Effects of agro-waste resources on characteristics of Fe/nanocellulose hybrids and their applications as novel Fenton-like catalysts in dye removal from wastewater

Abstract

Herein, a novel, effective and bio-based Fenton-like catalyst by in situ incorporation of Fe2O3 nanoparticles on the surface of nanocellulose (NCs) was synthesized from sugar beet pulp (SBP) and utilized for efficient removal of three different dyes. Firstly, different NC samples were synthesized by acid hydrolysis of two different biomass (SBP and Q-quinoa husk) at various concentrations of H2SO4. The characterization analyses of samples showed that SBP-based NCs prepared using 60% concentration of H2SO4 (1 h string at 50 °C) showed the highest crystallinity (56.7%), lowest aggregation, highest surface negative charge (−38.5 mV), and largest surface area (13.9 m2/g) compared to the Q-based NCs. Both SBP and Q-based nanocatalyst utilized for degradation of dyes (methylene blue (MB), crystal violet (CV), and congo red (CR)), and SBP-based sample (Fe/NC-S3) displayed the best results in dye removal due to its larger specific surface area (39.8 vs. 9.2 m2/g), and higher content of magnetic nanoparticles (6.7 vs. 3.7 at% of Fe) than Q-based catalyst. At optimum conditions, Fe/NC-S3 nano-catalyst (2 g/L), in the presence of H2O2 (30 mM) removed MB, CV, and CR dyes (30 mg/L), in 30 min, at neutral pH, with 98%, 96%, and 62% removal efficiencies, respectively. Kinetic studies revealed that pseudo-first-order model was appropriate model to explain the decolorization of dyes at these conditions, and the rate constants were 0.0217, 0.018, and 0.0113 min−1 for the degradation of MB, CV, and CR, respectively. Moreover, raising the temperature from 15 ºC to 35 ºC resulted in enhancement of removal performance of nano-catalyst for all dyes. Fe/NC-S3 nano-catalyst showed proper reusability (just around 20% decrease for removal of all three dyes after ten consecutive reuse runs). Treatment of real water effluent (collected from a textile factory) containing mixture of all three dyes by Fe/NC-S3 and H2O2 approved the practical application of nano-catalyst in dye removal from complex matrixes even after nine reusing cycles. The results confirmed that SBP biomass could effectively turn to valuable NC nanocarriers for synthesis of advanced and innovative catalysts with proficient catalytic activity, stability, and recyclability.