Discipline: Technology and Engineering
Subcategory: Materials Science
Alayna Huckleby - Tuskegee University
Co-Author(s): Shaik Jeelani and Vijaya Rangari
Agricultural byproducts, such as peanut hulls a bulky waste generated in large amounts about 400,000 tons per year. They are often burned, dumped or left to deteriorate, which can cause tremendous environmental pollution. The objective of this research is to convert peanut hulls into activated carbon by pyrolysis. Activated carbon has become very resourceful for applications such as composite fillers, battery electrodes and the removal of pollutants from waste water. This not only helps solve the disposal problem but also helps reduce shortages in several materials. The application of activated carbon in adsorption process mainly depends on the surface area and pore structure of the porous carbon. The characteristics of peanut hulls that allow it to be suitable for these applications are because of its low ash content, low density and high degree of porosity. There are two different ways to activate carbon; physical activation which is a simple carbonization at high temperatures, or chemical activation which is a carbonization at low temperatures with the presence of a dehydrating agent. In this study the physical activation is carried out on these peanut hulls. The pyrolysis process at high temperature/pressure transformed the peanut hulls to porous carbon. The first sample contained only crushed peanut hulls, while the second sample contained crushed peanut hulls and calcium carbonate (extracted from eggshells) as a catalysts. They both were then carbonized at a high temperature of 800°C at a constant pressure of 1.3 atm for 2 hours. The prepared carbon was characterized using X-ray diffraction (XRD) and Scanning electron microscopy (SEM) analysis. The sample without the catalyst’ XRD showed high crystallization of silica dioxide, carbon and silica carbide. The SEM images show the particles having a non-uniform structure as well as relatively low porosity. The sample with the catalyst’ XRD results showed high crystallization of calcium oxide, carbon and slight traces of silica carbide. Further cleaning needs to take place on the catalyst sample in order to purify it and reduce the amount of calcium oxide left behind after burning it. The SEM images show the particles having a non-uniform structure and a relatively high porosity. The porosity of the catalyst sample is higher than the non-catalyst sample, ultimately showing that the calcium carbonate helped improve the carbonization of the peanut hulls.
Funder Acknowledgement(s): NSF Rise and Crest.
Faculty Advisor: Vijaya Rangari, firstname.lastname@example.org
Role: All of it in conjecture with help and feed back from my mentor.