sustainability Article Environmental Risk Mitigation by Biodiesel Blending from Eichhornia crassipes: Performance and Emission Assessment Hasanain A. Abdul Wahhab 1 and Hussain H. Al-Kayiem 2, *   Citation: Abdul Wahhab, H.A.; Al-Kayiem, H.H. Environmental Risk Mitigation by Biodiesel Blending from Eichhornia crassipes: Performance and Emission Assessment. Sustainability 2021, 13, 8274. https:// doi.org/10.3390/su13158274 Academic Editors: Lucian-Ionel Cioca and Elena Rada Received: 1 July 2021 Accepted: 21 July 2021 Published: 24 July 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Mechanical Engineering Department, University of Technology, Baghdad 10081, Iraq; 20085@uotechnology.edu.iq 2 Mechanical Engineering Department, Universiti Teknologi PETRONAS, Seri Iskandar 32610, Malaysia * Correspondence: hussain_kayiem@utp.edu.my Abstract: The aggressive growth of Eichhornia crassipes (Water Hyacinth) plants causes severe damage to the irrigation, environment, and waterway systems in Iraq. This study aims to produce, character- ize, and test biofuel extracted from the Eichhornia crassipes plant in Iraq. The extracted biodiesel was mixed at 10%, 20%, and 40% with neat diesel to produce three biodiesel samples. The methodology consists of the physiochemical properties of the samples that were characterized. The performance of the IC engine fueled by neat and biodiesel samples was measured under various operational conditions. The exhaust gases were analyzed to estimate the compounds to assess the environmental impact. The results showed that the density and viscosity of mixtures increase and the calorific value decrease with biodiesel. The engine test showed that the diesel + 10BE, diesel + 20BE, and diesel + 40BE enhanced brake thermal efficiency using 2.6%, 4.2%, and 6.3%, respectively, compared to neat diesel. Exhaust tests show a slight reduction, of 0.85–3.69% and 2.48–6.93%, in CO and HC emission, respectively. NOx is higher by 1.87–7.83% compared with neat diesel. The results revealed that biodiesel blended from Eichhornia crassipes is a viable solution to mitigate the drastic impact on the environment and economy in Iraq. The blended biodiesel has good potential to be mixed with the locally produced diesel from oil refineries. Keywords: biofuel; Eichhornia crassipes; emission of biodiesel; fuel technology; water hyacinth plant; waste to wealth 1. Introduction 1.1. Background and Research Literature Oil and natural gases, which are depleting resources, represent the main economic pillar of Iraq and the main source of energy for power production and transportation. Meanwhile, emissions caused by combustion have considerably increased environmental pollution in the country [1]. In the last few years, scientists in Iraq have directed their interests in discovering alternatives to fossil fuels. One of these alternatives is vegetable oils to produce biofuels as renewable energy, which is environmentally friendly, renewable, and biodegradable [2,3]. Biodiesel is a better lubricant than diesel oil that lengthens engine life. Several vegetable oils, such as castor, sunflower, and palm trees, are available in Iraq. However, all these vegetable oils have high values and important uses other than biodiesel production. A certain raw material must be readily available during selection. Also, it must not be useful for another purpose rather than being used for biodiesel production. Hirkude and Padalkar [4] have reported waste-fried oil methyl ester blend and [5] reported biodiesel production from used cooking oil. Benjumea et al. [6,7] characterized and reported biodiesel blended from palm oil. In contrast, the authors of [8] have reported their experimental result about a diesel engine’s performance and emission assessment fueled with methyl chloroformates of a rubber seed oil. Eichhornia crassipes (E. crassipes), also named Water Hyacinth, has been a source of interest in recent studies to blend and characterize biodiesel. In their review article, the Sustainability 2021, 13, 8274. https://doi.org/10.3390/su13158274 https://www.mdpi.com/journal/sustainability