Production of activated carbon from coffee grounds using chemical and physical activation method

Air pollution gives impacts to human’s health which is caused by the harmful gas components contained in smokes, such as CO, NO_x, SO_x, and aldehyde. CO, NO_x, SO_x are also abundant in off gas produced by oil refinery units. One of the innovation that could solve the problem is by using activated carbon from coffee grounds residue as an adsorbent. Coffee grounds residue is selected as adsorbent because it contains good lignocellulosic structure and is produced abundantly by the coffee industry; the production rate goes as high as 748,000 tons per year or about 6.6% from the world’s total production. This research aims to make activated carbon from coffee grounds. Coffee grounds residue, typically Robusta coffee grounds, is dried and then carbonized at 300°C for 1 hour to reduce several components, such as steam, volatile compounds, and lignocellulosic so that the carbon content will increase by the end of the process. Then, the product will be activated to improve surface area of the charcoal. The method used to activate coffee residue is by using chemical activation with ZnCl₂ on temperature 100°C, physical activation with CO₂ on temperature 600°C, and also a combination of both. The best yield from those activation methods are resulted by chemical activation 92.97%, then physical activation 82.8%, and combination of both is 79.5%. After activating the carbon, dip coating will be conducted to coat the activated carbon on the surface layer of mask by adding TEOS compound. The characterization involves SEM, EDX, and Iod Number to observe the topography of activated carbon and surface area as result of activation. The best Iod number from those three activation method will be used to coat the mask. The best surface, according to the testing of Iod Number, is produced by chemical activation by 432.60 mg/g equivalent with 405.68 m²/g. In comparison, the Iod number for physical activation and chemical-physical activation are 196.61 mg/g and 259.47 mg/g.