Thermodynamic Investigation Research Articles

Isotherm, kinetic, and thermodynamic studies of adsorption of copper (II) and nickel (II) ions using low‐cost treated orange peel from aqueous solutions

AbstractThe aim of this study was to utilize processed orange peel waste (TOP) as an adsorbent to remove Cu(II) and Ni(II) ions from aqueous solutions. As a result of systematic experiments to determine the optimal conditions, it was determined that the most suitable conditions for the effective removal of Cu(II) ions were 400 mg/L initial concentration, 100 min contact time, 0.2 g adsorbent dosage, and a solution pH of 5.92. Similarly, the optimal conditions for the removal of Ni(II) ions were determined by systematic experiments to be 300 mg/L initial concentration, 0.2 g adsorbent dosage, 100 min contact time, and a solution pH of 6.19. The systematic experiments also included further investigation of the surface properties of TOP, and promising results were obtained by tests at three different temperatures (298, 308, and 318 K). The adsorption capacities for Cu(II), Ni(II), and Ni(II) were determined as 72.99, 75.18, and 76.33 mg/g, 42.55, 44.44, and 46.29 mg/g, respectively. Further analysis of the adsorption kinetics revealed that the pseudo‐second‐order model accurately represented the experimental data for both ions. Thermodynamic investigations provided strong evidence that the adsorption process of these noble metal ions on TOP is endothermic and spontaneous. The results of this study emphasize that TOP, with its low cost, easy‐to‐use nature, and high adsorption capacity, can be considered a long‐term solution for environmental remediation and water treatment in sustainable engineering applications.

Reversible CO2 insertion into the silicon-nitrogen σ-bond of an N-heterocyclic iminosilane.

The reversible insertion of carbon dioxide into the silicon-nitrogen bond of an N-heterocyclic iminosilane is reported. Solution-phase thermodynamic investigations indicate that this process is thermoneutral and reversible, whereas in the solid-phase CO2 can be stored for extended periods and is only released upon heating to 133 °C.

Hydration behavior of D-calcium pantothenate (vitamin B5) in the presence of sugar-based deep eutectic solvents at different temperatures: experimental and theoretical study

Considerable efforts have been devoted in recent years to enhancing the efficacy medicinal substance, leading to the discovery of innovative drug formulations and delivery techniques. The successful design of these processes necessitates a profound understanding at the molecular level of how these substances interact with biological membranes. Thorough thermodynamic investigations provide invaluable insights into these interactions and aid in selecting suitable compounds for pharmaceutical production. This study aims to determine the density and speed of sound for D-calcium pantothenate in mixtures of water and deep eutectic solvents (DESs), specifically choline chloride/sucrose, choline chloride/ glucose, and choline chloride/ fructose (with 2:1 molar ratio) over a temperature range of 288.15 K to 318.15 K under atmospheric pressure. In order to predict the behavior of molecules, COSMO model (the Conductor-Like Screening Model) offer complementary strengths in quantum chemistry. This approach allows for calculating solvation free energies, making it ideal for predicting properties like solubility, where understanding solvent-solute interactions is crucial. By correlating the measured parameters using standard relationships, important partial molar parameters such as apparent molar volumes and apparent molar isentropic compressibility are calculated. Additionally, apparent molar isobaric expansion, and Hepler’s constant are derived from the density and speed of sound data. The experimental apparent molar volumes, and apparent molar isentropic compressibility data is fitted to the Redlich-Meyer equation to obtain significant quantities such as standard partial molar volume, and partial molar isentropic compression. The comprehensive thermodynamic analysis of this studied system holds immense significance for advancements in the pharmaceutical industry.

Physicochemical, steric, and energetic characterization of kaolinite based silicate nano-sheets as potential adsorbents for safranin basic dye: effect of exfoliation reagent and techniques.

Kaolinite was subjected to advanced exfoliation processes to form separated nano-silicate sheets (EXK) with enhanced physicochemical properties as adsorbents. This involved the incorporation of different exfoliating agents, urea (U/EXK), KNO3 (N/EXK), and CTAB (C/EXK), highlighting their impacts on their textural and surficial properties as adsorbents for safranin dye. The applied characterization techniques confirmed the higher exfoliating degree of C/EXK, followed by N/EXK and U/EXK. This appeared significantly in the determined surface area (55.7m2/g (C/EXK), 36.7m2/g (U/EXK), and 47.1m2/g (N/EXK)) and adsorption performances. The C/EXK structure displayed a better safranin uptake capacity (273.2mg/g) than N/EXK (231mg/g) and U/EXK (178.4mg/g). Beside the remarkable differences in textural properties, the advanced mathematical modeling and the corresponding steric and energetic parameters illustrate the mentioned uptake properties. The interface of C/EXK is highly saturated by active uptake sites (Nm = 158.8mg/g) as compared to N/EXK (109.3mg/g) and U/EXK (93.4mg/g), which is in agreement with the characterization findings and the expected higher exposure of siloxane groups. Each of these sites can be filled with four dye molecules using C/EXK and N/EXK, which implies the vertical orientation of these adsorbed ions and the effective operation of multi-molecular mechanisms. The energetic (ΔE < 40kJ/mol) and thermodynamic investigations indicate the spontaneous, physical, and exothermic uptake of safranin molecules by EXK particulates. These mechanisms might involve dipole bonding (2-29kJ/mol), electrostatic attraction (2-50kJ/mol), van der Waals forces (4-10kJ/mol), and hydrogen bonding (<30kJ/mol).

Elastic mechanical thermodynamic and thermoelectric properties of pristine and titanium doped Mg2Si: a density functional theory study

Herein, we report a systematic investigation of the effect of Titanium doping on the structural, elastic, mechanical, thermodynamic, and thermoelectric (TE) dynamics of Mg2Si Compounds using first-principle investigation. The present study has been carried out using the full potential linearized augmented plane wave method as implemented inWien2kcode undermBJexchange potentials. The investigations revealed that Mg2-xTixSi compounds have structural stability with cubic phase (Fm-3msymmetry) and possess degenerate semiconducting nature. The analysis of elastic constants revealed mechanical stability of the investigated compounds following Born criteria. Thermodynamic investigations have been carried out in the temperature range of 100-1500 K at zero pressure and the quantities like heat capacity, Debye temperature, Grüneisen constant, and thermal expansion coefficient have been critically analyzed. Lastly, the TE performance of Mg2-xTixSi compounds has been predicted by estimating the thermopower (S2σ) and TE figure of merit (zT) in the temperature range of 300-1500 K. The predicted value ofzTmaxfor Mg2-xTixSi compound is 0.67 at 800 K forx= 0.25 titanium content, suggesting materials promising application for TE energy harvesting and mechanical devices.

Adsorption of Congo red on magnetic cobalt-manganese ferrite nanoparticles: Adsorption kinetic, isotherm, thermodynamics, and electrochemistry.

Magnetic Co0.5Mn0.5Fe2O4 nanoparticles were successfully prepared via the combustion and calcination process, with an average particle diameter of 31.5 nm and a saturation magnetization of 25.25 emu·g-1, they were employed to adsorbe Congo red (CR) from wastewater, the Pseudo-second-order kinetic and Freundlich isotherm were consistent with the adsorption data, indicating that their adsorption was a multilayer chemisorption process, the thermodynamic investigation showed that the adsorption was a favored exothermic process. The ionic strength of Cl- in CR solution had no obvious effect on the adsorption efficiency of Co0.5Mn0.5Fe2O4 nanoparticles, and the maximum adsorbance was 58.3 mg·g-1 at pH 2, decreasing as the pH of the CR solutions increased from 2 to 12. The ion leaching experiment and XRD demonstrated that Co0.5Mn0.5Fe2O4 nanoparticles had excellent stability, and the relative removal rate was 93.85% of the first time after 7 cycles. Cyclic voltammetry and electrochemical impedance spectroscopy demonstrated that CR was adsorbed onto Co0.5Mn0.5Fe2O4 nanoparticles, and the electrical conductivity of Co0.5Mn0.5Fe2O4 nanoparticles decreased after adsorption of CR. Magnetic Co0.5Mn0.5Fe2O4 nanoparticles displayed a promising application in wastewater treatment.

Ecofriendly k-Carrageenan-Based Hydrogel with Strong Adsorption and Higher Abilities to Remove Crystal Violet from Aqueous Solution: Thermodynamic, Isotherm and Kinetic Investigation

Ecofriendly k-Carrageenan-Based Hydrogel with Strong Adsorption and Higher Abilities to Remove Crystal Violet from Aqueous Solution: Thermodynamic, Isotherm and Kinetic Investigation

A theoretical thermodynamic investigation on solar-operated combined electric power, heating, and ejector cooling cycle driven by an ORC turbine waste heat, tri-generation cycle system

The current study investigated a solar thermal power plant to simultaneously produce multiple energy outputs, including electric power, process heating, and cooling. This integrated approach aligns with the concept of a tri-generation system, where three different forms of energy are produced from a single source. The study involves a parametric analysis, where the impact of each influencing parameter including, turbine inlet temperature, and turbine inlet pressure is systematically varied with DNI ranging from 600 W/m2 to 1000 W/m2 to understand its effects on both first-law and second-law efficiencies. Further, the exergy analysis shows the irreversibility's occur within the system. Notably, the central receiver and heliostat are identified as major sources of exergy loss. The comparison to a combined power and heating (CPH) cycle without an ORC-ejector indicates that the additional technologies significantly contribute to improving the system's performance, approximately 3.97 % and 2.3 % for both efficiencies, respectively.

Porous calix[4]pyrrole-based polymers with high surface area for efficient removal of polar organic micropollutants from water

Herein, effort was made to construct innovative adsorbent for the removal of polar organic micropollutants (OMPs) from water. Tetra-meso resorcinol-functionalized calix[4]pyrrole (CP) featured with endo-functionalized attribute and polyphenol hydroxyl structure was crosslinked by π-electron-rich 4,4′-bis(chloromethyl)biphenyl (BCMBP) through Friedel-Crafts reaction to generate porous calix[4]pyrrole-based polymers (PCPPs) with high surface area. The porosity of the PCPPs could be tuned by adjusting the molar ratio of hydrophilic CP to hydrophobic BCMBP, and diversified binding sites were integrated together. Based on adsorption kinetics and isotherm studies, PCPP(1–16) showed rapid adsorption rate and high removal efficiency (RE) as well as advanced adsorption capacity. The REs towards the tested polar OMPs by PCPP(1–16) were all above 95% in 30 min. Compared with granular activated carbon (GAC), the rate constant of pseudo-second-order model (k2) and adsorption capacity upon PCPP(1–16) were 8–230 times and 1.3–3.1 times greater than those by GAC. Adsorption mechanism studies confirmed the presence of multiple interactions and thermodynamic investigation revealed the spontaneous and physical adsorption nature. Besides, PCPP(1–16) showed excellent adsorption performance in real water samples at environmental levels and exhibited advanced absorption ability in flow-through mode. Accompanied by facile regeneration under eluting with methanol and cost-effective preparation, PCPP(1–16) demonstrated great potential as promising adsorbent for water treatment.

Sustainable synthesis and dual adsorption of methyl orange and cadmium ions using biogenic silica-based fibrous silica functionalized with crown ether ionic liquid

In pursuit of sustainable nanomaterial production, this study presents a novel biogenic fibrous silica sphere functionalized with a crown ether ionic liquid for advanced dual-adsorption of methyl orange and Cd(II) from aqueous solutions. Sorghum waste serves as the silica source in the adsorbent preparation process, ensuring an eco-friendly approach. The benzo-15-crown-5 ionic liquid is coupled to thiol-functionalized fibrous silica spheres through an efficient thiol-ene click reaction. Under constant conditions (temperature: 298 K, solution volume = 50 mL, adsorbent dosage = 5 mg, pH = 7, shaking speed = 200 rpm), the synthesized material demonstrates maximum adsorption capacities of 507.1 mg/g and 306.3 mg/g for methyl orange and Cd(II), respectively, according to the Langmuir model. Thermodynamic investigations reveal endothermic adsorption for methyl orange with an enthalpy change of −77.49 KJ mol−1, while exothermic adsorption is observed for Cd(II) with an enthalpy of +24.10 KJ mol−1. The entropy change of adsorption is −0.153 KJ mol−1 K−1 for methyl orange, indicating a more ordered state, and + 0.192 KJ mol−1 K−1 for Cd(II), suggesting increased disorder. The change in Gibbs free energy ranges from −32.66 to −29.60 KJ mol−1 for methyl orange and −32.29 to −35.99 KJ mol−1 for Cd(II), demonstrating that both adsorption processes are spontaneous. These results indicate that the adsorbent has potential as a dual-adsorption material for water remediation applications.

ZnO/nZVI nanoparticle-enhanced double-slope U-shaped solar distillation: A thermodynamic investigation of cephalexin adsorption

The increasing need for sustainable methods to remove pharmaceutical contaminants like cephalexin and improve water desalination is critical. This study explores ZnO/nZVI nanoparticles synthesized with Jackfruit peel extracts as eco-friendly, cost-effective adsorbents, enhancing water purification in solar desalination systems. This work used a matte black paint coating within a double slope U-shaped solar distiller (DSUD) in a discontinuous experimental setting to examine potential improvements in solar distillation performance. Activated carbon (AC) and bioactive powdered nanoparticles of ZnO/nZVI (nano zerovalent iron), produced from jackfruit peel extracts (JP) were combined in a synergistic way. The effectiveness of cephalexin removal was assessed taking into account the JPAC solution parameters, reaction duration, ZnO/nZVI concentrations in the nanocomposite dosage, and initial nanocomposite concentration. The best conditions for cephalexin adsorption were found to be pH 5 and reaction time of 50 min, which resulted in high absorption efficiencies of 94.74% (nZVI) and 97.53% (ZnO) at room temperature with a JPAC dose of 2.50 g L⁻1. The efficiency of the eco-friendly adsorbent in getting rid of cephalexin was calculated using “pseudo-second-order kinetics” for nanocomposites, which is consistent with the “Langmuir” isothermal absorption process. The nanocomposites as absorbent materials in solar thermal desalination processes, efficient heat transmission and energy storage have been established. JPAC and the addition of steel balls (S) with a silver hue to the DSUD improved the internal heat transfer mechanisms. Thermodynamic of Gibbs free energy and the Laplacian method (TGL), two thermodynamic concepts, were used to extensively study the temperature dynamics of the DSUD with SJPAC components. For ZnO/JPAC, an exceptional distillate production rate was noted from 8:00 to 18:00, with a noteworthy 4.932 L/m2 output in winter and 5.833 L/m2 per day in summer. Using silver balls, ZnO/JPAC generated significant yields over a 24-h period: 8.957 L/m2 in summer and 7.253 L/m2 in winter, with an ideal energy efficiency of 51.05%. The unique advancements in TGL procedures and their environmental consequences are presented in this paper. The field of thermal energy transduction will advance if silver balls are used in DSUD for the synthesis of JPAC, ZnO/JPAC, and nZVI/JPAC, as supported by the theoretical insights presented here.

Thermodynamic investigation of the efficiency of ammonia-powered marine solid oxide fuel cells with gas turbine

Improvement of marine power plants includes increasing their efficiency and drastically reducing emissions of pollutants, which involves transitioning to carbon-free fuels. This article discusses the evolution of a marine power system designed for decarbonization, utilizing ammonia and comprising solid oxide fuel cells with a gas turbine. To enhance efficiency, the system incorporates a steam supply into the fuel burning device of a gas turbine. By adding superheated steam, the system's performance improves significantly. Thermodynamic calculations identified optimal parameters for the gas turbine, which enhances efficiency by utilizing off-gases from the fuel cells. Key parameters include compressor and exhauster pressure ratios, which can be used to increase the specific power. A combined energy system with an overexpansion turbine achieves a total efficiency of 60.62 % at a fuel cell temperature of 1190 K during operation, with the SOFC efficiency being 43.76 %. These findings highlight potential improvements for marine power systems using ammonia and provide insights into the energy conversion processes within such hybrid systems.

Thermodynamic investigation and 4Es analysis of a VCR diesel engine using emulsified diesel with catalytic co-pyrolysis fuel derived from waste LDPE and Pongamia pinnata seeds

Global challenges for massive plastic waste disposal and regular decrement of conventional resources, converting plastic and biomass seeds waste into transportation-grade fuels through co-pyrolysis offer a better option for providing a promising solution. This investigation signifies a thermodynamic power cycle model, and 4Es (Energy, Exergy, Environmental, Economic) analysis of a direct injection unmodified diesel engine powered with various blends of test fuels derived from thermo-catalytic co-pyrolysis of low-density polyethylene (LDPE) wastes and Pongamia pinnata seeds at 500 °C with calcium oxide as catalyst, mixed with diesel. The fuel mixtures of pure diesel and pyrolytic test fuels are utilized for diesel engine testing with varying compression ratio. The synergistic effects of major parameters such as full engine load, varying compression ratios (16:1, 17:1, 18:1, and 19:1), and fuel blends (10, 20, 30, and 40 %) are considered for engine run. The Brake thermal energy was found to increase for the 20 % blend at 6.6 % (40 % load) in comparison to pure diesel. Also, the Brake specific fuel consumption was the least for the same blend, 0.31 kg/kWh at 18:1 CR. The smoke was also found to have lowered by 22 % for the 20 % blend in comparison to pure diesel. At a compression ratio of 18:1, the NOx formation also decreased by approximately 1.4 % in comparison to the pure diesel for almost all considered fuel blends. The fuel efficiency was observed to increase for the 20 % blend compared to pure diesel by 20 %. The cost and exergy destruction analysis also confirmed the D80PB20 to have the least and maximum values respectively for both parameters. The energy, exergy, emission, and economic (4Es) analysis confirmed the suitability of blended fuels for achieving improved engine performance and emissions. In addition, the economic and fuel sustainability analysis foster the techno-economic feasibility of the test fuels as compared to conventional diesel fuel.

Kinetics and thermodynamics investigations of efficient and eco-friendly removal of alizarin red S from water via acid-activated Dalbergia sissoo leaf powder and its magnetic iron oxide nanocomposite.

The present work aimed to highlight an efficient, readily accessible, and cost-effective adsorbent derived from Dalbergia sissoo (DS) leaf powder for removing the environmentally hazardous dye "alizarin red S" (ARS) from hydrous medium. A variant of the adsorbent is activated via sulfuric acid and composited with magnetic iron oxide nanoparticles (DSMNC). Both adsorbents are thoroughly characterized using techniques such as Fourier transform infrared spectroscopy, point of zero charge, energy-dispersive X-ray spectroscopy, and scanning electron microscopy, which show that they have a porous structure rich in active sites. Different adsorption conditions are optimized with the maximum removal efficiency of 76.63% for DS and 97.89% for DSMNC. The study was highlighted via the application of various adsorption isotherms, including Freundlich, Langmuir, Temkin, and Dubinin-Radushkevich, to adsorption data. Pseudo-first-order, pseudo-second-order, and intra-particle diffusion models were utilized to investigate the kinetics and mechanism of adsorption. The Freundlich model and pseudo-second-order kinetics exhibited the best fit, suggesting a combination of physical interactions, as confirmed by the D-R and Temkin models. The dominant adsorbate-adsorbent interactive interactions responsible for ARS removal were hydrogen bonding, dispersion forces, and noncovalent aromatic ring adsorbent pi-interactions. Thermodynamic parameters extracted from adsorption data indicated that the removal of the mutagenic dye "ARS" was exothermic and spontaneous on both DS and DSMNC, with DSMNC exhibiting higher removal efficiency.

Thermodynamic Investigation of Propagating Behavior in SHS for Equiatomic and Non-Equiatomic NiTi Alloys Using Factsage Software

Thermodynamic Investigation of Propagating Behavior in SHS for Equiatomic and Non-Equiatomic NiTi Alloys Using Factsage Software

Thermodynamic investigation of biomass-steam gasification in converter vaporisation flue for synthesis gas production

Biomass gasification for hydrogen production is a highly promising technology for energy conversion and utilisation. This paper proposed a novel technology for the injection of biomass and steam into the flue of a converter vaporisation to produce hydrogen-rich syngas. The feasibility of hydrogen generation through gasification between biomass, steam, and carbon dioxide in the high-temperature flue gas was investigated based on the thermodynamic principle of Gibbs free energy minimisation. The influence of gasification parameters on the composition of syngas was also explored. The results indicate that in the gasification process, biomass and steam injected into the converter vaporisation flue can effectively inhibit the generation of by-products such as tar. As the steam volume increases, the volume fraction of hydrogen in the product also increases, while the concentration of carbon monoxide decreases. By adjusting the steam-to-biomass ratio, syngas with a hydrogen content exceeding 20% can be produced. At a reaction temperature of 1200 °C, with a steam addition of 5%, a biomass addition of 8 g/L, and a [Formula: see text] ratio of 3, the gas products are composed of 25% hydrogen and 67% carbon dioxide. The process has the potential to achieve a hydrogen yield of up to 90%, a syngas yield of 94%, and a CO2 conversion rate of 70%. Additionally, the lower heating value of the syngas is measured at 11.24 MJ/Nm3. The research results have confirmed the viability of the new technology, thus establishing a theoretical foundation for the industrial implementation of injecting biomass and steam into the converter vaporisation flue to produce hydrogen-rich syngas.

Tangerine peel modified with sodium hydroxide for the removal of methylene blue: A calorimetric approach

Biosorbents have been studied as low-cost and efficient materials for removing dyes from wastewater. However, thermodynamic investigations into the interactions between these materials and dyes remain scarce, particularly concerning the effects of chemical modifications to the biosorbents. This article describes the biosorption of methylene blue (MB) by unmodified tangerine peel (BN) and tangerine peel modified with sodium hydroxide (BM). The materials were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and by assessing the point of zero charge as well as the number of acidic and basic functional groups. The biosorption studies combined kinetic and equilibrium analyses with isothermal titration calorimetry (ITC) measurements to characterize the sorption process in detail. BM exhibited a sorption capacity (328 mg g−1) approximately three times higher than that of BN. The adsorption process was enthalpically driven and at least 3 kJ mol−1 more exothermic for the untreated material, indicating that treatment with NaOH was unfavorable for the interaction between the dye and biosorption sites but favored the process entropically. The enthalpy of sorption depended on the amount adsorbed, indicating a high heterogeneity of biosorption sites within the materials. The results suggest that the lower availability of biosorption sites in BN led to the sorption of MB dimers, whereas in BM, the sorption of monomers was the preferred mechanism at less hydrophilic sites.

Effect of adsorption of two green biopolymers on the corrosion of aluminum in 1.0 M NaCl solution: Physicochemical, spectroscopic, surface and quantum chemical exploration

Although aluminum is an extremely versatile material and can be manufactured and used for a wide range of industrial purposes, it has a limited resistance to corrosion. Hence, the efficacy of two linear biopolymers, keratan (Ker) and chitosan (Chi), was explored, for the first time, as ecologically safe metallic corrosion inhibitors (CIs) for Al in 1.0 M NaCl solution at different temperatures. For performing this study, several experimental and theoretical methods were applied. By combining these methods, it was confirmed that the investigated biopolymers were set to be effective inhibitors for Al corrosion in 1.0 M NaCl solution. Using a 500 mg/L dose of CIs, inhibition efficiencies (% IEs) of 92.7 % and 86.4 % were achieved for Ker and Chi, respectively, indicating their strong adsorption on the metal surface. Thermodynamic and kinetic investigations signified that the adsorption was founed to be physical and obeyed the Langmuir isotherm. The kinetics and mechanism of Al corrosion as well as its inhibition by the tested biopolymers were inspected. The results demonstrated that these biopolymers behaved as mixed-type and interface-type inhibitors. To investigate the inhibition mechanism, theoretical quantum chemical methods were also applied. The experimental investigations were validated by theoretical computations.

Investigation of kinetics, reaction mechanisms, thermodynamics, and synergetic effects in co-pyrolysis of wood sawdust and linear low-density polyethylene using the thermogravimetric approach.

This study focused on investigating thermal degradation behaviors, kinetics, reaction mechanisms, synergistic effects, and thermodynamic parameters of wood sawdust (WSD), linear low-density polyethylene (LLDPE), and their blends (LW1:3, LW1:1, and LW3:1) during co-pyrolysis in a thermogravimetric analyzer (TGA). Thermal behavior exhibited a LW1:3 blend (25 wt.% LLDPE) showing significant mass loss at lower temperatures (150 to 300°C) compared to the individual feedstocks, such as 150 to 400°C and 300 to 520°C for WSD and LLDPE, respectively. The iso-conversional methods (KAS, FWO, and FM) were used to determine the kinetic parameters (Ea and A), and the activation energy drop was highest for the LW1:3 blend. According to the master plots, the third-order reaction (O3), nucleation (P2/3), and diffusional model (D4) were the predominant reaction mechanisms for the co-pyrolysis of the LW1:3, LW1:1, and LW3:1 blend, respectively. The thermodynamic parameters demonstrate that a small amount of plastic addition into WSD can improve the reactivity of the blend, shorten the reaction time, and cause less energy-intensive reactions. The values of ΔH, ΔG, and ΔS also confirmed the co-pyrolysis process's spontaneity and endothermic nature. The Fourier transforms infrared spectrometer (FTIR) spectra of raw feedstock, blends, and their biochar revealed some of the peaks were shifted, the intensity was reduced, and disappearance can happen when the temperature was increased. Using the experimental and theoretical/predicted activation energies, the parity chart illustrates the synergistic effects of co-pyrolysis of different blends, and the LW1:3 blend has a favorable synergistic impact. These results could be helpful in process optimization and designing an effective reactor system for co-pyrolysis.

Magnetic iron-based waterworks sludge modified by chitosan and FeS for aqueous Cr(vi) adsorption and reduction.

Heavy metals have been considered an evolving environmental concern due to their harmful and long-lasting impacts. We synthesized a composite of FeS/CS@MIBWS for aqueous Cr(vi) adsorption and reduction utilizing the iron-based waterworks sludge modified by chitosan and FeS. After determining the optimal conditions for the FeS/CS@MIBWS preparation, its Cr(vi) removal capability was evaluated using material characterisation and static Cr(vi) adsorption assays. Cr(vi) elimination by the composite was a pH-dependent process, with pH 2 being the optimum in the range of 2-10. The adsorption process was befitted a pseudo-second-order model, and the equilibrium results agreed well with the Langmuir model. The thermodynamics investigation showed that Cr(vi) removal by the composite has both spontaneous and endothermic nature. Considering the ionic effects, Cl-, SO4 2- and PO4 3- decreased Cr(vi) elimination in the sequence of Cl- < SO4 2- < PO4 3-. The key mechanisms for Cr(vi) elimination were physical and chemical adsorption, chelation, and Cr(vi) reduction into Cr(iii). Furthermore, FeS/CS@MIBWS demonstrated steady reusability (removal effectiveness of 70% after 5 cycles). FeS/CS@MIBWS's rapid, high-performance, reusable, and easily separable adsorption properties make it a promising choice for heavy metal environmental cleaning.