Adsorption of Erochrom Black T azo dye by nanocomposite of activated carbon from sugar beet and LaFeO3

Nanocomposite of organic–inorganic materials was prepared. Activated carbon was prepared by carbonization of sugar beet pulp at 800°C (ACSB). The ACSB@LaFeO3 nanocomposite was prepared by ACSB and nanoparticles of LaFeO3. The structure and surface morphology was studied by Fourier-transform infrared spectroscopy, X-ray diffraction, Brunauer–Emmett–Teller (BET), field emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy methods. BET surface area of ACSB, LaFeO3, and ACSB@LaFeO3 were 825, 15, and 780 m2/g, respectively. Adsorption of Eriochrome Black-T (EBT) azo dye by ACSB and ACSB@LaFeO3 nanocomposite were investigated. The effect of various parameters such as carbonization temperature, dye concentration, contact time, pH, and dosage of adsorbent were investigated in batch mode. The optimum conditions were obtained at 70 mg/L initial dye concentration, 0.4 g adsorbent dose, and pH of 3. The pseudo-second-kinetic model (k2 = 4.54 × 10–2 g/mg/min for ACSB@LaFeO3) exhibited better fit than pseudo-first-order and intraparticle diffusion models for the kinetic studies. The Langmuir, Freundlich, and Temkin isotherm models were used for modeling adsorption isotherms. The adjustments of models were confirmed by the Chi-square (χ2) test and the correlation coefficients (R2). The Langmuir model appears to be better appropriate for describing the adsorption of EBT. The calculated thermodynamic parameters such as ΔG°, ΔH°, and ΔS° showed that the adsorption of EBT was feasible, spontaneous, and endothermic at temperature range 288–338 K. ACSB@LaFeO3 nanocomposite can be used as an effective, reusable, low cost, and eco-friendly adsorbent for EBT removal from aqueous solution.