Selenate Adsorption from Water Using the Hydrous Iron Oxide-Impregnated Hybrid Polymer

Hybrid adsorbent, based on the cross-linked copolymer impregnated with hydrous iron oxide, was applied for the first time for Se(VI) adsorption from water. The influence of the initial solution pH, selenate concentration and contact time to adsorption capacity was investigated. Adsorbent regeneration was explored using a full factorial experimental design in order to optimize the volume, initial pH value and concentration of the applied NaCl solution as a reagent. Equilibrium state was described using the Langmuir model, while kinetics fitted the pseudo-first order. The maximum adsorption capacity was found to be 28.8 mg/g. Desorption efficiency increased up to 70%, and became statistically significant with the reagent concentration and pH increase, while the applied solution volume was found to be insignificant in the investigated range. Based on the results obtained, pH influence to the adsorption capacity, desorption efficiency, Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analysis of loaded adsorbent, it was concluded that the outer- and inner-sphere complexation are mechanisms responsible for Se(VI) separation from water. In addition to the experiments with synthetic solutions, the adsorbent performances in drinking water samples were explored, showing the purification efficiency up to 25%, depending on the initial Se(VI) concentration and water pH. Determined sorption capacity of the cross-linked copolymer impregnated with hydrous iron oxide and its ability for regeneration, candidate this material for further research, as a promising anionic species sorbent.

KARAKTERISTIK CEBAKAN EPITERMAL TIPE SULFIDASI TINGGI DI DAERAH ERELEMBANG, TOMBOLO PAO, KABUPATEN GOWA, PROVINSI SULAWESI SELATAN

Mineralisasi di wilayah Erelembang, Tombolo Pao, Kabupaten Gowa, Sulawesi Selatan merupakan salah satu tipe mineralisasi yang cukup menarik di kawasan ini. Penciri utama proses mineralisasi adalah munculnya alterasi silisifikasi, argilik-argilik lanjut, dan propilitik yang membentuk suatu zona. Kehadiran mineral alterasi spesifik yang teridentifikasi meliputi alunite, halloysite, jarosite, kaolinite, dickite, dan pyrophyllite, sebagai zona argilik-argilik lanjut, dengan luas sebarannya lebih dari 2 km2, menunjukkan zona ubahan bersifat asam. Selain itu, hal lain yang menonjol adalah tekstur vuggy silica dalam zona batuan terubah karena proses pelarutan. Hasil pengamatan pada sayatan poles diketahui mineral sulfida yang teridenfifikasi adalah pirit, tetrahidrit, kovelit, enargit, serta hydrous iron oxide, dan sedikit kalkopirit, malakit, tenantit, galena dan hematit yang terdapat secara tersebar dalam zona argilik-argilik lanjut. Korelasi mineral ubahan yang spesifik (alunite, halloysite, jarosite, kaolinite, dickite, phyrophyllite), dengan mineral bijihnya (enargit, tenantit, tetrahedrit, dan kovelit) serta vuggy silica dapat memberikan gambaran mineralisasinya tipe epitermal sulfidasi tinggi. Munculnya konsentrasi anomali merkuri di wilayah tertentu, menunjukkan bahwa model cebakannya adalah tipe epitermal sulfidasi tinggi yang terbentuk pada lingkungan yang dangkal. Penelitian ini akan memberikan informasi baru terkait dengan konsep eksplorasi yang akan diterapkan di wilayah ini.