Javed Hanif

Selective adsorption of uranium on activated charcoal from electrolytic aqueous solutions

Abstract Adsorption of uranium on activated charcoal has been studied as a function of shaking time, amount of adsorbent, pH, concentration of adsorbate, and temperature. Uranium adsorption obeys the Langmuir isotherm. ΔHΔ and ΔSΔ were calculated from the slope and intercept of plots of ln KD vs 1/T. The influence of different anions and cations on uranium adsorption has been examined. The adsorption of other metal ions on activated charcoal has been studied under specified conditions to check its selectivity; consequently, uranium was removed from Cs, Ba, Zn, and Co. More than 98% adsorbed uranium on activated charcoal can be recovered with 65 mL of 3 M HNO3 solution. A wavelength dispersive x-ray fluorescence spectrometer was used for measuring uranium concentration.

Surface characterization and thermodynamics of adsorption of Sr2+, Ce3+, Sm3+, Gd3+, Th4+, UO 2 2+ on activated charcoal from aqueous solution

Surface parameters of the activated charcoal were measured using precise instrumental techniques for dehydration, carbon content, trace metals impurities, anions, bulk, tap and true densities, surface area, pore volume, porosity and average particle diameter. The adsorption of Sr2+, Ce3+, Sm3+, Gd3+, Th4+ and UO22+ ions on activated charcoal from aqueous solution was studied as a function of temperature. Thermodynamic parameters such as ΔHH0 and ΔS0 were calculated from the slopes and intercepts of the linear variation of lnK1 vs. 1/T, whereK3 is obtained from Langmuir equation. The results show endothermic heats of adsorption, but negative free energy values indicate that the adsorption process of metal ions on activated charcoal is favored at high temperature. The value of isosteric heat of adsorption, calculated from the Clausius-Clapeyron equation, shows that the surface of the activated charcoal is heterogeneous with respect to activity. A wavelength dispersive x-ray fluorescence spectrometer was used for measuring the concentration of metal ions.

EFFECT OF ALKALI METALS, ALKALINE EARTH METALS AND LANTHANIDES ON THE ADSORPTION OF URANIUM ON ACTIVATED CHARCOAL FROM AQUEOUS SOLUTIONS

Effects of alkali metals, alkaline earth metals and some lanthanides on the adsorption of uranium on activated charcoal from aqueous solutions have been studied. These effects are correlated with the ionic radii of metal ions present in the solutions. Adsorption capacity, Xm and binding energy contant, K for uranium adsorption were calculated from the Langmuir equätion. The mean energy of adsorption, Es was calculated from adsorption energy constant, K, values determined from the Dubinin-Radushkevich isotherm equation. Wavelength dispersive X-ray fluorescence spectrometry was used for measuring the uranium concentration.

Selective adsorption of thorium on activated charcoal from electrolytic aqueous solution

The adsorption of thorium on activated charcoal has been studied as a function of shaking time, amount of adsorbent, pH, concentration of adsorbate and temperature. Adsorption of thorium obeys the Langmuir isotherm. ΔH0 and ΔS0 were calculated from the slope and intercept of ln KD vs. 1/T plots. The influence of different anions and cations on thorium adsorption has been examined. The adsorption of other metal ions on activated charcoal has been studied under specified conditions to check its selectivity. Consequently, thorium was removed from Cs, Co, Ba, Cr, Sr, Cd, Cu, Mn and Zn. More than 98% adsorbed thorium on activated charcoal can be recovered with 55 ml 3M HNO3 solution. Wavelength dispersive X-rays fluorescence spectrometer was used for measuring thorium concentration.

Adsorption of dysprosium ions on activated charcoal from aqueous solutions

Abstract The adsorption of dysprosium ions onto activated charcoal from aqueous solution has been investigated in relation to pertinent variables, such as shaking time, pH, concentration of dysprosium ions, and temperature. The conditions leading to maximum adsorption have been established. The adsorption of dysprosium ions obeys the Langmuir and the Dubinin-Radushkevich isotherm equations. Thermodynamic quantities, namely AH and AS, have been calculated from the slopes and intercepts of plots of In (KD) versus 1 T . The results indicate that the adsorption of dysprosium ions on activated charcoal is an endothermic process. The influence of different cations and anions on the adsorption of dysprosium ions has been examined. The adsorption of other metal ions on activated charcoal has been measured under specified conditions to evaluate their selectivity. Approximately 98% of the dysprosium adsorbed on the activated charcoal was recovered using 40 ml of 3M HNO3 solution.

Uptake of thorium ions from aqueous solutions by a molecular sieve (13X type) powder

The adsorption of thorium(IV) ions on molecular sieve (13X type) powder from aqueous solutions has been studied as a function of shaking time pH, thorium ion concentration and temperature. The conditions of maximum adsorption of thorium ions obeys Langmuir and D-R isotherms over the entire concentration range studied. Thermodynamic quantities such as ΔH, ΔG and ΔS have been calculated fromKD values determined at various temperatures. The results show endothermic heat of adsorption, but negative free energy value indicates that the process of thorium adsorption on molecular sieve powder is favored at high temperature. The influence of various cations and anions on thorium(IV) ion adsorption was examined. A wavelength dispersive X-ray fluorescence spectrometer was used for measuring the thorium ion concentration in solutions.

Adsorption of gadolinium on activated charcoal from electrolytic aqueous solution

Adsoprtion of gadolinium on activated charcoal has been studied as a function of shaking time, pH, concentration of adsorbate and temperature. Gadolinium adsorption obeys the Langmuir isotherm. Δ Ho and Δ So were calculated from the slope and intercept of the In KD 1/T plot. The influence of different cations and anions on gadolinium adsorption has been examined. The adsorption of other metal ions on activated charcoal has been studied under optimum conditions to check the selectivity of gadolinium adsorption. Consequently, gadolinium was removed from Ni, V, Zn, Cu, Rb, Sr and Mn. More than 97% of the adsorbed gadolinium on activated charcoal can be recovered with 35 ml of 3M HNO3 solution. Wavelength dispersive X-ray fluorescence spectrometer was used for measuring gadolinium concentration.

SELECTIVE ADSORPTION OF CERIUM ON ACTIVATED CHARCOAL FROM AQUEOUS ELECTROLYTE SOLUTIONS

The adsorption of cerium on activated charcoal has been studied as a function of shaking time, pH, concentration of adsorbate and temperature. The adsorption of cerium obeys Freyndlich and Langmuir isotherms. The influence of different cations and anions on cerium adsorption has been exmined. The adsorption of other metal ions on activated charcoal has been studied under specified conditions to check its selectivity for cerium adsorption. Consequently, cerium was removed from a mixture containing Ce, Ba, Sr, Ru, Cs, Cr, Nd, Pr and In. About 99% of the adsorbed cerium on activated charcoal can be recovered with 3M HNO3 solution. A wavelelngth dispersive X-ray fluorescence spectrometer was used for measuring the cerium concentration.

XRF estimation of Cd, Hf, Hg, and Gd in uranium solution

A simple X-ray fluorescence (XRF) spectrometric method for the determination of Cd, Hf, Hg, and Gd in uranium solution has been developed, where sample solutions were introduced to the XRF spectrometer directly in simple polyethylene bottles. The matrix effects have been rectified using standards of similar composition. Statistical evaluation has established it as a fast and reliable method applicable to trace analysis.

Effect of pH on the adsorption of Ce3+, Sm3+, Eu3+ and Gd3+ ions on activated charcoal

The adsorption of metal ions such as Ce3+, Sm3+, Eu3+ and Gd3+ ions on activated charcoal has been studied as a function of pH. The adsorption mechanism of these ions is discussed in terms of hydrolyzed species formed in aqueous solution at different pH.