3.3. Effect of type, concentration and volume of eluent
In order to desorb cadmium and copper ions from DPCfunctionalized
nanoporous silica, a series of selected eluent
solutions, such as HNO3, HCl and CH3COOH at different concentrations
were used. As shown in Table 1, it was eventually found that
HCl (2 mol L−1) provided effective elution of cadmium and copper
ions from DPC-functionalized nanoporous silica. The effect of eluent
volume on the recovery of cadmium and copper ions was also
studied. As Table 1 shows, quantitative recovery could be obtained
with 5 mL of HCl (2 mol L−1). Therefore, volumes of 5 mL of eluent
for desorption of the cadmium and copper ions were used in the
remaining experiments.