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All Journal Jurnal Penelitian Saintek Jurnal Sains Dasar Indonesian Journal of Science and Technology Jurnal Pengabdian Masyarakat MIPA dan Pendidikan MIPA Indonesian Journal of Chemistry and Environment Jurnal Elemen Kimia TPACK-IPA (Technological Pedagogical Content Knowledge)
Siti Marwati
Departemen Pendidikan Kimia FMIPA UNY
Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Decision Sciences, Operations Research & Management Education Environmental Science Materials Science & Nanotechnology

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Pengaruh suhu dan waktu proses terhadap karakter biodiesel hasil sintesa dari minyak biji ketapang Siswani, Endang Dwi; Kristianingrum, Susila; Marwati, Siti; Noviantara, Arief; Yuniastuti, Rosa
Jurnal Sains Dasar Vol 2, No 2 (2013): October 2013
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21831/jsd.v2i2.3345

Abstract

Abstrak Penelitian ini bertujuan mengetahui pengaruh suhu dan waktu proses transesterifikasi terhadap karakter biodiesel hasil sintesa dari minyak biji ketapang. Karakter biodiesel dilakukan menggunakan standar SNI. Penelitian ini dilakukan di laboratorium Kimia, Jurusan Pendidikan Kimia, FMIPA UNY, sedangkan pengujian karakter biodiesel hasil sintesa dilakukan di Laboratorium Teknologi Minyak Bumi, Gas, dan Batubara, Jurusan teknik Kimia, Fakultas teknik UGM. Sintesa biodiesel dari minyak biji ketapang dilakukan melalui dua (2) tahap. Tahap pertama adalah pengambilan minyak dari biji ketapan, dan tahap kedua adalah proses transesterifikasi dengan menggunakan metanol. Proses dilaksanakan pada berbagai berbagai harga suhu, yaitu: 35, 57, 78 dan 89 oC dan berbagai waktu, yaitu: 60 dan 120 menit. Biodiesel hasil sintesa dianalisis menggunakan FTIR, sedangkan karakter biodisel dicari dengan bantuan alat yang ada dalam Laboratorium Teknologi Minyak Bumi, Gas. dan Batubara, Fakultas Teknik UGM. Hasil penelitian ini adalah sebagai berikut. Variasi suhu proses transesterifikasi tidak memberikan perbedaan yang signifikan pada nilai massa jenis, viskositas, titik nyala, titik tuang, dan kalor pembakaran. Ada pengaruh suhu terhadap proses transesterifikasi terhadap jumlah biodiesel yang dihasilkan yaitu untuk suhu reaksi 35, 57, 78, dan 780C menghasilkan biodiesel berturut turut sebanyak 368, 450, 435, dan 316 mL. Nilai massa jenis biodiesel BA, BB, BC dan BD berturut turut adalah sebesar 869.5, 858.6, 859, dan 858.8 kg/m3. Nilai viskositas untuk biodiesel BA, BB, BC, dan BD berturut turut adalah sebesar 5.867 ± 0.00194, 5.300, 4.820 ± 0.0005 mm2/s, dan 4.700 mm2/s. Nilai titik nyala untuk biodiesel BA, BB, BC, dan BD berturut turut adalah sebesar: 176.5, 172.5, 172.5, dan 174.50C. Nilai titik tuang untuk biodiesel BA, BB, BC, dan BD adalah sebesar 90C. Nilai kalor pembakaran untuk biodiesel BA, BB, BC, dan BD hasil sintesis berturut-turut adalah sebesar: 9466.472, 9482.149, 9561.2445, dan  9506.199 kal/g. Ada pengaruh waktu 60 dan 120 menit pada proses transesterifikasi terhadap jumlah biodiesel yang dihasilkan yaitu waktu 60 menit menghasilkan biodiesel sebanyak  ±260 mL (biodiesel BP), dan waktu 120 menit menghasilkan biodiesel sebanyak ±275 mL (biodiesel BQ). Nilai densitas, viskositas, titik tuang, titik nyala, kalor pembakaran masing-masing biodiesel secara berturut-turut adalah untuk biodiesel BP (waktu transesterifikasi 60 menit) yaitu (888,800 kg/m3; 10,48 cSt; 6 0C; 188,5 0C; 9889,64 kal/g) dan untuk biodiesel BQ (waktu transesterifikasi 120 menit) yaitu (88,800 kg/ m3; 11,99 cSt; 6 0C; 188,5 0C; 9788,003 kal/g).   Kata kunci:  minyak biji ketapang, variasi suhu, waktu transesterifikasi, karakter biodiesel
OPTIMIZATION OF CONDITION ION Cu2+ ELECTRODEPOSITION IN ELECTROPLATING LIQUID WASTE WITH FORMALDEHYDE AS REDUCING AGENT Marwati, Siti; Padmaningrum, Regina Tutik
Jurnal Sains Dasar Vol 5, No 1 (2016): April 2016
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (796.156 KB) | DOI: 10.21831/jsd.v5i1.12670

Abstract

Abstract The aims of this research to determine of the optimum of formaldehyde concentration, teh optimum of electrodeposition time and the optimum pH of solution. In addition, this research also   aims to determine the character Cu deposite at optimum operational. The sample in this research was used   real electroplating liquid waste from Kotagede Yogyakarta.done at various formaldehyde concentration Electrodeposition was done at various formaldehyde concentration, electrodeposition time and varoius of pH. The optimum conditions could be seen  the  maximum efficiency. It could be obtained by measuring the final concentration of Cu2+ after electrodeposition process by  Atomic absorption spectrophotometry. The character of deposit could be seen by  visual and X-ray Diffraction. The result  of this research showed that the optimum of formaldehyde concentration as reducing  agent was 0.3 M. the optimum time was 4 hours and the optimum of  pH 9. The character of deposte was contained  Cu deposite and more subtle than deposite which electrodeposited without formaldehyde. Keywords: electrodeposition, formaldehyde, reducing agent
USE OF PRESIPITATION METHODS TO REDUCE Cu IN THE LIQUID WASTE INDUSTRY LIQUID IN KOTAGEDE Chanel Tri Handoko; Tri Budi Yanti; Halimatus Syadiyah; siti marwati
Jurnal Penelitian Saintek Vol 18, No 2: Oktober 2013
Publisher : Institute of Research and Community Services, Universitas Negeri Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (822.514 KB) | DOI: 10.21831/jps.v18i2.2140

Abstract

This research was to determine the optimal pH decreased level of Cu using precipitation method and effectivity of the reduction Cu metal level using lime solution as precipitatingagent. The research was conducted by collecting the silver industrial wastewater samples from 3 different places, analyzing the initial Cu level, precipitation treatment of the sample, and analyzing the Cu level after precipitation process. Precipitation process was done by reacting the waste water sample and a solution of Ca(OH)2 0.2 M at pH variation of 7, 8, 9, 10, and 11, then allowed to settle for 24 hours. Then the optimal pH of the experiment was used as a pH in the precipitation process using 5% lime solution.  Analysis of the Cu metal level in this study was using AAS instrument. Sample C has pH value =10.3 (alkaline), so no further precipitation process is carried out on sample C. Optimal pH precipitation to decresase Cu level is 8. Cu level after treatment precipitation using 5% lime solution at pH 8 is 0.6583 ppm for sample A and 0.4697 ppm for sample B. When compared with the initial Cu level it is 28132.7430 ppm for sample A and 11233.467 ppm for sample B, the precipitation method using lime solution effective to reduce Cu level. 
Pengaruh Konsentrasi Formaldehid sebagai Agen Pereduksi Terhadap Efisiensi Elektrodeposisi Ag+ dalam Limbah Cair Elektroplating Siti Marwati; Regina Tutik Padmaningrum; Susila Kristianingrum; Sunarto '
Jurnal Sains Dasar Vol 2, No 1 (2013): April 2013
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (187.061 KB) | DOI: 10.21831/jsd.v2i1.3361

Abstract

Abstrak penelitian ini bertujuan untuk mengetahui pengaruh konsentrasi formaldehid sebagai agen perduksi terhadap efisiensi elektrodeposisi ion Ag+ dalam limbah cair elektroplating dan mengetahui karakter logam Ag hasil elektrodeposisi. Proses elektrodeposisi dengan elektroda platina sebagai anoda dan katoda. Konsentrasi larutan formaldehid divariasi yaitu 0,4; 0,3; 0,2; 0,1 M dan tanpa penambahan formaldehid. Ion Ag+ yang masih tersisa dalam limbah cair elekroplating dilakukan analisis konsentrasi ion Ag+ dengan menggunakan AAS. Untuk mengetahui struktur kristal deposit dilakukan analisis dengan menggunakan XRD. Hasil penelitian ini diperoleh kesimpulan bahwa konsentrasi formaldehid sebagai agen pereduksi berpengaruh terhadap berat deposit yang dihasilkan. Konsentrasi formaldehid sebagai agen pereduksi berpengaruh terhadap efisiensi elektrdeposisi ion Ag+ dalam limbah cair elektroplating. Efisiensi elektrodeposisi ion Ag+ paling besar diperoleh pada penambahan formaldehid 0,2 M. Karakter deposit yang dihasilkan menunjukkan bahwa di dalam deposit terdapat logam Ag dan Cu yang terdeposisikan. Adanya formaldehid menyebabkan susunan atom-atom deposit Ag di setiap bidang kisi menjadi tidak teratur dan menurunkan tingkat kekristalannya. Kata kunci: formaldehid,agen pereduksi, elektrodeposisi, perak
Pemanfaatan limbah bonggol pisang sebagai bahan baku pembuatan bioetanol Sunarto '; Sulistyani '; Siti Marwati
Jurnal Sains Dasar Vol 2, No 1 (2013): April 2013
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (38.373 KB) | DOI: 10.21831/jsd.v2i1.3362

Abstract

Abstrak Penelitian ini bertujuan untuk mengetahui pengaruh penggunaan berbagai jenis substrat bonggol pisang terhadap hasil bioetanol dan untuk mengetahui Jenis bonggol pisang yang menghasilkan bioetanol yang terbaik  dan mengetahui ada tidaknya pengaruh jenis bonggol pisang terhadap kadar bioetanol. Sebanyak  0,5 kg substrat bonggol pisang Kepok,Raja dan Batu dihaluskan dan dikukus selama  30 menit. Setelah dingin masing masing ditambahkan 3 gram Ragi NKL dan dilakukan fermentasi selama 4 hari. Hasil fermentasi diambil sebanyak 1  ml dan dilakukan analisis menggunakan unit Micro Conway Difussion untuk menentukan kandungan bioetanolnya. Hasil analisis dilakukan uji Anava satu jalur untuk menentukan ada tidaknya pengaruh jenis substrat bonggol pisang terhadap kadar bioetanol. Hasil penelitian menunjukkan bahwa  bonggol pisang Raja memberikan hasil bioetanol terbaik yaitu 0,5 % dan tidak ada pengaruh yang signifikan terhadap penggunaan berbagai jenis substrat bonggol pisang terhadap hasil bioetanol. Hasil uji statistik  menunjukkan F hitung dari F table pada taraf signifikan 5 %.   Kata kunci: bioetanol, micro conway difussion
RECOVERY OF GOLD (Au) AND SILVER (Ag) METALS IN THE ELECTRONIC WASTE THROUGH MULTILEVEL PRECIPITATION PROCESS Siti Marwati; Regina Tutik Padmaningrum; Sunarto Sunarto
Jurnal Sains Dasar Vol 4, No 2 (2015): October 2015
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (121.655 KB) | DOI: 10.21831/jsd.v4i2.9099

Abstract

This research aims to determine the percent recovery of gold (Au) and silver (Ag) in the electronic waste such as CD-RW and determine the purity of gold and silver metals in the electronic waste such as CD-RW that through multilevel precipitation process. The first step was the optimization of the concentration of thiourea and time dissolution of gold and silver in the sample. The concentration of thiourea and the time dissolution optimum obtained from conentration of gold and silver maximum. By The percent recovery of gold and silver are determined by comparing the concentration of gold and silver between in the solution sample and in the sample without dissolution that be analyzed by XRF. The scond step was the multilevel precipitation process and calcination. Precipitation and calcination of the filtrat was dissolution results in the optimum condition. Reagent used was a solution of hydrochloric acid and potassium carbonate. The precipitation gold and silver produced from the precipitation of dissolution again and then be analyzed by atomic absorption spectrophotometry. The purity was determined by comparing the weight of gold and silver between in the precipitate and in the solution.  The results of this research showed that the percent recovery of the silver in the CD-RW through the process dissolution with thiourea 10 g/L and 4 hours soaking time were 21.09 %. The purity silver preipitate were 0.15 %. The percent recovery and the purity of gold can  not be determined because the gold contained in the sample were not detected or below the limit of detection equipment. Keywords: recovery, gold, silver, electronic  waste
VALIDATION OF CYCLAMATE ANALYSIS METHOD WITH SPECTROPHOTOMETRY AND TURBIDIMETRY Regina Tutik Padmaningrum; Siti Marwati
Jurnal Sains Dasar Vol 4, No 1 (2015): April 2015
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (99.479 KB) | DOI: 10.21831/jsd.v4i1.8435

Abstract

This research aims to validate methods of analysis by spectrophotometry and turbidimetry cyclamate in the sample drink mango-flavored jelly drink  by spectrophotometry with hypochlorite reagent, ultraviolet spectrophotometry (without reagent) and turbidimetry. The object of research was the validity parameters spectrophotometric method were linearity, linear range, the limit of detection, limit of quantitation, precision, and accuracy. The calibration curve of standard solution of sodium cyclamate in the spectrophotometric method with hypochlorite reagent, UV spectrophotometry (without reagent), and turbidimetry are linear. Linear range each method respectively at a concentration were (211.36-747.08); (16.000-146.434); and (1.8521-6.1717) ppm. The detection limit of each method successively were 53.6028; 0.5833; and 0.2723 ppm. Limit of quantitation each method successively were 66.9948; 1.9443; and 0.8068 ppm. Spectrophotometric analysis method cyclamate with hypochlorite reagent had good precision and accuracy. Ultra violet  spectrophotometric analysis method of cyclamate have a good precision but the accuracy was not good. Turbidimetric methods  analysis of cyclamate had  precision and accuracy were not good.Keywords:   method validation, spectrophotometry, turbidimetry, cyclamate
UTILIZATION OF COPPER WEIGHT METAL ION (II), KROMIUM (III), TIMBAL (II), AND SENG (II) IN LIQUID WASTE INDUSTRY FOR ELECTROPLATING IRON COATING Siti Marwati; Regina Tutik Padmaningrum; Marfuatun Marfuatun
Jurnal Penelitian Saintek Vol 14, No 1: April 2009
Publisher : Institute of Research and Community Services, Universitas Negeri Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (105.039 KB) | DOI: 10.21831/jps.v14i1.691

Abstract

This Research aim to  know:  1) the potential difference which can degrade the heavy metal ion concentration of Cu(II), Cr(III), Pb(II), and Zn(II) in liquid waste of electroplating maximally, 2) the efficiency of degradation of heavy metal ions concentration of Cu(II), Cr(III), Pb(II), and Zn(II) in liquid waste of electroplating at optimal potential difference, and 3)the potential difference yielding the nicest coat quality pursuant to its physical appearance.This research early with the preparation electroplating: 1) the preparation of sample liquid waste, 2) platinum electrode,and 3) iron metal to be arranged in layers. The instrument of this research is potentiometers Shimadzu NES_5F. Process the electroplating has been done at variations of potential difference that are 2.0; 2.5; 3.0; 3.5; 4.;, 4.5; and 5.0 V. Analysis of concentration of metal ions in liquid waste of electroplating  before and hereafter process the electroplating have been done by atomic absorbtion  spectrophotometric (AAS). Perception result of coating have been done visually by researcher. The result of this research are 1) the potential differences which can degrade the heavy metal ions concentration of Cu(II), Cr(III), Pb(II), and Zn(II) in liquid waste of electroplating maximally is 4 V, 2) efficiency of degradation of heavy metal ions concentration of Cu(II), Cr(II), Pb(II), and Zn(II) in liquid waste of electroplating at optimal potential difference successively are 21.30; 72.37; 51.00; and 58.60 %, and 3) potential difference yielding the nicest coat quality pursuant to its physical appearance is 4 V.
Stainless Steel Cyclic Voltammograms in Dioscorea Opposita Flour Media Isana Supiah Yosephine Louise; Siti Marwati; S. Sulistyani; Heru Pratomo Al; Felix Arie Setiawan
Indonesian Journal of Science and Technology Vol 6, No 3 (2021): IJOST: VOLUME 6, ISSUE 3, December 2021
Publisher : Universitas Pendidikan Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17509/ijost.v6i3.39078

Abstract

Improving the efficiency of hydrogen gas production in the water electrolysis process draws great attention from many scholars. To improve the efficiency of the process and reduction in the cost, stainless steel has been widely implemented in the industrial water electrolysis process. Electrolyte modification is also one of the methods to improve the water electrolysis process. The study used Dioscorea opposita tuber flour as a media addition in an alkaline solution. The efficiency of water electrolysis was evaluated by cyclic voltammetry. The result showed that the activity of the electrode and energy consumption were increased with values of 29 and 23%, respectively, by adding 3 g of the media. However, no media addition showed the lowest energy consumption regarding overpotential value. In general, the Dioscorea opposita tuber flour tends to cover the electrode and reduce the activity. Moreover, the utilization of wastewater from Dioscorea opposita flour industry is still beneficial to produce hydrogen gas instead of using freshwater.
PENGEMBANGAN MOLECULARLY IMPRINTED POLYMER (MIP) SEBAGAI ADSORBEN SELEKTIF ION LOGAM KADMIUM (Cd2+) Neny Rahmawati; Siti Marwati
Jurnal Elemen Kimia Vol 7, No 4 (2018): Jurnal Kimia Dasar
Publisher : Universitas Negeri Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

AbstrakPenelitian ini bertujuan untuk mengetahui karakteristik gugus fungsi Cd-MIP hasil sintesis, waktupengadukan optimum, pH larutan simulasi optimum, kapasitas adsorpsi Cd-MIP terhadap ion logam kadmium(Cd2+), dan selektivitas adsorpsi Cd-MIP terhadap ion logam kadmium (Cd2+) dengan ion logam kompetitor (Zn2+).Pembuatan Cd-MIP dilakukan dengan teknik polimerisasi ruah yang melibatkan 2-vinylpyridine sebagai monomerfungsional, ion logam kadmium sebagai template, etilen glikol dimetakrilat (EGDMA) sebagai crosslinker, danbenzoil peroksida sebagai inisiator. Karakterisasi Cd-MIP menggunakan FTIR. Kondisi optimum adosrpsi Cd-MIPterhadap ion logam kadmium (Cd2+) ditentukan melalui uji adsorptivitas dengan variasi waktu pengadukan dan pHlarutan simulasi. Selektivitas Cd-MIP diketahui menggunakan uji selektivitas dengan ion logam seng (Zn2+) sebagaikompetitor. Penentuan konsentrasi ion logam kadmium (Cd2+) menggunakan AAS. Hasil karakterisasi denganFTIR menunjukkan adanya gugus fungsi C-H alkana, C=O ester, C=C alkena, C-O ester, ikatan hidrogen, -CH2-metilen. Kondisi optimum adsorpsi Cd-MIP terhadap ion logam kadmium (Cd2+) diperoleh selama 1 jam dan padapH 6. Kapasitas adsorpsi adsorpsi Cd-MIP terhadap ion logam kadmium (Cd2+) pada kondisi optimum adalah2,4365 mg/g. Cd-MIP selektif terhadap ion logam kadmium (Cd2+) dengan ion logam Zn2+ sebagai kompetitor.Kata kunci: Adsorpsi, MIP, adsorben selektif, kadmium, 2-vinylpyridine.
Co-Authors Abdul Fikar Amigato Abdul Fikar Amigato Anti Kolonial Prodjosantoso Ardy Santosa Arief Noviantara Arum Wiranti Chanel Tri Handoko Das Salirawati Eko Widodo Endang Dwi Siswani Enny Dwi Cahyanti Felix Arie Setiawan Halimatus Syadiyah Heru Pratomo Al Isana Supiah Yosephine Louise Maretina W Wiyati, Maretina W Marfuatun Marfuatun Neny Rahmawati Regina Tutik Padmaningrum Ridho Naibaho, Ridho Rosa Yuniastuti S. Sulistyani Sukisman Purtadi Sulistyani ' Sunarto ' Sunarto Sunarto Susila Kristianingrum Tjokorda Gde Dalem Pemayun Tri Budi Yanti Wiraputri, Luthfia Yohan, Lestiana