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All Journal Jurnal Teknik Kimia USU Jurnal Online Mahasiswa (JOM) Bidang Teknik dan Sains Journal of Engineering and Technological Sciences Konversi Jurnal UNITEK Narra J Journal of Bioprocess Chemical and Environmental Engineering Science Jurnal Teknik Kimia USU Jurnal Pengabdian Masyarakat Bidang Sains dan Teknologi Jurnal Offshore: Oil, Production Facilities, and Renewable Energy Heca Journal of Applied Sciences Malacca Pharmaceutics Leuser Journal of Environmental Studies Infolitika Journal of Data Science JURNAL REKAYASA KIMIA & LINGKUNGAN
Zuchra Helwani, Zuchra
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Aerospace Engineering Agriculture, Biological Sciences & Forestry Automotive Engineering Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Decision Sciences, Operations Research & Management Dentistry Earth & Planetary Sciences Education Electrical & Electronics Engineering Energy Engineering Environmental Science Health Professions Immunology & microbiology Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mathematics Mechanical Engineering Medicine & Pharmacology Nursing Public Health Transportation Veterinary Other

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Journal : Leuser Journal of Environmental Studies

 1 
Utilization of Empty Palm Fruit Bunches as a Carbon Source for Cellulase Production to Reduce Solid Waste from Palm Oil Amraini, Said Zul; Nazaris, Nazsha Nayyazsha; Andrio, David; Mardhiansyah, Muhammad; Helwani, Zuchra
Leuser Journal of Environmental Studies Vol. 1 No. 1 (2023): July 2023
Publisher : Heca Sentra Analitika

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.60084/ljes.v1i1.41

Abstract

Cellulase enzymes are widely used in textile, food, detergent, pulp and paper industries and biofuel, so the need for enzymes continues to increase every year. One of many biomass wastes found in Indonesia is empty fruit bunches (EFB) that can be used as a carbon source as a substitute for expensive pure cellulose (CMC) and Bacillus subtilis isolates. This study aims to obtain the optimum conditions the production of cellulase enzymes with variations in the pre-treatment of EFB and pH variations of the medium using Bacillus subtilis. Pre-treatment was carried out to hydrolysed lignocellulosic biomass was more easily and increased glucose levels which would enter the next production stage. Variations in pre-treatment were carried out by adding acids, bases and organosolv process, as well as variations in pH at 6.5; 7.0 and 7.5, respectively. Enzyme activity was calculated using the Nelson-Somogyi method. When using acid, the enzyme activity is 0.041, while using organosolv, it is obtained 0.057 each at pH 7. The results showed that the highest enzyme activity was obtained at a pH of 7.0 and a temperature of 40 ºC on EFB substrate pretreated with a base of 0.204 U/ml. These findings emphasize the potential benefits of using EFB waste as a substrate for cellulase enzyme production, by providing an alternative approach to decrease raw material expenses and mitigate environmental pollution.
Biocomposite Innovation: Assessing Tensile and Flexural Performance with Maleated Natural Rubber Additives Fatra, Warman; Anuar, Kaspul; Oktriyono, Febri Dwi; Fernando, Rivo; Helwani, Zuchra; Rusyana, Asep; Zul Amraini, Said
Leuser Journal of Environmental Studies Vol. 1 No. 2 (2023): November 2023
Publisher : Heca Sentra Analitika

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.60084/ljes.v1i2.98

Abstract

Fiberglass is the most common reinforcing fiber used in composites, with polymer matrices having high tensile strength and chemical resistance, including an excellent insulating property; however, they are non-degradable. Natural fiber reinforced polymer composites have advantageous properties such as lower density and price, when compared to synthetic composite products. In addition, hybrid composites may be obtained depending on various properties such as the fibers' length, structure, content and orientation, matrix bonding and arrangement. This study was carried out to determine the effect of adding Maleated Natural Rubber (MNR) from natural rubber as a coupling agent, in order to produce the highest tensile and flexural strength. The hand lay-up and vacuum bag methods with the Response Surface Method-Central Composite Design (RSM). -CCD) were used. The composite arrangement pattern was E-glass/OPEFB/E-glass, the volume fraction of OPEFB (oil palm empty fruit bunches):E-glass was 40:60, 50:50 and 60:40, the fraction volume of OPEFB + E-glass:matrix was 40:60, 50: 50, 60: 40 and the coupling agent were added by 9, 10 and 11% of the total epoxy resin used. Furthermore, the composite mold was made of glass with dimensions of 200mm x 50mm x 50mm. The results showed that the composite product obtained from both methods had a tensile strength value, which was influenced by the variable OPEFB fiber and epoxy resin. Meanwhile, the flexural strength was influenced by the OPEFB fiber and the quadratic factor of the epoxy-MNR resin.
Urban Air Quality Classification Using Machine Learning Approach to Enhance Environmental Monitoring Idroes, Ghazi Mauer; Noviandy, Teuku Rizky; Maulana, Aga; Zahriah, Zahriah; Suhendrayatna, Suhendrayatna; Suhartono, Eko; Khairan, Khairan; Kusumo, Fitranto; Helwani, Zuchra; Abd Rahman, Sunarti
Leuser Journal of Environmental Studies Vol. 1 No. 2 (2023): November 2023
Publisher : Heca Sentra Analitika

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.60084/ljes.v1i2.99

Abstract

Urban areas worldwide grapple with environmental challenges, notably air pollution. DKI Jakarta, Indonesia's capital city, is emblematic of this struggle, where rapid urbanization contributes to increased pollutants. This study employed the CatBoost machine learning algorithm, known for its resistance to overfitting and capability to handle missing data, to predict urban air quality based on pollutant levels from 2010 to 2021. The dataset, sourced from Jakarta's air quality monitoring stations, includes pollutants such as PM10, SO2, CO, O3, and NO2. After preprocessing, we used 80% of the data for training and 20% for testing. The model displayed high accuracy (0.9781), precision (0.9722), and recall (0.9728). The feature importance chart revealed O3 (Ozone) as the top influencer of air quality predictions, followed by PM10. Our findings highlight the dominant pollutants affecting urban air quality in Jakarta, Indonesia and emphasizing the need for targeted strategies to reduce their concentrations and ensure a cleaner and healthier urban environment.
Eco-Friendly Approach to Palm Oil Biodiesel Production: Torrefied Palm Frond Carbon as a Source for CaO/C/NaOH Catalysts Helwani, Zuchra; Amraini, Said Zul; Asmura, Jecky; Othman, Mohd. Roslee; Peliciamanuela, Samantha; Anggriani, Rara Dewi
Leuser Journal of Environmental Studies Vol. 2 No. 1 (2024): April 2024
Publisher : Heca Sentra Analitika

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.60084/ljes.v2i1.171

Abstract

Biomass-based sources for energy generation have attracted much attention recently due to its environmental benefits. These days, using edible oils and alkali catalysts, such as CaO, is standard practice for the transesterification step of the biodiesel synthesis process. Glycerine and methanol will form hydrogen bonds with the oxygen ions on the CaO surface, increasing the viscosity of the glycerine and causing CaO to suspend. Even though CaO was utilized directly as a catalyst in the transesterification process, extracting the CaO and glycerine from the final product will be challenging. To solve this issue, any extra metal oxides or catalyst supports ought to be impregnated into the CaO. This work has investigated the possible use of eggshells and palm fronds in developing bifunctional catalysts for biodiesel production. A series makes the processes' catalyst, including impregnation, calcination, and torrefaction. To assess the catalyst's performance, the esterification and transesterification of palm oil with a 2.9% free fatty acid content were investigated at a methanol/oil ratio of 6:1, catalyst concentration of 1-3% by weight, reaction temperature of 70 °C, and duration of 3 hours. The catalyst was found to have a specific surface area of 8.266 m2/g. There was an 89.4% yield of biodiesel produced. A viable, economical, and ecologically friendly method of producing biodiesel is to use eggshells and palm fronds in catalyst synthesis.
Environmental Benefits of Palm Oil Biodiesel Enhancement: Urea Complexation Optimization via RSM Helwani, Zuchra; Amraini, Said Zul; Abd Rahman, Sunarti; Zahrina, Ida; Julhijah, Noni; Ulfaa, Suci Mas’ama
Leuser Journal of Environmental Studies Vol. 2 No. 2 (2024): October 2024
Publisher : Heca Sentra Analitika

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.60084/ljes.v2i2.214

Abstract

Indonesian commercial biodiesel products are unstable due to polyunsaturated fatty acids (PUFA). The urea inclusion compound (UIC) method is used during the fractionation process on PUFA to enhance its quality. This study aims to determine the effect of temperature, fatty acid ester metal (FAME)/methanol ratio, and crystallization time on increasing the concentration of PUFA concentrates and to produce high-performance biodiesel products with an iodine indicator <30–40 g I2/100 g. According to the most recent research, the UCF phase product is obtained at a combination of temperature and crystallization time of 20 °C and 4 h, respectively. It has an iodine number of 44.01 and an oxidation stability of 18.61 h, which is close to the criteria for high-performance biodiesel (<30 –40 g I2/100 g). Meanwhile, the results of this study obtained a UCF phase product that has an iodine number of 34.18 and yields 86.57% is obtained at a combination of temperature and crystallization time of 20 °C and 6 hr and FAME-methanol ratio of 6, respectively, which is close to the criteria for high-performance biodiesel (<30 –40 g I2/100 g). The longer complexation time and temperature significantly affected the FAME fractionation of the UCF phase.
Improving the Environmental Performance of Palm Biodiesel via AgNO₃-Assisted Removal of Polyunsaturated Fatty Acids Helwani, Zuchra; Zahrina, Ida; Amraini, Said Zul; Idroes, Rinaldi; Neonufa, Godlief Frederick; Rahman, Sunarti Abd
Leuser Journal of Environmental Studies Vol. 3 No. 1 (2025): April 2025
Publisher : Heca Sentra Analitika

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.60084/ljes.v3i1.274

Abstract

Indonesian biodiesel products commonly exhibit low oxidative stability and high cloud points, which limit their performance and widespread use. These drawbacks are primarily due to the high content of polyunsaturated fatty acids (PUFAs) in the fatty acid methyl ester (FAME) mixture that constitutes biodiesel. A more suitable biodiesel composition includes higher proportions of saturated and monounsaturated fatty acids, which offer better combustion properties, higher cetane numbers, and greater resistance to oxidative degradation. In contrast, PUFAs promote oxidation reactions, resulting in fuel instability, increased sludge formation, and higher emissions of unburned hydrocarbons, negatively impacting both engine performance and the environment.This study investigates the use of silver nitrate (AgNO₃) as a selective extraction agent to remove PUFAs from palm oil-derived FAME. The goal is to identify the most effective biodiesel-to-AgNO₃ volume ratio for separating saturated fatty acid fractions from unsaturated ones, in order to produce a more stable and environmentally friendly biodiesel. Experimental results show that a 1:2 volume ratio significantly reduces the iodine number, from 57.22 to 47.38 g I₂/100 g sample, indicating a decrease in unsaturated compounds. Furthermore, oxidative stability improved from 11.18 hours to 11.69 hours after extraction. The removal of PUFAs not only improves the fuel's storage and combustion stability but also enhances its environmental profile. More stable biodiesel burns more completely, reducing emissions of particulate matter and greenhouse gases, and contributing to cleaner air and lower environmental impact. Thus, PUFA extraction using AgNO₃ presents a promising approach for improving the sustainability and performance of palm-based biodiesel fuels.
Optimizing Palm Oil Biodiesel Purity for a Cleaner Environment: Urea Complexation and RSM Approach Zohera, Zohera; Helwani, Zuchra; Sunarno, Sunarno
Leuser Journal of Environmental Studies Vol. 3 No. 2 (2025): October 2025
Publisher : Heca Sentra Analitika

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.60084/ljes.v3i2.311

Abstract

The performance and stability of biodiesel are strongly influenced by its fatty acid composition, particularly the balance between saturated (SFA) and unsaturated fatty acids (UFA). This study employed the urea inclusion compound (UIC) method to fractionate biodiesel and optimize conditions for obtaining a high-yield, high-quality saturated fraction (UCF). A central composite design (CCD) under response surface methodology (RSM) was used to evaluate the effects of urea-to-methanol ratio, crystallization temperature, and crystallization time on UCF and NUCF yields and iodine values. Experiments were conducted using a range of crystallization temperatures (18–22 °C), times (3–5 h), and urea-to-methanol ratios (1:1.5–1:2.5). The response variables were analyzed and optimized using desirability functions. The results showed that all three factors significantly influenced both the yield and iodine value of the fractions. The optimal condition, urea-to-methanol ratio of 1:1.73, temperature of 19.99 °C, and time of 5 h, yielded 81.59% UCF with an iodine value of 36.65 g I2/100 g, falling within the desired range for high-performance saturated biodiesel. In contrast, the NUCF fraction was minimized to 1.76% and enriched in PUFA. These findings demonstrate the potential of UIC-based fractionation for producing biodiesel with improved oxidative stability and combustion properties, aligning with international quality standards and contributing to more sustainable fuel formulations.
Co-Authors Abd , Ammar Ali Abd Rahman, Sunarti Afriyenti, Mia Agustiyanti, Rini Dwi Agustiyanti, Rini Dwi Ahmad Fadli Ahmad, Khairunnas Akbar, Irfan Sarhadi Amir Awaluddin Amun Amri Anggraini, Diva Putri Anggriani, Rara Dewi Anjani, Putri Anuar, Kaspul Asep Rusyana Aswie, Viqha Bahruddin Bahruddin Bahruddin Boy M. Bachtiar Damayanti, Elok David Andrio Dhani Nur Miftahudin Dizikri, Dizikri Drastinawati Drastinawati Drastinawati Drastinawati, Drastinawati Dwi Septiana Edi Susanto Edy Saputra Eko Suhartono Emran, Talha Bin Febrina Dwi Putri Febrina Dwi Putri, Febrina Dwi Febrina, Wetri Fernando, Rivo Ghazi Mauer Idroes Hafiz, Fadlillahi Hanafi, Muhammad Rifter Hari Rionaldo Hari Rionaldo Hawa, Karfika Ainil Hawa, Karfika Ainil Hutagaol, Martiandes Ida Zahrina Idral Amri Idroes, Ghazi M. Idroes, Ghifari Maulana Jecky Asmura Julhijah, Noni Karfika Ainil Hawa Karina Octaria Putri Kemala, Pati Kesni Savitri Khairan Khairan Komalasari Komalasari Komang, Hendri Kusumo, Fitranto Lala, Andi Lubis, Vanizra F. Lukman Arifin Maulana, Aga Maulydia, Nur B. Miftahudin, Dhani Nur Miftahudin, Dhani Nur Muhammad Mardhiansyah Muhammad Zen, Muhammad Muliadi Ramli Mulya, Dynna Ardilla Putri Muslim Abdurrahman, Muslim Nasution, Muhammad Hatta Nazaris, Nazsha Nayyazsha Neonufa, Godlief Frederick Ningsih, Diana S. Noviandy, Teuku R. Nurfatihayati Nurwijayanti Oktariandi, Vito Oktriyono, Febri Dwi Olsy, Fradilla Othman, Mohd. Roslee Peliciamanuela, Samantha Perdana, Rendy Putra Prasetyo Arva S, Prasetyo Arva Pratama, Teddy Pratama, Yudistira Putra Zelly Nugraha, Putra Zelly Putra, Bayu Eldino Putra, Yogi Lesmana Putri, Karina Octaria Putri, Karina Octaria Qalbi, Tiffani Rafi, M Khaidiz Rahayu, Ricky Puji Rahman, Sunarti Abd Raja Heru Nur Alam Ichsan, Raja Heru Nur Alam Randi Sanjaya Randi Sanjaya, Randi Reno Susanto Reski, M. Rinaldi Idroes Rizki, Juliana Rizky, Muhammad Dian Rozanna Sri Irianty Saparullah, Zulkarnaen Saryono Saryono Setiadi, Fydel Simbolon, Kristin Madelin Siregar, Thasya Nurfadillah Sitorus, Mesakh Fridolin Sugesti, Heni Suhendrayatna Suhendrayatna Sunarno Sunarno Surya, Andry Pratama Susanty, Wenny Susilowati Susilowati Syafi’i, Abdullah Syahputra, Dede SYAIFUL BAHRI Tengku Mukhlis Teuku Rizky Noviandy Topan Herianto Trina E. Tallei, Trina E. TRINA EKAWATI TALLEI Triwahyuni, Vanny Efia Ulfaa, Suci Mas’ama Ulima, Riris Warman Fatra, Warman Wenny Susanty Yelmida Azis Yemita, Sylvia Yudha, Ricky Satria Z Zulfansyah Zahriah, Zahriah Zohera, Zohera Zul Amraini, Said Zulfansyah Zulfansyah Zultiniar, Zultiniar