Facile fabrication of a phosphonium-based ionic liquid impregnated chitosan adsorbent for the recovery of hexavalent chromium

Mochamad Lutfi Firmansyah; Thalabul Ilmi; Rino Rakhmata Mukti; Patmawati; Masahiro Goto

doi:10.1039/d2ra00064d

Facile fabrication of a phosphonium-based ionic liquid impregnated chitosan adsorbent for the recovery of hexavalent chromium

RSC Adv. 2022 Apr 11;12(18):11207-11215. doi: 10.1039/d2ra00064d. eCollection 2022 Apr 7.

Authors

Mochamad Lutfi Firmansyah¹, Thalabul Ilmi², Rino Rakhmata Mukti^{2

3

4}, Patmawati⁵, Masahiro Goto^{6

7}

Affiliations

¹ Nanotechnology Engineering, Faculty of Advanced Technology and Multidiscipline, Airlangga University Jl. Dr Ir. H. Soekarno Surabaya 60115 Indonesia ml.firmansyah@ftmm.unair.ac.id.
² Division of Inorganic and Physical Chemistry, Faculty of Mathematics and Natural Science, Institut Teknologi Bandung Jl Ganesha 10 Bandung 40132 Indonesia.
³ Research Center for Nanoscience and Nanotechnology, Institut Teknologi Bandung Jl Ganesha 10 Bandung 40132 Indonesia.
⁴ Research and Innovation Center for Advanced Materials, Institut Teknologi Sumatera Jl. Terusan Ryacudu Lampung 35365 Indonesia.
⁵ Department of Marine, Faculty of Fisheries and Marine, Universitas Airlangga Jalan Mulyorejo Kampus C Surabaya 60115 Indonesia.
⁶ Department of Applied Chemistry, Graduate School of Engineering, Kyushu University 744 Motooka, Nishi-ku Fukuoka 819-0395 Japan.
⁷ Center for Future Chemistry, Kyushu University 744 Motooka, Nishi-ku Fukuoka 819-0395 Japan.

Abstract

Chitosan adsorbents impregnated with a phosphonium-based ionic liquid (Chi_IL), trioctyldodecyl phosphonium chloride, were prepared for the adsorption of hexavalent chromium and compared to the performance of native chitosan. The physical and chemical properties of the adsorbents were characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Effects of various parameters, such as pH, adsorbent dosage, contact time, temperature, and multi-component systems, were systematically examined. Chi_IL showed a high adsorption capacity (282.6 mg g^-1) compared to native chitosan (238.1 mg g^-1). The adsorption kinetics of the metals followed a pseudo-second-order kinetic model, and the experimental data were a good fit for the Freundlich isotherm model. Following the isotherm and activation energy parameter, adsorption of Cr(vi) onto Chi_IL follows a chemisorption process, possibly through an anionic exchange with the anion of the IL. The thermodynamic parameters suggested that the adsorption of Cr(vi) is a spontaneous and exothermic reaction. In the column adsorption, Chi_IL exhibited a longer column exhaustion time than that of native chitosan owing to the enhanced adsorption capacity caused by the introduction of IL. Moreover, the column with the parameters of 6 cm bed depth, 5 mL min^-1 flow rate, and 50 mg L^-1 was able to achieve the best performance in Cr(vi) adsorption.