Search Results (6)

Thallium (I) was removed from aqueous solution by using gamma-alumina nanoparticles (γANPs) materials as nano adsorbents. Varied experimental conditions such as adsorbent dose, agitation time, initial concentration, pH, and temperature effects were carried out in batch conditions in view of the optimization of thallium (I) adsorption and the identification of the adsorption mechanisms in the system γANPs-Tl. The pH effect indicated a remarkable increase in the quantity of Tl(I) removed for pH values ranging from 4 to 8, an almost constant magnitude for pH values between 8 and 10, and a decrease for pH values above 10. Considering an initial Tl(I) concentration of 20 µg/L and an adsorbent dose of 1 g/L at a pH value of 8.5, the removal was achieved at 95.12 ± 0.02% efficiency. The pseudo-second-order kinetics and the Freundlich isotherm perfectly described the adsorption mechanism. The process of thallium (I) adsorption reaction, as highlighted by thermodynamic investigations, was found to be spontaneous and exothermic with coexistence of physisorption and chemisorption with a dominance of physisorption. The diffusion model predicted multi-linearity, suggesting an involvement of surface spread and intraparticle diffusion in the sorption process. Thallium removal was effective by using γANPs as nano adsorbents. Full article

Today, cancer treatment is an important issue in the medical world due to the challenges and side effects of ongoing treatment procedures. Current methods can be replaced with targeted nano-drug delivery systems to overcome such side effects. In the present work, an intelligent nano-system consisting of Chitosan (Ch)/Gamma alumina (γAl)/Fe₃O₄ and 5-Fluorouracil (5-FU) was synthesized and designed for the first time in order to influence the Michigan Cancer Foundation-7 (MCF-7) cell line in the treatment of breast cancer. Physico-chemical characterization of the nanocarriers was carried out using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), dynamic light scattering (DLS), and scanning electron microscopy (SEM). SEM analysis revealed smooth and homogeneous spherical nanoparticles. The high stability of the nanoparticles and their narrow size distribution was confirmed by DLS. The results of the loading study demonstrated that these nano-systems cause controlled, stable, and pH-sensitive release in cancerous environments with an inactive targeting mechanism. Finally, the results of MTT and flow cytometry tests indicated that this nano-system increased the rate of apoptosis induction on cancerous masses and could be an effective alternative to current treatments. Full article

A mathematical model of micropolar squeezing flow of nanofluids between parallel planes is taken into consideration under the influence of the effective Prandtl number using ethyl glycol $\left(C_2{H}_6{O}_2\right)$ and water $\left(H_{2}O\right)$ as base fluids along with nanoparticles of gamma alumina $\left(\gamma A{l}_2{O}_3\right)$. The governing nonlinear PDEs are changed into a system of ODEs via suitable transformations. The RKF (Range–Kutta–Fehlberg) technique is used to solve the system of nonlinear equations deriving from the governing equation. The velocity, temperature, and concentration profiles are depicted graphically for emerging parameters such as Hartmann number $M,$ micronation parameter $K,$ squeeze number $R$, Brownian motion parameter $N_b$, and thermophoresis parameter $N_t$. However, physical parameters such as skin friction coefficient, Nusselt number, and Sherwood number are portrayed in tabulated form. The inclusion of the effective Prandtl number model indicated that the effect of the micropolar parameter $K$ on angular velocity h(ξ) in both suction and injection cases is opposite for both nanofluids. It is observed that the increase in angular velocity is rapid for $\gamma {Al}_2{O}_3-C_2{H}_6{O}_2$ throughout the study. Full article

Gamma-alumina nanoparticles (γANPs) were obtained from a low-cost process by using natural bauxites. The γANPs materials were characterized by X-ray powder diffraction (XRPD), Fourier-transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) theory, scanning electron microscopy (SEM), atomic force microscopy (AFM), and were functionalized with N-cetyl-N, N, N, trimethylammonium bromide (CTAB), leading to CTAB modified γ-alumina nanoparticles (γANPs-CTAB). These novel functionalized γANPs-CTAB were characterized by XRPD, FTIR, and were used as an adsorbent for bisphenol-A (BPA) removal from water. Batch investigations were conducted under different experimental conditions (e.g., adsorbent dose, agitation time, initial concentration, and pH and surfactant loading) in order to optimize BPA adsorption and to identify the adsorption mechanisms in the system γANPs-CTAB-BPA. The effect of pH on the adsorption showed that the quantity of BPA removed increased remarkably until the pH value was 4, then remained almost constant until the pH value was up to 10, and then decreased for pH values greater than 10. For an initial BPA concentration of 20 mg/L and an adsorbent dose of 12.5 g/L at a pH value of 10, the removal efficiency achieved was 91.80 ± 0.21%. The adsorption mechanism was perfectly described by pseudo-second-order kinetics and the Langmuir isotherm. γANPs-CTAB materials were found to be effective adsorbents for BPA removal from water. Full article

In this article, the impact of effective Prandtl number model on 3D incompressible flow in a rotating channel is proposed under the influence of mixed convection. The coupled nonlinear system of partial differential equations is decomposed into a highly nonlinear system of ordinary differential equations with aid of suitable similarity transforms. Then, the solution of a nonlinear system of ordinary differential equations is obtained numerically by using Runge–Kutta–Fehlberg (RKF) method. Furthermore, the surface drag force $C_f$ and the rate of heat transfer $N_u$ are portrayed numerically. The effects of different emerging physical parameters such as Hartmann number (M), Reynold’s number (Re), squeezing parameter ( $\beta$ ), mixed convection parameter $\lambda$ , and volume fraction ( $\phi$ ) are also incorporated graphically for $\gamma —$ alumina. Due to the higher viscosity and thermal conductivity ethylene-based nanofluids, it is observed to be an effective common base fluid as compared to water. These observations portrayed the temperature of gamma-alumina ethylene-based nanofluids rising on gamma-alumina water based nanofluids. Full article

This research was performed to obtain high-value products from clay materials. High-grade nanometric delta-alumina (δ-Al₂O₃) was obtained from the modification of clay-based minerals, which could be potentially applied in the form of thin film for novel optoelectronic applications. The selective recovery process of alumina from clay materials presents an important advantage regarding the complete removal of other starting constituents such as silica, iron, titanium, alkali, and alkaline earth metals. To accomplish the selective removal of different species, an acid leaching route was used to extract the aluminum, then the iron impurities were eliminated by alkaline precipitation. The solution was acidized to precipitate the aluminum as aluminum chloride hexahydrate. Finally, the aluminum chloride hexahydrate was calcinated to obtain nano-delta-alumina with purity of over 98.5% Al₂O₃. The dominating crystalline phase was delta–gamma alumina (δ-phase and γ-phase), with a particle size of <140 nm. Then, these nanoparticles (NPs) were prepared as a stable colloidal dispersion to form a mesoporous layer employing the spin-coating technique. Initially, the synthesized alumina was characterized by atomic force microscopy (AFM) and TEM to determine the particle size and its morphology, whereas the colloidal dispersion was analyzed by rheological measurements. Finally, the findings of this investigation made it possible to get thin films with good porosity, which can be used in optoelectronic applications, specifically in perovskite solar cells. Full article