Lumpur Hitam Tanah Rawa Hutan Mangrove Karangsong (Kabupaten Indramayu): Komposisi Kimia dan Transformasi Fasa Mineral yang Dihasilkan melalui Penanganan secara Termal

Abstract

Penelitian ini dilakukan untuk menyelidiki kandungan unsur dan transformasi mineral-mineral utama lumpur hitam dari tanah rawa hutan mangrove Karangsong, Kabupaten Indramayu, Jawa Barat. Sampel lumpur hitam kering diberi perlakuan secara termal dan bertahap pada kisaran suhu 120 - 1000 °C. Kandungan mineral dan transformasinya kemudian dianalisis dengan metode difraksi serbuk sinar-X. Kandungan unsur-unsur berat sebelum dan sesudah perlakuan ditentukan dengan menggunakan metode fluoresensi sinar-X, sedangkan unsur-unsur yang lebih ringannya ditentukan berdasarkan interpretasi pola pergeseran spektrum FTIR. Berdasarkan tiga analisis dan karakterisasi, sampel lumpur mengandung unsur utama O, Si, Al, Fe, Cl, Na, S, dan Mg, dan sisanya masing-masing kurang dari 1% adalah K, Ca, Ti, P , Mn, V, Zn, Cr, Br, Rb, Cu, Ni, Ga, Y, dan Sc. Kehadiran unsur C dan N dideteksi secara kualitatif melalui pola spektrum inframerah. Fase yang terdeteksi pada sampel awal terutama meliputi kuarsa, hastingsit, halloisit, dan albit. Dua fase lainnya yang terdeteksi adalah pirit dan sfalerit. Dengan memperhatikan kandungan kimia dan transformasi mineral-mineralnya, lingkungan abiotik hutan mangrove menyimpan banyak informasi kimia yang berharga dalam memahami kemungkinan reaksi-reaksi katalisis di dalamnya sepanjang waktu geologi.

This research was to investigate the content of elements and transformation of the minerals of black mud samples from mangrove forest masrshland, Karangsong, Indramayu Regency, West Java. The dried black mud sample was treated gradually in the temperature ranges of 120 - 1000 °C. The mineral contents and their transformations were then examined by the X-ray powder diffraction method. The content of heavy elements before and after the treatment was determined using the X-ray fluorescence method, while the light elements was determined based on the interpretation of the FTIR spectrum shift patterns. The three analyses and characterizations indicate that the mud samples contained the main elements of O, Si, Al, Fe, Cl, Na, S, and Mg. The remaining of less than 1% contained K, Ca, Ti, P , Mn, V, Zn, Cr, Br, Rb, Cu, Ni, Ga, Y, and Sc. The presence of C and N elements were detected qualitatively through the infrared spectrum patterns. The phases detected in the initial sample mainly include quartz, hastingsite, halloysite, and albite. The other two phases detected were pyrite and sphalerite. Given the elements and transformation of such minerals, the abiotic environment of mangrove forests holds much valuable chemical information in understanding the possibility of catalysis reactions in them over geologic time.