Aim: To design and develop a novel, cost effective strategy for fluoride removal, applicable to rural areas of developing countries.
Study Design: Laboratory analysis for different parameters.
Place and Duration of Study: Department of Chemistry, University of Allahabad and Department of Chemistry, Institute of Engineering and Technology. June 2014 to January 2015 is the time duration for this analysis.
Methodology: Batch adsorption study was conducted to determine the optimum conditions for defluoridation. The effects of pH, adsorbent dose, initial fluoride concentration, and contact time on adsorption were studied. Natural Bagasse Carbon (NBC) and Modified Bagasse Carbon (MBC) were used as low-cost agricultural biomass based adsorbents.
Results: The NBC and MBC removed 51.8 and 58.4% respectively from an aqueous solution of 5 mg/L fluoride at pH 6.0, with the contact period of 75 min and a dose of 4 gm/L. All adsorption experimental data followed the Freundlich isotherm. Adsorption of fluoride on all studied adsorbents from aqueous solution followed pseudo-second order reaction, and the mechanism of fluoride removal on adsorbents was found to be complex.
Conclusion: Significant amount of fluoride can be reduced in the neutral pH range by these adsorbents, which makes them suitable for utilize in drinking water treatment, especially in rural areas where minimum facilities are available.
A simple room-temperature solution-phase and efficient method for the selective preparation of nanostructured copper hydroxide (Cu(OH)2), copper oxide (II) CuO or Cuprous oxide (Cu2O) from a Cu2+ solution was developed. Mono-disperse cubic Cu2O were obtained by sodium hydroxide addition to this solution in the presence of ethylene glycol (EG) while monoclinic CuO nano-particles were obtained in the presence poly-ethylene glycol (PEG) as dispersant agent.
By adjusting the amounts of EG, octahedron and truncated octahedron aggregates of copper oxide (I) nanoparticles (Cu2O) can be formed, whereas in case of PEG, Cu(OH)2 nanowires, CuO sheet-shaped nanoparticles () can be obtained. These observations were confirmed by X-ray diffraction, infrared spectroscopy and scanning electron microscopy.
It appears that the EG and PEG act as size-controlling and growth-directing agents in addition to their role as a dispersant.
The effects of substituents and solvents on the ground state molecular geometry, dipole moments (µ), polarisabilities (α) and frontier molecular orbital energies (EHOMO, ELUMO) and optical gap (ΔE) of 4-nitroaniline and its N-substituted alkyl derivatives were studied by the ab initio restricted HF-DFT self-consistent field method (B3LYP) using the 6-31G* basis set in vacuum, tetrahydrofuran and ethanol. The result revealed that 4-nitroaniline is non-planar but its µ, α and molecular size are enhanced upon successive perturbative substitution with size and number of alkyl group(s) at the amino nitrogen. The µ and α are found to increase as the solvents become more polar. Furthermore, it was found that the enhancement of these properties is associated with decrease in the optical gap of the molecules and/or increase in molecular radius. The findings imply an enhanced reactivity and ground state electro-optic susceptibility of the molecules. N,N-diethyl-4-nitroaniline exhibits the most reactivity and ground state electro-optic susceptibility.
The flood in 2012, which was recorded as the most devastating in the past 40 years in Nigeria, that caused colossal loss in material wealth, could also be a source of heavy metal pollution, especially at the lower reaches of the flood where deposition of flood transported materials occurs. Heavy metals (Fe, Ni, Cd, Cr, Zn, Cu and Pb) concentrations were determined in soil samples from two locations, an area submerged by the flood water (flooded) and an area at a higher elevation than the flood water (unflooded), which served as the control. The soil pH, texture, Total Organic Carbon, and Cation Exchange Capacity were also determined. Standard laboratory methods were employed for all the analyses. The soil in this study was characterized as sandy/clay/loam soil following the particle size analysis, with an average pH of 4.6 in the flooded soils and 6.5 in the unflooded soils. Total Organic Carbon (TOC) ranged from (0.936-1.989)% in the flooded soil and (0.663-0.939)% in the unflooded soil. Cation Exchange Capacity (CEC) was higher in the flooded soil (1.936-3.234) meq/100 g, than in the unflooded soil (1.164-1.722) meq/100 g. The results of the heavy metals revealed that heavy metals concentrations where higher in the flooded soil samples compared to the unflooded soil samples. There was also evidence of leaching of heavy metals. Eight Pollution Indices for heavy metals were applied to the data which comprised of four single pollution indices (The Contamination Factor, Ecological Risk Factor, Enrichment Factor and Index of Geo-accumulation) and four integrated pollution indices (Average Pollution Index, Degree of Contamination, Ecological Risk Index and Nemerow Pollution Index) to evaluate the soil pollution status. Amongst the pollution indices, the Nemerow Pollution Index was the most stringent. It was recommended as the pollution index to be applied for safety considerations.
Flavans consist of the 2-phenylchroman structural unit found naturally in the plant kingdom. They are important compounds due to their various pharmacological properties, such as anticarcinogenic, anti-inflammatory, antioxidant, antimalarial, antiviral properties and chemopreventive potential for Helicobacter pylori peptic ulcers. Because the flavans are only minutely available from natural sources improved synthesis of flavans are desirable to obtain sufficient quantities for biological testing. Thus, this review article aims at describing the synthetic protocols which exist in the literature. From the surveyed literature 153 synthetic flavans, flavens, isoflavan, neoflavans and anthocyanins were reported.