A comparative study of chemical and microwave synthesized activated carbornom corn cob

Project Abstract

This research project aims to conduct a comparative study between chemically and microwave synthesized activated carbon from corn cob. Activated carbon is a widely used material in various industries due to its high surface area and adsorption capabilities. Corn cob, an agricultural waste product, is a potential low-cost precursor for the synthesis of activated carbon. The two methods of synthesis, chemical activation with phosphoric acid and microwave activation, will be compared in terms of their efficiency, yield, and properties of the resulting activated carbon. The chemical activation process involves impregnating the corn cob with phosphoric acid followed by carbonization at high temperatures. This method is known for producing activated carbon with high porosity and surface area. On the other hand, the microwave activation method utilizes microwave radiation to heat the precursor material rapidly, resulting in shorter activation times and potentially different properties of the activated carbon. Various characterization techniques will be employed to compare the two types of activated carbon. This includes surface area analysis using Brunauer-Emmett-Teller (BET) method, pore size distribution analysis, scanning electron microscopy (SEM) for morphological studies, and Fourier-transform infrared spectroscopy (FTIR) for functional group analysis. The adsorption capacity of the activated carbons will be evaluated using methylene blue dye adsorption tests. The study aims to determine which method of synthesis yields activated carbon with superior properties for adsorption applications. Factors such as surface area, pore size distribution, and adsorption capacity will be compared between the chemically and microwave synthesized activated carbon. The cost-effectiveness and scalability of the synthesis methods will also be taken into consideration. The results of this comparative study will provide valuable insights into the optimization of activated carbon synthesis from corn cob. By understanding the advantages and limitations of each synthesis method, industries can make informed decisions on the selection of appropriate activated carbon for their specific applications. Additionally, the utilization of agricultural waste such as corn cob for activated carbon production contributes to sustainable waste management practices and reduces the environmental impact of industrial processes.

Project Overview

<p> </p><div><p><strong>INTRODUCTION</strong></p><p><strong>1.1 BACKGROUND OF STUDY</strong></p><p>Activated carbon, also widely known as activated charcoal or activated coal is a form of carbon which has been processed to make it extremely porous and thus to have a very large surface area available for adsorption or chemical reactions (Mattson <em>et al., </em>1971). The word active is sometimes used in place of activated. It is characterized by high degree of micro porosity. A gram of activated carbon can have a surface area in excess of 500 m2. Sufficient activation for useful applications may come solely from the high surface area, though further chemical treatment generally enhances the adsorbing properties of the material. Activated carbon is most commonly derived from charcoal.</p><p>Waste biomass is getting increasing attention all over the world for activated carbon development as it is renewable, widely available, cheap and environmentally friendly resource. The common method of development is thermochemical (<em>Kumar et al., </em>2005). The main concern is the removal of chemical component by adsorption from the liquid or gas phase (Bansal<em>&nbsp;et al., </em>1988). Today, activated carbon has been produced from various biomass such as corncob, rice husk, cherry stones, coconut shells, palm shells, to mention but a few.</p><p>Preparation of activated carbon with ultra-high specific surface area from biomass such as lignin, corncob, cornstalk, dates, etc., has attracted much attention. Among these carbon sources, corncob is a good precursor for preparing carbon with ultrahigh specific surface area (Li, 2007). The carbons prepared from corncob have been used in wastewater treatment such as removal of organic pollutants (Sun<em>&nbsp;et al., </em>2006).</p><p>However, a comprehensive study of activating corncob with different activation strategies to prepare carbon with ultra-high specific surface area and pore volumes, and their subsequent performance in water purification as the impurity adsorption has not to our knowledge been reported. Therefore, in this study we report the synthesis of ultra-high surface area carbon materials using two preparation strategies namely, chemical activation procedure using a chemical activator such as ammonium sulphate ((NH4)2SO4) and microwave-synthesized activation procedure. We also report the adsorption capacity of those carbons for water purification.</p><p>To prepare activated carbon, conventional heating method is usually adopted, in which the heat is produced by electrical furnace. However, in some cases, the thermal process may take several hours, even up to a week to reach the desired level of activation (Yuen<em>&nbsp;et al., </em>2009). Another problem related to the furnace is that the surface heating does not ensure a uniform temperature for different shapes and sizes of samples. This generates a thermal gradient from the hot surface to the kernel of the sample particle, blocks the effective diffusions of gaseous products to its surroundings and finally results in activated carbon quality decrease (Peng<em>&nbsp;et al., </em>2008). Furthermore, there is a considerable risk of overheating or even thermal runaway (exothermic process) of portion of sample, leading to the complete combustion of the carbon (Williams<em>&nbsp;et al., </em>2008).</p><p>Recently, microwave has been widely used in preparation and regeneration of activated carbon. The main difference between microwave devices and</p><p>conventional heating systems is heating pattern. In microwave device, the energy is directly supplied to the carbon bed. The conversion of microwave energy is not by conduction or convection as in conventional heating, but by dipole rotation and ionic conduction inside the particles (Jones, 2002). Therefore, the treatment time can be significantly reduced through microwave heating.</p><p><strong>1.2 STATEMENT OF PROBLEM</strong></p><p>In recent years, increasing awareness of environmental impact of organic and inorganic compounds has prompted the purification of waste water prior to discharge into natural waters. A number of conventional treatment technologies have been considered for treatment of waste water contaminated with organic substance. Among them, the adsorption process has been found to be the most effective method while activated carbon is regarded as the most effective material for controlling this organic load. Common active carbons available are usually developed by thermochemical means using activating agents and heating ovens, thus producing activated carbons which take a longer time with limited pore structures. With the advent of microwave technology, a better and efficient activated carbon can be produced within a short period and a cheaper cost.</p><p><strong>1.3 OBJECTIVE OF THE RESEARCH</strong></p><p>The aim of this research project is to determine and compare the performance of chemically and microwave synthesized activated carbon from corn cob.</p><p><strong>1.4 SIGNIFICANCE OF THE RESEARCH</strong></p><p>When this research project is successfully completed, it will provide the following benefits:</p><ul><li>Corn cobs are abundant in Nigeria.</li><li>Encourage the establishment of industries that will use Agricultural waste materials to produce activated carbon.</li><li>It will create job opportunities, thereby reducing unemployment in the country.</li><li>It will attract foreign exchange for Nigeria as activated carbon has very wide industrial applications.</li></ul><p><strong>1.5 SCOPE OF RESEARCH</strong></p><p>This research work focuses on the following:</p><ol><li>Preparation of activated carbon from corn cob by thermal and microwave means</li><li>Comparative study of the adsorption capacities of chemically and microwave synthesized activated carbon.</li></ol></div><h3></h3><br> <br><p></p>