Open Access Original Research Article

Synthesis, Spectral and Theoretical Studies of Macrocyclic Cu(II), Ni(II) and Co(II) Complexes by Template Reaction of Malonic Acid with Metal (II) Chloride and Urea or Thiourea

Omar Hamad Shehab AL-Obaidi, Abdalhady R. H. Al-Hiti

Chemical Science International Journal, Page 1-11
DOI: 10.9734/ACSJ/2012/1063

Six new macrocyclic complexes were synthesized by template reaction of urea or thiourea with malonic acid and metal (II) chloride. The metal to ligand ratio of the complexes was found to be (1:1). The Co(II) and the Ni(II) complexes are proposed to be square planar and Cu(II) complexes are proposed to be octahedral geometry. Macrocyclic complexes are (1:2) electrolytes for Cu(II) and Ni(II) complexes while Co(II) complexes are non-electrolytic nature as shown by their molar conductivities (ΛM) in DMSO (Dimethyl sulphoxide) of 10-3 M solution. The structure of metal complexes from FTIR, UV-Vis., magnetic susceptibility measurements, molar conductivity measurements, atomic absorption and melting points. A theoretical treatment of the formation of complexes in the gas phase was studied, this was done using the HYPERCHEM-6 program for the Molecular mechanics and Semi-empirical calculations.
The complexes have been tested for their antibacterial activities against Two types of human pathogenic bacteria (Staphylococcus aureus and Escherichia coli). The first are Gram positive while the second are Gram negative (by using agar well diffusion method). Finally, it was found that compounds show different activity of inhibition on growth of the bacteria.

Open Access Original Research Article

Kinetic Study of Utilizing Groundnut Shell as an Adsorbent in Removing Chromium and Nickel from Dye Effluent

S. Idris, Y. A. Iyaka, B. E. N. Dauda, M. M. Ndamitso, M. T. Umar

Chemical Science International Journal, Page 12-24
DOI: 10.9734/ACSJ/2012/908

Aims: To determine the adsorption of nickel and chromium in dye effluents using activated carbon prepared from groundnut shell and to determine the adsorption capacity at different contact time.
Study Design: Adsorption capacity of the adsorbent.
Place and Duration of Study: Department of Chemistry Federal University of Technology, Minna, Niger State, Nigeria, between April and November 2010.
Methodology: Activated carbon was prepared from groundnut shell using two step processes with H2SO4 as an activating agent. Three different activated carbon was produced at different residual time of 5, 10 and 15 minutes which are GS/H2SO4/5 (AC1), GS/H2SO4/10 (AC2) and GS/H2SO4/15 (AC3). Chromium and nickel batch adsorption was carried out at various contact time (30 to 150 minutes).
Results: The result indicated the maximum chromium and nickel adsorption at the contact time of 120 minutes and 150 minutes which implies that increase in contact time lead to increase in the adsorption of the heavy metals. Kinetic models including pseudo first-order, pseudo second-order and Elovich model were used to study the adsorption processes. Chromium and nickel adsorption could be best described by the pseudo second-order kinetic model.
Conclusion: The study revealed that groundnut shell, a low cost adsorbent can be effectively used as a raw material for the preparation of activated carbon for the adsorption of chromium and nickel from dye effluent.

Open Access Original Research Article

Equilibrium Studies of Some Metal Ions onto Modified Orange Mesocarp Extract in Aqueous Solution

Millicent U. Ibezim-Ezeani, Francis A. Okoye, Onyewuchi Akaranta

Chemical Science International Journal, Page 25-37
DOI: 10.9734/ACSJ/2012/1462

This paper examines the equilibrium removal of Zinc, Copper, Nickel and Cobalt ions from aqueous solutions by cation exchange resins synthesized using orange mesocarp extract. The percentage metal ion exchange of Carboxylated-Toluene Di-isocyanate Orange Mesocarp Extract Resin (CTOR) increased with increase in pH of the solution phase, while that of Sulphonated-Toluene Di-isocyanate Orange Mesocarp Extract Resin (STOR) was relatively uniform with increase in solution pH. The results also showed maximum ion exchange of 61.48%, 67.24%, 69.82% and 78.96% for Zn2+, Cu2+, Ni2+ and Co2+ ions respectively for CTOR, while 78.10%, 83.98%, 88.00% and 93.80% for Zn2+, Cu2+, Ni2+ and Co2+ ions respectively for STOR using 50mg/L metal ion solution at 29°C. It was found that the uptake of Zn2+, Cu2+, Ni2+ and Co2+ ions by CTOR and STOR is related to the dissociation power of the exchangeable hydrogen and in sequence similar to the ionic radii of the metal ions. Thermodynamic parameters were evaluated and values obtained show that the ion exchange process was spontaneous, exothermic and of low entropy value, suggesting strong interaction between the metal ions and the exchange sites. These findings can serve as parameters for designing ion exchange treatment systems for heavy metal-contaminated wastewater.