International Research Journal of Pure and Applied Chemistry

Synthesis and Properties of the LiMn2O4 Cathode Material for Lithium-ion Batteries

2024-04-12T13:18:57+00:00

Spinel LiMn2O4 was synthesized by high-temperature solid-state method with lithium salt and manganese salt as raw materials, which were mixing with anhydrous ethanol as solvent under stirring, and calcining at high temperature in in the oxygen atmosphere. X-ray diffraction (XRD) and scanning electron microscope (SEM) showed that the size of lithium manganese particles with spinel structure was 80 to 200 nm, and the particle size distribution was uniform. The results showed that the prepared LiMn2O4 sample sintered at 700°C exhibited superior electrochemical performance when used as a cathode material for lithium-ion batteries with a voltage window of 2.5–4.8 V. The first charge-discharge specific capacity and first discharge capacity can reach 158.0 mAh‧g-1 and 138.4 mAh‧g-1, respectively, at 0.1 A‧g-1 current density, and the first Coulomb retention efficiency is 87.6%. The discharge specific capacity of the LiMn2O4 material can be maintained at 114 mAh‧g-1 when the test current density was returned to 0.1 A‧g-1 after 60 cycles.

Evaluation of Pesticides and Trace Metal Contaminants in Grains, Fresh Fruits and Vegetables from Odoluwa Market Ile Oluji; Ondo State Nigeria

2024-04-06T13:28:49+00:00

Vegetables, fruits and grains are sources of food rich in vitamins, minerals, and fibers and also have beneficial ant oxidative effects Pesticides and trace metals typically contaminate these food products. Pesticides and trace metals are not biodegradable and have the potential for accumulation in different body organs, leading to unwanted side effects This study investigated the concentration of pesticide residues and some selected Trace metals in Vegetables, fruits and grains from Odolua market Ile-Oluji Ondo State. Samples were collected randomly from the market, representative portion of the samples was chopped into small pieces and blended using a blender..Quantitative determination of the pesticide for Herbicides, organochlorine and organophosphate was carried out using Gas Chromatography-Mass Spectrometer after liquid-liquid extraction. Trace Metal was determined using Inductively coupled plasma - optical emission spectrometry (ICP-OES). The results reveal the presence of pesticide residues in all the samples. The mean concentration of pesticides in the samples was below the maximum residue limits (MRs) value for World health organization (WHO) while some were higher. The results also shows that all the trace metals analyzed are present in the samples except for Cadmium which is below the detection limit while Lead and Cobalt are only detected in one sample each. Some concentrations of the trace metals were below the permissible limit for WHO while others were higher than the permissible limit.

Coordination of N, O-donor Appended Schiff Base Ligand N, N’-bis (3-Methoxy Salicylidenimino-1,3-diaminopropane) towards Nickel (II), Copper (II) and Zinc (II) : Synthèses, Crystal Structure

2024-04-23T07:32:25+00:00

New complexes prepared by the reaction of N,N’-bis(3-methoxysalicylidenimino-1,3-diaminopropane) (H₂L) with Ni(II), Zn(II) and Cu(II) ions are reported in this paper. The H₂L ligand is structurally characterized by elemental analysis, NMR, infrared, UV-Vis spectroscopies, conductance and magnetic room temperature measurement. The mononuclear complex of Ni(II) (C₁₉H₂₄N₂NiO₆) is characterized by single X-ray diffraction. The compound crystallizes in the orthorhombic system in the space group Pnma with the unit cell parameters a = 7.3754(5) Å, b = 21.9576(13) Å, c = 11.5546(6) Å, α = 90°, β = 90°, γ = 90° The ligand H₂L acts in tetradentate fashion in its di-deprotonated form. Two coordinated water molecules complete the coordination sphere. The environment around the Ni(II) center is best described as an octahedral geometry.

Iodine Fortification Study of Some Common Nigerian Vegetables Using Copper Complex

2024-04-23T07:43:50+00:00

Iodine deficiency (ID) is the result of insufficient dietary iodine intake in humans, the deficiency not only leads to goiter formation but also to severe retardation of growth, development and maturation of nearly all the tissues of the body, especially those that are fast developing. The aim of this research is to evaluate levels of iodine intake by ten Nigerian vegetables using copper complex. Dry alkaline ash method was used in the determination. The results obtained showed that all the ten vegetables used absorbed high concentrations of iodine when inoculated with 0.09 M and 0.14 M [Cu(I)4]2- . Iodine phytotoxicity was observed in all the plants when inoculated with 0.2-0.8 M of the copper complex as all the plants died. Increase in the concentration of copper complex from 0.09-0.14 M increased the absorption of iodine by Amaranthus hybridus, Corchorous olitoruis, Gongronema lotifolium and Solanum melongena. The reverse was observed with Murraya koenigii, Ocimum gratissimum, Talinium triangulare, Abelmoschus esculentus, Cucurbita pepo and Telfairia occidentalis. Ocimum gratissimum absorbed the iodine at 0.09M with value of 164.79 mg/kg, the vegetable also absorbed least at 0.14 M with a dose of 61.80 mg/kg. The intake of the iodine by the plants showed that the method can be used in the fortifying these Nigerian vegetables with iodine, thereby reducing the incidence of Iodine deficiency disorder in humans.