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The Use of Rice Husk Silica in Modified Zinc Oxide Photocatalysts to Reduce Chromium Concentration Diana Rakhmawaty Eddy; L Ahmad Na’ani; Rustaman Rustaman; Solihudin Solihudin
Jurnal Kimia Valensi Jurnal Kimia VALENSI Volume 6, No. 1, May 2020
Publisher : Syarif Hidayatullah State Islamic University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15408/jkv.v6i1.12324

Abstract

Rice husk ash contains approximately 90-98% dry weight of silica and they have been reported to have several advantages compared to mineral silica. One of these is its application as a filler in ZnO photocatalysts using the sol-gel method. This study was, therefore, conducted to determine the effect of adding rice husk silica to increase the ability of ZnO/SiO2 photocatalyst to reduce chromium concentration. Meanwhile, a previous effort has been made to degrade methylene blue dyes by 89%. This current research involved preparing rice husk charcoal using pyrolysis tubes after which they were extracted to produce silica while ZnO/SiO2 composites were made at a 95/5, 90/10, and 85/15 (w/w) ratio and composite activity test was conducted to determine its ability to reduce chromium concentration from practicum discharge. The SEM-EDS results showed the formation of SiO2 composites in ZnO while 82.6% decrease in total chromium concentration from waste was obtained after 2 hours irradiation with 95/5 composites using ultraviolet radiation.
AKTIVASI ARANG SEKAM PADI DENGAN LARUTAN NATRIUM KARBONAT DAN KARAKTERISASINYA Solihudin Solihudin; Atiek Rostika Noviyanti; Rukiah Rukiah
Chimica et Natura Acta Vol 3, No 1 (2015)
Publisher : Departemen Kimia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (609.59 KB) | DOI: 10.24198/cna.v3.n1.9168

Abstract

Sekam padi merupakan limbah pertanian yang cukup melimpah di daerah penghasil beras sepeti Jawa Barat, sangat potensial untuk dimanfaatkan sebagai sumber karbon karbon aktif yang dapat digunakan untuk adsorben, pendukung katalis dan elektrode. Sampai saat ini telah banyak penelitian pembuatan karbon aktif dari sekam padi namun masih menggunakan metode dan bahan kimia yang kurang ramah lingkungan serta biaya tinggi. Pada penelitian ini aktivasi arang sekam padi dilakukan dengan metode refluks menggunakan larutan natrium karbonat untuk melarutkan silikanya. Tujuan penelitian ini adalah untuk mengetahui pengaruh rasio mol silika dalam arang sekam padi dengan natrium karbonat, waktu refluks, dan suhu kalsinasi terhadap karakteristik karbon aktif yang dihasilkan. Metode yang digunakan adalah pelarutan silika oleh natrium karbonat dengan cara refluks kemudian dikalsinasi. Hasil aktivasi karbon tersebut dikarakterisasi dengan uji kadar abu, XRD, SEM-EDS, dan FTIR. Dari hasil penelitian ini didapatkan kondisi optimum aktivasi arang sekam padi yaitu rasio mol natrium karbonat dengan silika yaitu 1:3, waktu refluks selama 3 jam, dan suhu kalsinasi 900oC serta karbon yang didapatkan berupa amorf.
Fotokatalisis Komposit Silika Sekam Padi Modifikasi Seng Oksida Untuk Menurunkan Konsentrasi Kromium(VI) Diana Rakhmawaty Eddy; L. Ahmad Na’ani; Rustaman Rustaman; Solihudin Solihudin
Chimica et Natura Acta Vol 7, No 3 (2019)
Publisher : Departemen Kimia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (264.777 KB) | DOI: 10.24198/cna.v7.n3.26290

Abstract

Penelitian ini bertujuan untuk mengetahui pengaruh penambahan silika sekam padi untuk meningkatkan efektifitas degradasi limbah oleh fotokatalis ZnO/SiO2. Hasil sebelumnya ZnO/SiO2 komposisi 95/5 (w/w) telah menurunkan konsentrasi kromium yang ada dalam buangan limbah hasil praktikum sebesar 82,6%. Tahapan penelitiannya dengan preparasi arang sekam padi dengan menggunakan tabung pirolisis kemudian diekstraksi untuk menghasilkan silika, pembuatan komposit ZnO/SiO2 dengan komposisi 95/5; 90/10; dan 85/15 serta uji aktivitas dalam menurunkan konsentrasi kromium(VI). Hasil SEM-EDS menunjukkan sudah terbentuknya komposit SiO2 pada ZnO. Penurunan konsentrasi kromium(VI) sebesar 83,3% pada komposisi silicon dioksida 90/10 (w/w).
BIODIESEL DARI MINYAK NYAMPLUNG TEROZONISASI MELALUI ESTERIFIKASI DAN TRANSESTERIFIKASI DENGAN BANTUAN GELOMBANG ULTRASONIK Haryono Haryono; Solihudin Solihudin; Rukiah Rukiah; Susi Suryani
Jurnal Sains Dasar Vol 5, No 2 (2016): October 2016
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (199.436 KB) | DOI: 10.21831/jsd.v5i2.13809

Abstract

Bahan bakar dari minyak bumi merupakan sumber energi paling dominan digunakan dan bersifat tak terbarukan. Hal ini menyebabkan semakin berkurangnya cadangan bahan bakar fosil. Hal tersebut mendorong dikembangkannya bahan bakar alternatif terbarukan seperti biodiesel. Tujuan penelitian ini adalah mensintesis biodiesel dari minyak nyamplung melalui proses esterifikasi dan transesterifikasi dengan bantuan ozonisasi dan gelombang ultrasonik. Ozonisasi dilakukan selama 30 menit, sedangkan reaksi transesterifikasi dibantu dengan gelombang ultrasonik pada variasi frekuensi 28 dan 35 kHz masing-masing selama 30 menit. Hasil penelitian menunjukkan bahwa penggunaan gelombang ultrasonik dengan frekuensi 35 kHz pada reaksi transesterifikasi terhadap minyak nyamplung terozonisasi dari reaksi esterifikasi dihasilkan biodiesel yang relatif sesuai dengan standar biodiesel Indonesia. Biodiesel yang dihasilkan pada kondisi tersebut memiliki bilangan asam 0,70 mgKOH/g biodiesel, bilangan iodium 50,34 g I2/100 g, titik nyala 122,4°C, bilangan cetana 102,5, densitas 0,9088 g/cm3, dan viskositas 9,5 cSt. Yield biodiesel yang diperoleh pada kondisi terbaik adalah sebesar 77,0%. Kata Kunci: biodiesel, minyak nyamplung, ozonisasi, transesterifikasi, ultrasonik. Abstract Fuel from petroleum is the most dominant source of energy used and is non-renewable. This causes the reduction in fossil fuel reserves. It encourages the development of alternative renewable fuels such as biodiesel. The purpose of this study was to synthesize biodiesel from Calophyllum inophyllum oil through esterification and transesterification process with the help of ozonation and ultrasonic waves. Ozonation is performed for 30 minutes, while the transesterification reaction is aided by ultrasonic wave frequency variation 28 and 35 kHz respectively for 30 minutes. The results showed that the use of ultrasonic waves with frequency of 35 kHz in the transesterification reaction to the ozonized Calophyllum inophyllum oil from esterification reaction produced biodiesel relatively accordance with the standards of biodiesel Indonesia. Biodiesel produced in these conditions have the acid value of 0.70 mgKOH/g biodiesel, iodine number 50.34 g I2/100 g, the flash point of 122.4°C, cetana numbers of 102.5, density of 0.9088 g/cm3, and a viscosity of 9.5 cSt. Biodiesel yield that obtained from the best synthesis condition is 77.0%. Keywords:   biodiesel, Calophyllum inophyllum oil, ozonation, transesterification, ultrasonic.
Limbah Cair Industri Minyak Goreng Sawit sebagai Bahan Baku Pembuatan Biodiesel Haryono MT; Solihudin Solihudin; Evy Ernawati; Surya Pramana
EduChemia (Jurnal Kimia dan Pendidikan) Vol 4, No 1 (2019)
Publisher : Department of Chemical Education Faculty of Teacher Training and Education Universitas Su

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (504.775 KB) | DOI: 10.30870/educhemia.v4i1.5030

Abstract

Pada proses produksi minyak goreng sawit dihasilkan berbagai jenis limbah, salah satunya adalah limbah cair. Limbah cair tersebut diperkirakan masih mengandung asam lemak yang relatif potensial sebagai bahan baku untuk sintesis biodiesel. Penelitian ini bertujuan menentukan kondisi terbaik tahap transesterifikasi dengan katalis NaOH pada pemanfaatan limbah cair industri minyak goreng kelapa sawit sebagai bahan baku sintesis biodiesel. Kondisi terbaik tahap transesterifikasi tersebut dipelajari berdasarkan parameter rasio mol minyak terhadap metanol (1:5, 1:7, 1:9, dan 1:1) dan kadar katalis NaOH (0,3, 0,5, dan 0,7%-b/b). Sintesis biodiesel pada penelitian ini dilakukan melalui 5 tahap, yaitu: karakterisasi bahan baku, tahap esterifikasi dengan katalis H2SO4, tahap transesterifikasi dengan katalis NaOH, pemurnian biodiesel, dan karakterisasi biodiesel. Hasil penelitian menunjukkan bahwa kondisi terbaik pada tahap transesterifikasi dicapai pada reaksi dengan rasio mol minyak terhadap metanol sebesar 1:5 dan kadar katalis NaOH sebanyak 0,5%. Pada kondisi tersebut dihasilkan biodiesel dengan rendemen 87,62% dan karakteristik berupa densitas, viskositas, bilangan asam, titik nyala, dan kandungan energi berturut-turut sebesar 863,5 kg/m3, 4,1 mm2/s, 1,61 mg KOH/g biodiesel, 140ºC, dan 38,22 MJ/kg.
Isolation of Silica-Lignin Composites from Rice Husk and Their Adsorption to Cr(VI) Yati B. Yuliyati; Seli Listiani; Solihudin Solihudin; Atiek Rostika Noviyanti
ALCHEMY Jurnal Penelitian Kimia Vol 14, No 2 (2018): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.14.2.19818.267-276

Abstract

Rice husk is the most abundant agricultural waste in Indonesia. It can be used as a precursor for multifunctional materials such as silica-lignin composite for adsorbents. Silica-lignin can reduce heavy metal content in an industrial waste, such as the content of Cr(VI). This study aims to isolate and characterize silica-lignin composite, and determines the isotherm type of silica-lignin for hexavalent chromium adsorption. The isolation from rice husk used an alkali extraction method. Confirmation of typical functional groups in the silica-lignin composite was characterized by FTIR, while the morphology was characterized by SEM, respectively. The results reveal that the silica-lignin isolation was successfully performed.  FTIR spectra indicate a typical wavenumber of the silica-lignin.  The SEM image of the composite showed homogeneous morphology. The silica-lignin adsorption process on hexavalent chromium followed a Brunauer–Emmett–Teller (BET) isotherm type indicated by multilayer adsorption with a surface area of 948.8421 mg. g-1.
Pengaruh Suhu Kalsinasi terhadap Karakteristik Komposit Forsterit-Karbon Tersintesis dalam Medium Gas Argon Solihudin Solihudin; Haryono Haryono; Atiek Rostika Noviyanti; Muhammad Rizky Ridwansyah
ALCHEMY Jurnal Penelitian Kimia Vol 16, No 2 (2020): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.16.2.34845.163-170

Abstract

Komposit forsterit-karbon merupakan salah satu material modifikasi dari forsterit yang berpotensi memiliki sifat isolator panas baik. Karbon dalam komposit dapat mengisi cacat titik pada kristal forsterit. Arang sekam padi (residu gasifikasi) mengandung SiO2 amorf dan karbon yang tinggi. Penelitian ini bertujuan menentukan pengaruh suhu kalsinasi dalam medium gas inert (dengan pengaliran gas argon) terhadap karakteristik komposit forsterit-karbon dari arang sekam padi dan magnesium karbonat. Metode penelitian meliputi preparasi arang sekam padi hasil gasifikasi, dan sintesis forsterit-karbon. Proses sintesis komposit forsterit karbon dilakukan dengan cara mencampurkan arang sekam padi dengan kalium karbonat pada rasio mol magmesium terhadap silikon sebesar 2 : 1 kemudian dikalsinasi dengan suhu divariasikan (700, 800, 900, dan 1000 oC). Selanjutnya sampel hasil sintesis dikarakterisasi dengan Fourier-transform infrared (FTIR), X-ray diffraction (XRD), dan scanning electron microscope-energy dispersive spectroscopy (SEM-EDS). Hasil karakterisasi dengan FTIR dan XRD diperoleh kesimpulan bahwa forsterit mulai terbentuk pada suhu kalisiasi 800 oC dan sempurna pada suhu 1000 oC, karenanya komposit yang terbentuk pada 1000 oC dimungkinkan sebagai forsterit-karbon, di mana unsur-unsur yang terkandung ditunjukkan oleh SEM-EDS. The Effect of Calcination Temperature on the Characteristics of Forsterite-Carbon Composites Synthesized in Argon Gas Medium. Forsterite-carbon composite is one of the material modifications of forsterite, which potentially has a good heat insulation property. Carbon in composites can fill point defects in forsterite crystals. Rice husk charcoal, as gasification residues, contains high amorphous SiO2 and carbon. This study aims to determine the effect of temperature on the calcination of a mixture of rice husk charcoal and magnesium carbonate under an inert gas (argon gas) on the characteristics of the forsterite-carbon composite produced. The experimental research performed includes the preparation of gasified rice husk charcoal and the synthesis of the carbon-forsterite composite. The synthesis process of the carbon-forsterite composites was carried out by mixing rice husk charcoal with potassium carbonate at a mole ratio of magnesium to silicon of 2 : 1. The mixture was then calcined with varying temperatures (700, 800, 900, and 1000 °C). Furthermore, the synthesized sample was characterized by Fourier-transform infrared (FTIR), X-ray diffraction (XRD), and scanning electron microscope-energy dispersive spectroscopy (SEM-EDS). The FTIR and XRD analysis show that the forsterites began to form at a calcination temperature of 800 °C and perfectly formed at a temperature of 1000 °C; therefore, the composite formed at 1000 °C is possible as forsterite-carbon, in which the contained elements were indicated by SEM-EDS.
Pengaruh Konsentrasi Natrium Silikat terhadap Laju Korosi Paduan Aluminium dalam Lingkungan Natrium Klorida 3,5% Rukiah Rukiah; Diding Mandala Putra; Solihudin Solihudin; Yeni Wahyuni Hartati; Atiek Rostika Noviyanti
ALCHEMY Jurnal Penelitian Kimia Vol 16, No 2 (2020): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.16.2.40927.218-226

Abstract

Korosi merupakan proses penurunan kualitas logam akibat reaksi logam dengan lingkungannya. Air laut merupakan salah satu sistem yang korosif karena tingginya kadar ion klorida. Ion silikat dengan konsentrasi optimum mampu memperlambat laju korosi pada logam, seperti aluminium. Penelitian ini menguji pengaruh ion silikat dalam larutan natrium klorida 3,5% terhadap laju korosi aluminium yang diuji dengan metode potensiostat dan dihitung dengan Ekstrapolasi Tafel. Pengaruh konsentrasi ion silikat terhadap laju korosi diamati pada variasi konsentrasinya yaitu 0, 25, 50, 75, dan 100 mM. Konsentrasi optimum natrium silikat untuk menurunkan laju korosi adalah 25 mM,  laju korosi turun dari 0,0118 menjadi 0,0084 mm/tahun. Sebaliknya, penambahan konsentrasi natrium silikat hingga 100 mM,  dapat meningkatkan laju korosi menjadi 0,101 mm/tahun.The Effect of Sodium Silicate Concentration on the Corrosion Rate of Aluminum Alloy in Sodium Chloride 3.5%. Corrosion is a process of decreasing the quality of metals due to the reaction of metals with their environment. Seawater is one of the corrosive systems because of the high levels of chloride ions. Silicate ions with optimum concentrations can slow the rate of corrosion in metals, such as aluminum. This research examines the effect of silicate ions on the aluminum corrosion rate in a solution of sodium chloride 3.5%, tested by the potentiostat method and calculated by Tafel extrapolation. The effect of silicate ion concentration on the corrosion rate was observed in various concentrations of 0, 25, 50, 75, and 100 mM. The optimum concentration of sodium silicate in reducing the corrosion rate is 25 mM, in which the corrosion rate drops from 0.0118 to 0.0084 mm/year. Conversely, increasing the concentration of sodium silicate to 100 mM increased the corrosion rate to 0.101 mm/year.
SYNTHESIS AND CHARACTERIZATION OF GAMMA ALUMINA AND ITS ADSORPTION CAPABILITY TEST FOR POMALAA MAGNESIUM LATERITE, SOUTHEAST SULAWESI Titin Siti Fatimah; Atiek Rostika Noviyanti; Juliandri Juliandri; Solihudin Solihudin
Indonesian Mining Journal Vol 22, No 1 (2019): INDONESIAN MINING JOURNAL, Vol. 22 No. 1, April 2019
Publisher : Puslitbang tekMIRA

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1748.461 KB) | DOI: 10.30556/imj.Vol22.No1.2019.977

Abstract

Based on variations in calcination temperature, gamma alumina has successfully been made using a simple sol-gel method for Pomalaa magnesium-laterite adsorption from the South East of Sulawesi. The laterite leached by sulfuric acid was then precipitated by ammonia, to make the magnesium was separated from its main impurities (Si, Fe and Al). Temperature variations at 500, 650, 800 and 950 °C in gamma alumina making formed the gamma alumina phase while the alpha alumina phase was formed at 1100 °C. The higher calcination temperature the lower the specific surface area respectively from 196.385, 156.239, 105.725, 96.134 and 15.396 (m2/g). This results in decreasing the magnesium of the laterite 9.04, 8.70, 8.09, 6.39 and 0.29 (mg/L) respectively. The 800 °C-calcination gamma alumina has the highest volume of the pore, namely 0.3265 mL/g and the radius of 61.76 Å. The gamma alumina isotherm curve is type IV. The SEM-EDS test shows an aggregation spherical shape. Gamma alumina was detected to adsorb Mg laterite. The X-ray mapping of SEM-EDS test shows even distribution between gamma alumina, magnesium and nickel. The highest adsorption is retained by GA-800/3 sample, namely 81.31 %.
Kalsium Silikat sebagai Bahan Komposit Biosemen Gigi dengan Penyiapan Silika dari Sekam Padi melalui Metode Sol-Gel Haryono MT; Diana Rakhmawaty Eddy; Atiek Rostika Noviyanti; Solihudin Solihudin; Laelaturrohmah Laelaturrohmah
Jurnal Kartika Kimia Vol 1 No 1 (2018): Jurnal Kartika Kimia
Publisher : Department of Chemistry, Faculty of Sciences and Informatics, Jenderal Achmad Yani University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (263.245 KB) | DOI: 10.26874/jkk.v1i1.4

Abstract

Rice husk has the content of organic and inorganic compounds that have not been utilized maximally, one of them is silica. High silica content in rice husks can be used as an alternative source of potential silica for the synthesis of calcium silicate as a base material of Trioxide Aggregate mineral composites in tooth biocement. In this study, calcium silicate was obtained through two stages of the process, namely silica isolation from rice husk ash by sol-gel method, and reacting between silica and calcium oxide. Silica and calcium oxide are reacted to the mole ratio between silica to calcium oxide of 7:3, 6:4, 4:6, and 3:7. The isolated silica is characterized by the distribution of the size and composition of each element with Particle Size Analyzer (PSA) and EDS. The formation of calcium silicate and its size distribution from the synthesis stage is determined by XRD and PSA. The result showed that silica isolation from rice husk ash with sol-gel method obtained silica with content and particle size of 71.6% and 52.82 mm. While the optimum condition of calcium silicate synthesis was achieved at the mole ratio of silica to calcium oxide by 4:6. In the mole ratios obtained calcium silicate type b-dicalcium silicate with an average particle size of 102.2 mm.