科研之友
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摘要
Amino, di-amino, and tri-amino groups functionalized mesoporous silica (N-SBA-15, 2 N-SBA-15, and 3 N-SBA-15) were synthesized using reed ash as silica source. Batch experiments were conducted to investigate the impact of contact time, adsorbent dosage, solution pH, temperature, and concentration of Pb(II) ions onto SBA-15, N-SBA-15, 2 N-SBA-15, and 3 N-SBA-15. The results revealed that the overall adsorption process well fitted the pseudo-second-order kinetic model. The maximum adsorption capacity of N-SBA-15, 2 N-SBA-15, and 3 N-SBA-15 for Pb(II) was 108.16, 102.77, and 93.65 mg/g at 298 K, respectively. The adsorption capacities increased with the increase in temperatures and with the decrease in soluble salt concentrations. Thermodynamics analysis showed that the adsorptions of Pb(II) were feasible, spontaneous, and exothermic in nature. The capacity of the modified SBA-15 did not lose significantly after six adsorption-desorption cycles. The Pb(II) adsorption process was dominated by chemical adsorption process. The results suggested that reed ash was an ideal silica source to prepare N-SBA-15, 2 N-SBA-15, and 3 N-SBA-15 for the removal of Pb(II) ions from aqueous solutions.
