Simultaneous Adsorption of Humic Acid and Copper (II) Ions from Aqueous Solution onto Cetylpyridinium Bromide (CPB) Modified Zeolite

Adsorption of humic acid (HA) and Cu(II) onto cetyl pyridinium bromide (CPB) modified zeolite was investigated in single- and binary-adsorbate systems. The equilibrium adsorption data of HA and Cu(II) onto CPB modified zeolite in the single-adsorbate system were analyzed by the Langmuir and Freundlich isotherm models. The equilibrium adsorption data were well described by the Langmuir isotherm model, and the predicted maximum monolayer adsorption capacities for HA and Cu(II) at pH 6.0 and temperature 298 K were 292 mg/g and 13.3 mg/g, respectively. The pseudo-first-order and pseudo-second-order kinetic models were applied to describe the kinetic adsorption data in the single-adsorbate system. The experimental data fitted well with the pseudo-second-order kinetic model. The presence of HA enhanced Cu(II) adsorption onto CPB modified zeolite. Similarly, the presence of Cu(II) enhanced HA adsorption onto CPB modified zeolite. Results of this work indicate that CPB modified zeolite is a promising adsorbent for simultaneous removal of HA and Cu(II) from aqueous solution.