Adsorption of vanadium using a new anionic Schiff Base adsorbent and its application to vanadium separation from boiler ash

Background

This study reports the preparation of 2-hydroxy-3-(4-(((2-((2-(((E)-4-(2-hydroxy-3-(trimethylammonio)propoxy)-3-methoxybenzylidene)amino)ethyl)amino)ethyl)imino)methyl)-2-methoxyphenoxy)-N,N,N-trimethylpropan-1-aminium (HYM/QA). The adsorbent was employed to extract and concentrate vanadium from its solutions and boiler ash samples.

Results

The impact of initial dosage, pH, reaction time and temperature on the sorption behavior of V(V) was examined. Under optimal conditions (pH 5, 0.08 g dose, 45 min at room temperature), a sorption capacity of 392.25 mg g⁻¹ was achieved. The uptake of V(V) on HYM/QA was effectively reversed using 1 mol L⁻¹ NaOH, regenerating the material. After six cycles of sorption and elution, the sorption capability remained at 91.4% of its initial value. The efficiency and selectivity of HYM/QA toward V⁵⁺ ions were assessed using the separation factor parameter, revealing limited interference from heavy metals such as Mn²⁺, Cr³⁺, Pb²⁺, Si⁴⁺, Al³⁺, NO₃²⁻, HCO₃⁻ and Zn²⁺. The uptake process of HYM/QA for V(V) conformed to the Langmuir and Dubinin–Radushkevich isotherm models and the pseudo-second-order kinetic model. HYM/QA was characterized by infrared, Brunauer–Emmett–Teller surface area, ¹H NMR, ¹³C NMR and gas chromatography–mass spectrometry analyses, confirming successful preparation. Thermodynamic assessments suggested that the sorption process is endothermic, spontaneous and becoming more favorable with rising temperature.

Conclusion

The optimized conditions were used to adsorb vanadium from boiler ash samples, and the obtained vanadium pentaoxide was analyzed and confirmed using various tools, demonstrating the material's effectiveness for vanadium extraction. © 2024 Society of Chemical Industry (SCI).