Chitosan@Carboxymethylcellulose/CuO-Co2O3 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-Co2O3) crosslinked by using AlCl3 were successfully prepared. The beads were then coated with chitosan (Cs), Cs@CMC/CuO-Co2O3. The prepared beads, CMC/CuO-Co2O3 and Cs@CMC/CuO-Co2O3, were utilized as adsorbents for heavy metal ions (Ni, Fe, Ag and Zn). By using CMC/CuO-Co2O3 and Cs@CMC/CuO-Co2O3, 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-Co2O3 beads. The metal ion adsorbed on the beads were converted into nanoparticles by treating with reducing agent (NaBH4) and named Ni/Cs@CMC/CuO-Co2O3. Further, the prepared nanoparticles-decorated beads (Ni/Cs@CMC/CuO-Co2O3) 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 NaBH4. Among all catalysts, Ni/Cs@CMC/CuO-Co2O3 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 x 10(-1), 4.58 x 10(-3), 4.26 x 10(-3) and 5.1 x 10(-3) s(-1), respectively. Additionally, the catalytic activity of the Ni/Cs@CMC/CuO-Co2O3 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.

Automated summary

An efficient nanocatalyst was developed by preparing carboxymethyl cellulose-copper oxide-cobalt oxide nanocomposite beads and coating them with chitosan. The designed nanocatalyst showed high catalytic activity in the reduction of organic and inorganic pollutants, achieving significant removal rates.