Polyacryl-dimethyl-heptadecanamine-Mullite as a promising sorbent for chromium and vanadium sorption from ilmenite

Abstract

The growing global demand for economic vanadium and chromium metals has prompted numerous studies into their recovery from ores and various other effluents. The polyacrylic 16,16-dimethyl-heptadecanamine-Mullite adsorbent (P(AA-co-PJMT/Mullite)) was formed by polymerizing acrylic acid in the presence of Mullite and an organic solvent containing the active groups responsible for binding processes with the desired materials using free radical gamma irradiation. The sorbent was fully described using EDX, SEM, FT-IR, XRD and DTA-TG to determine its shape and chemical composition in order to characterize the interplay with the V and Cr ions. The monolayer sorption capacities of V and Cr ions on the prepared sorbent are obtained at 161.64 mg g−1 (3.173 mmol g–1) and 112.61 mg g−1 (2.166 mmol g–1) respectively, using the optimized sorption parameters of feed solution pH 4.0, stirring time 60 and 90 min for V and Cr ions, metal ion concentration 500 mg L−1, sorbent to feed solution ratio 1/1000 (g mL−1), and room temperature (25 ± 2 °C). Sorption kinetics and isotherm studies indicated that the sorption of V ions on P(AA-co-PJMT/Mullite) matched with the Langmuir isotherm, whereas Cr ions matched with Freundlich. The sorption reaction fitted well with a pseudo-second-order kinetic model, demonstrating the chemisorption interaction between metal ions and the sorbent. The thermodynamic results demonstrated that the sorption processes are spontaneous and endothermic. EDTA is used to efficiently desorb V and Cr ions from the loaded sorbent instead of mineral acids, which has a detrimental effect on the decomposition of the Mullite content in the synthesized sorbent. The P(AA-co-PJMT/Mullite) sorbent successfully recovers V and Cr ions from two effluent solutions.