Coffee Waste Lab Report

The coffee wastes which are washed under distilled water are spread evenly on a tray which are then placed into an oven at a temperature of 105OC for a total time of 24 hours. The coffee wastes are then crushed by using a home blender. The resulting particles are then sieved and these samples are used for the rest of the experimental work. Based on the literature, the particle sizes of raw materials used in the production of activated carbon from coffee wastes are generally in the range of 0.2-2 mm. Due to the heterogeneous physical structure of the coffee wastes, smaller size particles of coffee wastes are preferred. Hence, in order to obtain uniform size of samples, the grinding of the coffee wastes are needed.

In this experiment, the effect

First, the coffee wastes are placed inside small boats are placed inside a horizontal tube furnace (Carbolite) which has an internal diameter of 27 mm. The temperature of the horizontal tube furnace is heated to a temperature of 600K. A flow of nitrogen which has a flow rate of 50cm3 min-1 is then introduced into the furnace. The purpose of the flow of nitrogen gas is to reduce the amount of volatile matter content of the starting material which is the dried coffee wastes. This is due to the higher rate of removal of gases which is evolved during the carbonization process will consequently favours the development of micropores. This implies that a lower concentration of these gases will eventually synthesize a higher degree of the development of micropores. The samples inside the furnace is then subjected to a continuous nitrogen flow for a total of 30

Next the coffee waste is then covered with a layer of solid KOH. Next, the mixture is then heated at heating rate of 5K min-1 until the temperature reaches 600K. The flow rate of the nitrogen gas is then increased to 300cm3 min-1 which is introduced into the horizontal tube furnace. The temperature of 600K in the tube furnace is then held for a total duration of 1 hour in order to allow the solid KOH to melt, dehydrate and lastly in order to ensure that the coffee waste are mixed intimately with the solid KOH. The carbonization-activation process is completed by heating up the mixture up to a temperature of 600K with a nitrogen flow rate of 300cm3 min-1 and maintaining this temperature for a total duration of one hour. After one hour, the mixture is allowed to be cooled down by introducing a flow of nitrogen gas into the char. The char is then washed thoroughly with distilled water until a neutral pH of the char is achieved. Next, the washed char is then dried at a temperature of 383K for a total duration of 24 hours inside a forced-air convection oven. In this research, one of the parameters which are being investigated is the ratio of the amount of solid KOH to the amount of char being mixed with the solid KOH. In this experiment, the ratio being investigated is 1:1, 1:2 and 1:4. The activation