Adsorption Behavior of Congo Red onto Barium-Doped ZnO Nanoparticles: Correlation between Experimental Results and DFT Calculations.

Ba-loaded ZnO nanoparticles (Ba/ZnO) were obtained by the co-precipitation process and employed as a sorbent for Congo Red (C32H22N6Na2O6S2) dye (CR). Physicochemical parameters such as particle size, pH, and contact time were checked to characterize the adsorption process. The maximum adsorption capacity of Ba/ZnO NPs for CR (1614.26 mg/g) proves its potential utility in the elimination of CR dye from wastewater. The adsorption mechanism was studied via infrared spectroscopy and density functional theory calculations. The geometrical parameters and electronic properties of the CR-Ba/ZnO complex, particularly the interaction energy, the density of states, and the charge transfer, highlighted the Ba-ion mediation in the chemical bond formation between CR and the surface. The interaction between CR and Ba-doped ZnO has found to show strong chemisorption with charge transfer between the SO3- group and adsorbed Ba2+ ion on the surface.

Facile synthesis of TiO2@ZnO nanoparticles for enhanced removal of methyl orange and indigo carmine dyes: Adsorption, kinetics.

Water pollution represents one of the most important problems affecting the health of living organisms, so it was necessary to work on the formation of active materials to get rid of pollutants. In this study, Titanium dioxide (TiO2) doping Zinc oxide (ZnO) nanocomposites were produced via simple sonication method at 500 Hz in ethanol medium. At different weight concentrations (2.5, 5, 7.5, and 10 %). The morphology, structure configuration, chemical bonding, crystalline phase, and surface properties of obtained nanocomposites were characterized via FESEM, BET, XRD, XPS, RAMAN and FTIR instrumentation. The nanocomposites were employed as an adsorbent to eliminate the methyl orange (MO) and Indigo Carmine (IC) dyes from an aqueous solution. Batch removal experiments revealed that the elimination of MO and IC dyes by the TiZnO surface was pH and doping Ti concentration-dependent, with maximum removal occurring at pH = 7 for MO and pH = 3 for IC contaminants at 10 % doping Ti concentration (Ti (10 %)@ZnO). Langmuir model fit the absorptive removal of MO and IC dyes into the Ti (10 %)@ZnO surface well. The maximal removal capacity of Ti (10 %)@ZnO nanocomposite was found to be 994.24 mg. g-1 for MO and 305.39 mg. g-1 for IC. The Ti (10 %)@ZnO nanocomposite showed remarkable high stability towards the removal of both dyes through consecutive four cycles.

Fingerprinting of two an acylated polyoxypregnane glycosides from Caralluma quadrangula (Forssk.) N.E.Br. using UPLC-ESI-Q-TOF and computational study.

The present study has tentatively elucidated the structure of two acylated polyoxypregnane glycosides from Caralluma quadrangula (Forssk.) N.E.Br. (CQ). The analyses were performed using an electrospray-ionization quadrupole time-of-flight (ESI-Q-TOF) mass spectrometer in positive ionization modes to explore fragmentation pathways. The used ionization mode provided consistent and/or complementary information for most of the pregnane glycosides, their fragmentation sequences, and their aglycones. Presumably, this is due to higher efficiency, sensitivity, and better selectivity of the mass spectrometry-based method. The present experimental and theoretical report deals with the characteristic fragmentation behaviors of two acylated polyoxypregnane glycosides CQ1 and CQ2 from the aerial parts of C. quadrangular. A DFT Study was performed to elucidate the position of ikemoyl, and benzoyl residues in compounds CQ1 and CQ2, respectively.

Efficient Mesoporous MgO/g-C3N4 for Heavy Metal Uptake: Modeling Process and Adsorption Mechanism.

Removing toxic metal ions arising from contaminated wastewaters caused by industrial effluents with a cost-effective method tackles a serious concern worldwide. The adsorption process onto metal oxide and carbon-based materials offers one of the most efficient technologies adopted for metal ion removal. In this study, mesoporous MgO/g-C3N4 sorbent is fabricated by ultrasonication method for the uptake Pb (II) and Cd (II) heavy metal ions from an aqueous solution. The optimum conditions for maximum uptake: initial concentration of metal ions 250 mg g-1, pH = 5 and pH = 3 for Pb++ and Cd++, and a 60 mg dose of adsorbent. In less than 50 min, the equilibrium is reached with a good adsorption capacity of 114 and 90 mg g-1 corresponding to Pb++ and Cd++, respectively. Moreover, the adsorption isotherm models fit well with the Langmuir isotherm, while the kinetics model fitting study manifest a perfect fit with the pseudo-second order. The as fabricated mesoporous MgO/g-C3N4 sorbent exhibit excellent Pb++ and Cd++ ions uptake and can be utilized as a potential adsorbent in wastewater purification.

Enhanced adsorptive removal of indigo carmine dye by bismuth oxide doped MgO based adsorbents from aqueous solution: equilibrium, kinetic and computational studies.

Novel doped MgO nanoadsorbents were effectively fabricated at various Bi2O3 doping concentrations (0, 2.5, 5 and 10%). DFT-D3 study showed that the doping is done by substitution of two magnesium atoms by two bismuth atoms with the creation of a vacancy of one Mg atom. TEM, SEM, EDX, BET, XRD, and FTIR were used to characterize the obtained nanostructures. The removal of indigo carmine (IC) dyes from wastewater by doped MgO nanoparticles is investigated. Experimental parameters such as the initial dye concentration, contact time, Bi2O3 doping concentration, and pH were optimized to enhance the adsorption capacity. Bi2O3 doped MgO prepared at 5% (MgOBi2) is the best adsorbent with a maximum IC adsorption capacity of 126 mg g-1 at a solution pH equal to 7.00 and contact time of 74 min. The results indicated that the adsorption process followed pseudo-second-order (PSO) reaction kinetics, and the Freundlich isotherm model gave a better goodness-of-fit than the linear Langmuir model. The FTIR study established that IC molecules are successfully adsorbed onto the surface of MgOBi2 via a chemisorption process.

Highly Selective Removal of Cationic Dyes from Wastewater by MgO Nanorods.

The organic synthetic dyes employed in industries are carcinogenic and harmful. Dyes must be removed from wastewater to limit or eliminate their presence before dumping into the natural environment. The current study aims to investigate the use of MgO nanoparticles to eliminate basic fuchsine (BF), as a model cationic dye pollutant, from wastewater. The MgO nanorods were synthesized through a coprecipitation method. The obtained nanocomposite was characterized using various techniques such as X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Brunauer-Emmett-Teller (BET), and FTIR spectroscopy. It was found that the variation of dye concentration and pH influenced the removal of BF by MgO. The adsorption capacity of 493.90 mg/g is achieved under optimum operating conditions (pH = 11, contact time = 236 min, and initial BF concentration = 200 ppm). Pseudo-second-order adsorption kinetics and Freundlich isotherm models best fitted BF sorption onto MgO nanorods. The BF sorption mechanism is associated with the electrostatic attractions and hydrogen bond between the O-H group of MgO and the NH2 groups of BF, as indicated by the pH, isotherms, and FTIR studies. The reusability study indicates that MgO was effectively used to eliminate BF in at least four continuous cycles. The investigation of MgO with different dyes suggests the high adsorption selectivity of BF, crystal violet (CV), and malachite green (MG) dyes compared with methyl orange (MO) dye. Overall, MgO nanorods can act as a potential and promising adsorbent for the efficient and rapid removal of cationic dyes (CV, MG, and BF) from wastewater.

Comprehensive polyoxypregnane glycosides report in Caralluma quadrangula using UPLC-ESI-Q-TOF and their antioxidant effects in human plasma.

ETHNOPHARMACOLOGICAL RELEVANCE: Caralluma quadrangula (Forssk.) N.E.Br. (Syns: = Stapelia quadrangula Forssk. = Monolluma quadrangula Forssk.) is an indigenous member of the genus Caralluma and it is a rather common species on rocky hillsides in the southwestern part of Saudi Arabia. Several members of this genus have found medicinal uses in the treatment of rheumatism, diabetes, leprosy and as antiseptics and disinfectants. All parts are edible but rather more bitter and can cause diarrhea. AIM OF THE STUDY: The present report was tentatively elucidated the structure of acylated and non-acylated polyoxypregnane glycosides from Caralluma quadrangula. MATERIALS AND METHODS: The analyses were performed using an electrospray-ionization quadrupole time-of-flight (ESI-Q-TOF) mass spectrometer in both positive and negative ionization modes to explore fragmentation pathways. The antioxidant and prooxidant properties of the different mobility portions of human plasma were evaluated in vitro using thiobarbituric acid reactive substance assay (TBARS). RESULTS: The analyses showed sixty-five characteristic ion peaks which could be more efficient to assignment the aglycones and fragmentation sequences of sugar moieties. The used ionization modes provided consistent and/or complementary information for most of the pregnane glycosides, their fragmentation sequences, and their aglycones. A DFT Study was performed to elucidate the neutral loss of H2O molecules sequences from aglycones and the esterification linkage. CONCLUSIONS: This report could be useful to reduce material consuming and time in phytochemistry analysis of the different medicinal plants. The two portions significantly depleted TBARS were subjected to autoperoxidation assay in the presence of hydrogen peroxide.

Copper nanoparticles of well-controlled size and shape: a new advance in synthesis and self-organization.

Here, we report a new synthetic route for spherical small copper nanoparticles (CuNPs) with size ranging from 3.5 nm to 11 nm and with an unprecedented associated monodispersity (<10%). This synthesis is based on the reduction of an organometallic precursor (CuCl(PPh3)3) by tert-butylamine borane in the presence of dodecylamine (DDA) at a moderate temperature (50 to 100 °C). Because of their narrow size distribution, the CuNPs form long-range 2D organizations (several µm(2)). The wide range of CuNPs sizes is obtained by controlling the reaction temperature and DDA-to-copper phosphine salt ratio during the synthesis process. The addition of oleic acid (OA) after the synthesis stabilizes the CuNPs (no coalescence) for several weeks under a nitrogen atmosphere. The nature and the reactivity of the ligands were studied by IR and UV-visible spectroscopy. We thus show that just after synthesis the nanoparticles are coated by phosphine and DDA. After adding OA, a clear exchange between phosphine and OA is evidenced. This exchange is possible thanks to an acid-base reaction between the free alkylamine in excess in the solution and OA. OA is then adsorbed on the NPs surface in the form of carboxylate. Furthermore, the use of oleylamine (OYA) instead of DDA as the capping agent allows one to obtain other NP shapes (nanorods, triangles and nanodisks). We get evidence that OYA allows the selective adsorption of chloride ions derived from the copper precursor on the different crystallographic faces during the growth of CuNPs that induces the formation of anisotropic shapes such nanorods or triangles.