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Sulfonated Mesoporous Silica-Carbon Composite Derived from a Silicate-Polyethylene Glycol Gel and Its Application as Solid Acid Catalysts Shofiyya Julaika; Agus Farid Fadli; Widiyastuti Widiyastuti; Heru Setyawan
Bulletin of Chemical Reaction Engineering & Catalysis 2022: BCREC Volume 17 Issue 1 Year 2022 (March 2022)
Publisher : Department of Chemical Engineering - Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.9767/bcrec.17.1.11795.13-21

Solid acid catalyst is a promising alternative to the counterpart homogeneous acid for esterification reaction from the viewpoint of reusability and environmental concerns. This work aims to develop sulfonated mesoporous silica-carbon composite as solid acid catalyst for the esterification. The catalyst was synthesized from sodium silicate as the silica precursor and polyethylene glycol (PEG) as both carbon precursor and template via a sol-gel route in an aqueous system. Then, it was carbonized to produce mesoporous silica-carbon composite. Using the proposed method, the surface area of the silica-carbon composite could reach as high as 1074.21 m2/g. Although the surface area decreased to 614.02 m²/g when it was functionalized with sulfonate groups, the composite had a high ionic capacity of 5.3 mEq/g and exhibited high catalytic activity for esterification reaction of acetic acid with ethanol. At a reaction temperature of 80 °C, the acetic acid conversion reached 76.55% in 4 h. In addition, the catalyst had good reusability, which can be comparable with the commercial catalyst Foltrol F-007. It appears that the sulfonated silica-carbon composite prepared from sodium silicate using PEG as the carbon source a promising candidate as catalyst for esterification and the related area. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Carbonization of Lignin Extracted from Liquid Waste of Coconut Coir Delignification Widiyastuti Widiyastuti; Mahardika Fahrudin Rois; Heru Setyawan; Siti Machmudah; Diky Anggoro
Indonesian Journal of Chemistry Vol 20, No 4 (2020)
Publisher : Universitas Gadjah Mada

Lignin as a by-product of the pulping process is less widely used for worth materials. In this study, the utilization of lignin by-product of the soda delignification process of coconut coir converted to the activated carbon by a simple precipitation method followed by the carbonization at various temperatures is presented. The by-product liquor of the soda delignification process having a pH of 13.4 was neutralized by dropping of hydrochloric acid solution to achieve the pH solution of 4 resulting in the lignin precipitation. The precipitated was washed, filtered, and dried. The dried lignin was then carbonized under a nitrogen atmosphere at various temperatures of 500, 700, and 900 °C. The dried lignin and carbonized samples were characterized using SEM, XRD, FTIR, and nitrogen adsorption-desorption analyzer, to examine their morphology, X-Ray diffraction pattern, chemical bonding interaction, and surface area-pore size distribution, respectively. The characterization results showed that the functional groups of lignin mostly disappeared gradually with the increase of temperature approached the graphite spectrum. The XRD patterns confirmed that the carbonized lignin particles were amorphous and assigned as graphitic. All samples had a pore size of 3–4 nm classified as mesoporous particles. This study has shown that the carbonization lignin at a temperature of 700 °C had the highest surface area (i.e. 642.5 m2/g) in which corresponds to the highest specific capacitance (i.e. 28.84 F/g).

Electrochemical Behaviour of Silica Deposited on Stainless Steel by Electrophoretic Deposition Ni Made Intan Putri Suari; Delyana Ratnasari; Sahara Tulaini; W. Widiyastuti; Heru Setyawan
ASEAN Journal of Chemical Engineering Vol 22, No 2 (2022)
Publisher : Department of Chemical Engineering, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ajche.72638

The purpose of this paper is to evaluate the characteristics of corrosion protection of stainless steel substrates coated with silica by electrophoresis with pulsed direct current (PDC) and constant direct current (CDC) with anodization. Electrophoresis was carried out using silica sol from sodium silicate solution as an electrolyte solution. Stainless steel functioned as an anode and carbon as a cathode with a constant electrode distance of 2 cm. The amplitude, duty cycle, and anodization effect on stainless steel corrosion protection characteristics were evaluated. The samples were characterized by linear polarization and electrochemical impedance spectroscopy (EIS) to see the characteristics of metal corrosion protection and scanning electron microscopy (SEM) analysis to see the morphology of the coating. This study showed that PDC electrophoresis and CDC accompanied by anodization could obtain silica film with good corrosion protection characteristics (high pore resistance and low admittance). Linear polarization results showed that metal corrosion protection behavior was increased by anodization. Similar results were obtained by EIS analysis which showed that pore resistance increased by anodization. The highest pore resistance obtained by the constant current with anodization is 543 ohms, and the lowest admittance is 0.0217. Corrosion protection characteristics are also influenced by the amplitude and duty cycle during electrophoresis. Silica film with a high pore resistance and a low admittance were obtained at a frequency, amplitude, and duty cycle of 80 Hz, 0.5 volts, and 60%, respectively. The silica film produced by pulsed electrophoresis resulted in better coating characteristics than by constant current with anodization, which is seen from the pore resistance value and its admittance.

Graphitization of Coconut Shell Charcoal for Sulfonated Mesoporous Carbon Catalyst Preparation and Its Catalytic Behavior in Esterification Reaction Fahmi Fahmi; Widiyastuti Widiyastuti; Heru Setyawan
Bulletin of Chemical Reaction Engineering & Catalysis 2020: BCREC Volume 15 Issue 2 Year 2020 (August 2020)
Publisher : Masyarakat Katalis Indonesia - Indonesian Catalyst Society (MKICS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.9767/bcrec.15.2.7745.538-544

Here, we reported the utilization of coconut shell charcoal used for solid acid catalysts and its performance in the esterification reaction of acetic acid and methanol. The graphitization of coconut shell charcoal was carried out by the calcination and KOH activation at the temperature of 400 °C for an hour and continued at the temperature of 800 °C for an hour under nitrogen flow resulted in graphitic carbon. The effect of the addition of KOH activation was observed by varied the weight ratio of coconut shell charcoal as raw material (RM) and KOH. The selected weight ratio of RM:KOH was 1:1, 1:2, and 1:4. The resulted graphitic carbon was sulfonated by heating with the sulfuric acid to obtain a solid acid catalyst. The sulfonic time was evaluated for 5 and 10 hours. The generated particles were characterized to examine the morphology, the crystallinity, the specific surface area, the chemical bonding, and the ionic capacity using Scanning Electron Microscopy (SEM), X-Ray diffraction (XRD), nitrogen gas absorption-desorption, Fourier Transform Infrared Spectroscopy (FTIR), and titration method, respectively. The best condition for graphitization of raw material is the use of RM:KOH = 1:4, resulting in the highest surface area reaching 1259.67 m2/g and the most dominant of the sulfonic group of −SO3 bond. Furthermore, increasing the sulfonating time from 5 to 10 hours led to the increase of the yield of esterification reaction from 85% to 96.57% for graphite synthesized using RM:KOH = 1:4. Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Sulfonated Mesoporous Silica-Carbon Composite Derived from a Silicate-Polyethylene Glycol Gel and Its Application as Solid Acid Catalysts Shofiyya Julaika; Agus Farid Fadli; Widiyastuti Widiyastuti; Heru Setyawan
Bulletin of Chemical Reaction Engineering & Catalysis 2022: BCREC Volume 17 Issue 1 Year 2022 (March 2022)
Publisher : Masyarakat Katalis Indonesia - Indonesian Catalyst Society (MKICS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.9767/bcrec.17.1.11795.13-21

Solid acid catalyst is a promising alternative to the counterpart homogeneous acid for esterification reaction from the viewpoint of reusability and environmental concerns. This work aims to develop sulfonated mesoporous silica-carbon composite as solid acid catalyst for the esterification. The catalyst was synthesized from sodium silicate as the silica precursor and polyethylene glycol (PEG) as both carbon precursor and template via a sol-gel route in an aqueous system. Then, it was carbonized to produce mesoporous silica-carbon composite. Using the proposed method, the surface area of the silica-carbon composite could reach as high as 1074.21 m2/g. Although the surface area decreased to 614.02 m²/g when it was functionalized with sulfonate groups, the composite had a high ionic capacity of 5.3 mEq/g and exhibited high catalytic activity for esterification reaction of acetic acid with ethanol. At a reaction temperature of 80 °C, the acetic acid conversion reached 76.55% in 4 h. In addition, the catalyst had good reusability, which can be comparable with the commercial catalyst Foltrol F-007. It appears that the sulfonated silica-carbon composite prepared from sodium silicate using PEG as the carbon source a promising candidate as catalyst for esterification and the related area. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Kinetic Model of LiFePO4 Formation Using Non-Isothermal Thermogravimetric Analysis Abdul Halim Abdul Halim; Widiyastuti Widiyastuti; Heru Setyawan; Sugeng Winardi
Bulletin of Chemical Reaction Engineering & Catalysis 2014: BCREC Volume 9 Issue 1 Year 2014 (April 2014)
Publisher : Masyarakat Katalis Indonesia - Indonesian Catalyst Society (MKICS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.9767/bcrec.9.1.5508.60-65

The formation reaction of LiFePO4 from decomposition of precursors LiOH, FeSO4.7H2O and (NH4)2HPO4 with mol ratio of Li:Fe:P=1:1:1 was investigated. The experiment was carried out by thermogravimetric differential thermal analysis (TG-DTA) method using nitrogen as atmosfer at a constant heating rate to obtain kinetic constant parameters. Several heating rates were selected, there are 5, 7, 10, 15, 17.5, 22.5 and 25 °C/min. Activation energy, pre-exponential factor and reaction order were taken using Kissinger method and obtained respectively 56.086 kJ/mol, 6.95×108 min-1, and 1.058. Based on fitting result between reaction model and experiment were obtained that reaction obeyed the three dimension diffusion model. © 2014 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)

Peningkatan Stabilitas Busa dengan Nanofluida Silika Untuk Meningkatkan Produksi Gas Alam Ajiz, Hendrix Abdul; Mawarani, Lizda Johar; Widiyastuti, Widiyastuti; Setyawan, Heru
BERKALA SAINSTEK Vol 8 No 1 (2020)
Publisher : Universitas Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19184/bst.v8i1.15401

Pemanfaatan gas alam sebagai sumber energi alternatif masih belum optimal karena masalah beban cairan pada sumur gas, surfaktan merupakan solusi yang menjanjikan untuk mengatasi masalah tersebut, namun dengan kondisi sumur gas yang ekstrem diperlukan stabilizer untuk meningkatkan stabilitasnya. Penelitian ini mempelajari pengaruh pencampuran surfaktan dan stabilizer berupa silika (SiO2) nanopartikel yang disintesa dari sodium silikat (Na2SiO3) untuk mendapatkan kondisi optimum nanofluida SiO2 terhadap waktu paruh busa yang menunjukkan kestabilannya. Silika nanopartikel disintesa dengan metode sol-gel dan dipertahankan dalam fase koloid stabil yang kemudian didispersikan ke dalam larutan surfaktan tanpa perlu penambahan bahan penyambung. Nanofluida SiO2 kemudian dimatangkan dengan variasi waktu dan konsentrasi silika. Dari hasil yang diperoleh menunjukkan bahwa peningkatan waktu pematangan dan konsentrasi silika memengaruhi nilai tegangan permukaan yang berakibat menurunkan waktu paruh busa. Penurunan kestabilan busa terjadi karena peristiwa adsorbsi fisik molekul surfaktan oleh silika nanopartikel yang ditunjukkan oleh nilai tegangan permukaan, karena silika yang bersifat hidrofilik akan membentuk ikatan fisik dengan surfaktan, semakin meningkatnya waktu pematangan dan konsentrasi silika yang didispersikan kedalam larutan akan meningkatkan adsorbsi molekul surfaktan pada permukaan silika dan menyebabkan terjadinya peningkatan nilai tegangan permukaan nanofluida. Stabilitas busa terbaik diperoleh pada sampel dengan waktu pematangan selama 6 jam dan konsentrasi silika 0,001% menghasilkan waktu paruh selama 1170 menit yang jika dibandingkan dengan surfaktan tanpa penambahan silika nanopartikel hanya memeroleh waktu paruh selama 90 menit, sehingga penggunaan silika nanopartikel sebagai stabilizer memberikan efek yang signifikan terhadap kestabilan busa.

PENDAMPINGAN PENGEMBANGAN POTENSI DESA NGREJENG KECAMATAN GRABAGAN KABUPATEN TUBAN SEBAGAI OBJEK DESTINASI ETNOWISATA MELALUI PENGUATAN POKDARWIS RENGIT ASRI Musrifah, Sri; Kurniahu, Hesti; Putri, Rizca Yunike; Juliansa, Egita Manda Putri; Setyawan, Heru; Febrianti, Ossy; Al-Muhtadhi, M. Zain; Wandani, Yuni Tri; Setiawan, Sony; Rodliyah, Nur Afifatur; Asysidiqi, Moch. Hasybi
Amaliah: Jurnal Pengabdian Kepada Masyarakat Vol 8 No 2 (2024): Amaliah Jurnal: Pengabdian kepada Masyarakat
Publisher : LPPI UMN AL WASHLIYAH

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32696/ajpkm.v8i2.3495

Desa Ngrejeng Kecamatan Grabagan Kabupaten Tuban memiliki destinasi etnowisata berupa Makam Mbah Shodiqo yang telah dikenal dan dikunjungi oleh masyarakat baik dari dalam maupun luar Tuban. Desa Ngrejeng juga memiliki potensi yang belum banyak digali diantaranya potensi pertanian dan peternakan, atraksi budaya, bentang alam dan kuliner. Kegiatan Pengabdian kepada Masyarakat ini bertujuan untuk melakukan penguatan kepada Pokdarwis Rengit Asri Desa Ngrejeng untuk mengembangkan potensi desa sebagai Objek Destinasi Tujuan Wisata (ODTW) terpadu dengan Makam Mbah Shodiqo. Metode yang digunakan dalam pendampingan kepada masyarakat ini adalah Focus Group Discussion (FGD). Tim PKM bersama mitra melakukan diskusi dua arah untuk menggali potensi desa dan kendala pengembangannya menjadi ODTW. Hasil dari kegiatan Pengabdian kepada Masyarakat ini adalah Pokdarwis Rengit Asri mendapatkan peningkatan pengetahuan dan motivasi untuk mengelola potensi desa sebagai ODTW. Selain itu kegiatan ini juga membuka peluang untuk meningkatkan keterampilan Pokdarwis Rengit Asri terkait dengan pengelolaan desa wisata.

KESADARAN HUKUM MAHASISWA TERHADAP ATURAN TENTANG AREA KAWASAN TANPA ROKOK (Studi di Kampus Universitas Negeri Surabaya) Setyawan, Heru
NOVUM : JURNAL HUKUM Vol. 5 No. 03 (2018): Novum : Jurnal Hukum
Publisher : Universitas Negeri Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.2674/novum.v5i3.36058

Kawasan tanpa rokok adalah area yang dinyatakan dilarang untuk kegiatan produksi,penjualan,iklan, promosi dan atau penggunaan rokok. Kesadaran hukum adalah kesadaran yang ada pada setiap manusia tentang apa hukum itu atau apa seharusnya hukum itu. Kesadaran hukum terkait kawasan tanpa rokok di tempat proses belajar mengajar pada kenyataannya masih banyak terjadi pelanggaran. Pelanggaran dilakukan pada area yang dinyatakan dilarang menggunakan rokok di Universitas Negeri Surabaya. Tujuan penelitian ini yaitu untuk menganalisis kesadaran hukum mahasiswa dan upaya yang dilakukan Universitas Negeri Surabaya dalam meningkatkan kesadaran hukum mahasiswa terhadap peraturan tentang area kawasan tanpa rokok. Penelitian ini merupakan penelitian yuridis empiris yang berlokasi di Universitas Negeri Surabaya. Data yang digunakan adalah data primer dan sekunder. Pengumpulan data dilakukan melalui kuesioner,wawancara, dan dokumentasi. Informan dalam penelitian ini adalah mahasiswa S1 Universitas Negeri Surabaya yang berjenis kelamin laki-laki dan Kepala Bagian Umum,Hukum,Tata Laksana dan Perlengkapan Universitas Negeri Surabaya. Teknik analisis data menggunakan metode kuantitatif deskriptif. Hasil penelitian menunjukan bahwa kesadaran hukum mahasiswa S1 Universitas Negeri Surabaya tergolong dalam kriteria penilaian yang rendah, terbagi dalam empat indikator kesadaran hukum yaitu, pengetahuan hukum tergolong dalam kategori tinggi, pemahaman hukum tergolong dalam kriteria rendah, sikap hukum tergolong dalam kriteria rendah, dan perilaku hukum tergolong dalam kriteria yang rendah. Kendala dalam meningkatkan kesadaran hukum mahasiswa yaitu pihak universitas belum melakukan sosialisasi, aturan larangan merokok diterapkan sepenuhnya di lingkungan universitas, serta pemberian sanksi yang ringan kepada pelanggar. Upaya yang dapat dilakukan adalah dengan melakukan sosialisasi di lingkungan internal,menerapkan aturan larangan merokok di seluruh lingkungan Universitas,serta melakukan pengawasan dan pembinaan.

Pelapisan Silika pada Stainless Steel secara Elektroforesis Disertai Anodisasi untuk Perlindungan Korosi Suari, Ni Made Intan Putri; Ratnasari, Delyana; Tulaini, Sahara; Widiyastuti, Widiyastuti; Setyawan, Heru
Jurnal Rekayasa Kimia & Lingkungan Vol 14, No 1 (2019): Jurnal Rekayasa Kimia & Lingkungan (June, 2019)
Publisher : Chemical Engineering Department, Syiah Kuala University, Banda Aceh, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23955/rkl.v14i1.13159

Penelitian ini mempelajari pengaruh anodisasi terhadap karakteristik perlindungan korosi lapisan silika pada permukaan stainless steel. Anodisasi dilakukan menggunakan larutan asam oksalat dengan memvariasikan waktu anodisasi dan beda tegangan. Elektroforesis dilakukan menggunakan campuran sol silika, isopropanol dan asam asetat dengan perbandingan mol 0,0028 : 0,5048 : 0,1938 selama 10 menit dengan amplitudo 0,5 V, frekuensi 80 Hz dan duty cycle 60%. Dilakukan uji Particle Size Analyzer (PSA) terhadap sol silika. Diperoleh distribusi ukuran partikel sebesar 3,19 nm dan zeta potensial -31,68 mV. Dilakukan analisa polarisasi linear dan Electrochemical Impedance Spectroscopy (EIS) dengan larutan NaCl 3,5% serta Scanning Electron Microscopy (SEM) terhadap lapisan yang terbentuk pada permukaan stainless steel. Dari hasil analisa diperoleh logam yang telah dianodisasi dan elektroforesis memiliki kemampuan perlindungan korosi lebih baik dibanding logam tanpa perlakuan. Waktu dan beda tegangan saat anodisasi berpengaruh terhadap karakteristik perlindungan korosi lapisan pada logam. Diperoleh waktu anodisasi optimum selama 20 menit dan voltase 10 volt dengan laju korosi sebesar 0,000659 mm/tahun. Untuk uji EIS, nilai admitan dan nilai tahanan pori masing-masing sebesar 1.824,7 ohm dan 0,0010226 Mho. Hasil SEM menunjukkan bahwa setelah dilakukan anodisasi terbentuk lapisan yang berpori yang nantinya menjadi tempat menempelnya silika pada proses elektroforesis.

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