The molecular aggregation states of tris(8-hydroxyquinoline)aluminum(III) (Alq) adsorbed in the transparent mesoporous silica (MPS) films with the different pore sizes (3.0 and 5.4&#x2009;nm) were successfully clarified. The Alq molecules were easily incorporated into the films from the solution without the segregation on the surfaces. The adsorbed amount of Alq was controlled by changing the added amount in the initial solution to resultantly give the transparent and yellow-color films. The photoluminescence spectra significantly revealed that the state of Alq molecules in the mesopore varied depending on the adsorbed amount of Alq as well as the pore size, suggesting the characteristic mobility of the adsorbed Alq molecules in the mesopores as compared with that at the bulk or solution state. Therefore, the guest-guest interactions between Alq molecules as well as the host-guest interactions between Alq and mesopore were elucidated. This finding by the use of the mesoporous film hosts will be utilized for including luminescence species and be applicable for optical devices.

Motohiro Tagaya

Kenji Shinozaki

Yuri Maruko

A Simple Incorporation Route of Tris(8-hydroxyquinoline)aluminum(III) into Transparent Mesoporous Silica Films and Their Photofunctions

The tolerance of Acacia decurrens, an invasive species, was exploited pharmacologically in this study. Phytochemical screening revealed important secondary metabolites. Importantly, the assay shows that ethyl acetate and methanol fractions are sources of phytochemicals compared to the hexane and chloroform fractions. A bioassay-guided in vitro assay of the extracts led to the eventual isolation of four bioactive compounds by column chromatography, identification, and characterisation with the aid of GCMS, UV-Vis, FTIR, and NMR. The antimicrobial screening by disc diffusion assay revealed 22.2&#x25;, 44.4&#x25;, 66.7&#x25;, and 77.8&#x25; microbial inhibition by 2-methyl-octahydro-indene-4-carboxylic acid (AD1), 6-methyldecahydro-1H-phenanthren-9-one (AD2), 8-hydroxytetradecahydro-chrysene-1-carb aldehyde (AD3), and 8,9-dihydroxy-7-(2-hydroxy-ethyl)-9,9a-hexahydro-1H,3H-2-thia-5a-aza cyclopenta[b]anthracen-6-one (AD4), respectively. Compounds AD3 and AD4 are the most potent antibacterial compounds against Gram-positive bacteria with MIC 12.5&#x2013;6.25&#x2009;&#x3bc;g/ml. Antioxidant study of the compounds assayed with DPPH and ABTS&#x2022;+ revealed that compound (AD4) is the most efficient DPPH radical scavenger with IC50 30.07 &#xb1; 0.31 and ABTS&#x2022;+ scavenging activity of 4363.2 &#xb1; 452.4&#x2009;&#x3bc;mol of TE/gDW. This provides scientific information on four pharmacophores with phyto-antioxidants and antimicrobial potential, despite the classification of A. decurrens as a Category 2 invasive plant by the National Water Act.

Bamidele Joseph Okoli

Johannes Sekomeng Modise

New Pharmacophore from the Stem Bark Fractions of Acacia decurrens (Willd), an Invasive South Africa Tree

Excessive fluoride in potable water is a serious health problem in rural areas of many developing countries. Hence, there is a need to find a simple and cost-effective method for water defluoridation in such areas. In the northern part of Cameroon, clay pots are used for cooking food and water storage. The firing of these pots consists of intensive burning using fire wood. They were tested as a potential adsorbent for removing excess fluoride from water. Experiments were carried out in a jar test at room temperature (25 &#xb1; 2&#xb0;C). Effects of contact time (0&#x2013;90&#x2009;min), pH (4, 5, 7, 8, and 9), stirring speed (60, 90, 120, and 200&#x2009;rpm), and ionic strength (0&#x2013;1000&#x2009;mg/L) were investigated. Results showed that equilibrium was attained in 10&#x2009;min whatever the pH. Pseudo-second-order and pore diffusion models described well the adsorption process. The highest amount of fluoride adsorbed (1.6&#x2009;mg/g) was obtained at pH 4-5 and the optimum stirring speed is 120&#x2009;rpm. Ionic strength has a significant effect on fluoride adsorption.

G. P. Kofa

V. H. Gomdje

C. Telegang

S. Ndi Koungou

Removal of Fluoride from Water by Adsorption onto Fired Clay Pots: Kinetics and Equilibrium Studies

Copper oxide (CuO), titanium oxide (TiO2), and Cu-doped TiO2 nanoparticles have been synthesized by pyrolysis of their corresponding precursors initially prepared by precipitation in aqueous solution using A. carambola fruit juice as a natural source of the precipitating agent (oxalate). The precursors were synthesized and characterized by FTIR, TGA, and PXRD. The results revealed that the precursors obtained were CuC2O4, TiO2(OH&#x2212;)2C2O4, copper-doped titanium hydroxyl oxalate, and copper titanium hydroxyl oxalate. Complete decomposition for the as-prepared precursors containing titanium ions occurs at 600&#xb0;C while impurity free copper oxalate decomposed at 450&#xb0;C. The as-prepared precursors were decomposed and calcined at 600&#xb0;C for 4 hours and the calcination products were characterized by XRD, SEM, and EDX. The results revealed the decomposition products to correspond to CuO, TiO2, Cu0.131Ti0.869O2, and CuO/TiO2.

Ekane Peter Etape

Lambi John Ngolui

Josepha Foba-Tendo

Divine Mbom Yufanyi

Beckley Victorine Namondo

Synthesis and Characterization of CuO, TiO2, and CuO-TiO2 Mixed Oxide by a Modified Oxalate Route

Vegetable oil-based fuels are promising alternative fuels for diesel and light fuel engines because of their environmental and economic strategic advantages. In this study, Ongokea gore oil (OGO) and its fully hydrogenated oil were transesterified by means of ethanol in the presence of sodium ethoxide. Fatty acid ethyl esters (FAEE) products were confirmed by 1H NMR and characterized by physical-chemical methods in accordance with the ASTM D 6751 and AFNOR M 15-009 specifications for biodiesels and light biofuels. These methods concern determination of color, density, viscosity, flash and pour points, ash, water and sulfur contents, and corrosion on copper. It was found that pure fatty acid ethyl esters of Ongokea gore oil (B100) and its hydrogenated oil (B100-H) meet standard requirements for most of the biodiesel characteristics studied. Only the kinematic viscosity and density values were outside recommended biodiesel standard limits which makes them unsuitable for use in diesel engines. In accordance with the AFNOR M 15-009 specifications of light fuels, they can be used in light fuel engines. Physical-chemical properties of B20, a FAEE blend in petrodiesel, are within the limits prescribed for petrodiesel standards. In brief, Ongokea gore seeds, a nonedible and high-oil-producing feedstock, are suitable starting material for production of light biofuel. The latter blends in petrodiesel can be used as fuel in diesel engines.

J. K. Ntumba

A. Mulula

K. T. Kashishi

M. N. Mifundu

R. Robiette

K. M. Taba

Physicochemical Properties of Diacetylenic Light Fuel Oil from Congolese Oleaginous Plant Ongokea gore (Hua) Pierre

About this journal

Journal profile

Meet the editorial board

Editor spotlight

Find out more

This journal's articles appear in a wide range of abstracting and indexing databases, and are covered by numerous other services that aid discovery and access. Find out more about where and how the content of this journal is available.

Journal of Applied Chemistry