Optimisation of Copper Oxide Impregnation on Carbonised Oil Palm Empty Fruit Bunch for Nitric Oxide Removal using Response Surface MethodologyNorhidayah Ahmad, Sing Hung Yong, Naimah Ibrahim, Umi Fazara Md Ali, Fahmi Muhammad Ridwan and Razi AhmadE3S Web Conf., 34 (2018) 02029DOI: https://doi.org/10.1051/e3sconf/20183402029