The adsorption behaviour of Cu2+ onto maghnite was conducted under batch conditions. The effect of time, pH of the dispersion, temperature and initial metal concentration on the adsorption of Cu2+ onto maghnite was in...The adsorption behaviour of Cu2+ onto maghnite was conducted under batch conditions. The effect of time, pH of the dispersion, temperature and initial metal concentration on the adsorption of Cu2+ onto maghnite was investigated. In this study, 94% of Cu(II), was adsorbed on the maghnite clay when the equilibrium was reached at 120 min. The adsorption of Cu2+ was a fast process that followed the pseudo-second-order kinetics. This process could be described by the Langmuir model and gave a maximum Cu2+ adsorption capacity of 21.78 mg/g at 293 K. The thermodynamic parameters such as variation of enthalpy ΔH, variation of entropy ΔS and variation of Gibbs free energy ΔG were calculated from the slope and intercept of lnKd vs. 1/T plots. The adsorption was endothermic reaction. The adsorption process for this natural maghnite is more spontaneous because the values of ΔG are less negative. The results suggested that natural maghnite was suitable as sorbent material for the recovery and adsorption of metal ion from aqueous solutions.展开更多
The cationic ring-opening polymerization of tetrahydrofiiran using maghnite-H~＋ is reported.Maghnite-H~＋,is a non-toxic solid catalyst issued from proton exchanged montmorillonite clay.Polytetrahydrofuran,also call...The cationic ring-opening polymerization of tetrahydrofiiran using maghnite-H~＋ is reported.Maghnite-H~＋,is a non-toxic solid catalyst issued from proton exchanged montmorillonite clay.Polytetrahydrofuran,also called ＂poly（butandiol） ether＂,with acetate and hydroxyl end groups was successfully synthesized.Effects of reaction temperature, weight ratio of initiator/monomer and reaction time on the conversion of monomer and on the molecular weight are investigated.A cationic mechanism of the reaction was proposed.This chemistry can be considered as a suitable route for preparing poly（THF） as a soft segment for thermoplastic elastomers.展开更多
Maghnite clay obtained from Tlemcen, Algeria was investigated to remove heavy metal ion from wastewater. Thus, the present study includes the adsorption of Ni(II) in aqueous solution on maghnite clay through the proce...Maghnite clay obtained from Tlemcen, Algeria was investigated to remove heavy metal ion from wastewater. Thus, the present study includes the adsorption of Ni(II) in aqueous solution on maghnite clay through the process of adsorption under various conditions (with variable concentration of metal ion, temperature, pH and mixing time). Increasing pH favours the removal of metal ions till they are precipitated as the insoluble hydroxides. The uptake is rapid with maximum adsorption being observed within 10 min for Ni(II). In addition, the results obtained from adsorption isotherm indicated that these data can be better fitted with the Langmuir and Freundlich equations than the Dubinin-Radushke- vich (D-R) equation.展开更多
文摘The adsorption behaviour of Cu2+ onto maghnite was conducted under batch conditions. The effect of time, pH of the dispersion, temperature and initial metal concentration on the adsorption of Cu2+ onto maghnite was investigated. In this study, 94% of Cu(II), was adsorbed on the maghnite clay when the equilibrium was reached at 120 min. The adsorption of Cu2+ was a fast process that followed the pseudo-second-order kinetics. This process could be described by the Langmuir model and gave a maximum Cu2+ adsorption capacity of 21.78 mg/g at 293 K. The thermodynamic parameters such as variation of enthalpy ΔH, variation of entropy ΔS and variation of Gibbs free energy ΔG were calculated from the slope and intercept of lnKd vs. 1/T plots. The adsorption was endothermic reaction. The adsorption process for this natural maghnite is more spontaneous because the values of ΔG are less negative. The results suggested that natural maghnite was suitable as sorbent material for the recovery and adsorption of metal ion from aqueous solutions.
文摘The cationic ring-opening polymerization of tetrahydrofiiran using maghnite-H~＋ is reported.Maghnite-H~＋,is a non-toxic solid catalyst issued from proton exchanged montmorillonite clay.Polytetrahydrofuran,also called ＂poly（butandiol） ether＂,with acetate and hydroxyl end groups was successfully synthesized.Effects of reaction temperature, weight ratio of initiator/monomer and reaction time on the conversion of monomer and on the molecular weight are investigated.A cationic mechanism of the reaction was proposed.This chemistry can be considered as a suitable route for preparing poly（THF） as a soft segment for thermoplastic elastomers.
文摘Maghnite clay obtained from Tlemcen, Algeria was investigated to remove heavy metal ion from wastewater. Thus, the present study includes the adsorption of Ni(II) in aqueous solution on maghnite clay through the process of adsorption under various conditions (with variable concentration of metal ion, temperature, pH and mixing time). Increasing pH favours the removal of metal ions till they are precipitated as the insoluble hydroxides. The uptake is rapid with maximum adsorption being observed within 10 min for Ni(II). In addition, the results obtained from adsorption isotherm indicated that these data can be better fitted with the Langmuir and Freundlich equations than the Dubinin-Radushke- vich (D-R) equation.
