Articles

Found 5 Documents
Search

Mekanisme Proses Tahap Ekstraksi Karagenan Dari Eucheuma cottonii Menggunakan Pelarut Alkali (The Mechanism of Carrageenan Extraction from Eucheuma cottonii Using Alkaline Solvent) Distantina, Sperisa; Rochmadi, Rochmadi; Wiratni, Wiratni; Fahrurrozi, Moh.
Agritech Vol 32, No 4 (2012)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (276.616 KB) | DOI: 10.22146/agritech.9583

Abstract

Carrageenan recovery process was developed for Eucheuma cottonii by investigating the effects of distilled water, KOH (0.1-0.5 N) and NaOH (0.1-1.0 N) as the solvent on carrageenan yield and gel properties. Extraction process was carried out with a constant ratio of seaweed weight to solvent volume (1: 50; g/mL) at 80oC.  A certain amount of the liquid sample was withdrawn at regular interval time for analysis. Filtrate was separated from residue by pouring ethanol. The precipitated carrageenans were collected and oven dried at 50-60oC to a constant weight. The extraction product was found to have virtually identical infrared spectra to the reference samples of kappa-carrageenan. Distilled water was the most efficient solvent with regard to yield but certainly not gel strength. Increasing KOH concentration led to carrageenan containing less sulfate content. In extraction process using alkali, the ion exchange occurred between cation from alkali solution and anion from sulphate in the seaweed. Compared with cation of sodium, the cation of potassium was able to form helixes aggregation indicated by the higher gel strength value. Alkali concentrations affected the gel strength of the extracted carrageenan significantly.ABSTRAKPenelitian ini bertujuan mengembangkan proses ekstraksi karagenan dari rumput laut Eucheuma cottonii dengan mempelajari pengaruh jenis pelarut pada tahap ekstraksi, yaitu air suling, KOH, dan NaOH terhadap rendemen dan sifat gel karagenan.  Ekstraksi dilakukan dengan perbandingan bobot rumput laut – volume pelarut dijaga tetap yaitu 1:50 g/mL pada 80oC. Cuplikan diambil setiap interval waktu tertentu untuk dianalisis. Karagenan dalam filtrat diendapkan dengan etanol dan serat yang dihasilkan dikeringkan sampai bobot konstan. Spektrum infra merah menunjukkan bahwa karagenan yang dihasilkan identik dengan jenis kappa. Air suling merupakan pelarut yang efisien untuk mendapatkan rendemen yang tinggi, tetapi kekuatan gel karagenan yang dihasilkan rendah. Konsentrasi KOH semakin tinggi akan menghasilkan karagenan dengan kadar sulfat semakin rendah dan kekuatan gel meningkat.   Pada tahap ekstraksi menggunakan alkali, terjadi peristiwa pertukaran ion antara kation dalam pelarut dengan ion sulfat dalam rumput laut. Dibandingkan dengan kation Na, kation K mampu membentuk agregasi heliks yang terindikasi berdasarkan kekuatan gel yang lebih kuat.
PURIFICATION AND CHARACTERIZATION OF POLY-HYDROXYBUTYRATE (PHB) IN CUPRIAVIDUS NECATOR De Rooy, Sergio Leon; Wahyuni, Endang Tri; Wiratni, Wiratni; Syamsiah, Siti; Ismail, Jamil
Indonesian Journal of Chemistry Vol 7, No 3 (2007)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (266.719 KB) | DOI: 10.22146/ijc.21664

Abstract

Purification and characterization of biodegradable plastic namely Polyhydroxybutyrate (PHB) in Cupriavidus necator have been carried out. C. necator was grown on a Ramsay medium with fixed substrate conditions and optimized for time. Stepwise purification of PHB was carried out, by using hydrogen peroxide and chloroform. The effect of temperature, time, and hydrogen peroxide concentration on the purification were also evaluated. The extracted PHB was studied with XRD, FTIR and 1H-NMR and 13C-NMR to determine its structure and purity. Yield and crystallinity were also studied with HPLC and XRD, respectively. The results of the research showed that higher concentrations of hydrogen peroxide gave better yields, whereas higher temperatures and longer lysis times led to different results. Higher crystallinity was observed when purification temperatures were elevated, but higher hydrogen peroxide concentration and longer extraction time gave varying crystallinity. The highest yield ca 66.10 % DCW was reached by purification using H2O2 20 %, at 100 oC for 2 h. The results of   TGA analysis indicated that the purity of the PHB obtained was about 75 % and by using DSC, it was found that the PHB showed good thermal properties.
Lanthanum and Nickel Recovery from Spent Catalyst using Citric Acid: Quantitative Performance Assessment using Response Surface Method Petrus, Himawan Tri Bayu Murti; Wijaya, Ardyanto; Iskandar, Yusuf; Bratakusuma, Danu; Setiawan, Hendrik; Wiratni, Wiratni; Astuti, Widi
Metalurgi Vol 33, No 2 (2018): Metalurgi Vol. 33 No. 2 Agustus 2018
Publisher : Pusat Penelitian Metalurgi dan Material - LIPI

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (523.642 KB) | DOI: 10.14203/metalurgi.v33i2.437

Abstract

Heavy metals and Rare earth elements (REEs) are nowadays being used widely in many industries from electronics to petroleum industries as catalysts. However, their disposal caused serious problems to the environment. With the sharp growth in its usage, there is a better way to use and utilize valuable metals from secondary sources such as their disposal rather than using new raw materials. The aim of this work is to study the potential of citric acid as a leaching agent to extract lanthanum and nickel in various acid concentration and leaching temperature. The raw material used in this work is spent catalyst from Pertamina Refinery Unit VI, Balongan, Indonesia. The spent catalyst is decarbonized with a heat treatment at 725°C for 10 minutes before the leaching process. The leaching process used 0.1; 1; and 2 M of citric acid with a varied temperature of 30, 60, and 80°C. The lanthanum recovery was calculated by comparing the mass percentage of lanthanum before leaching process and after leaching process using Energy Dispersive X-Ray Spectroscopy (EDX). The results were analyzed by response surface methodology (RSM) and are proved to be a reliable method to depict and analyze the leaching characteristics. The molarity of the citric acid is the most significant independent variables used in the research for lanthanum recovery response. However, based on the Pareto analysis result there are no significant variables that affect the recovery of nickel. The second order polynomial fitting model is also proved to be compatible with the response of lanthanum recovery but is less compatible with nickel recovery.
PRE-TREATMENT DAN FERMENTASI HIDROLISAT KULIT BUAH KAKAO MENJADI ASAM LAKTAT MENGGUNAKAN LACTOBACILLUS PLANTARUM Irwanto, Dodi; Wiratni, Wiratni; Rochmadi, Rochmadi; Syamsiah, Siti
Reaktor Volume 16 No.3 September 2016
Publisher : Dept. of Chemical Engineering, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (350.831 KB) | DOI: 10.14710/reaktor.16.3.123-127

Abstract

Abstract COCOA POD HUSK PRE-TREATMENT AND HYDROLYZATE FERMENTATION INTO LACTIC ACID USING LACTOBACILLUS PLANTARUM. Lactic acid is a raw material that is widely used in food industry as preservatives in meat, vegetables or canned fish. In the pharmaceutical industry is used as raw material for the manufacture of drugs. Lactic acid can be made from natural materials such as lignocellulosic waste one of them is cocoa shell waste. Indonesia is number three cocoa-producing country in the world. 70% cacao fruit components such as pod husk are composed of cellulose, hemicellulose and lignin, so it has the potential to be converted into lactic acid. In this study been the conventional method to determine the overall process in order to know what parts need to be further developed to become a method more effective and efficient. The conventional method is done through several processes, namely the delignification, hydrolysis and fermentation using microorganisms. This study aims to determine the extent of the potential for cocoa pod husk waste to be converted into lactic acid. The results showed that the pod husks delignification with sodium hydroxide solution reaches optimum at a concentration of 6% which results in lower levels of lignin from 30.46 to 24.64%. The process of acid hydrolysis of the pod husks achieve optimum conditions at a concentration of 2.0%, a temperature of 120°C and a 30 minute production of glucose at 32g/L. Glucose is the result of acid hydrolysis produces lactic acid by 13.268g/L. Keywords: lactic acid; delignification; fermentation; hydrolysis; cocoa pod husks   Abstrak Asam laktat adalah salah satu bahan baku yang banyak dimanfaatkan pada industri makanan sebagai bahan pengawet daging, sayuran atau ikan kalengan. Dalam industri farmasi digunakan sebagai bahan baku pembutan obat-obatan. Asam laktat dapat dibuat dari bahan alam berupa limbah lignoselulosa yang salah satunya adalah limbah kulit kakao. Indonesia merupakan negara penghasil kakao nomor tiga di dunia. Komponen buah kakao 70% berupa kulit buah yang terdiri dari selulosa, hemiselulosa dan lignin, sehingga berpotensi untuk dikonversi menjadi asam laktat. Pada penelitian ini dipilih metode konvensional untuk mengetahui proses secara keseluruhan sehingga diketahui bagian mana yang perlu dikembangkan lebih lanjut untuk menjadi metode yang lebih efektif dan efisien. Metode konvensional dilakukan melalui beberapa proses, yakni delignifikasi, hidrolisis, dan fermentasi menggunakan mikroorganisme. Penelitian ini bertujuan untuk mengetahui sejauh mana potensi limbah kulit buah kakao untuk dikonversi menjadi asam laktat. Hasil penelitian menunjukkan bahwa delignifikasi kulit buah kakao dengan larutan sodium hidroksida mencapai kondisi optimum pada konsentrasi 6% yang menyebabkan penurunan kadar lignin dari 30,46% menjadi 24,64%. Proses hidrolisis asam terhadap kulit buah kakao terdelignifikasi mencapai kondisi optimum pada konsentrasi 2,0%, suhu 120°C dan waktu 30 menit yang menghasilkan glukosa sebesar 32g/L. Glukosa hasil hidrolisis asam menghasilkan asam laktat sebesar 13,268g/L. Kata kunci: asam laktat; delignifikasi; fermentasi; hidrolisis; kulit buah kakao 
PEMODELAN MATEMATIS ADSORPSI CO2 DENGAN STRONG BASE ANION EXCHANGE RESIN SEBAGAI ADSORBEN UNTUK PURIFIKASI BIOGAS Mutiari, Anies; Wiratni, Wiratni; Mindaryani, Aswati
Jurnal Teknologi Bahan dan Barang Teknik Vol 5, No 1 (2015)
Publisher : Center for Material and Technical Product

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (256.148 KB) | DOI: 10.37209/jtbbt.v5i1.54

Abstract

Pemurnian biogas telah banyak dilakukan untuk menghilangkan kadar CO2  dan meningkatkan kandungan CH4  yang terkandung di dalamnya. Kandungan CH4 yang tinggi akan memberikan unjuk kerja yang lebih baik. Model  matematis proses adsorpsi CO2 disusun berdasarkan teori lapisan film antar fasa, dimana pada proses yang ditinjau terdapat tiga fase yaitu gas, cair dan padat. Model matematis dari data eksperimental   kecepatan dan kesetimbangan proses adsorpsi CO2 melalui mekanisme pertukaran ion di suatu kolom adsorpsi telah dibuat. Model ini dibuat untuk mencari konstanta yang dapat dipergunakan pada proses scale up data laboratorium ke skala pilot plant. Parameter proses kecepatan yang dicari nilainya adalah koefisien transfer massa massa volumetris CO2 pada fase cair (kLa), koefisien transfer massa volumetris CO2 pada fasegas (kGa) dan tetapan laju reaksi (k1 dan k2). Pada hasil penelitian ini ditunjukkan bahwa nilai parameter yang diperoleh sesuai hasil fitting data dengan model matematis yang digunakan, yaitu model transfer massa pada lapisan film antar fase secara seri: adalah kGa, kla, k1 dan k2  dengan nilai Sum of Squares Error (SSE) rata-rata 0,0431. Perbandingan nilai kGa hasil simulasi dan teoritisnya memberikan kesalahan rata-rata 18,79%. Perbandingan nilai kLa hasil simulasi dan teoritis memberikan kesalahan rata-rata 7,92%.Kata kunci: model matematis, adsorpsi CO2, pemurnian biogas