International Journal of Green Energy, 9: 685–701, 2012 Copyright © Taylor & Francis Group, LLC ISSN: 1543-5075 print / 1543-5083 online DOI: 10.1080/15435075.2011.625583 BIODIESEL FROM WASTE COOKING OIL: OPTIMIZATION OF PRODUCTION AND MONITORING OF EXHAUST EMISSION LEVELS FROM ITS COMBUSTION IN A DIESEL ENGINE Muhammad Waseem Mumtaz 1,2 , Ahmad Adnan 1 , Zahid Mahmood 3 , Hamid Mukhtar 4 , Muhammad Faheem Malik 5 , Fahim Ashraf Qureshi 1 , and Ahtisham Raza 1 1 Department of Chemistry, GC University, Lahore, Pakistan 2 Department of Chemistry, University of Gujrat, Gujrat, Pakistan 3 Department of Chemistry and Biochemistry, Agriculture University, Faisalabad, Pakistan 4 Institute of Industrial Biotechnology, GC University, Lahore, Pakistan 5 Department of Environmental Sciences, University of Gujrat, Gujrat, Pakistan Present study describes optimized production of waste cooking oil biodiesel (WCOB) using chemical and enzymatic transesterification. Maximum WCOB yield was 89% for chemical transesterification catalyzed by NaOCH 3 and 95.9% for enzymatic transesterification using NOVOZYME-435. Optimized WCOB yield was procured for chemical transesterification when reactions were performed for 90 min at 45 ◦ C using 0.75% NaOCH 3 and 6:1 methanol to oil molar ratio, whereas, enzymatic transesterification at 32.50 ◦ C for 60 h using 0.75% NOVOZYME-435 and 6:1 methanol : oil molar ratio. When compared the exhaust emis- sion levels from diesel engine exhaust operated on conventional diesel fuel with the waste cooking oil biodiesel blends (WCOB), a notable reduction (%) in CO and PM levels was observed for WCOB5, WCOB20, WCOB40, WCOB50, WCOB80, and WCOB100 whereas in case of NOx emissions reduction (%) was observed only in case of WCOB5, WCOB20, and WCOB40, respectively. Keywords: Waste cooking oil; NaOCH 3 ; NOVOZYME-435; Transesterification; Emissions; Enzymatic INTRODUCTION World today is facing serious concerns regarding the declining nature of petroleum reserves and environmental degradations because of the pollutants and their health con- sequences. Diverse studies have been conducted by various scientists to evaluate the impact of exhaust emissions from diesel-operated engines. Severe health problems and complications have been identified, which are found to be associated with these emis- sions. It has been recognized by International Agency for Research on Cancer that these emissions are possibly carcinogenic both for human beings and animals on long-term expo- sures. Inhalation of soot particles along with adsorption of some organic pollutants (PAH Address correspondence to Muhammad Waseem Mumtaz, M.Phil, Department of Chemistry, University of Gujrat, Gujrat, Pakistan. E-mail: waseem_pk56@yahoo.com 685