The concentration of non-steroid anti-inflammatory drugs like Ibuprofen in water bodies is alarming that may cause adverse effects on the aquatic ecosystem and human beings. This study investigated the removal of Ibuprofen in an aqueous solution using the acid-modified (phosphoric acid) Acacia sawdust activated carbon (ASAC). The ASAC underwent Scanning Electron Microscopy and Fourier Transform Infrared Spectroscopy analyses. The Ibuprofen (IBP) removal using ASAC was investigated in a batch experiment using a central composite design and considering the effects of adsorbent dose, contact time, and initial IBP concentration. Mechanisms that explained the adsorption of IBP onto ASAC were determined through isotherm and kinetic modeling. The findings revealed that the ASAC contained active site micropores and functional groups such as O–H, C–O, and COOH, which were responsible for adsorption via hydrogen and oxygen bonding between ASAC and IBP. The optimum IBP removal of 98.61% was attained at 0.20 g ASAC adsorbent dosage, 60 min contact time, and 400 ppm initial IBP concentration. The IBP compound was attached in the monolayer to the ASAC, with R ² of 0.9787 of the Langmuir isotherm model. The physical attachment of IBP molecules onto the surface of ASAC via Van der Waals forces was known through the R ² of 0.9863 of the pseudo-first-order kinetic model. Overall, the ASAC removed IBP from an aqueous solution with an adsorption capacity of 121.95 mg/g, suggesting its considerable potential as a novel source of activated carbon.

This study examined the performance, combustion, and emission characteristics of a diesel engine fueled with Semecarpus anacardium biodiesel (BD20) and TiO₂ nanoparticles. TiO₂ nanoparticles were dispersed in BD20 biodiesel at different concentrations (50, 75, and 100 mg/L). In addition, a dispersant (QPAN80) was added at a ratio of 1:1 for the surface modification of the TiO₂ nanoparticles. Injection pressures of 200, 225, and 250 bar were used to investigate the effect of the aforementioned variables on performance. The dispersion of nanoparticles in BD20 improved the brake thermal efficiency (BTE) and specific fuel consumption (BSFC) of the nanofuel. The cylinder pressure (CP) and net heat release rate (NHRR) of BD20 blended with nanoparticles were significantly higher than those of conventional diesel. The NO_x emission levels were lower. An increasing in the injection pressure improved the operating characteristics. At an FIP of 250 bar, the progressive BTE and minimum BSFC were 34.46% and 0.234 kg/kWh, whereas the peak CP and NHRR were 69.66 bar and 70.14 J/°C, respectively. CO, HC, NO_x, and smoke were 0.02%, 33 ppm, 846 ppm, and 37.58%, respectively, for BD20 + 75 mg/L of TiO₂ + 75 mg/L of QPAN.

The use of water containing antibiotics can result in adverse effects on humans and other living organisms. Therefore, it is essential to remove them from water. Adsorption is a promising method for their efficient removal since it is inexpensive and effective. In this study, the efficiency of an adsorbent prepared from kaolinite clay, coconut husk and stearic acid (SMC) for the removal of ciprofloxacin and tetracycline from aqueous solution was investigated. In batch adsorption, 99% of both ciprofloxacin and tetracycline were removed in 120 min at a pH of 6; SMC dose of 0.05 g; and initial concentration of 40 mg/L. Experimental data best fit the Brouers–Sotolongo isotherm with maximum adsorption capacities of 88.1 mg/g and 93.4 mg/g for ciprofloxacin and tetracycline, respectively. Kinetic data fitted best the fractal kinetics (R ² = 0.995) and the intraparticle diffusion (R ² = 0.970) models for ciprofloxacin and tetracycline adsorption, respectively. The results demonstrate that adsorption occurred via more than one interaction on active sites with different energies, while intraparticle diffusion played a significant role in the adsorption. The regeneration studies performed on SMC revealed that at the beginning of the third cycle of adsorption–desorption, the adsorbent maintained 97% efficiency. This shows that SMC is easily regenerated and can be reused multiple times while maintaining a high adsorption capacity. SMC which is prepared from readily available, low-cost materials is a highly sustainable alternative adsorbent for the effective removal of ciprofloxacin and tetracycline from wastewater.

Ionic liquids (ILs), and deep eutectic solvents (DESs), the eco-friendly solubilizing agents for processing of lignocellulosic feedstock, facilitate effective delignification and enhanced carbohydrates accessibility to hydrolytic enzymes for proficient bioconversion. Furthermore, the efficacy of these solvents may be increased by combinative application of microwave irradiation. In the present report, a novel and intensified strategy were developed for sugarcane bagasse (SCB) biomass pretreatment by using combined application of microwave irradiation and IL (1-butyl-3 methylimidazolium chloride, [Bmim]Cl) or DES (choline chloride, ChCl)/glycerol). The in-house enzyme preparation developed from Aspergillus assiutensis VS34 was employed for the saccharification of the pretreated SCB. The maximum sugar was released by combined microwave-[Bmim]Cl + PEG-8000 pretreatment (327.76 ± 1.8 mg/g biomass) followed by microwave + [Bmim]Cl (308.1 ± 2.4 mg/g biomass), and microwave-choline chloride/glycerol (297.36 ± 2.4 mg/g biomass) after 7 min of microwave irradiation. The analysis of combinatorially pretreated biomass by physicochemical techniques such as ¹H NMR, FT-IR, XRD, and SEM showed that combined pretreatment induced severe biomass structural deformities, which facilitated the enzymatic hydrolysis and hence, improved the yield of reducing sugars. Fermentation of the sugar hydrolysate yielded an ethanol content of 146.96 ± 1.9 mg/g biomass (bioconversion efficiency, 44.39%). The results of the current study substantiate the effectiveness of microwave-aided combinatorial pretreatment approach with DESs/ILs for an efficient biomass conversion. Comprehensive physicochemical analysis of suitably pretreated SCB biomass may help unraveling the underlying functional processes of combinatorial pretreatment, and for developing biomass specific designer pretreatments for efficient conversion.

Artificial roughness in the form of repeated ribs on a surface is an effective technique to improve the heat transfer rate. A numerical study on the heat transfer characteristics and flow structure of a fully developed turbulent flowing fluid in a rectangular duct having repeated transverse rib roughness. The thermo-hydrodynamic performance was obtained by varying important parameters, such as rib configurations: Six different configurations were analyzed. In this analysis, the Reynolds number of the flow is chosen in the range (40,000, 100,000). The system of equations governing the physical phenomenon is composed of nonlinear partial equations whose analytical solution is complex, and approximation methods are therefore essential. In this work, we have adopted numerical modeling based on a finite volume scheme allowing us to pass from the problem defined on a continuous study domain and governed by a system of equations with an infinite number of unknowns to the equivalent problem defined on a discrete study domain and governed by a system of equations with a finite number of unknowns. The turbulence phenomenon is modeled using the classical turbulence model (k–ɛ). The results show the relative evolution of the Nusselt number for the different cases studied. The different cases: case (1), case (2), case (3), and case (4) show better performance, respectively, by 54.12; 54.08; 69.27, and 74.89% compared to the case of a smooth channel. The results also indicate that the thermal performance improvement factor is more significant in cases (3) and (4).