Muhammad Iqbal Bhanger

Geochemical factors controlling the occurrence of high fluoride groundwater in the Nagar Parkar area, Sindh, Pakistan.

Fluoride concentrations in groundwater near Nagar Parkar in the Thar Desert of southeastern Pakistan range from 1.13 to 7.85 mg/l, and roughly 78% of the samples contain fluoride in concentrations that exceed the drinking water standard of 1.5mg/l set by WHO. The groundwater is alkaline (pH 7.1-8.4), brackish (TDS 449-15,933 mg/l), and classified as Na-Cl type water. This prevailing chemical character reflects the influence of saltwater intrusion, high evaporation rates, and ion exchange. Groundwater is also supersaturated with respect to calcite, which promotes the removal of Ca(2+) and HCO(3)(-) from solution. As a result, groundwater is generally undersaturated with respect to fluorite, the mineral that typically controls the upper limit of fluoride concentrations. This study examines a number of geochemical parameters in an effort to discover the controls on fluoride concentrations in groundwater. High fluoride concentrations are associated with high TDS, high pH, high Na concentrations, and high sodium absorption ratios (SAR). This suggests that elevated fluoride levels are the result of enhanced fluorite solubility due to Ca depletion and high ionic strength and the release of fluoride from colloid surfaces under high pH conditions. Contrary to what has been found in other studies, sample depth and water temperature do not appear to have a significant role in the distribution of fluoride within the groundwater.

Banana peel: A green and economical sorbent for the selective removal of Cr(VI) from industrial wastewater

This study describes the use of banana peel, a commonly produced fruit waste, for the removal of Cr(VI) from industrial wastewater. The parameters pH, contact time, initial metal ion concentration, and temperature were investigated and the conditions resulting in rapid and efficient adsorption (95% within 10 min) were determined. The binding of metal ions was found to be pH dependent with the optimal sorption occurring at pH 2. The retained species were eluted with 5 mL of 2M H(2)SO(4). To elucidate the mechanism of the process, total amounts of chromium and Cr(VI) were analyzed using flame atomic absorption and ultraviolet-visible (UV-vis) spectroscopic techniques, respectively. The Langmuir and Dubinin-Radushkevich (D-R) isotherms were used to describe the partitioning behavior for the system at different temperatures. Kinetics and thermodynamics of Cr(VI) removal by banana peel were also studied. The influence of diverse ions on the sorption behavior revealed that only Fe(II) ions (of those tested) suppressed the sorption of Cr(VI) ions to some extent. The method was applied for the removal of Cr(VI) from industrial wastewater.

Lithological influences on occurrence of high-fluoride groundwater in Nagar Parkar area, Thar Desert, Pakistan

Factors regulating the occurrence of high fluoride (F(-)) concentrations in groundwater near Nagar Parkar Town, SE corner of Pakistan have been investigated considering lithological influences. F(-) ion concentrations in groundwater range up to 7.85 with mean value of 3.33 mg L(-1). Plots of major elements and their normative mineral composition reflect granitic composition of the rocks in the study area. Modal mineralogical analysis show high perthite, plagioclase feldspars and quartz, while micas, amphiboles and pyroxenes occur in minor quantities. Water-rock interactions, based on dissolved ions of F(-), SiO(2), Na(+), K(+), Mg(2+), Li(+) and Sr(2+) suggest that fluoriferous groundwater originates from granitic rocks, typically from albite, biotite, hornblende and pyroxene and its alteration products such as kaolin and soil. The Log TDS, Na/Na+Ca ratio, Mg/Ca+Mg and Cl/Sigma anions are significant to review the impact of weathering processes which promote the availability of F(-) ions in the groundwater of study area. Principal component analysis (PCA) also renders close association among F(-) ions and other elements in the rocks and groundwater. Studies on F(-) estimation in the granite rock, china clay, soil and sand samples also indicate the presence of high F(-) concentration in these materials and average values have been found to be 1939, 710, 254 and 16 mg kg(-1), respectively.

Removal of fluoride from aqueous environment by modified Amberlite resin

Fluoride in drinking water above permissible level is responsible for human being affected by skeletal fluorosis. In this study, Amberlite XAD-4 has been modified by introducing amino group onto the aromatic ring for its application in fluoride remediation. Characterization of the modified resin was made by, FT-IR and elemental analysis (CHNS) techniques. The pH 9 was optimum value for quantitative sorption of fluoride in both batch and column experiments. The desorption of fluoride was achieved by using 10% HCl. The batch and column sorption studies of fluoride with modified resin were carried out to evaluate sorption isotherms too. Thus equation isotherms such as Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) were successfully used to model the experimental data. The sorption capacity of modified Amberlite XAD-4 resin was found as 5.04 x 10(-3) mol g(-1). From the D-R isotherm parameters, it has been evaluated that the uptake of fluoride by modified resin occurs through ion exchange adsorption mechanism. The study will contribute toward the removal of fluoride from the aqueous environment as well as in the field of analytical and environmental chemistry.

GC-MS quantification of fatty acid profile including trans FA in the locally manufactured margarines of Pakistan.

Ten margarine brands of Pakistan were analyzed for their fatty acid composition with emphasis on trans fatty acids (TFA) using GC-MS. Saturated, cis-monounsaturated and polyunsaturated fatty acids were present at 24.2-58.1, 5.7-35.4 and 3.8-37.4% of total fatty acids, respectively. Among the saturated fatty acids, palmitic acid (16.9-33.8%) was dominant in all analyzed margarine brands and its higher amount indicates that palm oil was a major contributor in the margarine manufacturing. Among samples tested only one contained a low level of TFA (2.2%) while the rest contained very high amounts of TFA (11.5-34.8%) which clearly shows that hydrogenated oils were used in the formulation of margarines. Fatty acid profiles demonstrated that all samples belong to the hard margarine category containing high amounts of trans and saturated fatty acids which is an alarming issue for the health of consumers.

An economically viable method for the removal of selected divalent metal ions from aqueous solutions using activated rice husk

Biosorption of divalent metal ions, i.e. Pb(II), Cd(II), Zn(II) and Cu(II) onto rice husk activated (RHA) is investigated over pH range (1-10) via batch adsorption technique. The chemical and thermal activation of rice husk with 0.1M HNO(3) and 1M K(2)CO(3) at 473 K enhanced the removal efficiency of RHA (35+/-2.1-99+/-0.5%, 33+/-1.2-97+/-0.6%, 32+/-1.3-96+/-0.8% and 28+/-1.8-95+/-0.9% before and after treatment, respectively). The surface area analysis of RHA by BET (Brunauer, Emmett and Teller) nitrogen adsorption method provided pore area and average pore diameter to be 542+/-2.3m(2)g(-1) and 1076+/-5.6 nm respectively. SEM and FTIR analyses of RHA were carried out to determine the surface morphology and functional groups involved in metal binding mechanism, respectively. The adsorption equilibrium was well described by Freundlich, Langmuir and Dubinin-Radushkevish (D-R) isotherm models by employing (4.8-48, 8.9-89, 15.3-153 and 15.7-157)x10(-5)M solution concentrations of sorbates, respectively, at equilibrium time of 20 min at pH 6 and onto 0.2g of sorbent. The kinetics of mass transfer and intra-particle diffusion for metal ions sorption onto RHA were studied with Lagergren and Morris-Weber kinetic models. The numerical values of thermodynamic parameters indicated the exothermic nature, spontaneity and feasibility of the sorption process. The desorption study of metal components from RHA surface was carried out with 0.1M HCl. The sorption mechanism developed illustrates the strong interactions of sorbates with the active sites of the sorbent coupled with efficient and environmentally clean exploitation of rice waste product.

Use of modified sorbent for the separation and preconcentration of chromium species from industrial waste water.

A simple and sensitive method based on solid phase extraction (SPE) on acetyl acetone modified XAD-16 has been established for separation of Cr (III) and Cr (VI) from and industrial water samples. Two forms of chromium showed different exchange capacities at different pH values, viz. Cr (III) selectively retained at pH 5-7 whereas Cr (VI) retained at pH 1. Hence complete separation of the two forms of chromium is possible. Retained species were eluted with 5 mL of 2 mol L(-1) HNO(3) and 2 mol L(-1) NaOH. The detection limit of 0.02 and 0.014 microg mL(-1) was achieved for Cr (III) and Cr (VI), respectively, with an enrichment factor of 100 and 140. Various kinetic and thermodynamic parameters were also determined. The metal ion concentration was measured by atomic Absorption Spectroscopy. The possible retention mechanism is also discussed. The method was successfully applied for the speciation of chromium in industrial water samples.

Application of microwave heating for the fast extraction of fat content from the poultry feeds.

A rapid method has been developed to extract and quantitatively measure the total oil content in poultry feeds using a domestic microwave oven. The optimized extraction procedure involves the replicate (6x) extraction of 5 g of ground feed with 12 ml of hexane for 20 s in a 900 W oven. Each replicate involves the collection of the resulting miscella and its replacement with fresh solvent for re-extraction. The collected extracts were centrifuged and transferred to a vial. The solvent was evaporated to a constant weight and the residual lipid weighed. In comparison to conventional Soxhlet extraction method, lipid contents obtained using the optimized microwave procedure was not significantly different. However, FTIR analysis indicated that the microwave procedure was superior in minimizing the formation of free fatty acids (FFA) relative to the Soxhlet procedure if the temperature of the sample was kept within the range of 45-50 degrees C. This simple, sequential extraction procedure is rapid, highly efficient and provides a simple mean of quantitating the lipid content of poultry feed in less than 40 min without the need for specialized microwave oven.

Simultaneous assessment of zinc, cadmium, lead and copper in poultry feeds by differential pulse anodic stripping voltammetry.

In the present work four metals (Zn, Cd, Pb and Cu) were determined simultaneously in 28 commercial broiler poultry feeds by differential pulse anodic stripping voltammetry (DPASV) using hanging mercury drop electrode (HMDE). The digestion of poultry feeds was carried out with concentrated nitric acid and hydrogen peroxide (2:1) with the help of microwave heating. Acetate buffer of pH 5 was used as a supporting electrolyte. The limit of detection for Zn, Cd, Pb and Cu was 0.69, 0.35, 0.68 and 0.24 microg/kg, respectively. The amount of Zn, Cd, Pb and Cu in the analyzed poultry feeds was ranged between 54.3-482.2, 3.8-33.6, 23.2-32.6 and 12.3-65.8 mg/kg, respectively. In most of analyzed poultry feed samples, the amount of Cd and Pb was found to be greater than the maximum tolerable level (MTL) which could be harmful for the poultry.

Changes in Composition and Antioxidant and Antimicrobial Activities of Essential Oil of Fennel (Foeniculum vulgare Mill.) Fruit at Different Stages of Maturity

The chemical composition and antioxidant and antimicrobial activities of the hydro-distilled essential oils from the fruit of sweet fennel (Foeniculum vulgare Miller) were investigated at three stages of maturity (immature, intermediate, and mature). Maximum essential oil content (3.5%) was observed in the mature, and the minimum oil content (2.8%) was observed in immature fruit. GC–MS analysis of the fennel essential oils from the plants revealed the presence of trans-anethole (65.2%, 69.7%, 72.6 %); fenchone (8.8%, 10.0%, 11.0%); estragole (6.9%, 6.9%, 7.2 %); and limonene (7.8%, 4.7%, 3.5 %) as the main components at immature, intermediate, and mature stages, respectively. Both the essential oils and trans-anethole, the principal constituent, exhibited appreciable antioxidant and antimicrobial activities as assessed by 2,2-diphenyl-1-picrylhydrazyl free radical-scavenging ability, bleaching β-carotene in linoleic acid system, inhibition of linoleic acid oxidation, disc diffusion, and microdilution broth assays. The variations in the content of most components with antioxidant and antimicrobial activities in the essential oils as the fruit matured were significant (p < 0.05).