Decontamination of Toxic Volatile Organic Compounds in Charcoal Processed from &amp;lt;i&amp;gt;Erythrophleum guineense&amp;lt;/i&amp;gt; (Sassy Wood)

John Stephen Gushit,Ester Habila

doi:10.11648/j.jcebe.20200402.15

Abstract

The work aimed at decontaminating potentially toxic compounds found in the charcoal sample, started with collecting the sample of charcoal processed from Erythrophleum guineense (Sassy wood) established in an earlier work to be emitting toxic compounds. The sample was subjected to combustion in a chamber and the volatiles organic compounds (VOCs), formaldehyde (HCHO) and other air quality parameters detected from the hot smoke emitted using the Air Pollutant Detector (Air Master). The VOCs and HCHO average concentration of 2.98mg/m3 and 1.27mg/m3 respectively were detected in the sample, giving indication of extremely high concentration beyond standard permissible limits. The decontaminants which includes; CaO, NaCl, KOH, NaCl/CaO (1:1) and Al2O3 were prepared by dissolving pulverized portion of each in a small amount of distilled water and diluted with purified dual-purpose kerosene (DPK), after which each solution was uniformly sprayed on the pre-weighed charcoal in the combustion chamber. On applying the prepared decontaminants: CaO, NaCl, KOH, NaCl/CaO and Al2O3 on the charcoal, the VOCs concentration of 0.32mg/m3, 0.60mg/m3, 0.61 mg/m3, 1.11 mg/m3 and 2.88mg/m3 respectively were detected, which showed significant reduction in the concentration of the VOCs emitted that is far below the WHO limits for short term exposure of 0.1 mg/ m3, indicating that using the decontaminants is required if such charcoals must continue to be used. The VOCs were characterized in all the samples after they were adsorbed, desorbed, extracted, purified, concentrated and finally detected using the Gas chromatography Mass Spectrometry (GC-MS). The VOCs detected are; Octadecanoic, n-hexadecenoic acid, levomenthol acid and cyclobutanol acid widely reported to be toxic. Therefore, the work recommends that charcoal fires should not be ignited and used in enclosures, and appropriate Government regulatory agencies should create awareness on the need to avoid the use of Erythrophleum guineense (sassy wood) charcoal. If it must be used, decontaminant like CaO prepared from this work should be used since it is a cheap and accessible waste material found in auto mechanic garages indiscriminately discarded by gas welders.

Highlights

Charcoal is the dark-grey residue consisting of carbon and any remaining of heating wood and other substances in the absences of oxygen, often obtained from plant-based materials through the process of pyrolysis [1]
This study reveals that Erythrophleum guineense (Sassy wood) locally known as ‘gwaska’ is used for medicinal purposes
Because the local charcoal making is a stable means of livelihood for the communities where this is used, they produce the charcoal from this plant and sell it to the city dwellers who know nothing about the sources of the charcoal

Summary

Introduction

Charcoal is the dark-grey residue consisting of carbon and any remaining of heating wood and other substances in the absences of oxygen, often obtained from plant-based materials through the process of pyrolysis [1]. It is an excellent domestic fuel and can be made from virtually any organic material like wood, coconut shells, rice husks and bones. Charcoal though an old source of energy is still being used for cooking both in rural and urban centers. The lack of readily available, John Stephen Gushit and Ester Habila: Decontamination of Toxic Volatile Organic Compounds in Charcoal

Objectives

Methods

Results

Conclusion