The effect of chemical activators on the properties of activated carbon from sago waste was conducted in this study by using ZnCl2, H3PO4, KOH, and KMnO4 chemical solutions. The carbonized sago waste was added to each chemical solution, boiled at 85 °C for 4 h, and heated at 600 °C for 3 h. The porosity, microstructural, proximate, and surface chemistry analyses were carried out using nitrogen adsorption with employing the Brunauer Emmett Teller (BET) method and the Barret-Joyner-Halenda (BJH) calculation, scanning electron microscopy by using energy dispersive spectroscopy, X-ray diffractometer, simultaneous thermogravimetric analysis system, and the Fourier-transform infrared spectroscopy. The results showed that the activated carbon prepared using ZnCl2 acid had the highest specific surface area of 546.61 m2/g, while the KOH activating agent surpassed other chemicals in terms of a refined structure and morphology, with the lowest ash content of 10.90%. The surface chemistry study revealed that ZnCl2 and KOH activated carbon showed phenol and carboxylate groups. Hence, ZnCl2 acid was suggested as activating agents for micropore carbon, while KOH was favorable to producing a mesopore-activated carbon from sago waste.

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There is a significant interest in employing solid acid catalysts for pre-treatment of biomasses for subsequent hydrolysis into sugars, because solid acid catalysts facilitate reusability, high activity, and easier separation. Hence the present research investigated pretreatment of four lignocellulosic biomasses, namely Switchgrass (Panicum virgatum L 'Alamo'), Gamagrass (Tripsacum dactyloides), Miscanthus (Miscanthus × giganteus) and Triticale hay (Triticale hexaploide Lart.) at 90°C for 2 h using three carbon-supported sulfonic acid catalysts. The catalysts were synthesized via impregnating p-Toluenesulfonic acid on carbon (regular) and further impregnated with iron nitrate via two methods to obtain magnetic A and magnetic B catalysts. When tested as pre-treatment agents, a maximum total lignin reduction of 17.73±0.63% was observed for Triticale hay treated with magnetic A catalyst. Furthermore, maximum glucose yield after enzymatic hydrolysis was observed to be 203.47±5.09 mg g -1 (conversion of 65.07±1.63%) from Switchgrass treated with magnetic A catalyst. When reusability of magnetised catalysts were tested, it was observed that magnetic A catalyst was consistent for Gamagrass, Miscanthus × Giganteus and Triticale hay, while magnetic B catalyst was found to maintain consistent yield for switchgrass feedstock. Our results suggested that magnetised solid acid catalyst could pre-treat various biomass stocks and also can potentially reduce the use of harsh chemicals and make bioenergy processes environment friendly.

In this chance, I also like to thank my former teacher Prof Yohanes Surya and Dr. Topo Suprihadi whom have encouraged me to pursue my study in the US and have taught me a good foundation to be an educator in the future. I would also like to thank Fulbright for the scholarship and all the hard work from IIE that helped me to adjust in the US and always help me with any administration issues. I would also like to thank AMINEF in Indonesia for all the help and guidance since the beginning. I would also like to thank Papuan Government and Surya Institute for partial funding. I would also like to thank a very wonderful friend of mine Korinus Waimbo in United Kingdom, for all the prayer, love and support along the way. I would also like to take this opportunity to thank some people that we have talked and shared frequently thought internet, my beloved sister April in Japan, my lovely friend Anike in France, my lovely friends Zakaria in Netherland, Yosef in Australia and George in Papua, thank you so much for all your caring, love and prayer. Last but not least, I would also like to acknowledge friends v from The Pioneers of Papua community, thank you for the visions we have shared and learned together. vi

Activated carbon is a powerful adsorption material which mainly used as pollutants adsorption. The adsorption properties own derived from the main functional groups or chemical atoms derived from the activation processes. In this study, the activated carbon was prepared from waste sago and activated using two different chemicals activation agents called phosphoric acid and potassium hydroxide. The aim of this study was to identify the surface functional group on waste sago activated carbon produced. The results showed that activated carbon with phosphoric acid activator contained OH, C=C, CO and CH functional groups, while activated carbon with potassium hydroxide activator contained O-H, C≡C, C=C, C-O and C-H functional groups. These results lead to support the recommendations for the development of the application of waste sago activated carbon made as adsorbents in the purification of lead (II) and cadmium (II) wastewater.

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