solution (mL); and m is the mass of

solution (mL); and m is the mass of the adsorbent(g).Results and discussionSynthesis of polymer grafted RS via SI-ATRPfor purification treatment processThe procedure for preparing RS-based compositesthrough SI-ATRP as described in the experimentalsection is illustrated in Fig. 1. In order to purify the oil/water mixtures containing heavy metal ions in simulated wastewater treatment, biomass RS was modifiedto produce C18-RS-Br and RS-Br via the esterificationreaction of bearing hydroxyl groups with BiBB andstearoyl chloride. Then, C18-RS-g-PS and RS-gPSAN were prepared by PS and PSAN grafting fromthe cellulose-Br sites via SI-ATRP, respectively. RSg-PSAN was modified for removal of heavy metal ionsvia heterogeneous reaction with TEPA. The obtainedC18-RS-g-PS was demonstrated to be superhydrophobic and highly efficient for oil/water separation andRS-g-APSAN was designed as high performanceadsorbent for removal of heavy metal ions due to theintroduced chelating amidoxime groups. The molecular weight of the grafting polymer could be welltailored by the addition of EBiB as a sacrificialinitiator (Table S1). The chemical structures of thecorresponding reaction products at each stage towardsthe target RS composites were listed (Fig S1).The treatment process of oil/water mixtures containing heavy metal ions is illustrated in Fig. 2.According to the proposed continuous purificationstrategy, the oil is separated from heavy metal ionscontaminated oil/water mixture through the treatmentwith C18-RS-g-PS (step 1). Because of the low surfacetension, the oil is absorbed by C18-RS-g-PS and thenpenetrates, and eventually passes through the RScomposites. The heavy metal ions in the residual waterare adsorbed by RS-g-APSAN, owning to the chelating interaction with amidoxime and amine groups(step 2). Therefore, the oil/water mixtures containingheavy metal ions are separated into oil and purifiedwater.