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All Journal Indonesian Journal of Chemistry Communications in Science and Technology Advance Sustainable Science, Engineering and Technology (ASSET) Jurnal Ekonomika dan Bisnis Islam Jurnal Ekonomi, Teknologi dan Bisnis Sewagati Jurnal Teknik Kimia dan Lingkungan International Journal of Renewable Energy Development Jurnal Polimesin
Rahmawati, Zeni
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Arts Humanities Astronomy Automotive Engineering Chemical Engineering, Chemistry & Bioengineering Chemistry Control & Systems Engineering Earth & Planetary Sciences Economics, Econometrics & Finance Education Electrical & Electronics Engineering Energy Engineering Industrial & Manufacturing Engineering Languange, Linguistic, Communication & Media Materials Science & Nanotechnology Mechanical Engineering Public Health Social Sciences Other

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Ultrafiltration membranes for dye wastewater treatment: Utilizing cellulose acetate and microcrystalline cellulose fillers from Ceiba Pentandra Abdullah, Romario; Astira, Dinia; Zulfiani, Utari; Rahmad Widyanto, Alvin; Rahmawati, Zeni; Gunawan, Triyanda; Kusumawati, Yuly; Hafiz Dzarfan Othman, Mohd; Fansuri, Hamzah
Communications in Science and Technology Vol 9 No 1 (2024)
Publisher : Komunitas Ilmuwan dan Profesional Muslim Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21924/cst.9.1.2024.1345

Abstract

Dye hurts the threat of human health problems and environmental pollution. Microcrystalline cellulose (MCC) based membrane is a good material to be used as an dye separation membrane for having the high hydrophilicity of the membrane. It has been successfully isolated from kapok (ceiba pentandra) with characteristic X-ray diffraction patterns and FTIR absorption peaks, which corresponded to the typical peaks of cellulose. The ultrafiltration membrane was made up of a cellulose acetate matrix created using the phase inversion method. Characterization results indicated that the inclusion of MCC derived from kapok led to a reduction in the contact angle from 65 to 52o, and an increase in membrane porosity from 82 to 85%. In the separation of dye, the composite membrane incorporating MCC filler demonstrated superior performance compared to the membrane lacking MCC, manifesting in an elevated water flux from 43 to 84 L/m².h and methylene blue (MB) rejection from 64 to 99%. The use of MCC as a filler in cellulose acetate membranes can enhance the characteristics and performance of the membrane in MB separation.
LITERASI EKONOMI SYARIAH PADA SANTRI PONDOK PESANTREN BAHRUL ULUM TAMBAKBERAS KABUPATEN JOMBANG Rahmawati, Zeni; indrarini, rachma
Jurnal Ekonomika dan Bisnis Islam Vol 4 No 3 (2021): Desember
Publisher : Universitas Negeri Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (850.631 KB) | DOI: 10.26740/jekobi.v4n3.p1-14

Abstract

Islamic economics and finance in Indonesia have developed rapidly in last two decades. However, Indonesia’s Islamic economic literacy is still low at 16,3%. One way that the government has taken toincrease Islamic economic literacy is by encouraging Islamic boarding schools to increase Islamic economic and financial literacy.  The purpose of this research is to determine the level of Islamic economic literacy High School Santri of Islamic Boarding School Bahrul Ulum Tambakberas Jombang using a quantitative approach. Sources of data in this research are primary data and secondary data. Primary data is obtained from answers given by respondents in distributed questionnaires. Secondary data were obtained from library research. The number of respondents was 89 santri. Data were collected using a questionnaire. The test on the research instrument was the validity test and reliability test. The data analysis technique used is descriptive statistics. The result showed that the Islamic economic literacy level of santri was in the sufficient literate category with an average of 73,64%. The Islamic economic literacy index is obtained by calculating the literacy rate of each aspect multiplied by the weight of the constituent aspects, so the result of islamic economic literacy index of santri is 36,61% (well literate).
Enhancing Surface Properties Through the Applications of Silica Superhydrophobic Coating Widati, Alfa Akustia; Salsabilah, Andina Fitriyah; Aisyah, Aisyah; Rahmawati, Zeni; Wan Abdullah, Wan Nazwanie
Indonesian Journal of Chemistry Vol 25, No 4 (2025)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.99793

Abstract

Superhydrophobic silica coatings have gained enormous attention due to their significant contribution to self-cleaning, anti-fouling, anti-icing, anti-corrosion, and moisture-resistance. This mini-review provides an overview of silica surface modification, including functionalization, roughness control, and deposition methods. Functionalization aims to reach hydrophobic properties by the application of low surface energy compounds. Surface roughness control at the micro- and nano-scale across different scales also results in various surface topographies. The type of deposition technique also influences the coating surface properties, including roughness texture, adhesion, and coating thickness. This paper also explains the challenges and gaps of research rarely reported by previous studies, such as the stability of coating in harsh environments, scalability, cost-effectiveness, and sustainability. Furthermore, this article also addresses promising future innovations in developing long-lasting coatings, multifunctional properties, and economic points of view.
Synthesis of sodalite-natural dolomite as novel bifunctional catalyst for biodiesel production: Experimental study of performance and emissions on diesel engine Fatah, Misbakhul; Hamid, Abdul; Rahmawati, Zeni; Saiful, S.; Purbaningtias, Tri Esti; Jakfar, Amin
International Journal of Renewable Energy Development Vol 14, No 5 (2025): September 2025
Publisher : Center of Biomass & Renewable Energy (CBIORE)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.61435/ijred.2025.61434

Abstract

The development of catalysts derived from natural minerals was investigated in this study for biodiesel production due to their high catalytic activity, abundant availability, low production cost, and environmentally friendly. Biodiesel was produced from Calophyllum Inophyllum (CI) oil using bifunctional catalyst synthesized from natural dolomite and sodalite. In addition, an experimental study was conducted to evaluate the performance and emission characteristics of the produced biodiesel in a diesel engine. The natural dolomite catalyst contains a high composition of CaO-MgO, while sodalite, consisting of Si and Al precursors, was synthesized from natural kaolin. The bifunctional catalysts were synthesized via wet impregnation method with varying loadings of natural dolomite (5, 10, 15, 20, and 25 wt%). FTIR, XRD, SEM-EDX, and N2 adsorption-desorption analyses were employed to characterize the physicochemical properties of the catalysts. The optimum biodiesel yield of 94.14 % was obtained at dolomite loading of 25 wt%. Engine performance tests revealed that the B10 fuel blend produced maximum power and torque of 1.252 kW and 69.151 N.m, respectively, at 1250 rpm. While the optimum specific fuel consumption was obtained at 0.0004 Kg.HP/h at 1250 rpm for all fuel blends.The lowest CO emission was recorded for the B40 fuel blend at 414 ppm, while the lowest NO and NOx emissions were observed for the D100 fuel at 88 and 86 ppm, respectively.
Pembuatan Biobriket dari Kotoran Sapi di kampung Sanan Blimbing Malang Kusumawati, Yuly; Gunawan, Triyanda; Zetra, Yulfi; Burhan, Perry; Rahmawati, Zeni; Fadlan, Arif; Nugraheni, Zjahra Vianita; Utomo, Wahyu Prasetyo; Fansuri, Hamzah; Widiastuti, Nurul; Putri, Oktavina Kartika
Sewagati Vol 9 No 4 (2025)
Publisher : Pusat Publikasi ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j26139960.v9i4.2397

Abstract

Kampung Sanan merupakan kampung yang mengelola perternakan sapi, sehingga menghasilkan banuak kotoran Sapi. Untuk memanfaatkan kotoran sapi di Kampung Sanan, kami mengajak warga Kampung Sanan mengembangkan pemanfaatan kotoran sapi menjadi biobriket. Biobriket yang dihasilkan dari kampung Sanan ini telah memenuhi standar SNI dan memiliki kualitas yang layak dengan pengujian sifat fisik dan termal. Selain itu, Program ini berpotensi menjadi aplikasi yang berkelanjutan dalam mendukung energi terbarukan berbasis biomassa, sekaligus memberikan dampak positif bagi pengelolaan limbah dan pemenuhan kebutuhan energi lokal.
Pengaruh Gaya Kepemimpinan, Budaya Organisasi, Dan Motivasi Terhadap Kinerja Keuangan PT Swabina Gatra Rahmawati, Zeni; Aufa, Muhammad
Jurnal Ekonomi Teknologi dan Bisnis (JETBIS) Vol. 1 No. 4 (2022): Jurnal Ekonomi, Teknologi dan Bisnis
Publisher : Al-Makki Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.57185/jetbis.v1i4.24

Abstract

Penelitian ini bertujuan untuk mengetahui (1) pengaruh gaya kepemimpinan terhadap kinerja keuangan. (2) pengaruh budaya organisasi terhadap kinerja keuangan. (3) pengaruh motivasi terhadap kinerja keuangan. (4) pengaruh gaya kepemimpinan, budaya organisasi, dan motivasi terhadap kinerja keuangan. Populasi penelitian ini adalah pegawai yang bekerja di PT Swabina Gatra yang berjumlah 145 orang. Dan sampel yang digunakan dalam penelitian ini berjumlah 59 orang. Pengumpulan data menggunakan kuosioner dan observasi. Dan teknik pengolahan data menggunakan deskriptif statistic, uji validitas, uji reliabilitas, uji t, uji f dan determinasi koefisiensi. Hasil penelitian menunjukkan bahwa variabel gaya kepemimpinan berpengaruh positif dan signifikan terhadap variabel kinerja keuangan. Variabel budaya organisasi berpengaruh positif dan signifikan terhadap variabel kinerja keuangan, dan variabel motivasi berpengaruh positif dan signifikan terhadap variabel kinerja keuangan. Jadi, di PT Swabina Gatra gaya kepemimpinan, budaya organisasi dan motivasi berpengaruh terhadap kinerja keuangan yang mana jika gaya kepemimpinan, budaya organisasi dan motivasi berlangsung efektif maka akan meningkatkan kinerja keuangan dan akan memberikan pengaruh yang baik terhadap kinerja keuangan di PT. Swabina Gatra.
Waste cooking oil biodiesel via a sodium hydroxide-catalyzed transesterification process: effects on diesel engine performance and emissions Hamid, Abdul; Syafa, Muhammad Badrus; Fatah, Misbakhul; Jakfar, Amin; Rahmawati, Zeni; Purbaningtias, Tri Esti; Fikri, Mohammad Anas; Rohmah, Faizatur; Wilujeng, Auliana Diah
Jurnal Polimesin Vol 23, No 5 (2025): October
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/jpl.v23i5.7374

Abstract

This study reports the synthesis of biodiesel from locally sourced Waste Cooking Oil (WCO) using sodium hydroxide (NaOH) catalyst. The main objective of this research is to assess the feasibility of utilizing WCO-based biodiesel as a sustainable alternative fuel by analyzing its physicochemical properties and application in a Yanmar® TF 70 LY-DI diesel engine. The production process involved degumming, acid-catalyzed esterification, and base-catalyzed transesterification to address the high free fatty acid content of WCO. The resulting biodiesel met ASTM D6751 standards, with a kinematic viscosity of 5.06 cSt, a flash point of 164°C, a density of 885 kg/m3, a FAME yield of 98.17%, and an acid number of 0.12 mg-KOH/g. Engine tests were performed using blends from B10 to B40 and benchmarked against pure diesel. Results showed that B10 and B20 blends maintained comparable engine performance, while higher blends (B30–B40) exhibited reductions in power and torque and increased Specific Fuel Consumption (SFC). CO emissions decreased significantly with increasing biodiesel content, whereas NO and NOx emissions rose due to higher combustion temperatures. These findings demonstrate the technical feasibility and environmental benefits of WCO-derived biodiesel, particularly at lower blend ratios (≤ B20), as a locally available and sustainable fuel. The study is limited to laboratory-scale testing on a single-cylinder engine without long-term durability assessments, which should be addressed in future studies.
Optimization of Biodiesel Production from Sunflower Oil Using Sodalite-Based Catalyst via Taguchi Method Hamid, Abdul; Jakfar, Amin; Rahmawati, Zeni; Armansyah, Muhammad Doni; Wahyuni, Tri; Purbaningtias, Tri Esti; Febriana, Ike Dayi; Abdullah, Mohammad; Ilmah, Aurista Miftahatul; Rohmah, Faizatur
Jurnal Teknik Kimia dan Lingkungan Vol. 9 No. 2 (2025): October 2025
Publisher : Politeknik Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33795/jtkl.v9i2.7345

Abstract

The growing demand for alternative fuels has highlighted biodiesel as sustainable substitute for fossil diesel. In this study, biodiesel was produced from sunflower seed oil using heterogeneous catalyst synthesized from natural kaolin into sodalite via hydrothermal process. The synthesized catalyst was characterized using XRD, FTIR and SEM-EDS, confirming the transformation of kaolinite to sodalite. The transesterification reaction was conducted under varying methanol-to-oil molar ratios (1:12, 1:18, and 1:24) and temperatures (60, 65, and 70°C). A Taguchi orthogonal array (L9) was employed to statistically evaluate the effects of these parameters on methyl ester yield. Experimental results showed that both methanol ratio and reaction temperature significantly influenced biodiesel yield, with the highest yield of 90.44% obtained at 70°C and 1:18 molar ratio. Signal-to-noise ratio and ANOVA analysis indicated that the methanol-to-oil ratio was the most dominant factor (46.05%) compared to temperature (40.55%). The resulting biodiesel exhibited a flash point of 158°C, acid value of 0.06 mg-KOH/g, and iodine value of 84.06 g-I₂/100g, satisfying most ASTM D6751 and SNI 7182:2015 standards, though viscosity and density exceeded standard limits. Emission testing showed 16% reduction in CO emissions with increasing biodiesel blends, while NO and NOx emissions slightly increased.
Identification of Landslide Prone Areas with Schlumberger Configuration Geoelectric Method, Kalongan Village, East Ungaran in 2023 Rahmawati, Zeni; Niyartama, Thaqibul Fikri; Wibowo, Nugroho Budi; Andi, Andi
Advance Sustainable Science, Engineering and Technology Vol 6, No 2 (2024): February - April
Publisher : Universitas PGRI Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26877/asset.v6i2.18163

Abstract

Landslides are one of the natural disasters that occur in Semarang Regency. The landslide event in Kalongan Village, East Ungaran Subdistrict took place in 2022 to 2023. The dimension of the landslide is large and has the potential to cause damage to infrastructure and settlements, mitigation measures are needed. One of the mitigation measures is to identify the lithology of the landslide area and its surroundings. This study aims to determine the lithology of the landslide area and its surroundings using the Schlumberger configuration geoelectric method. Geoelectric acquisition using a set of naniura geoelectric, with a line variation of 120 to 300 meters. The number of measurement lines is 6 VES located in the landslide zone in the Kaligetas Formation. The results showed that the avalanche zone is composed of Tufan Sandstone with a resistivity of 0.17 Ωm to 334.9 Ωm, Tuff with a resistivity of 10.03 to 26.96 Ωm, and Lava Flow with a resistivity of 1161.91 Ωm to 3040.05 Ωm. Avalanche materials were identified to be associated with lithologies such as tufan sandstone and tuff with a thickness between 5 to 50 m.
Co-Authors Abdul Hamid Abdullah, Mohammad Abdullah, Romario Aisyah Aisyah Alfa Akustia Widati Andi Andi Armansyah, Muhammad Doni Astira, Dinia Auliana Diah Wilujeng Aurista Miftahatul Ilmah Fadlan, Arif Fatah, Misbakhul Febriana, Ike Dayi Fikri, Mohammad Anas Gunawan, Triyanda Hafiz Dzarfan Othman, Mohd Hamzah Fansuri Jakfar, Amin Kusumawati, Yuly Muhammad Aufa Nugraheni, Zjahra Vianita Nugroho Budi Wibowo Nurul - Widiastuti Oktavina Kartika Putri Perry Burhan, Perry Rachma Indrarini Rahmad Widyanto, Alvin ROHMAH, FAIZATUR Saiful, S. Salsabilah, Andina Fitriyah Syafa, Muhammad Badrus Thaqibul Fikri Niyartama Tri Esti Purbaningtias tri wahyuni Wahyu Prasetyo Utomo Wan Abdullah, Wan Nazwanie Zetra, Yulfi Zulfiani, Utari