| The adsorption properties of clay minerals have been studied extensively in recent years,from the studies,montmorillonites have been considered as effective in the removal of metal ions from aqueous solution.In this thesis,the use of natural bentonite for the adsorption of copper(Cu2+),lead(Pb2+)and zinc(Zn2+)ions from aqueous solution was studied.Characterization of the bentonite clay interactions responsible for adsorption was studied using x-ray diffraction(XRD),surface area and pore size(BET),infrared spectroscopy(FT-IR),SEM(Scanning electron microscope),and x-ray fluorescence(XRF).In this study,nitrate salts of copper,lead and zinc were used to prepare adsorbate solutions of Cu2+,Pb2+ and Zn2+.Batch adsorption experiment was used to determine the removal efficiencies of mixture of the target metals by bentonite clay with respect to operating conditions such as pH,metal concentration,and contact time.Equilibrium studies was conducted at different metal concentrations,with pH,contact time,rotary speed and temperature constant at 4,60 min,150 RMP and 25 ?.The results of the equilibrium studies indicated a high efficiency of bentonite in the removal of Pb2+,Cu2+and Zn2+ions,with the highest removal for Cu2+ Pb2+and Zn2+being 98.59%,97.76%and 96.15%at optimum initial concentrations of 10 mg/L,15 mg/L and 10 mg/L respectively.According to correlation coefficient,the obtained adsorption process could be better described with Langmuir isotherm model.The maximum adsorption capacity of clay for Cu2+,Zn2+and Pb2+ions fitted with Langmuir isotherm was found to be 2.4,2.9 and 2.8 mg/g respectively.Contact time studies were conducted using 60 mins to 300 mins.The results for 60 mins showed the highest%removal for all three metals with Cu2+recording 98.59%adsorption removal efficiency,Pb2+having 96.81%and Zn2+with 96.15%.The results in the paper proposed the potential role of natural bentonite clay obtained from Santai,China in wastewater treatment processes as an affordable,safe and environment friendly natural adsorbent material. |
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