, the interaction between water and cementitious mineral micropore surfaces behaves differently under various circumstances, which can be investigated by molecular simulation methods in detail. Molecular simulations based on Grand Canonical Monte Carlo method were performed to obtain the water vapor adsorption isotherms on the surface of tricalcium silicate (C3S) and calcium hydroxide (CH), which are selected as typical cement mineral and hydration product respectively. The adsorption behavior of C3S and CH is compared by the adsorption energy and adsorption isotherm model. The condensation processes were explained by the Kelvin equation. The critical pore sizes of C3S and CH for condensation are 19 Å and 15 Å respectively. Beyond the critical pore size, water adsorption shows monolayer adsorption performance. The water adsorption process on the surface includes three stages: rapid adsorption, stable adsorption and slightly condensed adsorption, which are related to the surface interaction of minerals with water molecules. The Langmuir model is more suitable for the CH with homogeneous surface, while the Freundlich model is more suitable for the C3S model with nonhomogeneous surface. The adsorption heat of the first layer of water film and adsorption energy on the surface of CH are higher.

Quantum Dot Metal Salt Interactions Unraveled by the Sphere of Action Model.

Postsynthetic metal salt treatments are frequently employed in the luminescence enhancement of quantum dots (QDs); however, its microscopic picture remains unclear. CsPbBr3-QDs, featuring strong excitonic absorption and high photoluminescence (PL) quantum yield, are ideal QDs to unravel the intricate interaction between QDs and such surface-bound metal salts. Herein, we study this interaction based on the controlled PL quenching of CsPbBr3-QDs with BiBr3. Upon the addition of BiBr3, an instant and complete PL quenching is observed, which can be fully recovered after the addition of an excess of PbBr2. This, together with the complete preservation of the excitonic absorption suggests a surface-driven adsorption equilibrium. Additionally, time-resolved studies reveal a non-homogeneous surface trap formation. Based on the so-called sphere of action model for the adsorption process, we show that already a single BiBr3 adsorption suffices to completely quench a QD's luminescence. This approach is expanded to analyze size-, ligand-, and metal-dependent quenching dynamics. Facet junctions are identified as regions of enhanced surface reactivity. A Langmuir-type ligand coverage is exposed with a strong impact on adsorption. Our results provide a detailed mechanistic insight into postsynthetic interaction of QDs with metal salts, opening pathways for future surface manipulations.

MOF-derived bimetallic coordination polymer@cobalt-aluminum layered double hydroxide for highly selective CO2 adsorption: Experiments, mechanisms

Selective capture of CO2 is one of the most effective strategies for combating the greenhouse effect. In this study, we report the synthesis of a novel adsorbent—an amine-based cobalt-aluminum layered hydroxide with a hafnium/titanium metal coordination polymer (denoted as Co-Al-LDH@Hf/Ti-MCP-AS)—through the derivatization of metal–organic frameworks (MOFs) for selective CO2 adsorption and separation. Co-Al-LDH@Hf/Ti-MCP-AS achieved the maximum CO2 adsorption capacity of 2.57 mmol g−1 at 25 °C and 0.1 MPa. The adsorption behavior followed the pseudo-second-order kinetics and Freundlich isotherm models, indicating that chemisorption occurs on a non-homogeneous surface. Co-Al-LDH@Hf/Ti-MCP-AS also exhibited selective CO2 adsorption in CO2/N2 and excellent stability over six adsorption–desorption cycles. An in-depth analysis of the adsorption mechanism through X-ray photoelectron spectroscopy and density-functional theory and frontier molecular orbital calculations revealed that adsorption occurs through acid–base interactions between amine functional groups and CO2 and that the tertiary amines (N3) have the highest affinity toward CO2. Our study provides a novel strategy for designing high-performance adsorbents for CO2 adsorption and separation.

Fractal study of the mechanical properties of hardened hydraulic hammer parts

Abstract. Problem. Intensive abrasive wear of hydraulic hammer parts during operation leads to a decrease in their residual life. Since the existing methods of volumetric and surface strengthening of parts do not give a significant effect, the involvement of the ion-plasma chrome plating method has become relevant. Methodology. High-quality chrome coatings are obtained at a substrate temperature of at least 80–100°C. On the basis of experimental studies, the effect of ion-plasma chromium plating on the wear resistance and mechanical properties of hydraulic hammer parts was established, and structural changes in the material were also analyzed. The technology of ion-plasma chrome plating ensures the operation of hardened parts without chipping and crushing and increases their wear resistance by 1.75 times. Zones of structural transformations, characteristic of secondary hardening phenomena, are noted in the areas of damage to the parts. Results. Fractal theory, in particular, multifractal analysis using the Rényi equation, was used to analyze the non-homogeneous surface of hydraulic hammer parts (hammers, picks). The sorbitol structure of the bran and peaks was considered at ´ 100. Models describing the relationship between mechanical properties and multifractal characteristics of the structure were obtained: homogeneity of D600, orderliness (hidden periodicity D = D1-D600 , regularity K = D-600-D600. Adequacy of the models is confirmed by Durbin-Watson statistics at the level of 2.62 and 3.12. The sensitivity of the studied multifractal statistical characteristics of cementite to the strength properties sB (0.80) and s0.2 (0.96), as well as ferrite to plastic properties d (0.97) and y (0.97) was established. Practical value. The obtained results allow us to use this approach as an express method of non-destructive control when predicting the mechanical properties of the relevant parts of the hydraulic hammer after ion-plasma chrome plating.

Synthesis of innovative and sustainable gelatin@graphene oxide-crosslinked-zirconium silicate@gelatin nanobiosorbent for effective biosorption of basic fuchsin dye

Most dye stuffs and coloring materials are mainly categorized as hazardous pollutants in water effluents due to their nature as non-biodegradable, highly toxic and extremely carcinogenic. For this reason, rapid and efficient eradication of waste dyes from wastewaters before discharging into water streams must be accomplished by an acceptable approach as adsorption technique. Therefore, the present study is aimed and devoted to synthesize a novel nanobiosorbent from three different constituents, gelatin (Gel) as a sustainable natural product, graphene oxide (GO) as an example of highly stable carbonaceous material and zirconium silicate (ZrSiO4) as an example of combined metal oxides for the formation of Gel@GO-F-ZrSiO4@Gel by using formaldehyde (F) as a cross-linkage reagent. Several characterization techniques as FT-IR were employed to identify the incorporated surface reactive Functionalities in Gel@GO-F-ZrSiO4@Gel as –OH, =NH, –NH2, –COOH and C=O, etc. The morphology for particle shape and size of Gel@GO-F-ZrSiO4@Gel were confirmed from the SEM and TEM analyses providing 15.75- 32.79 nm. The surface area was determined by the BET and found to correspond to 219.46 m2 g-1. Biosorptive removal of basic fuchsin (BF) pollutant as an example of a widely applicable dye in various activities was monitored and optimized under the influence of pH (2–10), reaction time (1–30 min), initial BF pollutant concentration (5–100 mg L−1), nanobiosorbent dosage (5–60 mg), temperature (30–60 °C) and interfering ions. The maximum biosorptive removal values of BF dye were established as 96.0 and 95.2% using 5 and 10 mg L−1, respectively at the recommended pH 7 condition. The Thermodynamic parameters demonstrated that the BF dye adsorption onto Gel@GO-F-ZrSiO4@Gel was taken place via spontaneous and endothermic reaction. Chemisorption is the predominant adsorption mechanism by forming multilayers upon nonhomogeneous surface in accordance with Freundlich model hypothesis. The applicability of the optimized Gel@GO-F-ZrSiO4@Gel in biosorptive removal of BF pollutant from real water sample was successfully accomplished by the batch technique. Thus, this study clearly shows that Gel@GO-F-ZrSiO4@Gel exhibited significant influences on remediation of industrial effluents containing BF pollutant with superior efficiency.

Parametric modelling and analysis to optimize adsorption of Atrazine by MgO/Fe3O4-synthesized porous carbons in water environment

BackgroundPesticide contamination to water, continues to raise ecotoxicological and human concerns. Studying the application of green adsorbents for removing pesticides from water can significantly reduce ecotoxicological impacts and sustain reclamation of water bodies.ResultsThe current study investigated the adsorption capacity of MgO/Fe3O4 modified coconut shell biochar (MCSB) towards Atrazine removal in water. The prepared adsorbents were structurally constricted and obtained relative amount of mesopore spaces filled by nanoparticles which equally provided active occupancy/binding sites for Atrazine molecule deposition. Equilibrium isotherm studies under temperature regimes of 300 K, 318 K and 328 K were best described by the Freundlich isotherm (R2 = 0.95–0.97) with highest adsorption capacity corresponding to the highest temperature range (328 K) at (KF = 9.60 L mg−1). The kinetics modelling was best fitted to the pseudo second-order kinetic (R2 = 0.90–0.98) reaction pathways revealing that Atrazine uptake and removal occurred majorly over non-homogenous surfaces and high influence of surface functional groups in the process. Atrazine uptake by the adsorbent were mostly efficient within pH ranges of 2–6. Thermodynamics values of free energy ΔG° were negative ranging (ΔG° = − 27.50 to − 29.77 kJ mol−1) across the varying reaction temperature indicating an exothermic reaction, while enthalpy (ΔH°) (34.59 kJ mol) and entropy (ΔS°) (90.88 JK−1/mol) values were positive revealing a degree of spontaneity which facilitated Atrazine uptake. The adsorbents regeneration capacities over five cycles were observed to decrease proportionally with maximum yields up to 50–60%. Optimization of the adsorption condition by response surface modelling (RSM) and Central Composite Design (CCD) could reveal optimum conditions for Atrazine removal through interaction of different variables at pH = 12, adsorbate initial concentration at 12 mg L−1, adsorbate dosage at 0.5 g and reaction temperature at 54 °C. The overall mechanisms of the adsorption could be contributed by availability of surface functional groups on the MCSB surface through increase in hydrophilicity facilitating easy Atrazine molecule attachment via hydrogen bonding and improved surface complexation.ConclusionsThe as-synthesized MCSB adsorbent could uptake and remove Atrazine in water. A high pH, low concentration, low adsorbent dosage and high reaction temperature could be optimized conditions to attain highest Atrazine removal by the synthesized adsorbent.Graphical

The (φ,ψ) Orlicz mixed Petty bodies

In this paper, the homogeneous (φ,ψ) Orlicz mixed affine and geominimal surface areas are introduced. Their homogeneity, affine invariance and affine isoperimetric inequalities are established. Under some assumptions, the existence and uniqueness of the homogeneous (φ,ψ) Orlicz mixed Petty bodies are established. Base on these, the continuity of the homogeneous Orlicz mixed geominimal surface areas is given. Moreover, the nonhomogeneous (φ,ψ) Orlicz mixed affine and geominimal surface areas are defined, and the continuity of the nonhomogeneous (φ,ψ) Orlicz mixed geominimal surface for some special φ and ψ is obtained as well.