Creatininium tartrate (CT) single crystals were effectively grown via the slow evaporation technique and established to crystallise in the orthorhombic system. The crystals exhibited excellent optical properties, counting a UV cut-off at 235 nm and a strong photoluminescence emission at 572 nm, indicating high transparency and material purity. The laser damage threshold was intended to be 3.24 GW/cm & sup2;, demonstrating robust resistance to high-intensity laser irradiation, while thermogravimetric analysis confirmed stability up to 460 K. Nonlinear optical investigations showed a second harmonic generation (SHG) efficiency 1.23 times greater than standard KDP and third-order nonlinear susceptibility chi & sup3; = 2.104 & times; 10(-)(4) esu, highlighting the crystal's strong third-order optical response. The material also exhibited an optical limiting threshold of 1.79 & times; 10 & sup1;(6) J/cm & sup2;, confirming its potential for high-power laser protection. These results found creatininium tartrate single crystals to be promising candidates for applications in nonlinear optics, photonic devices, laser systems, and optical sensor technologies.
Copper oxide nanoparticles (CuO-NPs) were synthesized using coffee effluent as a reducing agent through a simple, cost-effective and eco-friendly approach. The synthesized nanoparticles were characterized by UV-Vis spectroscopy, FTIR, SEM, DLS and XRD analyses. SEM revealed an average particle size of 165 nm, while DLS analysis showed a zeta potential of 32.57 mV, indicating good nanoparticle stability. XRD confirmed the crystalline nature of the CuO-NPs with a monoclinic phase. The antioxidant potential of the nanoparticles was evaluated using the DPPH assay, which demonstrated 61.79% radical scavenging activity at a concentration of 500 mu g/mL. Antibacterial activity assessed by the well diffusion method against Streptococcus mutans, Bacillus subtilis and Pseudomonas putida showed the highest inhibition against S. mutans, with a 27 mm zone of inhibition at 5 mg/mL. The photocatalytic efficiency of CuO-NPs was investigated using two azo dyes, malachite green and congo red, achieving degradation efficiencies of 94% and 77%, respectively, within 210 min. These findings demonstrate the multifunctional potential of coffee effluent-mediated CuO-NPs as antioxidant, antibacterial, and photocatalytic agents, highlighting their promising applications in environmental remediation, water treatment, food packaging and biomedical fields. Further studies are needed to evaluate their cytotoxicity, biocompatibility, and in vivo performance.
In this study, an extrusion technique was successfully employed to produce a cost-effective tubular membrane using a composition of fly ash (80%), calcium carbonate (5%), titanium dioxide (5%), and quartz (10%). The resulting membrane exhibited a mechanical strength of 12 MPa, a porosity of 41%, and a micron-sized pore diameter of 0.12 & micro;m. This fabricated membrane demonstrated excellent performance in the microfiltration of total suspended solids (TSS) and chemical oxygen demand (COD) present in wastewater from livestock farms. Additionally, it provided a viable solution for the disposal of fly ash generated by power plants. The membrane's permeate stream, obtained through microfiltration, successfully met environmental discharge standards and complied with water quality safety regulations for reuse. The developed membrane effectively eliminated organic pollutants from livestock farm effluents. Consequently, this membrane holds promise in mitigating water pollution and addressing water scarcity issues.
The present study explores the performance of a hybrid electrocoagulation-bioflocculation (EC-BF) system for efficient greywater (GW) treatment, focusing on microplastics (MP) removal. Initially, the operational parameters, namely electrode material, electrolyte concentration, current intensity, reaction time and settling time, were optimised for the EC system. In order to reduce the reaction time to 30 min, a bioflocculant derived from Psidium guajava (guava) leaves was introduced. The hybrid EC-BF system was further optimised for the bioflocculant particle size, dosage, stirring speed, stirring time and settling time. Experimental results demonstrated that the performance of the hybrid EC-BF system was comparable with the EC system, with a reduced reaction time of the EC system. As a result, the hybrid system achieved a notable reduction in energy consumption of 34.06%. Additionally, a multi-criteria evaluation considering the capital cost, efficiency, energy consumption, reaction time and electrode loss confirmed the practical superiority of the EC-BF system over the conventional EC process. This research highlights the potential of bio-based hybrid technologies as a sustainable solution for MP mitigation.
Accurate predictive modelling of Heat Recovery Units (HRUs) is crucial for optimising direct reduction iron (DRI) plants. However, existing models lack the capability to predict performance for individual tube bundles. This study develops and industrially validates a novel, high-fidelity heat transfer model (HRU model) to address this research gap and to optimise the performance of heat recovery units. The model was developed using real-time operational data from a large-scale PERED technology DRI plant (0.8 million-tons sponge iron annual capacity). Predictive accuracy was quantified using root mean square error (RMSE). The model achieved high predictive accuracy across all HRU bundles, with RMSE values between 3.84% and 6.49%. The parametric analysis revealed two key technology-specific optimizations. First, centrifugal compressors reduced the required surface area by 6-11.5% compared to lobe-type compressors. Second, the natural gas preheater, which is essential for Midrex technology, was found to be unnecessary in PERED configurations. This work presents the first industrially validated model for comprehensive HRU performance prediction. The findings reveal distinct efficiency pathways for different DRI technologies, providing critical insights for operational and design optimisation.
The tanning industry is known to have serious environmental effects, as it consumes a significant amount of water, chemicals and dyes, and the resulting tannery wastewater has high total dissolved solids (TDS), chemical oxygen demand (COD), and chromium species. These pose a threat to the ecosystem and human beings. Conventional treatment methods like coagulation, flocculation, and biological processes show limited efficiency and generate contaminated sludge. Hybrid systems combining flocculation, photocatalysis, and membrane filtration offer better performance, but challenges remain in handling high salinity, chromium-rich sludge, and overall operational costs. Electrochemical methods offer an efficient and eco-friendly approach to treating highly saline tannery wastewater containing toxic metals, colour, and refractory organics. Techniques like electrocoagulation (EC), electrochemical oxidation (EO), and electro-fenton (EF) remove pollutants effectively with minimal chemical use. Using sacrificial electrodes (Fe, Al) in EC and inert electrodes (graphite, Ti-MMO, BDD) in EO/EF, these systems generate strong oxidants that degrade complex pollutants, reduce sludge, enhance chromium removal, and provide a scalable, energy-efficient solution. Overall, they offer better control and higher efficiency than conventional wastewater treatment methods. In general, the review suggests the potential of innovative electrochemical treatment methods to achieve effective pollutant removal, resource recovery, and sustainable tannery wastewater treatment.
A powder of peach (Prunus persica) stone (PSP) was utilised as a renewable, cost-effective and sustainable adsorbent for the removal of methyl violet (MV) dye. The Box-Behnken Design (BBD) was employed to optimise the adsorption key parameters, including PSP dosage (coded A: 0.02-0.1 g/100 mL), pH of MV dye solution (coded B: 4-10) and contact time (coded C: 10-90 min). The BBD results show that the setting of MV solution pH =10, 0.1 g/100 mL of PSP dosage and contact time = 50 min obtained the best removal of MV (50 mg/L) = 92.1%. The significant interactions between PSP dosage vs pH (AB) and pH vs contact time (BC) were confirmed by analysis of variance (ANOVA). The adsorption kinetic investigation indicates that the adsorption process of MV dye onto the PSP surface can follow both pseudo-first order (PFO) and pseudo-second order (PSO), revealing the possibility of a physicochemical adsorption process. Hence, the adsorption isotherm model was well explained by the Langmuir isotherm model with a monolayer maximum of 141.8 mg/g of MV dye onto the PSP surface. The thermodynamic investigation indicates a spontaneous and endothermic adsorption process of MV onto the surface. Hence, this research work introduces PSP as a natural and renewable adsorbent for toxic dye removal.
This research comprehensively analyses extracted Mahua oil, with a notably high free fatty acid (FFA) content of 12%. To make it suitable for the synthesis of biolubricant, the FFA content was effectively reduced through acid-catalysed esterification using methanol and amberlyst 15 dry as a heterogeneous catalyst, achieving significant reduction with an oil-to-methanol molar ratio of 1:20 and 5% catalyst weight. In the subsequent transesterification process, the oil was initially converted to its fatty acid methyl ester, achieving an optimum yield of 90.2% with 1% w/w catalyst, 1:7 oil to methanol ratio, and 70 degrees C. This methyl ester then undergoes transesterification with neopentyl glycol. The Characterisation of neopentyl glycol ester was performed using Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared Spectroscopy. The drop point and viscosity profiles were also evaluated to assess potential applications. This study not only clarified the properties of Mahua oil and its derivatives but also presented an effective method for reducing FFA in oils, contributing to the development of biolubricating greases. The production and characterisation of neopentyl glycol ester further contribute to the development of biolubricating greases, paving the way for more sustainable and environmentally friendly lubrication solutions.
In this study, choline chloride (ChCl) with glycerol (Gly) deep eutectic solvent (ChCl:2Gly) was prepared and used as a solvent for the mixing of lignite coal (LC) and cashew nutshell waste (CNSW) at different molar ratios (1:3, 2:2 and 3:1). The pure LC, CNSW and their blended material in the presence of ChCl:2Gly were characterised using Fourier-transform infra-red (FT-IR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis and differential scanning calorimetry (TG-DSC) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). Results of the FT-IR spectra confirm that there is a structural change while mixing LC and CNSW in the presence of ChCl:2Gly. Thermal stability and thermal behaviour of blended material at 1:3 and 2:2 are better than 3:1 ratio, which indicates that CNSW and ChCl:2Gly influence their chemical structure changes, high thermal stability, morphology defects and amount of carbon reduction.
Sustainable bio-based polymer nanocomposites have gained significant attention for environmental applications. This work reports the development and characterisation of nanographene oxide-silica-epoxy polymer nanocomposites (PNC) synthesised using waste cooking oil as a renewable precursor. The oil was converted into an epoxidised triglyceride that served as the polymer matrix, while nano-graphene oxide and in situ generated nano-silica acted as reinforcing agents, producing a mechanically robust composite. The PNC was characterised using thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, energy-dispersive X-ray spectrometry, and Fourier-transform infrared spectroscopy. The adsorptive performance of the PNC was evaluated for methylene blue (MB) removal, achieving a maximum removal efficiency of approximately 88% and an adsorption capacity of 0.717 mg/g. Adsorption behaviour was studied using Langmuir, Freundlich, Redlich-Peterson, Toth, and Sips isotherm models. Both linearised and nonlinear regression approaches were applied to the equilibrium and kinetic models, with nonlinear fitting providing more reliable parameter estimates. The Redlich-Peterson model exhibited the best correlation with the experimental data, with an R2 value of 0.997. Overall, the study demonstrates that the GO-PNC derived from waste cooking oil is an efficient, thermally stable, and environmentally sustainable adsorbent for removing synthetic dyes from wastewater.
In the treatment of automobile exhaust gases, monoliths are the most popular structured reactors, consisting of numerous parallel channels that provide a large open frontal area, ensuring exhaust systems at the end of pipes require a straight gas flow with a very low pressure drop. The outstanding doping qualities and inherent physicochemical properties of spinel-type catalysts have led to their widespread use in automotive exhaust purification. Synthesised cobaltite spinel catalysts (MCo2O4, where M = Ni, Co, Cu, Zn) are effectively applied to monolithic carriers using the dip-coating technique, which produces a secondary layer with a greater specific surface area for the best possible dispersion of active species. Characterisation of the catalysts was performed using the XRD, FTIR, SEM, SEM-EDX, TGA, BET and XPS techniques. The adherence test was performed to evaluate the mechanical stability of the catalyst layer and wash-coat. The catalysts were made using the co-precipitation process and then calcined for four hours at 550 degrees C . The following order describes the catalysts' CO oxidation activity: NiCo2O4 >CoCo2O4 > CuCo2O4 > ZnCo2O4. To test the stability, the catalysts were heated to 550 degrees C for 50 hrs, and the catalysts showed satisfactory thermal stability.
In the present work, a novel configuration of an extractive divided wall column (DWC) with a side reboiler is proposed for the separation of a THF-water equimolar mixture with dimethyl sulfoxide (DMSO) as a solvent. Simulation analysis indicated that the total annual cost (TAC) of the proposed DWC configuration is 29.2% less than the conventional two-column distillation to achieve the same purity of products. A novel heat-pump-assisted DWC configuration (HP-DWC) with side reboiler is also proposed and analysed, and it was found to reduce the operating cost significantly; however, reduction in TAC against the DWC configuration could not be seen with a payback period of 3 years due to higher capital cost involved in the compression. The proposed DWC configuration with side reflux minimises DMSO losses from the water side stream and helps in improving the overall economics for the THF Water System.
In this study, a catalytic converter was developed using activated carbon derived from rice husks coated with copper using a screen-printing method. Rice husks were chosen because they have high cellulose, lignin, and silica contents. These contents provide favourable characteristics for producing activated carbon. The fabrication process was carried out by pre-carbonisation at 400 degrees C for 2 h. Subsequently, chemical activation was performed using a mixture of HCl, H3PO4, and NaOH. The next step was carbonisation at 650 degrees C for 12 h. The resulting activated carbon was characterised by XRD, FTIR, and SEM-EDS analyses to evaluate the crystal structure, functional groups, and pore morphology. The catalytic converter coated with a 250 & micro;m copper layer showed the best performance, with a reduction in HC emissions from 674 ppm to 173 ppm and CO emissions from 2.84% to 1.68%. The engine performance improved, as indicated by the increased torque and power, and noise reduction of 7.5%, 9%, and 4.7%, respectively. These results indicate that the developed catalytic converter is an efficient, low-cost, and environmentally friendly solution for reducing vehicle emissions.
This paper presents a chatter-free sliding mode control method designed to enhance stability, accuracy, and overall performance of PEM fuel cell systems, addressing chattering and instability in traditional controllers under varying loads and disturbances conditions. An integrated mathematical model of the fuel cell air-supply sub-system was developed, and a new control law that used an integral sliding surface was developed as a result of a Lyapunov stability analysis to guarantee an asymptotic convergence. The controller had been verified by extensive MATLAB simulations in the presence of noise, delay, and parameter uncertainty, and the performance of the controller had been compared to the neural-network-based proportional-integral-derivative and model predictive control baselines. Determinations show that the proposed controller attains a stable deviation of less than 0.05, which is less than 1 percent, and settling times of less than 1.5 seconds. Quantitative indices verify the significant improvement in performance with the decreases in root-mean-square error and over 75 percent in the integral error indices relative to the benchmark controllers. Results show the chatter-free sliding mode method reduces oscillations, improves transient response, and maintains healthy oxygen-excess-ratio regulation. The results give a considerable impetus to the attainment of accurate, noise-controlled fuel cell systems with clean-energy applications.
Efficient wastewater treatment using reverse osmosis (RO) is often constrained by membrane fouling, energy penalties and limited predictive control strategies. Existing studies primarily address fouling analysis or optimisation in isolation, leaving a gap in integrated real-time monitoring and decision support. The study was validated on a pilot-scale RO treatment setup operated under real wastewater conditions. Model performance was assessed over an extended 30-day validation period to capture both slow and accelerated fouling phases. This scale and duration ensure that the forecasting results reflect realistic operational variability and practical applicability. This work introduces a predictive optimisation framework that combines multivariate sensor data (BOD, COD, SDI, TDS, flux, pressure and specific energy consumption) with fouling forecasting models to guide operational adjustments. Experimental validation demonstrated that colloidal fouling caused a similar to 50% reduction in permeate flux within 24 h, while specific energy consumption increased by similar to 32%. By applying the proposed predictive control, the system reduced energy usage by up to 18% and improved water recovery by 12% compared with fixed-schedule operation. The novelty lies in linking online monitoring, fouling prediction and RO operation optimisation. These results provide a pathway for extending membrane life, reducing operational costs and enhancing the sustainability of wastewater reuse.
