Novel green chitosan-pectin gel beads for the removal of Cu(II), Cd(II), Hg(II) and Pb(II) from aqueous solution

Chitosan-pectin gel beads (CPBs) were synthesized via a facile and green method and applied to remove heavy metals from aqueous solution. The structural characteristics of CPBs were investigated by SEM and FTIR, the mechanical strength of CPBs was measured by Texture Analyzer and the stability of CPBs was evaluated in acidic solution. To study the adsorption characteristics, the effect of pH, contact time, initial heavy metals concentration, temperature, adsorption mechanism and regeneration were systematically investigated. The adsorption kinetics fitted well pseudo-second-order model, and the adsorption isotherms were well described by Langmuir model. The maximum adsorption capacities of Cu(II), Cd(II), Hg(II) and Pb(II) were 169.4, 177.6, 208.5 and 266.5 mg/g, respectively. The adsorption-desorption experiments revealed that the CPBs exhibited a great reusability. Thus, the synthesized CPBs in this study had the potential to be utilized as an environment-friendly and green adsorbent for the removal of heavy metals. [Display omitted] •Synthesis of novel green chitosan-pectin gel beads (CPBs) for removing heavy metals•Addition of pectin greatly increased the stability, porosity and adsorption capacities of CPBs.•Adsorption of heavy metals was due to chemisorption, followed the pseudo-second-order model.•Adsorption-desorption studies emphasized the reusability performance of CPBs.