INGENIEUR
Biodiesel is a clean-burning diesel , made from fats or oils , that is simple to make . It is a reasonably simple alternative fuel to make and safe when used responsibly . Biodiesel can be made from vegetable oil or animal fats and can be used in any diesel engine without modification . It is non-toxic and biodegradable , emitting around 60 % less carbon dioxide than petroleum-based diesel since it is made from atmospheric carbon dioxide by plants through photosynthesis . Since some diesel engines can run on biodiesel , it can directly replace petroleum goods as a renewable fuel , reducing the country ' s reliance on imported oil ( Ong et al ., 2011 ).
The transesterification process produces biodiesel — a reaction of triglyceride with alcohol to form ester and glycerol in the presence of a catalyst . The esterification process is suitable for acid-catalysed transesterification and is much faster than acid-catalysed transesterification . However , for lipid feedstock with greater than two per cent free fatty acid , esterification is the first step , followed by transesterification . The esterification process is required to reduce the FFA to below two per cent since biodiesel cannot be produced directly by the alkaline catalyst .
In this research , biodiesel is produced through the reaction of palm oil with methanol in the presence of potassium hydroxide as a catalyst , supported by sea sand to maximise the biodiesel yield .
The main interest in recent studies was investigating the use of a green catalyst for biodiesel production and providing an economical process to produce biodiesel within the international standard . This project focuses on palm oil as a feedstock reacted with potassium hydroxide supported with sea sand as a catalyst for biodiesel production by the transesterification process . It also aims to optimise the ratio of KOH and sea sand to maximise biodiesel yield ( Jin et al ., 2011 ).
Materials and Method
Materials Preparation Sea sand was collected from the beach at Port Dickson , Negeri Sembilan , Malaysia . Potassium hydroxide was purchased from Sigma-Aldrich , Germany . Palm oil or cooking oil was bought at a market in Malaysia .
Catalyst preparation and transesterification process The sea sand was washed and dried in the oven at 110 º C overnight to remove water and moisture . After that , the sea sand underwent a calcination process at 900 º C for three hours . Then the sea sand was impregnated with KOH . The calcined sea sand was kept in a desiccator for further use .
In this process , KOH and calcined sea sand were used as catalyst loading with different ratios . Multiple experiments were performed by varying the KOH ( 1-5wt %) / sea sand ( 1-5wt %) ratio . The reaction was conducted for three hours at 65 ° C , 500 rpm , with a methanol : oil ratio of 15:1 to obtain the optimum biodiesel production . The solution was then transferred to and left overnight in a separating funnel . The upper layer was collected , as the denser glycerin will be at the bottom of the separating funnel . The bottom layer contains glycerin , excess alcohol , catalyst , impurities and traces of unreacted oil and needs to be removed ( de Oliveira et al ., 2022 ; Muciño et al ., 2014a ). The yield of methyl esters was calculated using Equation 1 ( Margaretha et al ., 2012 ).
Design Expert 6.0.8 software was used to perform the experiments . Response Surface Methodology ( RSM ) and the Central Composite Design ( CCD ) were used to find the variables ' interactions and predict the optimum condition for FAME yield conversion . The design used two numeric factors : the amount of sea sand and KOH . Based on the two factorial values by the software , two points ( highest and lowest ) were used for each factor . For this experiment , the total number of runs was 13 , with five centre points face-centred , and one response , biodiesel yield ( wt %), as shown in Table 2 .
The SEM analysis was done using an SEM JEOL JSM-6700F model to determine the catalysts ' morphologies . FTIR was done to study the functional group of catalysts . The green catalyst was examined using an FTIR ( BRUKER , tensor 27 ), ranging from 500 – 5000 cm -1 ( Sanuzi et al ., 2018 ).
54 VOL 91 JULY-SEPTEMBER 2022