The discharge of metals and dyes poses a serious threat to public health and the environment. What is worse, these two hazardous pollutants are often found to coexist in industrial wastewaters, making the treatment more challenging. Herein, we report an EDTA-cross-linked β-cyclodextrin (EDTA-β-CD) bifunctional adsorbent, which was fabricated by an easy and green approach through the polycondensation reaction of β-cyclodextrin with EDTA as a cross-linker, for simultaneous adsorption of metals and dyes. In this setting, cyclodextrin cavities are expected to capture dye molecules through the formation of inclusion complexes and EDTA units as the adsorption sites for metals. The adsorbent was characterized by FT-IR, elemental analysis, SEM, EDX, ζ-potential, and TGA. In a monocomponent system, the adsorption behaviors showed a monolayer adsorption capacity of 1.241 and 1.106 mmol g(-1) for Cu(II) and Cd(II), respectively, and a heterogeneous adsorption capacity of 0.262, 0.169, and 0.280 mmol g(-1) for Methylene Blue, Safranin O, and Crystal Violet, respectively. Interestingly, the Cu(II)-dye binary experiments showed adsorption enhancement of Cu(II), but no significant effect on dyes. The simultaneous adsorption mechanism was further confirmed by FT-IR, thermodynamic study, and elemental mapping. Overall, its facile and green fabrication, efficient sorption performance, and excellent reusability indicate that EDTA-β-CD has potential for practical applications in integrative and efficient treatment of coexistenting toxic pollutants.

The development of an environmentally benign process for the hydrolysis of cellulose into reducing sugars can be one of the key technologies for making full use of cellulosic biomass in the future. Here, a biomass char sulfonic acid (BC-SO 3 H)-catalyzed hydrolysis of cellulose in water was achieved under microwave irradiation. The BC-SO 3 H catalysts prepared cheaply from natural bamboo, cotton and starch, showed a much higher turnover number (TON, 1.33-1.73) for this reaction compared to a dilute H 2 SO 4 solution (TON, 0.02), which was likely due to their strong affinity to b-1,4-glycosidic bonds of cellulose. In addition, microwave irradiation played key roles in activating cellulose molecules and strengthening particle collision, which can lead to a remarkable acceleration effect on this heterogeneously catalytic process.

PEI acts not only as a cross-linker but also as a chelating agent for RE ions.

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