Kinetic, equilibrium and selectivity studies of heavy metal ions (Pb(II), Co(II), Cu(II), Mn(II), and Zn(II)) removal from water using synthesized C-4-methoxyphenylcalix[4]resorcinarene adsorbent

摘要

Batch-mode adsorption study was done for selected heavy metal ions (Pb(II), Co(II), Cu(II), Mn(II), and Zn(II)) using synthetic adsorbent (C-4-methoxyphenylcalix[4]resorcinarene 3) to investigate the effect of different parameters such as contact time and pH. Selectivity of the adsorbent towards a mixture of heavy metals adsorbates was investigated. Results showed optimum agitation time of 30min at pH 5.6 and initial concentration of 1ppm for all investigated heavy metals. Different kinetic models of Santosa first-order, Lagergren pseudo-first-order and Ho pseudo-second-order were applied on the adsorption experimental data. Results proved that all adsorption processes were followed and pseudo-second-order kinetic model was adopted. The adsorption capacity of C-4-methoxyphenylcalix[4]resorcinarene towards the selected heavy metal ions was 95.00, 89.76, 89.58, 86.43, and 80.96% for Cu(II), Mn(II), Zn(II), Pb(II), and Co(II), respectively. Selectivity of adsorption was tested on a mixture of Cu(II), Mn(II), Zn(II), Pb(II), and Co(II) with an initial concentration of 1ppm of each heavy metal and agitated time of 10min with the adsorbent; removal percentage of each metal ion showed different values from each heavy metal alone as it was in decreasing order Cu(II)>Zn(II)>Co(II)>Mn(II)>Pb(II). The rate constant value for each heavy metal adsorption mechanism obtained from Ho pseudo-second-order model was in the order Co(II)>Zn(II)>Pb(II)>Mn(II)>Cu(II).