The purpose of this study is to investigate the effectiveness of banana trunk as an adsorbent in removal of heavy metals in aqueous solution. Functional groups of adsorbent were determined using Fourier Transform Infrared spectroscopy (FTIR). Batch experiments were conducted to determine the adsorption percentage of heavy metals (Cu, As, Pb and Zn). The optimum adsorption using banana trunk was based on pH difference, contact time and dosage. Adsorption percentage was found to be proportional to pH, contact time and dosage. Maximum adsorption percentage of Cu, As, Pb and Zn at pH 6, 100 minutes and 8 gram of dosage are 95.80 %, 75.40 %, 99.36 % and 97.24 %, respectively. Langmuir and Freundlich isotherms were used to determine the equilibrium state for heavy metals ion adsorption experiments. All equilibrium heavy metals were well explained by the Freundlich isotherm model with R 2 = 0.9441, R 2 = 0.8671, R 2 = 0.9489 and R 2 = 0.9375 for Cu, As, Pb and Zn respectively. It is concluded that banana trunk has considerable potential for the removal of heavy metals from aqueous solution.Keywords: adsorption, heavy metals, banana trunk, pH, contact time Abstrak Kajian ini bertujuan untuk menyiasat keberkesanan batang pisang sebagai penjerap dalam penyingkiran logam berat di dalam larutan akueus. Kumpulan berfungsi penjerap ditentukan menggunakan Spektrospkopi Infra Merah Transformasi Fourier (FTIR). Eksperimen kelompok dilakukan untuk menentukan peratusan penjerapan logam berat (Cu, As, Pb dan Zn). Penjerapan optimum menggunakan batang pisang berdasarkan pH yang berbeza, masa sentuhan dan dos penjerap dianalisis dalam eksperimen kelompok. Peratus penjerapan didapati berkadar terus dengan pH, masa sentuhan dan dos penjerap. Peratus penjerapan maksimum Cu, As, Pb dan Zn pada pH 6, 10 minit masa sentuhan dan 8 gram dos penjerap masing-masing ialah 95.80 %, 75.40 %, 99.36 % dan 97.24 %. Isoterma Langmuir dan Freundlich telah digunakan untuk menentukan keadaan keseimbangan bagi eksperimen penjerapan logam berat. Semua keseimbangan logam berat dijelaskan dengan baik oleh model isoterma Freundlich dengan R 2 = 0.9441 , R 2 = 0.8671 , R 2 = 0.9489 dan R 2 = 0.9375 masing -masing untuk logam Cu, As, Pb dan Zn. Dapat disimpulkan bahawa batang pisang mempunyai potensi besar untuk penyingkiran logam berat daripada larutan akues.Kata kunci: penjerapan, logam berat, batang pisang, pH, masa sentuhan