Kandungan Asam Humat pada Sampel Batubara di Daerah Peranap, Kabupaten Idragiri Hulu, Provinsi Riau
DANDY FAHREZA, Prof. Dr. Ir. Ferian Anggara, S.T., M.Eng., IPM.
2024 | Skripsi | TEKNIK GEOLOGI
Asam humat adalah
senyawa organik yang telah mengalami proses humifikasi dan larut dalam alkali.
Pasar asam humat secara global terus mengalami peningkatan karena ekspansi
pangan organik yang telah berkembang pesat. Asam humat banyak digunakan dalam
bidang pertanian dan hortikultura, kedokteran, kesehatan, pengolahan air
limbah, dan aplikasi lainnya. Batubara merupakan salah satu sumber asam humat
dengan kadar maksimal hingga 90.2%. Asam humat tersebut bisa dihasilkan dengan
serangkaian proses ekstraksi pada batubara. Daerah Peranap merupakan salah satu
daerah penghasil batubara di Indonesia. Namun, batubara Peranap memiliki nilai
kalori yang cenderung rendah dan memiliki keterbatasan dalam pemanfaatannya. Penelitian
ini bertujuan untuk mengetahui dan mempelajari karakteristik batubara serta
hubungannya dengan kandungan asam humat dari sampel batubara daerah Peranap,
Kabupaten Indragiri Hulu, Provinsi Riau. Sampel batubara yang digunakan pada
penelitian ini berupa sampel yang diambil secara in-situ pada singkapan
dan sampel batubara yang diambil secara ex-situ pada stockpile.
Sampel batubara tersebut kemudian dilakukan analisis proksimat dan ultimat,
petrografi organik, proses ekstraksi asam humat, dan analisis FTIR.
Humic acid is an organic
material that has undergone a humification process and is soluble in alkali.
The global humic acid market continues to grow due to the rapid expansion of
organic food. Humic acid is widely used in agriculture, horticulture, medical,
health, wastewater treatment, and other applications. Coal is one of the sources
of humic acid, with a maximum content of up to 90.2%. This humic acid can be
produced through a series of extraction processes from coal. The Peranap area
is one of the coal-producer regions in Indonesia. However, Peranap coal has a
relatively low calorific value and limitations in its utilization. This
research aims to know and study the characteristics of coal and its
relationship with the humic acid content from coal samples in the Peranap area,
Riau Province. The coal samples used in this study were taken in-situ from
outcrops and ex-situ from stockpiles. These coal samples were then subjected to
proximate analysis, organic petrography, humic acid extraction processes, and
FTIR analysis.
The coal in the study
area consists of two lithotypes: dull banded coal and dull non-banded coal,
with ranks ranging from Lignite A to Subbituminuos C. The moisture content
11.84 – 43.39%, ash content 1.13 – 22.53%, volatile matter 22.63 – 42.91%,
fixed carbon 18.11 – 33.25%, calorific value 5364 – 8894 btu/lb, carbon 41.95 –
69.78%, hydrogen 4.21 – 5.88 %, nitrogen 0.57 – 1.32 %, oxygen 14.60 – 29.11%,
and sulfur 0.12 – 0.76%. The maceral content includes vitrinite 58.65 – 71.74 %vol, liptinite 21.10 – 32.41
%vol, inertinite 5.69 – 14.51 %vol, and mineral matter 0.36 – 1.75 %vol. The
preserved maceral content 52.64 – 66.91 %vol, degraded maceral 25.90 – 42.08
%vol, and oxidized maceral 2.94 – 9.02 %vol. The yield of humic acid produced
from the extraction process of Peranap coal samples is 11.35 – 49.88%. This
humic acid contains hydroxyl (OH) functional groups, aliphatic C-H stretching,
C=O stretching, C=C functional groups, and C-O stretching functional groups.
The high humic acid content in coal is influenced by the further degradation of
coal-forming materials, the higher the volatile matter content, fixed carbon
content, hydrogen content, and the lower content of moisture.
Kata Kunci : Asam humat, batubara, Peranap