Electronic Theses and Dissertation

Merkuri (Hg²⁺) merupakan logam berat yang bersifat toksik dan karsinogenik, serta mampu mencemari lingkungan dan membahayakan kesehatan manusia. Penelitian ini bertujuan mengevaluasi efektivitas arang aktif dari limbah batok kelapa muda yang diaktivasi dengan NaOH sebagai adsorben Hg²⁺ dalam larutan. Arang merupakan produk samping proses pirolisis pada suhu 400°C, kemudian dihaluskan menggunakan grinder dan disaring dengan ayakan 100 mesh, lalu diaktivasi dalam larutan NaOH 0,1 N selama 24 jam. Karakterisasi dilakukan menggunakan Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM), dan X-ray Diffraction (XRD). Spektrum FTIR menunjukkan peningkatan intensitas gugus fungsional –OH, C–H, C=O, C=C, dan C–O. Citra SEM mengungkapkan morfologi berpori dengan ukuran partikel sekitar 1 µm. Pola difraksi XRD menunjukkan puncak lebar pada sudut 2θ antara 15° hingga 20°, yang mengindikasikan struktur karbon amorf dan mendukung kapasitas adsorpsi. Uji adsorpsi dilakukan secara batch dengan variasi pH (1, 3, 5), waktu kontak (30–180 menit), konsentrasi awal Hg²⁺ (0,4–2,1 ppm), dan kecepatan pengadukan (100–200 rpm). Hasil menunjukkan kapasitas adsorpsi maksimum sebesar 0,1994 mg/g dan efisiensi hingga 94,01% pada kondisi optimal. Model isotherm Langmuir memberikan kecocokan terbaik (R² = 0,8074 dan qmax = 0,0318 mg/g), menunjukkan proses adsorpsi monolayer homogen, sementara kinetika adsorpsi mengikuti model orde dua (R² = 1 dan qmax = 0,2013), yang mengindikasikan mekanisme kemisorpsi dominan. Optimasi menggunakan metode Central Composite Design (CCD) melalui perangkat lunak Design-Expert versi 13.0.5 menghasilkan kondisi optimum dengan kapasitas adsorpsi 0,2011 mg/g dan efisiensi 97,90%. Temuan ini menunjukkan bahwa arang aktif nanopartikel dari limbah batok kelapa muda merupakan alternatif yang menjanjikan dan ramah lingkungan untuk pengolahan limbah merkuri.
Kata kunci: ion merkuri, arang aktif, isoterm. kinetika, optimasi

Mercury (Hg II) is a highly carcinogenic and toxic heavy metal that poses significant risks to both human health and the environment. Exposure to mercury can result in severe damage to the nervous system and kidneys, and its release into the environment can lead to the contamination of water, soil, and air. Moreover, mercury can accumulate in the food chain, thereby threatening the sustainability of ecosystems and disrupting ecological balance. As a result, the effective treatment of mercury waste is crucial for safeguarding human health and preserving environmental sustainability. This research aims to address Hg (II) contamination by utilizing activated charcoal adsorbent derived from young coconut shell waste. The primary objective of this study is to evaluate the adsorbent's ability to remove Hg (II) from aqueous solutions, and to investigate the adsorption kinetics, isotherm models, and optimize the adsorption process. The methodology involves the pyrolysis of young coconut shell waste at 400°C, which yields liquid smoke, tar, and charcoal. The resulting charcoal is chemically activated by immersion in a 0.1 N NaOH solution for 24 hours. Both the raw and activated charcoal samples are characterized using Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), and X-ray diffraction (XRD) analysis. The activated carbon is then employed to adsorb Hg (II) in a batch adsorption process, with various parameters including contact times (30, 60, 90, 120, 150, and 180 minutes), initial Hg concentrations (0,4; 0,8; 1,2; 1,7; and 2,12 ppm), stirring speeds (100 and 200 rpm), and pH values (1, 3, and 5) being systematically varied. The concentration of Hg (II) before and after adsorption is measured using an Atomic Absorption Spectrophotometer (AAS). The adsorption isotherms are analyzed using the Langmuir, Freundlich, and Dubinin-Kaganer-Radushkevich (DKR) models, while the adsorption kinetics are evaluated using first-order, second-order, and Elovich kinetic models. Finally, the optimization of Hg (II) adsorption is conducted using Design-Expert software version 13.0.5, applying the Central Composite Design (CCD) method. Keywords: mercury ion, activated carbon, isotherm, kinetic, optimization