Simultaneously enhanced removal and stepwise recovery of atrazine and Pb (II) from water using β-cyclodextrin functionalized cellulose: Characterization, adsorptive performance and mechanism exploration

Heavy metals and pesticides often coexist in contaminated water, while their potential competition behaviors make the adsorptive removal more challenging. Thus, decorating an adsorbent with independent functional sites could be a promising alternative to radically prevent the competitive process for improving the adsorption performance. Herein, beta-cyclodextrin functionalized rice husk-based cellulose (beta-CD@RH-C) was designed and applied for synchronous removal of atrazine and Pb(II). The characterization results supported the successful grafting of beta-cyclodextrin onto the cellulose. The beta-CD@RH-C presented a pH-dependent adsorption performance for Pb(II) with a theoretical monolayer adsorption capacity of 283.00 mg/g, while was mostly unrelated to pH for atrazine adsorption with a heterogeneous uptake of 162.21 mg/g in the mono-component system. Most importantly, the beta-CD@RH-C could efficiently achieve simultaneous removal of atrazine and Pb(II) via avoiding their competitive behaviors, which was due to the different adsorption mechanisms for atrazine (i.e. host-guest interaction) and Pb(II) (i.e. complexation and electrostatic interaction). Moreover, the adsorbed atrazine and Pb (II) could be sequentially desorbed with slight decrease in the adsorption performance of beta-CD@RH-C even after four cycles in the atrazine-Pb(II) multi-component system. All these results suggested beta-CD@RH-C to be a tailored adsorbent with high-performance elimination of co-existing heavy metals and organic pollutants in water.