G. Zuhra Memon

Characterization of banana peel by scanning electron microscopy and FT-IR spectroscopy and its use for cadmium removal

This study describes the use of banana peel, a commonly produced fruit waste, for the removal of Cd(II) from environmental and industrial wastewater. The banana peel was characterized by FT-IR and scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX) analysis. The parameters pH, contact time, initial metal ion concentration and temperature were investigated and found to be rapid ( approximately 97% within 10 min). The Langmuir adsorption isotherm was used to describe partitioning behavior for the system at room temperature. The value of Q(L) was found to be (35.52 mg g(-1)) higher than the previously reported materials. The binding of metal ions was found to be pH-dependent with the optimal sorption occurring at pH 8. The retained species were eluted with 5 mL of 5 x 10(-3)M HNO(3) with the detection limit of 1.7 x 10(-3)mg L(-1). Kinetics of sorption followed the pseudo-first-order rate equation with the rate constant k, equal to 0.13+/-0.01 min(-1). Thermodynamic parameters such as Gibbs free energy at 303K (-7.41+/-0.13 kJ mol(-1)) and enthalpy (40.56+/-2.34 kJ mol(-1)) indicated the spontaneous and endothermic nature of the sorption process. The developed method was utilized for the removal of Cd(II) ions from environmental and industrial wastewater samples using flame atomic absorption spectrophotometer (FAAS).

Adsorption of Methyl Parathion from Aqueous Solutions Using Mango Kernels: Equilibrium, Kinetic and Thermodynamic Studies

ABSTRACT The adsorption of methyl parathion from aqueous solutions by the low-cost and abundant adsorbent mango kernel was studied in a batch adsorption system. The adsorption was studied as a function of pH, contact time, initial pesticide concentration, adsorbent dose, and temperature. A maximum adsorption of 98% ± 1% was achieved. Physicochemical characterization of the adsorbent was carried out by EDXRF, BET, and CHNS analysis. Freundlich, Langmuir, and Dubinin-Radushkevich isotherms were employed to evaluate the adsorption capacity of the adsorbent. Lagergren, Morris-Weber, and Reichenberg equations were employed to study the kinetics of the adsorption process. Thermodynamic parameters Δ H, Δ S, and Δ G were computed. The developed adsorption method was applied to real environmental samples.

Adsorption of Selected Pesticides from Aqueous Solutions Using Cost effective Walnut Shells

In the present studies efforts are made to develop a low cost method to remove pesticides from water streams. Low cost walnut shells after chemical and thermal treatment are used to remove carbofuran and Chloropyriphos pesticides from aqueous solutions. The adsorption parameters i.e. pH, contact time, shaking speed and initial concentration have been studied. The adsorption was found to be rapid 97-99% within 30 min. The adsorption of pesticides on the adsorbent surface was found to be pH dependent. The adsorbent material was characterized by scanning electron microscopy (SEM) analysis and FT-IR spectroscopy. Elution experiments were performed to recover the adsorbed pesticide from the adsorbent surface. The Freundlich, Langmuir, D-R and Thomas models were used to study the partitioning behavior for the adsorption system along with kinetic and thermodynamic studies. The proposed adsorption method was utilized to remove carbofuran and Chloropyriphos pesticides from environmental water samples. Key word: Adsorption; pesticides; Walnut shell; Isotherms, Kinetics; thermodynamics.

Physicochemical Characterization of Gum Exuded From Prosopis Cineraria and Prosopis Glandulosa Species of Thar Desert Pakistan

Prosopis cineraria and prosopis glandulosa torryana wildly growing trees in Thar Desert Pakistan exude gum in appreciable quantities. The climatic conditions of desert catalyze gum exudation from trees and may affect their quality characteristics. No research work has been carried out to characterize these valuable gums and evaluate their potential for commercial exploitation. In the present study 135 samples (16kg) of P.glandulosa gum and 87 samples (9kg) of P.cineraria gum were collected and studied for their physicochemical properties. P. cineraria gum was sorted in three classes as amber, light yellow having dull luster and transparent golden yellow shades. P.glandulosa gum samples were sorted as dark brown and light brown samples. Among the physicochemical characteristics studied, moisture content of all classes of gums varied between 8-14%, ash 3-9%, protein 10 -21%, insoluble matter 0.8 - 1.9%, and the tannin content of transparent golden yellow samples of p.cineraria gum as 0.3-0.6%. The tannin content p. glandulosa was found to be fairly high making it unsuitable substitute of gum for food applications. All the samples were found to be dextrorotary and showed lower pH values. The intrinsic viscosity of gum samples ranged between 10.6- 13.6 ml/g and the values were used to calculate viscosity average molecular weight of gum samples. All the samples were found to be rich in amino acid content having Hydroxyproline between 300-380, tyrosine 270- 326, aspartic acid 170-210, and serine 170-195 residues per 10000 residues. Cationic composition of ash of gum samples revealed calcium magnesium sodium and potassium as major cations whereas no presence of toxic metals lead cadmium and mercury was detected. Comparative assessment of data indicated that P.cineraria gum was of better quality as compared to that of P. glandulosa and that the application of classification procedure has marked effect on gum quality and potential to make p. cineraria gum as suitable substitute of gum arabic.

Essential long chain polyunsaturated fatty acids in muscle tissue of freshwater fish Labeo calbasu under different cooking processes

The effect of different cooking methods (Raw, steaming, microwave cooking, baking, grilling, pan frying and deep frying) on proximate composition and fatty acid profile of Labeo calbasu fish species from Pakistan were analyzed to determine the nutritional qualities in terms of the long chain n-3 PUFA particularly EPA and DHA. In all cooking methods moisture content decrease and protein content increased as compare to raw sample. The moisture content of fish sample seemed to be inversely related to the total extractable lipid content. In steamed, microwave, baked, grilled and pan fried methods MUFA were the abundant fatty acids followed by SFA and PUFA. Deep fried fish sample had the opposite trend having highest PUFA as contrast to MUFA and SFA. Long chain n-3 PUFA were found higher in contrast to n-6 PUFA in all other cooking methods excluding deep frying. The results indicates that steamed and grilled cooking are the best cooking method for healthy eating as they contain more n-3 PUFA (EPA and DHA). Losses of n-3 content in pan fried and deep fried fish were higher than those of fish cooked by other methods.