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Komposit Polianilina/Kitosan/Perak Nanowires Sebagai Elektrokatalis Reaksi Evolusi Hidrogen dalam Medium Netral Fadli Fakhrullah; Purwantiningsih Sugita; Mohammad Khotib; Takeno Akiyoshi; Shinya Takahashi
ALCHEMY Jurnal Penelitian Kimia Vol 15, No 2 (2019): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (380.355 KB) | DOI: 10.20961/alchemy.15.2.30460.190-202

Abstract

Studi mengenai elektrokatalis untuk reaksi evolusi hidrogen (HER) dan evolusi oksigen (OER) sangat diperlukan terkait aplikasinya dalam pengembangan energi terbarukan berbasis hidrogen. Komposit perak nanowires (AgNWs) dengan polianilina (PANI) disiapkan dengan metode polimerisasi radikal dalam larutan matriks kitosan untuk menurunkan ukuran partikel PANI. Komposit disintesis dengan 3 perlakuan yang berbeda, yaitu perlakuan suhu ruang, suhu rendah, dan sonikasi. Aktivitas elektrokatalisis diukur dengan voltammetri sapuan linear (LSV). Informasi tentang densitas arus pertukaran dan overpotensial sebagai variabel utama pengukuran aktivitas elektrokatalisis diperoleh dari plot Tafel pada LSV. Semua komposit dengan perlakuan suhu dan sonikasi menunjukkan karakter katodik berdasarkan nilai overpotensialnya yang negatif (aktivitas HER), sedangkan komposit dengan perlakuan suhu rendah memiliki karakter anodik (aktivitas OER).A Composite of   Polyaniline/Chitosan/Silver Nanowires as Hydrogen Evolution Electrocatalyst in Neutral Medium. Study on electrocatalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is urgently needed related to its application in hydrogen-based renewable energy development. A composite of silver nanowires (AgNWs) with polyaniline (PANI) was prepared by radical polymerization method in chitosan matrix solution to reduce the PANI particle size. Each composite was synthesized under three different treatment conditions, which are room temperature, low temperature, and sonication. Linear sweeping voltammetry (LSV) was conducted to measure electrocatalytic activity of the composites. Information about exchange current density and overpotential as important variables in this field were obtained from Tafel plot in the LSV. The temperature and sonication-treated composites have cathodic character due to its negative overpotential (HER activity), while low temperature-treated composites have anodic character (OER activity).
Growth, Electronic Structure, and Electrochemical Properties of Cubic BaTiO3 Synthesized by Low-Pressure Hydrothermal-Assisted Sintering Mohammad Khotib; Bambang Soegijono; Zainal Alim Mas'ud; Gina Libria Nadjamoeddin
Indonesian Journal of Chemistry Vol 22, No 1 (2022)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.68978

Abstract

Cubic BaTiO3 was synthesized through low-pressure hydrothermal-assisted sintering using Ba(OH)2 and TiO2 as precursors with a mol ratio of Ba:Ti = 1.4:1. The single phase of cubic BaTiO3 was produced at a sintering temperature of 800 °C for 2, 4, 8, and 12 h. The absence of diffraction peak splitting at 2q of 45° was indicated cubic BaTiO3. The crystallite size of BaTiO3 ranged from 80–200 nm, and its size increased with increasing temperatures and sintering times. The micro-strain of the BaTiO3 crystal lattice had a range between 0.27 and 0.68%. The minimum bandgap on the indirect bandgap was about 1.75 eV from point M to Γ, while the direct bandgap was about 1.95 eV from Γ to Γ. Ti–O's interaction had a covalent character, while that of Ba–O had an ionic character based on the density of state (DOS) calculation. The characteristics of the BaTiO3 voltammogram show an irreversible redox mechanism with a more observable reduction peak in Ti4+/Ti3+. Higher current density at over potential indicated greater BaTiO3 capabilities in Oxygen Evolution Reaction (OER)-Oxygen Reduction Reaction (ORR) electrocatalysis. For that, purified cubic BaTiO3 offers potential application as an electrode for batteries, water splitting systems, and regenerative fuel cells.
PENGARUH PENGALAMAN KERJA DAN KOMPENSASI TERHADAP KINERJA KARYAWAN PT. BANK BNI TBK CABANG PAMEKASAN YANG DIMEDIASI OLEH PROFESIONALISME Mohammad Khotib; Chamariyah Chamariyah; Subijanto Subijanto
Digital Bisnis: Jurnal Publikasi Ilmu Manajemen dan E-Commerce Vol. 1 No. 3 (2022): September : Digital Bisnis : Jurnal Publikasi Ilmu Manajemen dan E-Commerce
Publisher : Universitas 45 Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (169.378 KB) | DOI: 10.30640/digital.v1i3.542

Abstract

The purposes of this study are: 1) To describe the work experience, compensation, professionalism and performance of employees of PT. Bank BNI Tbk Pamekasan Branch; 2) To test and analyze the effect of work experience on the performance of employees of PT. Bank BNI Tbk Pamekasan Branch; 3) To test and analyze the effect of work experience on professionalism at PT. Bank BNI Tbk Pamekasan Branch; 4) To test and analyze the effect of compensation on professionalism at PT. Bank BNI Tbk Pamekasan Branch; 5) To test and analyze the effect of compensation on the performance of employees of PT. Bank BNI Tbk Pamekasan Branch; 6) To test and analyze the effect of professionalism on the performance of employees of PT. Bank BNI Tbk Pamekasan Branch; 7) To test and analyze the effect of work experience on the performance of employees of PT. Bank BNI Tbk Pamekasan Branch mediated by professionalism; and 8) To test and analyze the effect of compensation on the performance of employees of PT. Bank BNI Tbk Pamekasan Branch mediated by professionalism. This type of research is explanatory, the research approach uses a quantitative approach, the number of samples is 96 employees. The sampling method used total sampling. Data analysis using SEM-PLS. Based on data analysis using PLS, the results showed that; 1) Work experience has a significant effect on employee performance, with the original sample value of 0.288; 2) Work experience has a significant effect on professionalism, with the original sample value of 0.388; 3) Compensation has a significant effect on professionalism, with the original sample value of 0.513; 4) Compensation has a significant effect on employee performance, with the original sample value of 0.242; 5) Professionalism has a significant effect on employee performance, with the original sample value of 0.442; 6) Work experience has a significant effect on employee performance mediated by professionalism, with the original sample value of 0.171; 7) Compensation has no significant effect on employee performance mediated by professionalism, with the original sample value of 0.227. The significance value of all research variables at = 0.05 with a 95% confidence level. The variable that has a significant dominant effect is compensation for professionalism.
Impact of Modifying Filler into Porous on Hydrophobicity Behaviour of The Silica-HDPE Composite Defrizal, Muhammad; Kemala, Tetty; Khotib, Mohammad
Jurnal Kimia Sains dan Aplikasi Vol 28, No 4 (2025): Volume 28 Issue 4 Year 2025
Publisher : Chemistry Department, Faculty of Sciences and Mathematics, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jksa.28.4.168-175

Abstract

Even though the approach is relatively simple and does not require additional treatment, the porous filler method has not been widely utilized to boost the composite’s hydrophobicity. Therefore, this study wants to show that silica’s porosity as a filler material affects the surface roughness and hydrophobicity of its composite (in this case, silica-HDPE). Pore formation in silica uses the soft-template method with Tween-80 as the mould. The amount of surfactant was varied by 0, 5, and 10 g. The particles are then physically composited into the HDPE matrix. Surface characterization of silica particles analyzed by Brunauer-Emmett-Teller (BET) shows enhancement in particle porosity as the amount of surfactant added is increased. When it is inserted into HDPE, the silica particles with the highest porosity have the greatest surface roughness. It is confirmed by the wavy surface texture of this composite when it is characterized using an Atomic Force Microscope (AFM). These results are accompanied by a significant enhancement in the contact angle value at each concentration. From the contact angle and AFM data, porous silica has the role of surface texture provider in raising its roughness. It affects the improvement of the hydrophobicity according to the Cassie-Baxter equation, which states that the more air fraction formed on a surface, the higher the contact angle obtained.
A New Superabsorbent Polymer Derived from Acrylamide and Fine Coal Khotib, Mohammad; Mas'ud, Zainal Alim; Eriza, Nurul; Subastiar, Ian; Nasrudin, M Fikry
Jurnal Rekayasa Kimia & Lingkungan Vol 19, No 2 (2024): Jurnal Rekayasa Kimia & Lingkungan (December, 2024)
Publisher : Chemical Engineering Department, Syiah Kuala University, Banda Aceh, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23955/rkl.v19i2.37341

Abstract

The fine coal was a by-product of the mechanical coal processing used at the coal mine, that can be converted to added value materials. The objective of this study to obtain the new superabsorbent polymers (SAP) derived from fine coal. The SAP synthesis was conducted via a free radical polymerization with various percentage of fine coal is 10; 25; and 40% of acrylamide and fine coal total. The copolymerization was carried out for 3 h at 70 C, followed by subsequent saponification with 1 M NaOH for 2 h. The superabsorbent composite was characterized by Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). FTIR spectra revealed that the acrylic acid was successfully grafted onto the fine coal backbone. As shown by SEM imaging, the resulting surface was homogeneous and exhibited an interconnected pore structure. The maximum absorption capacity was found for SAP C2, which had a composition of 25% fine coal, 75% acrylamide, 0.11% N,N-methylene-bis-acrylamide (MBA), and 1.11% ammonium persulfate. The absorption capacities for the unsaponified and saponified SAPs were 42.36 and 617.86 g/g, respectively. The maximum water absorption capacity of the superabsorbent polymer was achieved at pH 6.5. Based on water absorption capacity, this product is suitable for soil conditioner or agricultural application.
Quantitative Structure-Activity Relationship Study of Fatty Acid Derivatives as Lubricant Additive Sugesti, Rahmawita; Sutriah, Komar; Khotib, Mohammad
Jurnal Rekayasa Kimia & Lingkungan Vol 19, No 1 (2024): Jurnal Rekayasa Kimia & Lingkungan (June 2024 )
Publisher : Chemical Engineering Department, Syiah Kuala University, Banda Aceh, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23955/rkl.v19i1.27374

Abstract

Fatty acid compounds and their derivatives have been known in tribology as a source of bio-lubricant raw materials. New compounds were developed computationally to sort out the physical properties of the desired lubricant additive before synthesis in the laboratory. In this study, the correlation between the chemical structure of fatty acid derivative compounds and their physical properties through the quantitative structure-activity relationship (QSAR) using the density functional theory (DFT) was determined. QSAR model resulted in two linear regression equations for the wear rate performance test at (1) the value of the weld load with 5%, 500N variation and (2) the value of the wear scar diameter 5%, 150N variation. Validation of the regression model was conducted using the leave-one-out (LOO) method. The new additive lubricants were designed using the obtained QSAR models of the wear rate performance test with the descriptor of total energy, dipole moment, and softness. Stearoyl diethanolamine compound was proposed as a lubricant additive with the best performance parameter of weld load and wear scar diameter at 298.03 kg and 0.29 mm respectively. The percentage performance of stearoyl diethanolamine for weld load and wear scar diameter was increased by 24.18% and 47.60%, respectively.
Distribusi Bahan Organik dan Fraksi Sedimen di Perairan Teluk Lampung: Distribution of Sediment Fractions and Organic Matter in Lampung Bay Prartono, Tri; Koropitan, Alan Frendy; Khotib, Mohammad; Hartanto, Mochamad Tri; Kusumaningsih, Alvianita
Jurnal Ilmu dan Teknologi Kelautan Tropis Vol. 16 No. 1 (2024): Jurnal Ilmu dan Teknologi Kelautan Tropis
Publisher : Department of Marine Science and Technology, Faculty of Fisheries and Marine Science, IPB University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29244/jitkt.v16i1.48135

Abstract

Deposisi sedimen di perairan sangat dipengaruhi oleh proses-proses pantai yang menyebabkan variasi karakteristik fisik dan kimiawinya. Penelitian ini mengungkap komposisi ukuran sedimen dan bahan organik di sedimen Teluk Lampung untuk menduga proses deposisi. Analisis fraksi sedimen dilakukan berdasarkan pada American Society for Testing and Materials (ASTM) standards D422-63, sedangkan bahan organik dilakukan dengan menggunakan metode loss on ignition (LOI). Fraksi pasir lanau (75,95-78,73%) dan fraksi lempung (18,27-20,28%) memiliki persentase yang lebih tinggi dibandingkan dengan fraksi pasir (3,00-3,81%). Kandungan organik di sedimen perairan Teluk Lampung berkisar antara 10,67-13,48%. Distribusi fraksi sedimen dan bahan organik di perairan Teluk Lampung tidak berbeda signifikan antar stasiun, yang artinya stasiun yang berada di dekat kepala teluk (TL 1 dan TL 2) memiliki persentase fraksi sedimen dan bahan organik yang tidak berbeda signifikan dengan stasiun yang berada di tengah atau ke arah mulut teluk (TL 3-TL5).
Adsorption of Methylene Blue by Graft Copolymer Acrylamide onto Pineapple Peel Cellulose with the Addition of Activated Carbon Microwave-Assisted Permatasari, Putri; Sutriah, Komar; Khotib, Mohammad
Jurnal Rekayasa Kimia & Lingkungan Vol 18, No 1 (2023): Jurnal Rekayasa Kimia & Lingkungan (June, 2023 )
Publisher : Chemical Engineering Department, Syiah Kuala University, Banda Aceh, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23955/rkl.v18i1.26894

Abstract

Cationic dyes such as methylene blue are among the most widely used dye in the textile and paper industry. The dye waste produced causes environmental pollution and is harmful to human health. Thus, wastewater treatment becomes an important aspect of reducing this problem. Adsorption is a very effective method for treating various wastewaters due to its high selectivity and capacity. This study aims to prepare an adsorbent from graft copolymer acrylamide onto cellulose with the addition of activated carbon microwave-assisted and to test its performance as an adsorbent for methylene blue. The adsorbent synthesis was carried out using a microwave-assisted graft copolymer technique. The graft of acrylamide onto cellulose with the addition of activated carbon was carried out at various times (3, 4, and 5 minutes). Based on the FTIR spectra characterization of the adsorbent, the functional groups are C=O and N-H, and SEM analysis shows that the surface forms an interconnected network. At 3, 4, and 5 minutes of irradiation, grafting ratios were 329.72, 128.00, and 150.12, with grafting efficiency of 99.74, 72.94, and 78.02%. The maximum adsorption capacity of the adsorbent on methylene blue was 14.00, 6.04, and 9.97 mg/g, respectively, following the Langmuir isotherm model and pseudo second order kinetics. The experimental results show that the adsorbent can effectively remove or eliminate methylene blue in an aqueous solution.
KARAKTERISASI KARBON PELET CAMPURAN RUMPUT GAJAH (Pennisetum purpureum Scumach) DAN TEMPURUNG NYAMPLUNG (Calophyllum inophyllum Linn.) Santiyo Wibowo; Daniel P.O Laia; Mohammad Khotib; Gustan Pari
Jurnal Penelitian Hasil Hutan Vol. 35 No. 1 (2017): Jurnal Penelitian Hasil Hutan
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20886/jphh.2017.35.1.73-82

Abstract

Carbon pellet is a charcoal product made from carbonized biomass which is crushed into fine powder and compacted into pellet. Carbon pellets is designed for renewable energy alternatives for cooking, the combustion process and the possibilities for steam power plants as a substitute for coal. This paper studies the quality of carbon pellet made from a mixture of elephant grass with nyamplung shell. After carbonization, the elephant grass and nyamplung seed shell were crushed into 60 mesh powder for pellet with various ratio of elephant grass charcoal and nyamplung shell charcoal namely 100:0, 75:25, 50:50, 25:75, and 0:100 homogenously. Ten percent PVAC adhesive was added into the mixture prior to compression. Results show that the mixture composition of 75% elephant grass charcoal and 25% nyamplung shell charcoal is recommended for carbon pellet. The mixture composition improved physical properties with the average of 3.35% water 3 content, 26.19% volatile matter, 13.59% ash content, 60.21% carbon bound, 0.68 kg/cm density, 5.91 kg/cm compressive strength and calorific value of 6080 cal/g.
Synthesis and Characterization of HDTMA-Br Modified TiO₂/ZnO/CuO Photocatalyst Composite for Photodegradation of Textile Dye (Methyl Orange) Fatika, Siti; Sutriah, Komar; Khotib, Mohammad
Jurnal Kimia Sains dan Aplikasi Vol 28, No 8 (2025): Volume 28 Issue 8 Year 2025
Publisher : Chemistry Department, Faculty of Sciences and Mathematics, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jksa.28.8.436-441

Abstract

Methyl orange exhibits low biodegradability and is difficult to remove from aqueous solutions. Photodegradation using photocatalysts offers an efficient and practical alternative for treating methyl orange dye waste. Among various semiconductor materials, TiO₂ and ZnO have attracted considerable attention due to their strong photocatalytic activity. However, excessive use of TiO₂ can lead to turbidity in the solution, reducing light penetration and consequently diminishing the efficiency of the photoreduction and photooxidation processes. Numerous studies have been conducted to control the structure, morphology, and porosity of TiO₂ to enhance its photocatalytic performance. One effective approach involves the incorporation of surfactants into composites, which can modify the optical properties, structure, and morphology of the material, thereby improving its ability to degrade methyl orange. In this study, the composite was synthesized using the precipitation method. The highest degradation efficiency of 44% was achieved at 50 minutes for a methyl orange concentration of 30 mg/L, with a composite ratio of 1:1:0.3 and an HDTMA-Br concentration of 2 CMC. The addition of HDTMA-Br enhanced the photocatalytic performance by reducing electron–hole recombination, resulting in a band gap energy of 2.87 eV within the visible light range (1.77–3.1 eV).