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All Journal Reaktor IPTEK Journal of Proceedings Series IPTEK The Journal for Technology and Science Bulletin of Chemical Reaction Engineering & Catalysis Bulletin of Chemical Reaction Engineering & Catalysis

Widiyastuti Widiyastuti

Institut Teknologi Sepuluh Nopember

Author-ID : 2764343

Chemical Engineering, Chemistry & Bioengineering Chemistry Computer Science & IT Control & Systems Engineering Energy Materials Science & Nanotechnology

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Articles

Title

Corrosion Characteristics of Carbon Steel upon Exposure to Biodiesel Synthesized from Used Frying Oil Adhi Setiawan; Nora Amelia Novitrie; Agung Nugroho; W Widiyastuti
Reaktor Volume 17 No. 4 Desember 2017
Publisher : Dept. of Chemical Engineering, Diponegoro University

The use of biodiesel leads to corrosion of automotive material, which can potentially shorten engine lifetime. The study aims to investigate the effect of temperature and contact time on the corrosion characteristics of carbon steel upon exposure to biodiesel synthesized from used frying oil. The corrosion rate of carbon steel was analyzed based on weight loss measurement according to the standard of ASTM G31 as affected by temperature and contact time. The immersion temperatures used in this study were 30oC, 40oC, and 70o, respectively. The contact times studied were 30 days, 40 days, and 50 days respectively. The results show that the increase of temperature and contact time of biodiesel on carbon steel surface speeds up the corrosion rate. Maximum corrosion rate (0.083 mmy) was observed on the carbon steel contacted to biodiesel at 70oC for 50 days. The SEM results showed an irregular shape of the corroded carbon steel surface. XRD / FTIR analysis of carbon steel samples show the presence of peaks, detected as Fe2O3, FeO(OH) and Fe2O2CO3, as the corrosion products. Keywords: biodiesel; carbon steel; corrosion; FAME; used frying oil

KINETIKA REAKSI SINTHESIS BIOMATERIAL HIDROXYAPATITE DENGAN JENIS PREKURSOR NITRAT DAN ASETAT Adhi Setiawan; W Widiyastuti; Sugeng Winardi; Agung Nugroho
Reaktor Volume 15, No.2, OKTOBER 2014
Publisher : Dept. of Chemical Engineering, Diponegoro University

Hidroxyapatite (HAp) merupakan salah satu biomaterial yang banyak diaplikasikan dalam dunia medis untuk membuat implant jaringan tubuh terutama tulang dan gigi sehingga kemurnian produk HAp memegang peranan yang cukup penting. Agar diperoleh HAp dengan kemurnian tinggi, kinetika reaksi pembentukan HAp harus diketahui secara jelas. Metode yang digunakan untuk memperoleh kinetika reaksi HAp adalah dengan analisis TG-DTA yang dilakukan pada dua jenis prekursor HAp yaitu asetat dan nitrat. Metode TG-DTA tersebut dilakukan dengan memanaskan prekursor HAp dengan variasi laju pemanasan 10, 15, 17, dan 20 oC/menit. Hasil analisis TG-DTA menunjukkan bahwa reaksi dekomposisi prekursor asetat dan nitrat membentuk HAp masing-masing terjadi pada suhu 659 oC dan 560 oC. Hasil fitting parameter kinetika menunjukkan bahwa energi aktivasi pembentukan HAp pada prekursor asetat sebesar 161,56 kJ/mol dengan model kinetika Normal Grain Growth sedangkan pada prekursor nitrat sebesar 374 kJ/mol dengan model kinetika Johnson-Mehl-Avrami. Kata kunci: Biomaterial, hidroxypapatite, Dekomposisi, Energi Aktivasi ABSTRACT KINETIC STUDY OF THE BIOMATERIAS HIDOXYAPATITE SINTHESIS WITH PRECURSOR NITRATE AND ACETATE. Hidroxyapatite (HAp) is one of the biomaterials widely applied in the medical world to make implant tissues of the body, especially bones and teeth so that the purity of the HAp plays a fairly important. In order to obtain high purity HAp, reaction kinetics should be known clearly. TG-DTA is method used to obtain the reaction kinetics of HAp.TG-DTA analyzes were conducted on precursors acetate and nitrate. TG-DTA method is carried out by heating HAp precursor with variation heating rate 10, 15, 17, and 20° C/min respectively. The results of TG-DTA showed decomposition precursor acetate and nitrate formed HAp occurs on temperature 659° C and 560° C respectively. The results of the fitting kinetic showed activation energy of the HAp formation on acetate precursors about 161.56 kJ/mol with Normal Grain Growth kinetic model whereas the nitrate precursor about 374 kJ/mol with Johnson-Mehl-Avrami kinetic model.

SINTESIS BIOMATERIAL HYDROXYAPATITE DENGAN PROSES FLAME SPRAY PYROLYSIS DISERTAI PENAMBAHAN ADITIF ORGANIK Adhi Setiawan; W Widiyastuti; Sugeng Winardi; Agung Nugroho
Reaktor Volume 16 No.4 Desember 2016
Publisher : Dept. of Chemical Engineering, Diponegoro University

SYNTHESIS OF HYDROXYAPATITE BIOMATERIALS BY FLAME SPRAY PYROLYSIS PROCESS WITH ADDITION OF ORGANIC ADDITIVES. Hydroxyapatite is biomaterial which is widely used for biomedical aplication such as implant because biocompatible, bioactivity, and strong affinity to biopolymers. Therefore parameters of morphology and crystallinity becomes an important parameter to be controlled. The addition of the organic additive on HAp precursor with ethylene glycol, polyethylene glycol 400, and urea is the alternative to improve the size, morphology, and crystallinity of HAp particles. The equipment for flame spray pyrolysis process includes ultrasonic nebulizer, flame reactor, and eletrostatic precipitator. The amount of organic additives used in experiment is 30%, 50%, and 100% by mass of the precursor. The result of SEM and XRD showed HAp synthesized by the addition of additive material has a smaller size than without using the additive and crystallinity is better than no additive. In addition HAp synthesized by the addition of 30% PEG additive have smallest average particle size about 114 nm, crystalite size about 16,6 nm and spherical morphology with a low agglomeration. Keywords: Hidroxyapatite, organic additives, flame spray pyrolysis, morfology Abstrak Hydroxyapatite merupakan biomaterial yang seringkali diaplikasikan dalam biomedis sebagai bahan implant karena sifatnya yang biocompatible, bioactivity, dan memiliki afinitas yang kuat terhadap biopolimer. Oleh karena itu parameter morfologi serta kristalinitas partikel menjadi parameter penting untuk dikontrol. Penambahan aditif organik pada prekursor HAp dengan etilen glikol, polietilen glikol 400, serta urea merupakan alternativ agar memperbaiki ukuran, morfologi, serta meningkatkan kristalinitas partikel HAp. Peralatan utama flame spray pyrolysis meliputi ultrasonic nebulizer, reaktor flame, dan eletrostatik precipitator. Jumlah aditif organik yang digunakan pada eksperimen antara lain 30%, 50%, dan 100% massa prekursor. Hasil SEM dan XRD menunjukkan bahwa HAp yang disintesis dengan penambahan bahan aditif memiliki ukuran lebih kecil daripada tanpa menggunakan aditif dan tingkat kristalinitasnya lebih baik dibandingkan tanpa aditif. Selain itu HAp yang disintesis dengan penambahan aditif PEG sebanyak 30% memiliki ukuran rata-rata partikel yang terkecil yaitu sebesar 114 nm dengan ukuran kristal mencapai 16,6 nm serta memiliki morfologi bulat dengan tingkat aglomerasi yang rendah.

Co-Authors Abdul Halim Adhi Setiawan Agung Nugroho Agung Nugroho Ajiz, Hendrix Abdul Albar, Abdurrahman Anis Delyana Ratnasari Ervina Rumpakwakra Fadlilatul Taufany Fahmi Fahmi Hariyati Purwaningsih Heru Setyawan Iva Maula Lizda Johar Mawarani Muhamad Nirwan Ni Made Intan Putri Suari Nora Amelia Novitrie Sahara Tulaini Siti Machmudah Tantular Nurtono Winardi, Sugeng

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