The primary objective of the present study is to evaluate the optimization conditions such as kinetic and equilibrium isotherm models involved in the removal of Ni(II) from the aqueous solutions byTrichoderma viride. The biosorbent was characterized by FTIR and SEM. The optimum biosorption conditions were determined as a function of pH, biomass dosage, contact time, initial metal ion concentration, and temperature. The maximum Ni(II) biosorption was obtained at pH 4.5. The equilibrium data were better fit by the Langmuir isotherm model than by the Freundlich isotherm. The kinetic studies indicate that the biosorption process of the metal ion Ni(II) has followed well the pseudo-second-order model. The sum of the square errors (SSE) and chi-square (χ2) tests were also carried out to find the best fit kinetic model and adsorption isotherm. The maximum biosorption capacity (qm) ofT.viridebiomass was found to be 47.6 mg/g for Ni(II) ion. Therefore, it can be concluded thatT.viridebiomass was effective and low-cost potential adsorbent to remove the toxic metal Ni(II) from aqueous solutions. The recovery process of Ni(II) fromT.viridebiomass was found to be higher than 98% by using 0.25 M HNO3. Besides the application of removal of toxic metal Ni(II) from aqueous solutions, the biosorbentT.viridecan be reused for five consecutive sorption-desorption cycles was determined.
The removal of Ni(II) from aqueous solutions using biomass prepared from Ceiba pentandra hulls powder modified with citric acid treatment (CAMCPH) has been studied by batch method. The biosorbent was characterised before and after citric acid modification using SEM, FT-IR and XRD. Experimental parameters that influence the biosorption of Ni(II), such as pH, biosorbent dose, contact time and initial concentration of metal ion have been investigated. The adsorption of Ni(II) increased with increase in contact time and reached equilibrium within 50 min. The maximum removal of Ni(II) was observed at pH 5.0. The kinetic data were analysed using three adsorption kinetic models: the pseudo-first, second-order kinetics and intra-particle diffusion. The results showed that the pseudo-second-order model fits the experimental data very well. The equilibrium data were analysed using Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. Langmuir model provided the best correlation for the adsorption of Ni(II) by CAMCPH and the monolayer biosorption capacity for Ni(II) removal was 34.34 mg/g. Desorption experiments were carried out using HCl solution and the recovery of the metal ion from CAMCPH was found 98%. Desorption experiments showed the feasibility of regeneration of the biosorbent for further use after treating with dilute HCl.
Metoprolol, 1-isopropylamino-3-[4-(2-methoxy-ethyl)-phenoxy]-2-propanol, is a b1--selective aryloxy propanolamine used in the treatment of cardiovascular disorders such as hypertension, arrhythmia and heart failure (1). The drug is a lipophilic adrenoreceptor antagonist (b-blocker) with a short half-life.Various methods reported for the determination of metoprolol and its metabolites in human plasma include gas chromatography (GC) equipped with an electron capture detector (ECD) (2), nitrogen selective detector (NSD) (3), mass spectrometry (MS) detector (4, 5) and high performance liquid chromatography equipped with a ultra violet detector (6, 7), fluorescence detector (8-12), MS detector (13-15). Sample preparation for the extraction of metoprolol from human plasma is based on the solid phase extraction (4) and liquid-liquid extraction using dichloro methane (2,8,10,12), n-butyl chloride (11) and mixture of dichloromethane and diethyl ether (2,8 A high-performance liquid chromatography-tandem mass spectrometric method was developed and validated for the determination of metoprolol in human plasma. The analyte and internal standard, nevirapine, were extracted from plasma matrix by liquid-liquid extraction with ethyl acetate. Chromatographic separation was achieved on a C-18 analytical column with an isocratic mobile phase of 15:85 (V/V) 10 mmol L -1 ammonium acetate (pH 5.0)/acetonitrile. The atmospheric pressure chemical ionization technique was used for sample ionization in positive ion mode and enhanced selectivity was achieved by tandem mass spectrometric analysis via two multiple reaction monitoring (MRM) transitions, 268.2 ® 116.2 for metoprolol and 267.1 ® 226.2 for nevirapine, respectively. The assay was validated for human plasma over a concentration range of 1-200 ng mL -1 with the precision and accuracy ranging from 0.9 to 8.8 % and 89.9 to 105.8 %, respectively.
A separation and preconcentration procedure was developed for the determination of trace amounts of Cd(II), Cu(II), Ni(II), and Pb(II) in water and food samples using Amberlite XAD-2 fuctionalized with a new chelating ligand, 3-(2-nitrophenyl)-1H-1,2,4-triazole-5(4H)-thione (Amberlite XAD-2-NPTT). The chelating resin was characterized by Fourier transform infrared spectroscopy (FT-IR) and used as a solid sorbent for enrichment of analytes from samples. The sorbed elements were subsequently eluted with 10 mL of 1.0 M HNO(3), and the eluates were analyzed by inductively coupled plasma-atomic emission spectrometry. The influences of the analytical parameters including pH, amount of adsorbent, eluent type and volume, flow rate of the sample solution, volume of the sample solution, and effect of matrix on the preconcentration of metal ions have been studied. The optimum pH for the sorption of four metal ions was about 6.0. The limits of detection were found to be 0.22, 0.18, 0.20, and 0.16 μg L(-1) for Cd(II), Cu(II), Ni(II), and Pb(II), respectively, with a preconcentration factor 60. The proposed method was applied successfully for the determination of metal ions in water and food samples.
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