Removal and Recovery of Chromium(vi) Ion via Tri-N-Octyl Methylammoniumchloride-Kerosene Polypropylene Supported Liquid Membrane

Abstract

The presence of chromium in the natural water can be toxic to aquatic organism and is one of the major environmental problems. Therefore, the removal and recovery of chromium from industrial wastewater is very crucial to accomplish the standard discharge concentration limit. Supported liquid membrane is one of the processes which combines the extraction and recovery process in one single stage. This paper presents an experimental study on the removal and recovery of chromium ions from acidic aqueous solutions through a flat-sheet supported liquid membrane (FSSLM) system. Through this system, chromium ions were transported from feed phase into stripping phase via Tri-n-octyl-methylammoniumchloride (TOMAC)-kerosenepolypropylene supported liquid membrane (SLM). The liquid membrane phase was prepared by dissolving the corresponding volume of the carrier, TOMAC in organic diluent of kerosene. The stripping agent used was sodium hydroxide (NaOH) solution whereas the membrane support used was commercial Accurel polypropylene membrane with good features of 100 µm thickness, porosity of 72% and effective pore size of 0.10 µm. The chromium ion concentration in the feed and stripping phases as a function of time was analysed using an atomic absorption spectrometry (AAS). The effects of different operational variables such as TOMAC concentration in the membrane phase, NaOH concentration in the stripping phase and pH of the aqueous feed phase were investigated. The result demonstrated that about 90 and 98% of 150 ppm of chromium was removed and recovered, respectively at favorable condition of 1.0 M TOMAC, 0.5 M NaOH and pH 2 of the feed phase.Keywords: supported liquid membrane, chromium, removal, recovery, acidic aqueous solution Abstrak Kehadiran kromium di dalam sumber air semula jadi adalah toksik kepada organisma akuatik dan salah satu masalah utama alam sekitar. Oleh itu, penyingkiran dan pemulihan semula kromium daripada air sisa industri adalah sangat perlu untuk memenuhi had kepekatan piawaian pelepasan. Membran cecair berpenyokong adalah salah satu proses yang menggabungkan penyingkiran dan pemulihan semula dalam satu peringkat proses. Kertas kerja ini membentangkan satu kajian eksperimen tentang penyingkiran dan pemulihan semula ion kromium dari larutan berasid melalui sistem helaian rata membran cecair berpenyokong (FSSLM). Melalui sistem ini, ion kromium dibawa dari fasa suapan ke fasa pelucutan melalui Tri-n-oktil-metilammonium klorida (TOMAC)-kerosin-polipropilena membran cecair berpenyokong (SLM). Fasa cecair membran telah disediakan dengan melarutkan sejumlah pembawa, TOMAC dalam pelarut organik kerosin. Ejen pelucutan yang digunakan adalah larutan sodium hidroksida (NaOH) manakala membran sokongan yang digunakan ialah Accurel polipropilena membran komersial yang mempunyai ciri-ciri yang baik dengan ketebalan 100µm, keliangan 72% dan saiz liang 0.10 µm. Kepekatan ion kromium dalam ISSN -2506Raja Norimie & Norasikin: REMOVAL AND RECOVERY OF CHROMIUM(VI) ION VIA TRI-N-OCTYL METHYLAMMONIUMCHLORIDE-KERO...