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"Pada penelitian ini zeolite-A digunakan sebagai matriks pembawa aroma yang menahan laju pelepasan minyak atsiri mawar (Rosa damacena Mill.) yang dapat diregenerasi. Zeolite-A disintesis dari kaolin Bangka Belitung menggunakan metode hidrotermal yang terdiri dari proses metakaolinisasi dan zeolitisasi. Zeolite-A dengan 20 wt% bentonite dicampur untuk membentuk matriks ZAB. Bentonite berfungsi sebagai bahan pengikat yang memiliki kemampuan adsorpsi minyak atsiri sebesar 1,497 g/g bentonite. Zeolite-A dan matriks ZAB dikarakterisasi menggunakan X-Ray Difraction, Brunauer–Emmett–Teller, Fourier-transform infrared spectroscopy, Scanning Electron Microscopy- Energy Dispersive X-Ray Spectroscopy. Pengaruh aktivasi kimia zeolite-A terhadap kinerja adsorpsi matriks ZAB diamati dengan penggunaan zat aktivator berbeda, yaitu HCl 0,1 M dan NaOH 0,1 M. Pengamatan siklus regenerasi dilakukan sebanyak 10 kali. Jumlah minyak atsiri teradsorpsi per berat matriks diamati dengan analisis gravimetrik. Tanpa aktivasi kimia, matriks ZAB dengan diameter 0,4; 0,7; 1 cm dapat mengadsorpsi minyak atsiri masing-masing sebesar 1,807; 1,624; 1,411 g/g matriks. Matriks ZAB diameter 0,4 cm teraktivasi HCl 0,1 M dan NaOH 0,1 M berturut-urut mampu mengadsorpsi minyak atsiri mawar sebanyak 1,95 dan 1,807 g/g matriks. Hasil tersebut mengindikasikan aktivasi dengan HCl 0,1 M mampu memperbesar pori sehingga minyak atsiri semakin banyak teradsorbsi. Hingga minggu ke-5 matriks ZAB masih mengandung geraniol, feniletil alkohol, linalool, sitral, sitronellol dan eugenol dengan laju pelepasan masing-masing senyawa adalah 0,04; 0,07; 0,037; 0,021; 0,026; dan 0,011 g/minggu. Hasil ini menunjukkan pelet matriks berbasis zeolite-A mampu menahan pelepasan aroma pada minyak atsiri mawar lebih dari satu bulan

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In this study zeolite-A used as a fragrance carrier matrix which retained the rate of release of rose essential oil (Rose damacena Mill.) which can be regenerated. Zeolite-A was synthesized from Bangka Belitung kaolin using hydrothermal method which consists metakaolinization and zeolitization processes. Zeolite-A and 20 wt% bentonite are mixed to form ZAB matrix. Bentonite functiona as matrix binder which can adsorb rose essential oil 1,497 g/g bentonite. Zeolite-A and ZAB matrix was characterized using X-Ray Difraction, Brunauer–Emmett–Teller, Fourier-transform infrared spectroscopy, Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy. Observation of chemical activation effect on zeolite-A was carried out by using different activator substances, HCl 0.1 M and NaOH 0.1 M. Observation of regeneration cycle was carried out 10 times. The amount of essential oil adsorbed per matrix weight was observed by gravimetric analysis. Without chemical activation, ZAB matrix with a diameter of 0.4; 0.7; 1 cm each has the ability to adsorb essential oils 1.807; 1.624; 1.411 g/g matrix. The 0,4 mm ZAB matrix activated with HCL o.1 M and NaOH 0.1 M each has the ability to adsorb rose essential oil 1,95 and 1,807 g/g matrix, respectively. These results indicate that activation using HCl 0.1 M enlarge pores and allow matrix to adsorb more rose essential oil. Slow release of rose essential oil observed using Gas Matrix pellet still contained geraniol, phenylethyl alcohol, linalool, citral, citronellol and eugenol on the fifth week with release rate of 0.04; 0.07; 0.037; 0.021; 0.026; and 0.011 g/week, respectively. This result shows that zeolite-A-based matrix pellets are able to withstand the release of aroma in rose essential oil up to more than a month."

"Sintesis superabsorben dari selulosa sekam padi sebagai backbone dengan metode polimerisasi radikal bebas pada kopolimerisasi cangkok dengan monomer asam akrilat dan akrilamida dapat menghasilkan pupuk slow-release yang bersifat ramah lingkungan. Selulosa diisolasi dari sekam padi dengan tahapan ekstraksi lemak dengan toluen : etanol (2:1). Penghilangan hemiselulosa dan lignin dengan menggunakan kalium hidroksida 5% dan hidrogen peroksida 2% pH basa. Rendemen selulosa yang diperoleh adalah 39,5% untuk metoda I dan 59,50% untuk metoda II. Spektrum FTIR selulosa menunjukkan hilangnya serapan lignin pada bilangan gelombang 1728 cm-1 untuk selulosa I sedangkan pada selulosa II masih muncul gugus lignin. Indeks kristalinitas dari selulosa didapatkan dari hasil analisis XRD sebesar 68% untuk selulosa I sedangkan 60% untuk selulosa II. Kopolimerisasi berlangsung 2 jam pada suhu 70C dengan dialiri gas nitrogen. Inisiator dan agen pengikat silang yang digunakan adalah kalium peroksodisulfat dan N?N-metilena bis akrilamida. Hasil analisis SEM memperlihatkan bahwa permukaan kopolimer selulosa memiliki morfologi yang lebih kasar, homogen, dan merata disebabkan terjadinya pencangkokkan monomer ke selulosa sehingga jaringan superabsorben yang terbentuk semakin rapat. Superbasorben menunjukkan kapasitas pengembangan air dan urea dengan konsentrasi 200 ppm berturut-turut adalah 845,53 g/g dan 667,81 g/g untuk selulosa I dan 744,52 g/g dan 1459,13 g/g untuk selulosa II . Sedangkan kapasitas pelepasan air dan urea dari superbsorben yang paling baik adalah pada selulosa satu dengan kapasitas berturut-turut adalah 87,14 % dan 24,34%. Kinetika pengembangan dan pelepasan dari urea mengikuti orde pseudo-kedua.

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Superabsorbent that synthesized from rice husk cellulose as backbone and grafted with acrylic acid and acrylamide can be used as biodegradable slow release fertilizer. Cellulose was isolated from rice husk by extracted fat, wax, other extractive material with mixture of toluen and ethanol (2:1). Hemicellulose and lignin was removed by using potassium hydroxyde solution (5%) and hydrogen peroxyde solution (2%) in base condition. The average rendement of cellulose-1 obtained 39.50 % and 59.50 % for cellulose-2.

FTIR spectrum of cellulose showed that lignin from rice husk had been removed, it showed at wave number 1750 cm-1. The diffraction pattern of XRD obtained crystallinity index of rice husk 42.60 % which increased after isolated to 67.80% for cellulose-1 and cellulose-2 60.20 %. Copolymerization process was conducted at temperatur 70C for 2 hours and nitrogen gas was flowed into reactor. Potassium peroxodisulphate and N,N?-methylene bis-acrylamide was used as cross-linking agent and inisiator, respectively.

Mycrograph of SEM analysis showed that the surface of superabsorbent was rough and homogen because of monomer grafting that was done to cellulose. Swelling capacity of superabsobent in water and urea solution (200 ppm) were 845,53 g/g and 667,81 g/g for cellulose-1 and 744,52 g/g and 1459,13 g/g for cellulose-2, respectively. Release capacity of superbasobent for cellulose-1 was the best, and the release capacity were 87,14 % and 24,34% for water and urea solution respectively. Swelling and release kinetics of urea solution followed a pseudo-second order of rate law."

"ABSTRAKPolusi udara akibat penggunaan pengharum ruangan kimia merupakan salah satu ancaman bagi kesehatan. Dewasa ini, maraknya pemanfaatan minyak atsiri sebagai pengganti pengharum ruangan mendorong produsen untuk menghasilkan matriks yang mampu menahan laju pelepasan aroma. Penelitian ini mengusulkan pembuatan matriksLuffa acutangula dengan modifikasi permukaan sebagai pembawa aroma green tea oil (Camellia sinensis). Luffa yang bersifat biodegradable dan hidrofilik secara alami dimodifikasi dengan zeolit A (ZA), grafit (G) dan graphene oxide (GO) masing-masing menjadi matriks LZA, LG dan LGO melalui coating dengan metode dip and dry. ZA disintesis dengan metode hidrotermal. Grafit diberi perlakuan asam-basa. GO disintesis dengan metode Hummers. Sodium alginat digunakan sebagai bahan pengikat matriks. Hasil karakterisasi BET menunjukkan luas permukaan LZA, LG dan LGO masingmasing sebesar 323,601; 151,429 dan 538,021 m2/g. Hasil karakterisasi FTIR membuktikan interaksi matriks LZA, LG, dan LGO dengan green tea oil (GTO). Efisiensi adsorpsi matriks dianalisis dengan variasi massa porous material (ZA, G, dan GO). Perbandingan massa L:SA:PM sebesar 4:1:3, efisiensi adsorpsi yang terjadi adalah LZA3 6,067 g GTO/g LZA3, LG3 6,771 g GTO/g LG3 dan LGO3 10,916 g GTO/g LGO3. Karakteristik adsorpsi isoterm matriks LGO dianalisa menggunakan model Langmuir, Freundlich dan Temkin. Adsorpsi isoterm matriks LGO oleh matriks LGO terdeskripsikan paling baik oleh model adsorpsi isotherm Langmuir. Kinetika adsorpsi GTO oleh matriks LGO terdeskripsikan paling baik oleh model pseudo-second order. Analisa extended release menunjukkann LGO mampu pelepasan GTO ke udara hingga lebih dari 6 minggu dengan laju pelepasan rata-rata 5,07 g/minggu.

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ABSTRACTPollution due to chemical air freshener is one of the massive threats to the health. Nowadays, the growing public interest of essential oils utilization as air freshener alternative pushes fragrance indistry to produce matrix that can create long lasting product by controlling the release rate. In this work, the fabrication of surface modified luffa acutangula as green tea oil (Camellia sinensis) matrix carrier is proposed. Luffa sponge which is biodegradable and hydrophilic in nature, is made hydrophobic by coating with zeolite A (ZA), graphite (G) and graphene oxide (GO) each become LZA, LG and LGO matrix using dip and dry method. Initially, ZA was synthesized using hydrothermal method. Graphite was treated with acid-base treatment. GO was stnthesized using Hummers' method. Sodium alginate was used as matrix binder agent. The results obtained by BET indicate surface area of LZA, LG and LGO are 323.601; 151.429 and 538.021 m2/g, respectively. FTIR characterization indicate interaction between LZA, LG, and LGO matrix with green tea oil (GTO). Adsorption efficiency of the matrix was studied with mass variation of the porous material (ZA, G, dan GO). Mass ratio L:SA:PM of 4:1:3, resulted as the highest efficiency with LZA3 6.067 g GTO/g LZA3, LG3 6.771 g GTO/g LG3 and LGO3 10.916 g GTO/g LGO3. Adsorption isotherm model of Langmuir, Freundlich and Temkin of LGO was studied. The adsorption process of LGO matrix was well fitted to Langmuir equilibrium. The adsorption kinetic of LGO matrix was well fitted to Pseudo-seond order. The extended release study showed that LGO matrix was able to hold GTO release up to more that 8 weeks with the average release rate of 5.07 g/week."

"[ABSTRAKLatar belakang: Persalinan prematur sekarang ini menjadi tantangan dibidangobstetri. Ini terlihat dari tingginya angka prematur di dunia. Dua hal yang harusdiperhatikan dalam kehamilan prematur yaitu kontraksi dan pemberian kortikosteroiduntuk pematangan paru, maka dibutuhkan suatu penanganan dengan menggunakanobat tokolitik. Saat ini telah banyak digunakan terbutalin sulfat yang merupakangolongan agonis beta dan juga nifedipine yang merupakan golongan penyekat kanalkalsium. Namun penggunaan agonis beta menyebabkan efek yang kurang baik padaibu seperti takikardi, dispnoe dan ansietas sehingga penggunaannya sekarang mulaiterbatas. Tujuan: Tesis ini bertujuan mengetahui perbandingan efektifitas nifedipineoral dibandingkan dengan terbutalin sulfat sebagai tokolitik dalam kehamilanprematur. Metode: Penelitian ini merupakan uji klinis randomisasi tanpa penyamaranpada ibu hamil prematur di kurang dari 34 minggu di RSUPN Cipto mangunkusumo.Hasil: dari 60 subyek yang diikutsertakan dengan consecutive sampling, didapatkan56 subyek (93,3%) hilang kontraksi dengan rincian 27 subyek (90,0%) padakelompok nifedipin dan 29 subyek (96,7%) pada kelompok terbutalin (p=0,61).Kelompok yang diberikan nifedipin hilang kontraksi dengan median waktu 1,25(0,67-2,00) jam sementara kelompok yang diberikan terbutalin hilang kontraksi lebihcepat dengan median waktu 0,50 (0,50-1,50) jam (p<0,001). Tidak ada perbedaan efek samping yang ditemukan pada kedua kelompok. Simpulan: Nifedipin dan terbutalin memiliki efektifitas yang sama pada kehamilan prematur.

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ABSTRACTBackground: Preterm labour is considered as one of problems frequentlyencountered in obstetric and ginecologic department. To date, the incidence ofprematurity is still high worldwide. Two things should be noted: uterine contractionand corticosteroid for lung maturity of the baby. Thus, a tocolytic agent may be usefulin these circumstances. To date, terbutaline sulfate is widely used as it is known asbeta agonist. Beside, nifedine, a calcium channel blocker, is also widely accepted. Theuse of beta agonist might contribute several adverse events related to the mother,including tachycardia, dispnea, and anxiety. Some physicians have begun to restrictits use. Objective: This study aimed to compare the efficacy of slow releasenifedipine and terbutaline sulfate injection as a tocolytic agent for preterm labour.Methods: This is a randomized clinical trial unblinding. Subjects were pregnantwomen with prematurity (below 34 weeks of gestational age) at CiptoMangunkusumo hospital. Results: From a total of 60 subjects, 56 subjects (93.3%)had no contraction after given tocolytic (27 subjects (90.0%) in nifedipine group and29 subjects (96.7%) in terbutaline sulfate group; (p= 0.61). Subjects in nifedipinegroup lost their contraction after the drug was given with median time of 1.25 (0.672.00)hours while subjects in terbutaline sulfate group lost their contraction withmedian time of 0.50 (0.50-1.50) hours (p<0.001). There was no significantly differentproportion of adverse event found in both groups. Conclusions: Nifedipine and terbutaline sulfate have relatively same efficacy to vanish uterine contraction for prematurity management. ;Background: Preterm labour is considered as one of problems frequentlyencountered in obstetric and ginecologic department. To date, the incidence ofprematurity is still high worldwide. Two things should be noted: uterine contractionand corticosteroid for lung maturity of the baby. Thus, a tocolytic agent may be usefulin these circumstances. To date, terbutaline sulfate is widely used as it is known asbeta agonist. Beside, nifedine, a calcium channel blocker, is also widely accepted. Theuse of beta agonist might contribute several adverse events related to the mother,including tachycardia, dispnea, and anxiety. Some physicians have begun to restrictits use. Objective: This study aimed to compare the efficacy of slow releasenifedipine and terbutaline sulfate injection as a tocolytic agent for preterm labour.Methods: This is a randomized clinical trial unblinding. Subjects were pregnantwomen with prematurity (below 34 weeks of gestational age) at CiptoMangunkusumo hospital. Results: From a total of 60 subjects, 56 subjects (93.3%)had no contraction after given tocolytic (27 subjects (90.0%) in nifedipine group and29 subjects (96.7%) in terbutaline sulfate group; (p= 0.61). Subjects in nifedipinegroup lost their contraction after the drug was given with median time of 1.25 (0.672.00)hours while subjects in terbutaline sulfate group lost their contraction withmedian time of 0.50 (0.50-1.50) hours (p<0.001). There was no significantly differentproportion of adverse event found in both groups. Conclusions: Nifedipine and terbutaline sulfate have relatively same efficacy to vanish uterine contraction for prematurity management. ;Background: Preterm labour is considered as one of problems frequentlyencountered in obstetric and ginecologic department. To date, the incidence ofprematurity is still high worldwide. Two things should be noted: uterine contractionand corticosteroid for lung maturity of the baby. Thus, a tocolytic agent may be usefulin these circumstances. To date, terbutaline sulfate is widely used as it is known asbeta agonist. Beside, nifedine, a calcium channel blocker, is also widely accepted. Theuse of beta agonist might contribute several adverse events related to the mother,including tachycardia, dispnea, and anxiety. Some physicians have begun to restrictits use. Objective: This study aimed to compare the efficacy of slow releasenifedipine and terbutaline sulfate injection as a tocolytic agent for preterm labour.Methods: This is a randomized clinical trial unblinding. Subjects were pregnantwomen with prematurity (below 34 weeks of gestational age) at CiptoMangunkusumo hospital. Results: From a total of 60 subjects, 56 subjects (93.3%)had no contraction after given tocolytic (27 subjects (90.0%) in nifedipine group and29 subjects (96.7%) in terbutaline sulfate group; (p= 0.61). Subjects in nifedipinegroup lost their contraction after the drug was given with median time of 1.25 (0.672.00)hours while subjects in terbutaline sulfate group lost their contraction withmedian time of 0.50 (0.50-1.50) hours (p<0.001). There was no significantly differentproportion of adverse event found in both groups. Conclusions: Nifedipine and terbutaline sulfate have relatively same efficacy to vanish uterine contraction for prematurity management. , Background: Preterm labour is considered as one of problems frequentlyencountered in obstetric and ginecologic department. To date, the incidence ofprematurity is still high worldwide. Two things should be noted: uterine contractionand corticosteroid for lung maturity of the baby. Thus, a tocolytic agent may be usefulin these circumstances. To date, terbutaline sulfate is widely used as it is known asbeta agonist. Beside, nifedine, a calcium channel blocker, is also widely accepted. Theuse of beta agonist might contribute several adverse events related to the mother,including tachycardia, dispnea, and anxiety. Some physicians have begun to restrictits use. Objective: This study aimed to compare the efficacy of slow releasenifedipine and terbutaline sulfate injection as a tocolytic agent for preterm labour.Methods: This is a randomized clinical trial unblinding. Subjects were pregnantwomen with prematurity (below 34 weeks of gestational age) at CiptoMangunkusumo hospital. Results: From a total of 60 subjects, 56 subjects (93.3%)had no contraction after given tocolytic (27 subjects (90.0%) in nifedipine group and29 subjects (96.7%) in terbutaline sulfate group; (p= 0.61). Subjects in nifedipinegroup lost their contraction after the drug was given with median time of 1.25 (0.672.00)hours while subjects in terbutaline sulfate group lost their contraction withmedian time of 0.50 (0.50-1.50) hours (p<0.001). There was no significantly differentproportion of adverse event found in both groups. Conclusions: Nifedipine and terbutaline sulfate have relatively same efficacy to vanish uterine contraction for prematurity management. ]"

"Pembakaran batubara sebagai sumber energi fosil utama dunia menghasilkan produk samping berupa limbah fly ash. Produk samping ini termasuk ke dalam limbah berbahaya dan bersifat toksik. Jumlahnya yang melimpah dan terus bertambah dapat menimbulkan polusi bagi lingkungan sekitar. Dengan demikian, perlu dilakukan upaya pemanfaatan fly ash, salah satu caranya adalah sintesis silika mesopori sebagai media nutrient tanaman. Adanya kandungan silika (SiO2) sebesar 35 – 60 % dalam fly ash, sangat berpotensi dan sesuai untuk dimanfaatkan sebagai sumber silika dalam mensintesis silika mesopori. Pada penelitian ini, telah dilakukan sintesis silika mesopori yang berasal dari fly ash beserta pengaplikasiannya sebagai pupuk urea slow-release fertilizer (SRF). Silika mesopori yang dihasilkan kemudian dikarakterisasi dengan XRD, XRF, FTIR, SAA, dan UV-Vis. Hasil analisis XRD dan XRF pada pretreatment fly ash menunjukkan keberhasilan dalam proses penghilangan pengotor dengan indeks keberhasilan 82% dalam meningkatkan komposisi silika. Pada penelitian ini variasi paling optimum untuk menghasilkan material mesopori didapatkan oleh 2% CTAB yang dibuktikan dengan hasil analisis XRF dengan komposisi silikanya sebesar 97% dan dengan analisis SAA dengan SBET 1016 m2/g serta Sext 912 m2/g. Silika mesopori dengan 2% CTAB memiliki kemampuan swelling paling besar dengan ratio swelling 2.79 dibandingkan dengan variasi 1% CTAB dan 3% CTAB yang masing masing memiliki ratio swelling sebesar 2.27 dan 1.12.

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Coal combustion, the world's main fossil energy source, produces a by-product known as fly ash waste, which is classified as hazardous waste and toxic in nature. The abundance and proliferation of fly ash have polluted the environment. Therefore, it is necessary to optimize the utilization of fly ash in a variety of methods, one of which is use as a raw material for the synthesis of silica mesoporous as a plant nutrient medium. Around 35-60% of silica (SiO2) content, fly ash has emerged as a highly promising and suitabel source of silica for the synthesized of mesoporous silica. In this study, mesoporous silicas derived from fly ash were synthesized using sol-gel technique and applied as urea slow-release fertilizer. Silica mesoporous were then characterized using XRD, XRF, FTIR, SAA, and UV-Vis. The findings of XRD and XRF analysis on fly ash pretreatment indicated that 82% of impurities were successfully removed, therefore the silica composition was increased. In this research to obtain mesoporous material 2% CTAB achieved the best results, as evidenced by the XRF analysis with a silica composition of 97% and surface area of SBET 1016 m2/g and Sext 912 m2/g analyzed by SAA method. Mesoporous silica with 2% CTAB presented the best swelling ability with the ratio of 2.79, compared to 1% CTAB and 3% CTAB variations, which only showed swelling a ratio of 2.27 and 1.12, respectively."

"Peningkatan populasi manusia menyebabkan kebutuhan pangan meningkat. Untuk menjaga pertumbuhan dan kualitas tanaman sebagai sumber pangan, maka pemberian pupuk perlu dioptimalkan. Urea, sebagai pupuk nitrogen yang paling umum digunakan, memiliki potensi untuk meningkatkan produktivitas pertanian. Namun, urea cepat terdegradasi di tanah sehingga tidak terserap optimal oleh tanaman, sehingga diperlukan pendekatan baru seperti mekanisme slow-release fertilizer (SRF) yang dapat memenuhi kebutuhan nutrisi tanaman sekaligus menjaga keseimbangan lingkungan dari nutrisi yang berlebih. Penelitian ini, memanfaatkan fly ash sebagai sumber silika untuk sintesis silika mesopori sebagai SRF. Sintesis silika mesopori menggunakan surfaktan CTAB (Cetyltrimethylammonium bromide) sebagai template dan dilakukan variasi pH 6,8 dan 10 untuk mempelajari pengaruh pH dan CTAB terhadap karakteristik silika mesopori. Penggunaan CTAB menghasilkan ukuran partikel yang seragam dan luas permukaan yang lebih baik. Silika mesopori yang disintesis dengan CTAB pada pH 10 memiliki luas permukaan terbesar, yaitu 1351 m2/g dengan ukuran partikel 138,97 nm. Silika mesopori yang disintesis memiliki kemurnian 93-97%. Silika mesopori menunjukkan kemampuan adsorpsi urea dengan kinetika yang mengikuti model pseudo-orde dua. Kinetika release urea dari silika mesopori mengikuti model kinetika orde satu, yang berarti laju pelepasan dipengaruhi oleh konsentrasi urea yang tersisa dalam silika. Silika mesopori mampu mengadsorpsi urea hingga 565,83 mg/g dan mampu melepaskan urea sebesar 88% dalam 96 jam.

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The growing population leads to an increased demand for food. To ensure the growth and quality of plants as a food source, the application of fertilizers needs to be optimized. Urea, the most used nitrogen fertilizer, has the potential to boost agricultural productivity. However, urea degrades quickly in the soil, limiting its absorption by plants. Therefore, new approaches such as slow-release fertilizer (SRF) mechanisms are necessary to meet the nutritional needs of plants while maintaining environmental balance. This study explores the use of fly ash as a source of silica for the synthesis of mesoporous silica as SRF. The synthesis of mesoporous silica utilized the surfactant CTAB (Cetyltrimethylammonium bromide) as a template and varied pH at 6, 8 and 10 to investigate the impact of pH and CTAB on the characteristics of mesoporous silica. The use of CTAB resulted in uniform particle size and improved surface area. Mesoporous silica synthesized with CTAB at pH 10 exhibited the largest surface area at 1351 m2/g with a particle size of 138.97nm. The synthesized mesoporous silica demonstrated a purity of 93-97%. Mesoporous silica can absorb up to 565.83 mg/g of urea and release 88% of urea within 96 hours. The kinetics of urea adsorption follow the pseudo-second-order model. Urea release from mesoporous silica follows a first-order kinetic model, indicating that the release rate is influenced by the remaining urea concentration."

"Hidrogen adalah salah satu energi terbarukan yang menjanjikan dan berpotensi menjadi pengganti bahan bakar fosil. Namun, aplikasi hidrogen sebagai bahan bakar memiliki kekurangan, yaitu dalam hal penyimpanannya. Dalam suhu kamar dan tekanan atmosfir, hidrogen memiliki rasio energi yang sangat rendah terhadap volumenya jika disimpan dalam bentuk gas sehingga perlu dilakukan berbagai penelitian yang berkaitan dengan metode dan material untuk menyimpan hidrogen terus dilakukan. Sejauh ini metode penyimpanan hidrogen memakai prinsip adsorpsi dengan karbon aktif berbentuk granular sebagai adsorben sangat menjanjikan karena bisa menurunkan tekanan dalam tangki dengan kapasitas penyimpanan yang relatif sama. Pada penelitian ini, karbon aktif yang digunakan pada penelitian ini adalah karbon aktif berbahan dasar zeolite alam. Proses pengambilan data dilakukan dengan metode volumetrik dan tipe adsorpsi yang digunakan adalah adsorpsi isotermal. Penyerapan dilakukan pada 3 temperatur berbeda, pertama pada temperatur 35°C dan tekanan mencapai 40 bar, yang kedua adalah pada temperatur 25°C dan tekanan mencapai 40 bar, dan yang ketiga pada temperatur 0°C dengan tekanan mencapai 40 bar. Pada temperatur 35°C, penyerapan hidrogen sebesar 0.01162kg/kg pada tekanan 39.3620 Bar. Pada temperatur 25°C, penyerapan hidrogen sebesar 0.01991kg/kg pada tekanan 40.2015 Bar. Pada temperatur 0°C, penyerapan hidrogen sebesar 0.03042kg/kg pada tekanan 39.6427 Bar. Data yang didapat selanjutnya dikorelasi dengan menggunakan persamaan model Langmuir, Toth, dan Langmuir-Freudlich.

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Hydrogen is one of promising and potential new energy sources as the substitute of fossil fuel.But, the application of hydrogen as fuel still has weakness in a storage system. Inroom temperature and atmosphere pressure, hydrogen has a very low energy/volume ratio if the hydrogen is stored in gas phase, so it's needed to do some research about the method and materials to adsorp hydrogen. Nowadays, hydrogen adsorption's method using granular activated carbon as the adsorbent is very promising since can reduce the pressure in cell with the adsorption capacity relatively same as other methods. In this research, the activated carbon which used is natural zeolite.

The method which used in this research is volumetric method and the type of adsorption in this research is isothermal adsorption. The adsorptions in this research are in 3 temperatures, first adsorption in 35oC and the pressure up to 40 bars. Then second adsorption in 25°C and the pressure up to 40 bars, and the third adsorption in 0oC. At temperature 35°C, the hydrogen adsorption is 0.01162kg/kg at 39.3620 Bars. At temperature 25°C, the hydrogen adsorption is 0.01991kg/kg at 40.2015 Bars. At temperature 0°C, the hydrogen adsorption is 0.03042kg/kg at 39.6427 Bars.The Data are corelated with some model equations Langmuir, Toth, and Langmuir-Freudlich."

"ABSTRAKMerkuri adalah salah satu jenis logam berat yang sangat berbahaya dalam industri minyak dan gas, khususnya dalam proses produksi. Suatu modifikasi dilakukan pada penelitian ini bertujuan untuk membuat adsorben yang dapat mengurangi kandungan merkuri dalam hidrokarbon cair. Penelitian ini menggunakan zeolit klinoptilolit sebagai bahan utama yang dimodifikasi dengan menggunakan chitosan dan Fe3O4, dengan maksud untuk menambah kemampuan adsorpsi adsorben. Modifikasi adsorben dilakukan dengan coating oleh chitosan dan Fe3O4 kepada zeolit, sehingga terbentuklah adsorben zeolit-chitosan-Fe3O4. Adsorben dikarakterisasi dengan beberapa uji, seperti uji FTIR, SEM-EDX, dan BET. Pengukuran kadar merkuri juga dilakukan dengan mercury analyzer, sehingga dapat terlihat berapa kandungan merkuri yang teradsorp. Hasil uji adsorpsi merkuri dalam hidrokarbon cair menunjukkan bahwa modifikasi yang dilakukan dengan chitosan dan Fe3O4 dapat meningkatkan kemampuan adsorpsi adsorben dalam mengurangi kadar merkuri, terlihat dari konsentrasi merkuri setelah adsorpsi oleh adsorben zeolit-chitosan-Fe3O4 menyisakan merkuri sebesar 35 – 38 ppb, sedangkan adsorben zeolit tanpa modifikasi menyisakan merkuri sebesar 96 – 97 ppb dan adsorben zeolit-chitosan menyisakan merkuri sebesar 65 – 66 ppb.

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ABSTRACTMercury is one of very dangerous heavy metals in the oil and gas industry, particularly in the production process. A modification made in this study aims to make the adsorbent can reduce the mercury content in the liquid hydrocarbon. This study uses clinoptilolite zeolite as main material which is modified by using chitosan and Fe3O4, with a view to increase the adsorption capacity of the adsorbent. Modifications done by coating the Fe3O4 and chitosan to the zeolite, thus forming a zeolite adsorbent-chitosan-Fe3O4. The adsorbent is characterized by several tests, such as FTIR, SEM-EDX, and BET. Measurement of mercury levels were also conducted with mercury analyzer, so that it can be seen how much the mercury content adsorbed. The test results adsorption of mercury in liquid hydrocarbon shows that modifications made with chitosan and Fe3O4 can enhance the adsorption capacity of the adsorbent in reducing levels of mercury, seen from the mercury concentration after adsorption by the adsorbent zeolite-chitosan-Fe3O4 leaving the mercury at 35-38 ppb, while the adsorbent zeolite without modification leaving the mercury at 96-97 ppb and zeolite-chitosan adsorbent leaving the mercury at 65-66 ppb."

"Permintaan energi global yang semakin tinggi, ditambah dengan dampak emisi gas rumah kaca yang berbahaya dari bahan bakar fosil, telah memicu pencarian sumber energi alternatif yang tidak bersaing dengan pasokan makanan. Penelitian ini melakukan perengkahan katalitik minyak nyamplung menjadi senyawa biohidrokarbon menggunakan katalis zeolit berbasis fly ash yang dimodifikasi. Katalis zeolite didapatkan dari preparasi fly-ash dengan metode pencucian asam (HCl) dan peleburan alkali (NaOH) yang diimpergnasi dengan kalsium oksida (CaO) dan nikel oksida (NiO) untuk meningkatkan kinerjanya. Variasi rasio campuran katalis 5% dan 10% CaO, serta 1-3% NiO, suhu 450-550◦C, dan rasio minyak terhadap katalis 0-20%wt. Hasil reaksi perengkahan berupa bio-oil dikarakterisasi dengan Gas Cromatography-Mass Spectroscopy (GCMS) dan Fourier Transform Infra-Red (FT-IR). Hasil preparasi katalis dikarakterisasi dengan X-ray diffraction (XRD), X-ray fluorescence (XRF), Scanning Electron Microscopy (SEM), dan Brunauer–Emmett–Teller (BET). Berdasarkan hasil penelitian, minyak nyamplung berhasil dikonversi menjadi senyawa biohidrokarbon dengan variasi katalis zeolite fly ash (ZFA) yang dimodifikasi dengan CaO dan NiO. Jenis katalis ZFA terimpregnasi 3% NiO (3%NiO/ZFA) pada suhu 550◦C dan rasio massa katalis terhadap minyak umpan 10%wt menghasilkan konversi terbesar 81,89%. Berdasarkan hasil GCMS, hasil selektivitas fraksi rantai gasoline (C5-C11) sebesar 27,14%. Karakteristik sifat fisik dari biohidrokarbonnya mendekati standar biodiesel dengan nilai densitas (717 kg/m3), viskositas kinematic (2,69 cSt,), dan angka RON (94).

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Increasing global energy demand and the harmful effects of greenhouse gas emissions from fossil fuels, has fuelled the search for alternative energy sources that don’t compete with food supplies. This study conducted the catalytic cracking of nyamplung oil into bio-hydrocarbon compounds using a modified fly ash-based zeolite catalyst. The zeolite catalyst was obtained from fly-ash preparation by acid washing (HCl) and alkali melting (NaOH) impregnated with calcium oxide (CaO) and nickel oxide (NiO) to improve its performance. Variation of catalyst mixture of 5% and 10% CaO, with 1-3% NiO, temperature 450-550◦C, and ratio of oil to catalyst 0-20% wt. The results of the cracking reaction in the form of bio-oil were characterized by Gas Chromatography-Mass Spectroscopy (GCMS) and Fourier Transform Infra-Red (FT-IR). The catalyst preparation results were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), Scanning Electron Microscopy (SEM), and Brunauer–Emmett–Teller (BET). Based on the results of the research, nyamplung oil was successfully converted into bio-hydrocarbon compounds using a variety of zeolite fly ash (ZFA) catalysts modified with CaO and NiO. Catalyst type ZFA impregnated with 3% NiO (3%NiO/ZFA) at 550◦C and mass ratio of catalyst to feed oil of 10%wt produced the biggest conversion of 81,89%. Based on the GCMS results, the selectivity of the gasoline chain fraction (C5-C11) was 27,14%. The physical properties of the bio-hydrocarbons are close to those of biodiesel with a density value (717 kg/m3), kinematic viscosity (2,69 cSt,), and RON number (94)."