Print ISSN 2777-0168| Online ISSN 2777-0141| DOI prefix: 10.53893 https://journal.gpp.or.id/index.php/ijrvocas/index
50
The Utilization of Green Algae into Bioethanol Fuel with Hydrolysis Reaction of Sulfuric Acid
Hilwatullisan
1, *, Ibnu Hajar
2, Zurohaina
3Chemical Engineering Department, State Polytechnic of Sriwijaya, Jl. Srijaya Negara Bukit Besar 30139 South Sumatera, Indonesia.
Email address:
hilwalisan@yahoo.com (Hilwatullisan)
*Corresponding author
To cite this article:
Hilwatullisan, Ibnu Hajar, & Zurohaina. (2022). The Utilization of Green Algae into Bioethanol Fuel with Hydrolysis Reaction of Sulfuric Acid. International Journal of Research in Vocational Studies (IJRVOCAS), 2(1), 50–56. https://doi.org/10.53893/ijrvocas.v2i1.99 Received: January 22, 2022; Accepted: April 04, 2022; Published: April 30, 2022
Abstract:
The increase in population has increased the need for fuel oil and gas, our fossil energy reserve is increasingly decreasing, while its needs continue to increase. This fact opens up a chance to use renewable energy and reduce the use of fossil fuels. In addition to the depletion of the number of fossil fuels, other important reasons for reducing its use are environmental damage issues, ongoing prices, and greater subsidization burden. To overcome the situation, can be pursued in two ways. First reducing the level of consumption and both continue to develop other alternative energy sources, especially renewable energy sources. Lately emerged various findings. Ranging from cassava, sweet potatoes, to corn that is processed into bioethanol. But on its way, the development of the fuel is often burp. The clash with food needs is one of the challenges. While the crop fails and the land needed to be another problem that cannot be underestimated, especially amid the issue of global warming. BioEthanol itself is processed from carbohydrates or starch contained in natural materials. During this time bioethanol is produced by many food crops such as corn, cassava, and sweet potatoes. In fact, these materials are still needed as a support for foodstuffs. Through this study, the author lifted the green algae (Cladophora sp) as one of the alternative solutions in the production of bioethanol which can someday become an alternative fuel. This is because green algae (Cladophora sp) are scattered everywhere and the Carbohydrates content is quite high i.e. 52.54-60.98% (Khuantrairong et al., 2011). In this research researchers utilize the green algae to produce alternative fuels by looking at how the H2SO4 solvent concentration affects the resulting product.Keywords:
green algae, bioethanol, H2SO4, alternative energy1. Research Background
The increase in population has increased the need for transportation facilities and industrial activities resulting in increased needs and consumption of fuel oil (BBM). In addition, vehicles operating in Indonesia are mostly fueled by gasoline and diesel derived from fossil energy.
National fuel consumption has increased from year to year [1].
Our fossil energy reserves are decreasing, while the need continues to increase. This fact opens up opportunities for the use of renewable energy and reduces the use of fossil fuels. In addition to dwindling fossil fuel reserves, other
important reasons to reduce their use are environmental damage, soaring prices, and a growing burden of subsidies.
To overcome the situation, it can be achieved in two ways.
First it reduces its consumption rate and secondly continues to develop other alternative energy sources, especially renewable energy sources. Recently, there have been various findings. Starting from cassava, sweet potatoes, to corn that is processed into bioethanol. But on the way, the development of the fuel transfer often faltered.
Conflict with food needs is one of the challenges. While crop failure and needed land becomes another problem that
51 cannot be underestimated, especially in the midst of the issue of global warming.
Bioethanol itself is processed from carbohydrates or starches contained in natural materials. During this time bioethanol is produced from many food crops such as corn, cassava, and sweet potatoes. In fact, these ingredients are still needed as food support. Through this study, researchers raised Green Algae (Cladophora sp) as one of the alternative solutions in the production of bioethanol which could one day become an alternative fuel. This is because Green Algae (Cladophora sp) is spread everywhere and the carbohydrate content is quite high which is 52.54-60.98% [1].
2. Literature Review
2.1. Green Algae
First Green algae or green algae are a group of lorophilic plants consisting of one or many cells, colony-shaped and is the largest number of algae phyla in fresh water. In algae contain organic materials such as polysaccharides, hormones, vitamins, minerals, and bioactive compounds. These green algae have a cell wall in the form of cellulose and has pigments in the form of chlorophyll a and b, carotene, and xantofil.
Chlorophyll a has the most amount that causes the green color in this alga.
Figure 1. Green algae (Cladophora sp) Source: www.algaebase.org
So far the use of algae or algae as a trade commodity and industrial raw materials is still relatively small when compared to the diversity of algae species in Indonesia. Though the chemical components contained in algae are very beneficial for the raw materials of the biomass industry, food, cosmetics, pharmaceuticals and others.
Factors That Affect Green Algae Growth
The growth of green algae can be affected by external factors such as environmental factors. Environmental factors that affect the growth rate of algae include temperature, light, pH, and concentration of essential elements or nutrients used for photosynthesis.[2]
a. Temperature
Temperature is also very instrumental in controlling the condition of aquatic ecosystems. Aquatic organisms have a certain temperature range that is preferred for their growth.
Green algae will grow well in the 200C-300oC temperature range. The temperature scale for cladophora algae growth is between 150C-250oC [3].
b. Light
Light greatly influences the behavior of aquatic organisms.
Chlorophyll pigments absorb blue and red light, carotene absorbs blue and green light, ficoeritrin absorbs green, and ficosianin absorbs yellow light. According to Wells et al. In light waters have two main functions, namely heating water so that there is a change in temperature and density (density) and further cause the mixing of water mass and chemistry and is an energy source for the process of photosynthesis of algae and aquatic plants. Some filaments of algae begin to grow less than a meter by penetration of light reaching the bottom of the pond [4].
c. pH
pH also affects the toxicity of a chemical compound.
Ionized ammonium compounds are found in waters that have a low pH. Ammonium is non-toxic. However, in an alkaline atmosphere (high pH) more ammonia is found that is not ionized and toxic. At a pH of less than 4, most aquatic plants die because they cannot tolerate low pH.[5]
d. Nutrients
Nutrient supply comes from the decomposition of organic matter and the regeneration of nutrients, and by vertical stirring of water that allows nutrient preparations stored in the water layer below to be utilized in the surface water layer. [6]
state that the rate of green algae population in the waters is limited by phosphate concentrations. Nitrogen and phosphorus will fuse in the structure of algae cells with an N:P ratio of 16:1.
2.2. Bioethanol
Bioethanol is ethanol made from the fermentation of biological sources such as starch, sugar and cellulose plants using the help of microorganisms. Ethanol or ethyl alcohol marketed as alcohol is an organic compound with the chemical formula C2H5OH.
Bioethanol is one type of alternative fuel that will be prospective in the future. As an alternative fuel, for example bioethanol can be used for gasoline mixtures (gasolin) and then referred to as gasohol E-10, meaning that in each unit of fuel volume used the premium content is 90% and bioethanol 10%.
The use of ethanol as a fuel has several advantages over fuel, namely: a) high oxygen content (35%) so that if burned very clean, b) environmentally friendly because carbon-mono- oxide gas emissions are 19-25% lower than fuel so it does not contribute to the accumulation of carbon dioxide in the atmosphere and is renewable.[7]
Bioethanol can be made in several ways:
1. Ethanol for general consumption is produced by fermentation or distribution of foodstuffs containing starch or carbohydrates such as rice and tubers. The alcohol produced is usually low-grade. To obtain alcohol with higher levels, a refining process is required through distillation or distillation.
2. Through chemical synthesis through the reaction of ethylene gas and water vapor with acid as a catalyst.
2.3. Hydrolysis
The hydrolysis includes the process of breaking down polysaccharides in lignisleulose biomass, i.e. cellulose and hemiscellulose into their constituent sugar monomers. Perfect hydrolysis of cellulose produces glucose, while hemiscellulose produces several pentose sugar monomers (C5) and Hexose (C6). Hydrolysis can be done chemically (acidic) or enzymatic [8].
Hydrolysis can be done chemically using dilute acids or concentrated acids. The use of dilute acids in the hydrolysis process is carried out at high temperatures and pressures with a short reaction time (a few minutes). The required temperature is 200 °C. The dilute acid used is 0.2-4% by weight [9].
The use of dilute acid benefits from hydrolyzing ordinary cellulose capable of achieving reaction conversion of up to 50%. This low conversion is caused by the degradation of hydrolysis sugars formed due to the high temperature of the reaction used. Degradation of sugar not only decreases the conversion of the reaction but can also poison microorganisms during the fermentation reaction [10].
The use of concentrated acids in the process of cellulose hydrolysis is carried out at lower temperatures than diluted acids. The commonly used source of acid is sulfuric acid. The reaction temperature is 100°C and requires a reaction time of between 1- and 2-hours Lower temperatures minimize sugar degradation.
2.4. Starter
The starters are seeds of microorganisms. Starters to make bioethanol usually use pure breeds of sacharomyces cerevisiae, in addition, yeast can also be used. The yeast used in the manufacture of bioethanol from green algae is bread yeast.
Sacharomyces cerevisiae is the most widely used microorganism in alcohol-making fermentation because it rapidly breeds, is resistant to high levels of alcohol, resistant to high temperatures, has stable properties and adapts easily to fermentation media [11].
According to this starter is made by adding microbes that have been left in the breeding medium into the fermentation media. Starters added to substrates or fermentation media account for as much as 10% of the substrate volume. The more starters added the better because this will shorten the adaptation phase.
Complex media in general for starter and fermentation
0.02%, KNO3 0.02%. The purpose of breeding yeast in starters is to adapt cells in a fermentation medium. With the adaptation of the starter is expected as the initial stage of fermentation [12].
2.5. Fermentation
The fermentation comes from the word fervere which means boiling. As technology evolves, the definition of fermentation extends to all processes involving microorganisms to produce a primary product and a secondary product in a controlled environment.
At first the term fermentation was used to denote the process of converting glucose to ethanol that takes place anaerobically.
But then the term fementation developed again into a whole overhaul of organic compounds carried out microrgansm involving the enzymes it produces. In other words, fermentation is a change in the chemical structure of organic materials by utilizing biological agents especially enzymes as biocatalysts [13].
Yeast is known as an ingredient commonly used in fermentation to produce ethanol in beer, wine and other alcoholic beverages. Yeasts that are often used in the ethanol fermentation industry are Saccharomyces cerevisiae, Saccharomyces can grow well in aerobic and anaerobic conditions. But in anaerobic conditions, yeast will ferment the subtrate into sugar very quickly and will soon be converted to ethanol. As we already know that it turns out that in the air there are still many bacterial spores and living microorganisms.
In order not to interfere with the main fermentation, all spores and microorganisms in the air must be removed first. Removal of microorgansime is done by sterilization [14].
The fermentation process is divided into two types, namely aerobic and anaerobic fermentation. Aerobic fermentation will produce lactic acid, while anaerobic fermentation will produce alcohol. In fermentation the manufacture of bioethanol is used yeast to remodel glucose into bioethanol. The thing to note in this fermentation process is to prepare a container that does not have access to air to go in and out so that the fermentation process of bioethanol manufacturing can run well [15].
Alcohol produced from the fermentation process usually still contains gases such as CO2 produced from converting glucose into bioethanol and aldehydes compounds that need to be cleaned. CO2 gas in the fermentation usually reaches 35%
of the volume, so to obtain good quality bioethanol, the bioethanol must be cleaned from the gas. The process of cleaning (washing) CO2 is done by filtering bioethanol bound by CO2, so that clean bioethanol can be obtained from CO2 gas [16].
2.6. Distillation
In the manufacture of ethanol, distillation is the final stage of the process. This is done to increase the concentration of
53 chemical components based on differences in boiling points.
In this study, simple distillation was used.
Heating the solution at a range temperature between 78- 90oC at a pressure of 1 atm will result in some bioethanol or ethanol evaporating because the boiling point of ethanol is 78oC while the boiling point of water is 100oC.
Distillation can be done in two ways:
1. The formation of steam by boiling the solution to be separated where the steam is then rung without being returned to the distillation column.
2. Steam formation by boiling the solution to be separated where then the steam is rung and partially returned into the column so that there is contact between the steam that rises upwards with the returned dew.
Distillation is generally done continuously or continuously, at normal pressure or vacuum. In atmospheric distillation the most commonly performed is non-continuous operation. In this case the mixture to be separated is put into a vaporizing device (pumpkin) and boiled. Boiling continues to be carried out until a certain number of volatile components are separated.
During boiling, the fraction of volatile components in the liquid increases in magnitude, so the composition of the resulting destilat also continues to change.
3. Material and Methods
3.1. Research Objectives
The objectives of this study are:
1. Get bioethanol as an alternative fuel from Green Algae
2. Obtain data on how H2SO4 concentrates as a solvent 3. Reduce the number of green algae in the lake in the
Jakabaring area.
3.2. Benefits of Research
1. Besides being useful in terms of the development of science and technology, it also contributes as follows:
2. Utilize green algae (cladophora sp) as an alternative fuel for bioethanol.
3. Develop science and technology regarding the process of making bioethanol fuel from green algae (cladophora sp).
4. As a reference for further research.
3.3. Research Variables
The fixed variable in this study is the number of green algae while the variable change is the solvent H2SO4 in the hydrolysis process and the amount of yeast in the process of making the stater.
3.4. Research Design
This research seeks to obtain the most optimal bioethanol.In
this case, this type of research is an experimental study that is to find out the effect of the consequences caused by a treatment given intentionally by researchers. Starting with the preparation and pretreatment of raw materials then continued the manufacture of bioethanol with several variables changed, namely H2SO4 in the hydrolysis process and the amount of yeast at the time of the starter in the fermentation process is then methylated and last analyzed.
3.5. Research Stage
The stages of this research are:
1. The preparation stage, which is the piping stage of tools and raw materials and sterilization of equipment and materials.
2. Pretreatment stage.
3. Stage of implementation of hydrolysis.
4. Starter manufacturing stage.
5. Fermentation stage.
6. Distillation stage.
7. The analysis stage of bioethanol products is to measure bioethanol levels using gas chromatography, refractive index, pH, and type weight.
Pretreatment Process
1. Soaking Green Algae with Lime Water for 1 Hour.
2. After that separates Green Algae with Lime Water for the drying process in direct sunlight for 6 hours.
3. Drying again with the oven at 80oC, this process is carried out for 1 hour and then the hydrolysis process will be carried out.
Hydrolysis Process
1. Weighing Green Algae which each weigh 100 gr.
2. Prepare a solution of H2SO4 as much as 500 ml with a concentration of sulfuric acid each (0.1 M, 0.15 M, 0.2 M, 0.25 M, 0.3 M, 0.35 M) in a 1000 ml chemical glass. Then this sulfuric acid solution is heated on a hot plate.
3. Green algae are put in a chemical glass containing sulfuric acid while stirring for 1 hour. The temperature is maintained at 80oC.
4. Cool the mixture to room temperature and then filter it until a filtrate is obtained in the form of a glucose solution.
Starter Creation
1. Dissolve 50 grams of granulated sugar into water as much as 500 ml and filtered.
2. Pump the solution at 80oC for 15 minutes, then refrigerate to room temperature.
3. Add 5 grams of fermipan bread yeast, 0.6 grams urea, KNO3 0.05 grams, and Na3PO4 0.05 grams to the solution and stirring until even.
4. Move the seed solution (starter) into erlenmeyer 3000 ml which is tightly closed using a cork that will be used as a connecting medium with Erlenmeyer 250 ml containing H2SO4 solution.
5. Incubate the starter solution for 3 days at room temperature.
4. Result and Discussions
4.1. Results
Research on the use of green algae into bioethanol fuel is done by hydrolyzing green algae with a mass of raw materials of 100 grams each using an H2SO4 solution of 500 ml at a temperature of 80oC. The variations used are variations in H2SO4 concentrations (0.1 M, 0.15 M, 0.2 M, 0.25 M, 0.3 M, 0.35 M). After that the solution of glucose resulting from the hydrolyst process is fermented for 7 days at a temperature of 28-32oC and pH 4-5. The fermentation results are further distilled at a temperature of 78oC. The analysis is the determination of refractive index, determination of bioethanol levels in distillates using chromatography gas, determination of acidity (pH), determination of type weight and burn test.
Table 1. Data from Bioethanol Manufacturing Analysis from Green Algae
4.2 Discussion
4.2.1 Effect of the addition of H2SO4 solution concentrations to ethanol levels
Figure 1. Effect of increasing the concentration of H2SO4 solution on ethanol levels
In this study, the addition of H2SO4 concentrations was carried out at the hydrolysis stage, where the concentration of H2SO4 solutions was 0.1 M, 0.15 M, 0.2 M, 0.25 M, and 0.35 M, respectively. H2SO4 serves as a catalyst in the hydrolysis process that serves to break the polymer chains of green algae so as to produce glucose monomers used as raw materials for making biethanol.
Heating at 80oC, will increase the amount of cellulose in hydrolyzed algae, H2SO4 will dissociate to form H+ and SO42- ions. This H+ ion from H2SO4 breaks the cellulose polymer chain so that it forms free radicals and will react with OH- ions derived from water to form glucose monomers.
Determination of ethanol levels is done using a chromatography gas tool. It is seen from figure 1 that the greater the concentration of H2SO4, the greater the amount of ethanol levels. This happens because the increase in H2SO4
concentration increases the glucose content in the hydrolysis solution so that with the increased glucose content, the resulting ethanol levels increase, but the level of H+ ions also has a maximum limit in hydrolysis. Because if the H+ ion has exceeded the maximum limit, there is a decrease in the hydrolysis of cellulose caused by high levels of acid in the mixture so that there is no good pH in the hydrolysis process.
In addition, the decrease is likely caused by the different amount of fluid evaporated during the heating process in hydrolysis resulting in the concentration of H+ ions decreased,
20.71 31.34
47.1 56.08
49.17 47.66
0 10 20 30 40 50 60
0 0.1 0.2 0.3 0.4
Bioethanol levels (%)
Sulfuric Acid Concentration (M)
Conc entra tion Solut ion Hydr olysis H2SO
4
(M)
Mass Bake
r's Yeast
(gr)
Volu me Bioe than
ol (ml)
Index Bias
Densi ty (gr/
ml)
Burn Test
Bioet hanol Level
s at GC (%)
0.1 5 29 1.3356 0.882 Can’t
Burn 20.71 0.15 5 31 1.33968 0.877 Burn 31.34
0.2 5 28 1.34568 0.862 Burn 47.10 0.25 5 26 1.34868 0.852 Burn 56.08
0.3 5 28 1.34668 0.859 Burn 49.17
0.35 5 27 1.34568 0.861 Burn 47.66
55 on the graph, there is a decrease in ethanol levels at concentrations of 0.3 M and 0.35 M.
While the optimum point of ethanol levels is at a concentration of 0.25 M and the minimum point is at the concentration of 0.1 M. This proves that the optimal concentration of the hydrolysis process is at the sulfuric acid concentration of 0.25 M.
1.2.2 Effect of the addition of H2SO4 solution concentration to Index Bias
Figure 2. Effect of increasing the concentration of H2SO4 solution on ethanol bias index
In figure can be seen the relationship between the addition of sulfuric acid concentrations to the refractive index value.
The higher the concentration of sulfuric acid, the higher the refractive index value.
The increase and decrease in the value of this refractive index is in line with the ethanol levels produced on the graph of the relationship between variations in sulfuric acid concentrations and the resulting ethanol levels. The optimum point is at a sulfuric acid concentration of 0.25 M.
1.2.3 Effect of the addition of H2SO4 solution concentration on ethanol density
Figure 3. Effect of the addition of H2SO4 solution concentration on ethanol density
In figure, there is a relationship between variations in sulfuric acid concentrations and the resulting bioethanol density value. Refractive index measurements are performed using a picnometer tool.
The weight of the type of ethanol solution is getting smaller, so the ethanol levels in the solution are getting bigger.
This is because ethanol has a smaller type of weight than water so the smaller the weight of the solution type means the amount / level of ethanol is getting more. So that the higher the concentration of sulfuric acid, the greater the level of ethanol produced, and the density value tends to decrease towards the standard density value of ethanol which is 0.789 gr / ml.
The minimum density point is in the concentration of sulfuric acid 0.25 M. On the graph there is a decrease in the concentration of 0.1 M to 0.2 M. Then there is an increase in the value of ethanol density at a concentration of 0.25 M.
4.2.4 Effect of the resulting bioethanol levels on the burn test
In the analysis of burn tests conducted on bioethanol products, it turned out that ethanol at a rate of 20.71%. It can't burn. While at a rate of 31.34% to a level of 56.08%, ethanol can burn. So that the resulting bioethanol products can burn if they have ethanol levels > 30%.
4.3 Conclusion
1. Green algae can be used as a raw material for making bioethanol so as to reduce the buildup of green algae colonies that can disrupt freshwater ecosystems and reduce waste generated around these waters.
1.3356 1.33968
1.34568
1.34868
1.34668
1.34568
1.334 1.336 1.338 1.34 1.342 1.344 1.346 1.348 1.35
0 0.1 0.2 0.3 0.4
Index Bias
Sufuric Acid Conentration (M)
0.882 0.877
0.862
0.852 0.859
0.861
0.85 0.855 0.86 0.865 0.87 0.875 0.88 0.885
0 0.1 0.2 0.3 0.4
Densitu (gr/ml)
Sulfuric Acid conentration (M)
2. Sulfuric Acid used in hydrolysis has a major effect on the resulting bioethanol levels, the largest ethanol level is 56.08% with a distillate volume of 26 ml at a variation in sulfuric acid concentration of 0.25 M which is the optimum point of sulfuric acid concentration in the hydrolysis process.
3. From the burn tests conducted on bioethanol products, ethanol at a rate of 20.71% cannot be burned. While at a rate of 31.34% to a level of 56.08%, ethanol can burn if ethanol levels >30%.
5. Conclusion
1. Green algae can be used as a raw material for making bioethanol so as to reduce the buildup of green algae colonies that can disrupt freshwater ecosystems and reduce waste generated around these waters.
2. Sulfuric Acid used in hydrolysis has a major effect on the resulting bioethanol levels, the largest ethanol level is 56.08% with a distillate volume of 26 ml at a variation in sulfuric acid concentration of 0.25 M which is the optimum point of sulfuric acid concentration in the hydrolysis process.
3. From the burn tests conducted on bioethanol products, ethanol at a rate of 20.71% cannot be burned. While at a rate of 31.34% to a level of 56.08%, ethanol can burn if ethanol levels >30%.
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