The Potential of Coffee Husk as an Alternative Material for Pencil Lead

Abstract

INTRODUCTION

The Philippines is facing a conflict of the continuous expansion of mining. Graphite is yielded from mining, and it is used in the production of different materials, such as in lubricants, moderator, electrolytic anodes, and pencil. However, the way it is extracted can be very destructive for our environment. On the other hand, Amadeo is rich in coffee production and produces a thousand tons of wasted coffee husk. The researchers found a way to lessen and utilize this waste where coffee husk was used as an alternative for graphite as the writing core of the pencil to prevent the expansion of mining and lessen its negative effects on the environment.

METHODS

The experimental method of research was used in this study. Coffee husk was carbonized and pulverized by applying heat and using mortar and pestle. Kaolin and bentonite clay were mixed together with carbonized coffee husk, 0.5mL epoxy, and 2mL water at different proportion -70parts of clay with 30 parts of the carbonized coffee husk, 50 parts of clay with 50 parts of the carbonized coffee husk, and 30 parts of clay with 70 parts of carbonized coffee husk. This was molded, dried, soaked with oil, and dried again for 3 days. The hardness of the pencil lead was obtained from ASTEC Material Testing Corporation through a compression test, while the survey was provided to determine its writing quality.

RESULTS

The compression test revealed that the 70 parts of clay with 30 parts of carbonized coffee husk have the hardest compressive strength. The p-value of 0.013256 is less than 0.05 and the ratio of F value of 9.676056 and F critical value of 5.143253 is greater than 1, which implies that null hypotheses are rejected. Based on the survey, 60% of the respondents agreed that pencil lead with 30 parts of clay with 70 parts of carbonized coffee husk has the best writing core among the three different proportion.

DISCUSSIONS

Coffee husk can be carbonized and can produce pencil lead with the hardness that is directly proportional to the amount of clay that it has. However, its writing quality is directly proportional to the amount of carbonized coffee husk. ANOVA shows that there is a significant difference between the different proportions of the pencil lead. The study proves that, according to M.C. Sousa and J.W. Buchanan (2000), the lead is harder as long as it has more clay. Thus, the study can be concluded that carbonized coffee husk has the potential to be an alternative material for pencil lead.