Tumbuhan kecil air tawar, alga kiambang itik telah digunakan sebagai bahan berasaskan karbon untuk menghasilkan karbon teraktif untuk menyinkirkan pewarna hijau ‘Malachite’ (MG) daripada larutan akueus dan dinilai melalui ujian kumpulan penjerapan. Kiambang itik segar dikeringkan dan dijadikan palet. Palet kiambang kering kemudian dibakar dan diaktifkan melalui langkah pirolisis pada suhu 700ᵒC selama 1 jam. Karbon teraktif kiambang itik dihancurkan dan menyaring ke dalam pelbagai saiz iaitu 63, 75 dan 125 µm. Kajian meliputi daripada aspek kesan kepekatan awal yang pelbagai (100-500 ppm), masa sentuh, saiz AC, suhu larutan (30, 45 dan 60ᵒC) dan pH larutan (2-10). Dari keputusan, saiz AC yang lebih kecil (63µm) mempunyai kapasiti penjerapan yang lebih tinggi berbanding dengan saiz yang lebih besar (75 dan 125 µm). Penjerapan isoterma daripada MG pewarna ke karbon teraktif kiambang itik sesuai dipadankan di dalam isoterma Langmuir dengan kapasiti penjerapan monolayer yang maksimum iaitu sebanyak 476 mg / g. Dari penjerapan kinetik, penjerapan MG pewarna ke karbon teraktif kiambang itik sesuai dipadankan di dalam model Pseudo-tertib pertama. Termodinamik penjerapan dikaji telah dilakukan untuk parameter termodinamik diperolehi ∆Gᵒ, ∆Hᵒ, ∆Sᵒ dan Ea telah ditentukan.
_______________________________________________________________________________________________________
The small fresh water plant, duckweed algae was used as the carbon based material for produced activated carbon to removed Malachite green dye (MG) from aqueous solution was evaluated through batch adsorption test. Fresh duckweed was dried and pallet. The dried pallet duckweed then carbonized and activated through pyrolysis step at temperature 700ᵒC for 1 hour. The duckweed activated carbon was crushed and sieve into various sizes that were 63, 75 and 125 µm. The effect of various initial concentrations (100 to 500 ppm), contact time, size of AC, solution temperature (30, 45 and 60ᵒC) and solution pH (2 to 10) were investigate. From the result, the size of smaller AC size (63µm) has higher adsorption capacity compared to larger sizes (75 and 125 µm). Adsorption isotherm of MG dye onto duckweed activated carbon well fitted to the Langmuir isotherm with the maximum monolayer adsorption capacity that was 476 mg/g. From the adsorption kinetic studied, the adsorption of MG dye onto duckweed activated carbon was well fitted by Pseudo-first-order model. The adsorption thermodynamic studied was be done to obtained thermodynamic parameters ∆Gᵒ, ∆Hᵒ, ∆Sᵒ and Ea were determined.