Applied Chemistry

Thermo-chemically cracked cocos nucifera shells were converted into useful adsorbent using chemical activation method. Regeneration of the spent carbon was carried out via thermal regeneration method. The re-derived filter was used in the adsorption of nickel (Ni) from a simulated Ni2+ solution. Qualitative characterization was carried out using the Fourier Transformed Infra Red Spectrophotometer while Atomic Adsorption Spectrophotometer was used to analyze the equilibrium phase Ni2+ concentration. Comparative study of the derived and regenerated activated carbons was carried out using kinetic adsorption studies approach. From the experimental runs, it was evident that derived cocos nucifera shells activated Carbon provided slightly higher removal efficiency values than the vice for Nickel uptake. Investigations with applicability test supported the pseudo second order kinetics as best model in explaining the sorption rate (k2 = 0.744) as against the proposed linear and first order kinetics. Generally, reuse of spent coconut shell carbon and its investigated film diffusion transport mode in removal of Ni2+ is critical a study with a worthwhile adoption in remediation study.

The temperature dependent study was investigated by using a UV-Visible spectrophotometer. Activation parameters such as energy of activation Ea, free energy of activation , entropy of activation and enthalpy of activation were obtained from Eryring’s equation. The effect of substrates on the activation energy were in the order: benzoate ion > H+ > urea > OH- for Tris-(3,4,7,8-tetramethyl-1,10-phenanthroline)Iron(II) Sulphate, Fe(Me4phen)32+ and benzoate ion > H+ > OH- > urea for Tris-(4,7-dimethyl-1,10-phenanthroline)Iron(II) Perchlorate, Fe(Me2phen)32+. Higher values of was observed in Fe(Me4phen)32+ in all substrates. The rate constants of dissociation were obtained from earlier published results of rate constants of binding and binding constants. Dissociation constants generally decreased with increase in the concentration of the surfactant, SDS. Higher rate constant of dissociation was observed in SDS- Fe(Me4phen)32+ than SDS- Fe(Me2phen)32+ in all the substrates.

The dispersion of bioactive glass, (BG), sample was studied using cetyltrimethylammonium bromide (CTAB). An array of experimental techniques like adsorption, zeta potential and turbidity were used to achieve this goal. Turbidity was used as a parameter to reflect the degree of dispersion where a higher value of turbidity represents higher dispersion efficiency. Dispersion of the BG particles was largely affected by CTAB concentration and the solution pH. Dispersion of the BG particles was increased with increasing of CTAB concentration till the CMC of CTAB is reached. Beyond the CMC , the BG particles become hydrophilic causing a decrease in glass dispersion. On the other hand, dispersion of the BG particles was affected with the solution pH. It was increased with increasing pH till pH 9. At higher pH, dispersion was decreased where the formation of micelles is favored.

Phthalates are toxic for human beings and their toxicity can be expressed in various forms like teratogenic, mutagenic, estrogenic and carcinogenic effects as well as by endocrine disturbances. The most commonly encountered phthalate molecules in the environment are: DMP, DEP, DnBP, BBP, DisoDP, DALP, DNP), DEHP, and DnOP. In order to assess the health and environmental impacts of phthalates, it is necessary to access these compounds at the molecular level in natural systems, including water. Therefore, our study was devoted to setting up a protocol including phthalate extraction step, followed with a development of a HPLC/DAD analysis methodology, using artificial mixtures of different standard phthalate compounds and water standard reference material we made in our laboratory. As results, we obtained good performance characteristics such as detection limits (ranging 1.1 - 40.0 ng/L), limits of quantification (from 3.75 to 134 ng /L), coefficients of variation (CV) lower than 10 %, and quality control cards showing that the HPLC/DAD methodology we developed was under statistical control and suitable for phthalate determination in water.

Modern polymer chemistry is highly progressive in tailoring polymers to specific requirements such as mechanical, thermal and chemical stability, with better performance with wide range of pore size. Composite materials combine and maintain two or more distinct phases to produce a material that has properties far superior than either of the base materials. Nanoparticles made of chitosan, a naturally occurring polymer isolated from crab and shrimp shells, have shown to be promising as carriers of anticancer drugs, antitumor genes, and other novel therapeutic agents. Cross linking agents improve the properties of polymer and their products. Polymer nanocomposited are a class of reinforced polymer with low quantities of nanometric-sized clay particle, which improved their fair resistance, strength and its porosity deceases. Hence, in the present work nanochitosan was prepared using sodium tripolyphosphate and composite of nanochitosan were prepared with methylcellulose in the presence of clay. However, a greater understanding of the nanoscale features of clays, and the ability to disperse the ultrafine layers within other materials has led to increased interest in their application in composite materials; to provide properties to lightweight polymers that would usually only be found in heavier or more expensive materials (such as glass or metals). The formation of the polymer membrane made by the immersion precipitation process depends on a large number of material and process specific parameters such as choice of the polymer (molecular weight, molecular weight distribution), choice of the solvents, choice of the casting solution temperature and the casting atmosphere. The composites were analyzed for their thermal stability, porosity, X-ray diffraction studies, etc. The results show that the addition of clay along with the nanosized chitosan had decreased the transparency of methylcellulose and with decreased pore size suitable for developing as RO membranes.

The foot is among the heaviest producers of sweat in the body, as it is able to produce over 1 US pint (0.47 l) of perspiration per day. Socks help to absorb this sweat and draw it to areas where air can evaporate the perspiration. Although perspiration is odorless and 99% water, it provides a perfect medium for bacteria to grow. The bacteria cause foot odour. Foot odour is a type of body odour that affects the feet of humans and is generally considered to be an unpleasant smell. Wearing polyester or nylon socks may increase perspiration and therefore may intensify foot odor. In order to overcome this problem, a nylon sock was with increased moisture absorbency. The super absorbent solution was prepared by using various chemicals. Then the solution was examined for antibacterial activity by well diffusion method. The nylon socks were treated with this solution by dip dry method. The finished sample shows good moisture absorbency and also having antimicrobial activity when compared with the untreated sample by the testing method AATCC (147 and 30). It’s having odor control property and also there is no any irritant reaction to contact with dermatitis by the testing method of organoleptic evaluation and Contact dermatitis testing. Ultimately, it is applicable for athletic persons and also common socks wearers.

The assessment of heavy metals (Hg, Cu, Pb and Cd) by means of a Peroxidase - based assay is here presented. The method is based the inhibition of peroxidase activity by heavy metals. Measurements were made spectrophotometrically via the catalytic oxidation of guaiacol in the presence of H2O2. Preliminary characterization and optimization of the assay system revealed enzyme activity of 130 U/ml, Vmax of 0.178mM/min and Km of 0.184mM. Optimal reaction time was found to be 7 minutes; optimal pH was 6 and temperature was 40°C. Inhibition-based estimation of heavy metal ions was evaluated via calibration curves of metal concentration against %inhibition of peroxidase activity. The assay revealed detection limits between 0.006 – 0.045mg/L for the metals and repeatability in the range of 2.3 – 5.4% RSD. Application of the method to water analysis revealed percentage recoveries between 76.0 – 124.0%. Overall, the method showed good potential for further use in the biomonitoring of heavy metal pollutants

A methodology based on flame atomic absorption spectrometry (FAAS) was developed and validated to quantify lithium in spodumene mineral sample. Validation parameters, including linearity and range, precision, accuracy, limit of detection (LOD) and limit of quantification (LOQ), were evaluated. The method is linear over 1.0 – 9.0 µg mL-1, with a coefficient of correlation (r) > 0.999. The LOD and LOQ were 0.2 ?g mL-1 and 0.7 ?g mL-1. This method is very precise; intraday precision measurements had a relative standard deviation (RSD) value of 4.00 %. This RSD value was lower than that required by Horwitz. The mean recovery percentage was 99.06 %, indicating that this method could accurately quantify the lithium in the studied mineral. The percentage of lithium oxide in the spodumene mineral sample was 0.33 –0.39%.

Concentration of Cd, Cu, Pb, Ni and Zn were determined in the surface water of Usuma Dam and in the treated drinking water from the same source using Atomic absorption spectrophotometry. The concentrations of Cd, Cu, Pb, Ni and Zn in the surface raw water were 7.0, 17.0, 24.1, 14.0 and 43 µgl-1 respectively. While their concentration in the treated drinking water were 5.0, 10.0, 18.0, 9.0 and 25.3 µgl-1 respectively. The trend of the concentration is in the order of Zn > Pb> Cu> Ni> Cd in both the water samples. The result shows that the metal concentrations in the treated drinking water are lower than the metal concentration in the raw water. This may be attributed to water treatment processes and distribution.

New transition metal [V(V), Co(II), Ni(II), Cu(II), Pd(II) and Cd(II)] complexes of (EPMPB) have been investigated in solution using Potentiometric and spectrophotometric methods. The composition of the complexes was determined to be 1:1 and/or 1:2 (M: L), the optimum conditions favouring the formation of the coloured complexes were studied extensively; protonation constants and their stability constants of the complexes were calculated. The stability constants of the formed complexes increase in the order Pd (II) > V (V) > Cu (II) > Co (II) > Ni (II) > Cd (II). Adherence to Beer's law was observed for the µgmL-1 concentration range form 0.31- 3.49 and 1.06 - 4.25(?gml-1) for Cu(II) ion and Pd(II) ions, respectively, Molar absorptive was 6,899 and 10,788 L mol-1 cm-1 for Cu(II) and Pd(II) ions, respectively.