Chitosan@Carboxymethylcellulose/CuO-Co 2 O 3 Nanoadsorbent as a Super Catalyst for the Removal of Water Pollutants.

In this work, an efficient nanocatalyst was developed based on nanoadsorbent beads. Herein, carboxymethyl cellulose-copper oxide-cobalt oxide nanocomposite beads (CMC/CuO-Co 2 O 3 ) crosslinked by using AlCl 3 were successfully prepared. The beads were then coated with chitosan (Cs), Cs@CMC/CuO-Co 2 O 3. The prepared beads, CMC/CuO-Co 2 O 3 and Cs@CMC/CuO-Co 2 O 3 , were utilized as adsorbents for heavy metal ions (Ni, Fe, Ag and Zn). By using CMC/CuO-Co 2 O 3 and Cs@CMC/CuO-Co 2 O 3 , the distribution coefficients (K d ) for Ni, Fe, Ag and Zn were (41.166 and 6173.6 mLg -1 ), (136.3 and 1500 mLg -1 ), (20,739.1 and 1941.1 mLg -1 ) and (86.9 and 2333.3 mLg -1 ), respectively. Thus, Ni was highly adsorbed by Cs@CMC/CuO-Co 2 O 3 beads. The metal ion adsorbed on the beads were converted into nanoparticles by treating with reducing agent (NaBH 4 ) and named Ni/Cs@CMC/CuO-Co 2 O 3 . Further, the prepared nanoparticles-decorated beads (Ni/Cs@CMC/CuO-Co 2 O 3 ) were utilized as nanocatalysts for the reduction of organic and inorganic pollutants (4-nitophenol, MO, EY dyes and potassium ferricyanide K 3 [Fe(CN) 6 ]) in the presence of NaBH 4 . Among all catalysts, Ni/Cs@CMC/CuO-Co 2 O 3 had the highest catalytic activity toward MO, EY and K 3 [Fe(CN) 6 ], removing up to 98% in 2.0 min, 90 % in 6.0 min and 91% in 6.0 min, respectively. The reduction rate constants of MO, EY, 4-NP and K 3 [Fe(CN) 6 ] were 1.06 × 10 -1 , 4.58 × 10 -3 , 4.26 × 10 -3 and 5.1 × 10 -3 s -1 , respectively. Additionally, the catalytic activity of the Ni/Cs@CMC/CuO-Co 2 O 3 beads was effectively optimized. The stability and recyclability of the beads were tested up to five times for the catalytic reduction of MO, EY and K 3 [Fe(CN) 6 ]. It was confirmed that the designed nanocomposite beads are ecofriendly and efficient with high strength and stability as catalysts for the reduction of organic and inorganic pollutants.