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PEMURNIAN AMILASE MIKROBA AMILOLITIK DENGAN FRAKSINASI AMONIUM SULFAT DAN AMOBILISASI PADA AGAR-AGAR KOMERSIAL I N. Wirajana; R. R. Sirait; P. Suarya
Jurnal Kimia (Journal of Chemistry) Vol. 15, No.1, Januari 2021
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/JCHEM.2021.v15.i01.p07

Peningkatan penggunaan biokatalis amilase membutuhkan pemurnian dan amobilisasi enzim ini untuk berbagai keperluan yang lebih ekonomis. Tujuan penelitian ini adalah menentukan persen kejenuhan amonium sulfat untuk pemurnian amilase mikroba amilolitik dan persen konsentrasi agar-agar komersial terbaik untuk mendapatkan persen efisiensi dan kestabilan tertinggi.Amilase diproduksi dari isolat mikroba amilolitik dengan kode UU1.1. Ekstrak kasar amilase ekstraseluler difraksinasi dengan amonium sulfat dengan tingkat kejenuhan 0-20%, 20-40%, 40-60%, 60-80% dan 80-100%; selanjutnya tiap fraksi dilakukan dialisis dalam buffer fosfat pH 6. Pengukuran aktivitas amilase dilakukan dengan menentukan kandungan gula pereduksi sebelum dan setelah reaksi enzimatis yang diinkubasi pada suhu 37oC pH 6 selama 60 menit dengan metode Dinitrosalicylic acid (DNS). Penentuan kadar protein total setiap fraksi diukur dengan metode Biuret. Aktivitas spesifik amilase ditentukan dari hasil pembagian aktivitas amilase dengan kadar protein total setiap fraksi. Amobilisasi dilakukan pada konsentrasi agar-agar 1%, 2% dan 3% (b/v). Penentuan persen agar-agar terbaik untuk amobilisasi amilase ditentukan dari efisiensi amilase teramobil tertinggi dan kestabilannya. Tingkat kejenuhan amonium sulfat 20-40% atau fraksi 2 diperoleh aktivitas spesifik amilase tertinggi sebesar 6,0 U/mg, yang merupakan tingkat kemurnian amilase tertinggi. Aktivitas amilase tertinggi sebesar3,3 x 10-3 U/mL, diperoleh dari hasil fraksinasi pada tingkat kejenuhan amonium sulfat 40-60% atau fraksi 3, digunakan untuk amobilisasi dalam matriks agar-agar komersial. Amobilisasi amilase dengan efisiensi dan kestabilan tertinggi diperoleh pada konsentrasi agar-agar 3% (b/v), baik untuk ekstrak kasar amilase maupun amilase hasil fraksinasi. Kata kunci: agar-agar, amilase, amilum, amobilisasi, fraksinasi. Increased use of amylase biocatalysts requires the purification and immobilization of this enzyme for a variety of more economical purposes. The purpose of this study was to determine the percent saturation of ammonium sulfate for the purification of amylolytic microbial amylase and the best percent of commercial agar concentration to obtain the highest percent efficiency and stability. Amylase is produced from amylolytic microbial isolates with the code UU.1.1. Crude extract of extracellular amylase is fractionated with ammonium sulfate with saturation levels of 0-20%, 20-40%, 40-60%, 60-80% and 80-100%; then each fraction was dialyzed in a phosphate buffer 6. The measurement of amylase activity was carried out by determining the reducing sugar content before and after the enzymatic reaction incubated at 37oC pH 6 for 60 minutes with the Dinitrosalicylic acid (DNS) method. Determination of total protein content of each fraction was measured by the Biuret method. The specific activity of amylase is determined from the results of the division of amylase activity by the total protein content of each fraction. Immobilization is carried out at 1%, 2% and 3% (w / v) agar concentrations. Determination of the best agar agar for amylase immobilization is determined from the highest immobilized amylase efficiency and its stability. Ammonium sulfate saturation level of 20-40% or fraction 2 obtained the highest specific amylase activity of 6.0 U / mg, which is the highest level of purity of amylase. The highest amylase activity of 3.3 x 10-3 U / mL, obtained from fractionation at 40-60% ammonium sulfate saturation level or fraction 3, was used for immobilization in the commercial agar matrix. Amylase immobilization with the highest efficiency and stability was obtained at a concentration of agar 3% (w / v), both for crude extracts of amylase and fractionated amylase. Keywords: agar-agar, amylase, fractionation, immobilization, starch.

ADSORPSI PENGOTOR MINYAK DAUN CENGKEH OLEH LEMPUNG TERAKTIVASI ASAM P. Suarya
Jurnal Kimia (Journal of Chemistry) Vol. 2, No. 1 Januari 2008
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

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Preparation, characterization and application of acid activated clays as adsorbents on the purification of clove leavesoil have been conducted. The effects of concentration of acid on the quality of the activated clay and on theadsorption performance of the prepared activated clay were also studied. Characterization of the activated clay wascarried out using gas sorption analyzer and FTIR spectroscopyThe results showed that the spesific surface area of the activated clays increases with increasingconcentration of acid. At the concentration of acid of 0, 0.4, 0.8, 1.2, 1.6, and 2.0 M, the spesific surface areas were48.27; 48.75, 54.31; 65.21; 62.91 and 51.86 m2/g, respectively. From the adsorption test, it was observed that theactivated clay prepared with concentration acid of 1,2 M, showed the best performance. It’s was able to adsorp 284.2mg of impurity and thus purify 40 ml of crude clove leaves oil.

INTERKALASI TETRAETIL ORTOSILIKAT (TEOS) PADA LEMPUNG TERAKTIFASI ASAM SULFAT DAN PEMANFAATANNYA SEBAGAI ADSORBEN WARNA LIMBAH GARMEN P. Suarya; A. A. Bawa Putra; Devi Wisudawan
Jurnal Kimia (Journal of Chemistry) Vol. 4, No. 1 Januari 2010
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

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Interchalation of Tetraethyl orthosilicate (TEOS) with acid activated clay has been studied. As forcharacterization of the modified clay. Acid-base titration methode was used to determine the surface acidity.Methylen blue method was used to determine the surface area while spectrophotometer UV-Vis was used todetermine the amount of dye adsorbted by the modified clay.The results showed that activation of clay with sulphuric acid and interchalat ion with TEOS increased thesurface acidity of the clay. The value of surface acidity of S0-0(without activation); Sa-0(interchalated with TEOS 0%);Sa-5 (interchalated with TEOS 5%); Sa-10(interchalated with TEOS 10%); Sa-15 (interchalated with TEOS 15%) were0.5064; 0.8733; 0.8486; 1.0005; and 0.8926 mmol/gadsorbent respectively. The specific surface area of S0-0; Sa-0; Sa-5;Sa-10; Sa-15 were27.2391 m2/g; 28.4019 m2/g; 28.2767 m2/g; 29.2220; m2/g dan 29.1621 m2/g, respectively. Furthermore, it was shown that, acid actived clay interchalated with 10% TEOS was the best adsorbent which adsorbed83,64% of the dye indicated by the change of the colour from dark yellow to light yellow.

KARAKTERISASI ADSORBEN KOMPOSIT ALUMINIUM OKSIDA PADA LEMPUNG TERAKTIVASI ASAM P. Suarya
Jurnal Kimia (Journal of Chemistry) Vol. 6, No. 1 Januari 2012
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

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Composite of alluminium oxide in clay has been prepared. The materials were prepared as follow: first, clay was activated with 1.2 M sulphuric acid, then intercalated using polyoxycation of alluminium, and finally calcinated to form composite of alluminium oxide (Al2O3). X-ray diffraction (XRD) was employed to characterize basal spacing (d001). Acid-base titration was used for determining the surface acidity, and spectrophotometer UV-Vis for determining the specific surface area.The results show that activation of clay with sulphuric acid and interchalation with polyoxycation of alluminium increase the surface acidity of aluminium oxide composite in clay the namely. The specific surface area of CC0-0, CCa-0, CCa-1, CCa-2 and Cca-3 were 27.0307 m2/g; 28.2351 m2/g; 29.0040 m2/g; 29.2074 m2/g; and 29.1513 m2/g respectively. The X-ray results indicated that adsorbent was composed by montmorillonite, kaolinite, chlorite, feldspar, and calsite.

INTERKALASI BENZALKONIUM KLORIDA KE DALAM MONTMORILLONIT TERAKTIVASI ASAM DAN PEMANFAATANNYA UNTUK MENINGKATKAN KUALITAS MINYAK DAUN CENGKEH P. Suarya
Jurnal Kimia (Journal of Chemistry) Vol. 3, No. 1 Januari 2009
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

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This research was conducted to observe the surfactant intercalation into acid-activated montmorillonite clay.This clay was applied as adsorbent for increasing the quality of clove leaf oil. The acid used as an activation was 1.5M sulphuric acid and the surfactant for intercalation was Benzalkonium Chloride (BKC) with concentration variation(0; 0.1; 0.5; 1; and 2%). The result of the reseach showed that the changes of basal spacing d001 for S0-0; Sa-0; Sa-0,1;Sa-0,5; Sa-1; and Sa-2 were 15.15548; 15.40269; 15.20580; 14.62099; 14.77594; and 14.74415 Å respectively. Thesurface area for S0-0; Sa-0; Sa-0,1; Sa-0,5; Sa-1; and Sa-2 were 26.2239; 27.4035; 26.0482; 26.4557; 27.7885; and 26.6809m2/g respectively. The Sa-0,1 adsorbent had the highest surface acidity (1.0135 ± 0.01100 mmol/g). Every gram ofadsorbent Sa-0,1 had the highest adsorption capacity to clarify 20.0 mL clove leaf oil at 120 minutes contact time.After adsorption by Sa-0,1 the clove leaf oil was clearer and contained higher concentration of eugenol than beforeadsorption.

MODIFIKASI SILIKA GEL DARI ABU LIMBAH HASIL PROSES PEMBAKARAN INDUSTRI BATU BATA DENGAN DIFENILKARBAZON SEBAGAI ADSORBEN SERTA UJI DAYA SERAP TERHADAP ION LOGAM Cr(III) DAN Cu(II) I. W. Sudiarta; I G. D. V. Saputra; P. Suarya
Jurnal Kimia (Journal of Chemistry) Vol. 16, No.2, Juli 2022
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/JCHEM.2022.v16.i02.p14

Modifikasi silika gel dari abu limbah proses pembakaran batu bata dengan difenilkarbazon telah dilakukan. Silika gel termodifikasi difenilkarbazon (Si-DPZon) diperoleh dengan cara mendidihkan abu dengan larutan NaOH untuk menghasilkan natrium silikat dan dinetralkan dengan HCl untuk mendapatkan silika gel kemudian dimodifikasi secara fisik dengan ligan. Kajian yang dilakukan meliputi penentuan gugus fungsi adsorben secara spektrofotometer IR, keasaman permukaan dengan metode titrasi asam basa, luas permukaan spesifik dengan metode metilen biru, kondisi optimum adsorpsi (pH, waktu kontak) Cr(III) dan Cu(II) . Hasil FTIR menunjukkan Si-DPZon mengandung gugus fungsi amida (N-H), karbonil (C=O), silanol (Si-OH), siloksan (Si-O-Si) dan aromatik (C-H). Hasil penelitian menunjukkan bahwa Si-DPZon memiliki keasaman permukaan (Kal) sebesar 5,8384 ± 0,2466 mmol/g, jumlah situs aktif 12,3945x1020 atom/g, dan luas permukaan spesifik 12,6886 m2/g. Si-ABB memiliki keasaman permukaan (Kal) sebesar 4,5568±0,2453 mmol/g dengan jumlah situs aktif 27,4410x1020 atom/g dengan luas permukaan spesifik 11,6712 m2/g. Kondisi optimum adsorpsi krom (III) baik Si-DPZon maupun Si-ABB terjadi pada pH 5 dan 15 menit. Kemampuan adsorpsi Cr(III) oleh Si-DPZon pada kondisi pH dan waktu kontak optimum adalah 34,6927 mg/g dengan persentase adsorpsi 86,7317% dan Si-ABB diperoleh pada 34,5445 mg/g dengan persentase adsorpsi 86,3611%. Kemampuan adsorpsi Cu(II) oleh Si-DPZon pada kondisi pH dan waktu kontak optimum adalah 26,49672 mg/g dengan persentase adsorpsi 66,2418% dan Si-ABB diperoleh 24,93210 mg/g dengan persentase adsorpsi 62,3302%. Kata kunci: adsorpsi, krom (III), tembaga (II), ligan difenilkarbazon, sintesis silika gel. ABSTRACT The modification of silica gel, from the waste of the bricks burning process, with diphenylcarbazone has been done. The silica gel modified by diphenylcarbazone (Si-DPZon) was obtained by boiling the ash with NaOH solution to create sodium silicate and neutralized with HCl to get the silica gel, then physically modified with diphenylcarbazone ligand. The study included the determination of the adsorbent functional groups by spectrophotometer IR, surface acidity by acid-base titration method, specific surface area by absorption of methylene blue method, the optimum conditions (pH, contact time) of the adsorption of Cr(III) and Cu(II). FTIR analysis showed that the Si-DPZon contained amide (N-H), carbonyl (C=O), silanol (Si-OH), siloxane (Si-O-Si) and aromatic (C-H) functional groups. The results showed that Si-DPZon had a surface acidity (Kal) of 5.8384 ± 0.2466 mmol/g with the number of active sites of 12.3945x1020 atom/g with a specific surface area of 12.6886 m2/g. Si-ABB had a surface acidity (Kal) of 4.5568±0,2453 mmol/g with the number of active sites of 27.4410x1020 atom/g and with a specific surface area of 11.6712 m2/g. The optimum conditions for adsorption of chromium (III), both Si-DPZon and Si-ABB occurred at pH 5 and 15 minutes. The adsorption ability of Cr(III) by Si-DPZon at the pH and contact time optimum conditions was 34.6927 mg/g with an adsorption percentage of 86.7317% and Si-ABB was obtained at 34.5445 mg/g with the adsorption percentage of 86.3611%. Adsorption ability of Cu(II) by Si-DPZon at the pH and contact time optimum conditions was 26.49672 mg/g with the adsorption percentage of 66.2418% and Si- ABB was obtained at 24.93210 mg/g with the adsorption percentage of 62.3302%. Keywords: adsorptions, chromium (III), copper (II), diphenilcarbazone ligand, synthesis of silica gel.

Synthesis and Characterization of SRF Fertilizer using a Mixture of Urea and Bentonite Clays K. R. Pangestu; P. Suarya; I. A. G. Widihati
Jurnal Kimia (Journal of Chemistry) Vol. 17, No.1, Januari 2023
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/JCHEM.2023.v17.i01.p01

Penggunaan pupuk nitrogen secara berlebihan mengakibatkan pencemaran lingkungan serta merusak kondisi tanah. Penelitian ini bertujuan untuk membuat pupuk slow release fertilizer (SRF) mengunakan formula campuran lempung bentonit dengan urea. Sintesis pupuk SRF mengunakan metode pencampuran padat-cair dengan mengelusikan senyawa urea ke dalam 20 g lempung bentonit dengan variasi massa urea sebesar 10, 20, 30, 40, dan 50 g. Karakterisasi terhadap hasil sintesis pupuk SRF dilakukan dengan FTIR dan metode Kjeldahl. Spektra FTIR menunjukkan adanya vibrasi dari gugus fungsi N-H, C=O, dan C-N yang menjadi penyusun pupuk urea pada bilangan gelombang 3506.59, 1691.57, dan 1176.58. Kadar nitrogen yang terkandung dalam pupuk SRF di analisis dengan metode Kjeldhal dan didapatkan kadar nitrogen tertinggi sebesar 13.35 g/100g, dengan komposisi lempung bentonit 20 g dan 50 g pupuk urea. Kata kunci: lempung bentonit, slow release fertilizer, urea. ABSTRACT Excessive use of nitrogen fertilizers causes environmental pollution and damages soil conditions. This research aimed to synthesis a slow release fertilizer (SRF) using a mixture of bentonite clay with urea. The synthesis of SRF using the solid –liquid method was carried out by eluting the urea fertilizer in the 20 g of bentonite clay with various masses of urea of 10, 20, 30, 40, and 50 g. The characterization of the SRF was done by FTIR and Kjeldhal methods. The FTIR spectra showed the presence of vibration of N-H, C=O, and C-N functional groups, which indicated the urea constituents, at the wave number of 3506.59, 1691.57, and 1176.58 cm-1. The nitrogen content in the SRF analyzed by the Kjeldhal method resulted in the highest value of 13.35 g/100g prepared with a composition of 20 g of bentonite clay and 50 g of urea fertilizer. Keywords: bentonite clay, slow release fertilizer, urea.

KANDUNGAN HARA MAKRO SETELAH PENAMBAHAN PUPUK KOMPOS BLOTONG PADA TANAH PERKEBUNAN Rahmah, I.; Suarya, P.; Manuaba, I. B. P.; Ariati, N. K.
Jurnal Kimia (Journal of Chemistry) Vol. 18, No.1, Januari 2024
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/JCHEM.2024.v18.i01.p12

Blotong atau filter cake merupakan kotoran nira tebu dari proses pembuatan gula. Namun, blotong dapat dimanfaatkan menjadi pupuk organik karena kandungan hara dalam blotong cukup tinggi. Misalnya kandungan C, N, P, dan K yang dapat menjadi sumber hara serta meningkatkan kualitas tanah. Penelitian ini bertujuan untuk mengetahui peningkatan unsur hara C, N, P, dan K pada tanah setelah pemberian pupuk blotong. Metode yang digunakan dalam penelitian ini yaitu metode Walkley and Black untuk penetapan hara C, metode Kjeldahl untuk penentuan hara N, dan metode Bray I untuk penentuan hara P dan K. Perlakuan pemupukan dilakukan dalam skala kecil, dimana tanah perkebunan direparasi dalam wadah polybag berukuran 50 cm x 50 cm. Pemupukan dilakukan selama 4 minggu dengan takaran variasi pupuk setara 0 ton/ha, 10 ton/ha, 25 ton/ha, dan 60 ton/ha. Hasil penelitian menunjukkan bahwa pupuk blotong dapat meningkatkan kadar hara pada tanah perkebunan. Perlakuan 0 ton/ha diperoleh hasil kadar C, N, P, dan K berturut-turut sebesar 1,12%; 0,12%; 102,7588 ppm, dan 101,320 ppm. Perlakuan 10 ton/ha diperoleh hasil kadar berturut-turut sebesar 1,18%; 0,13%; 122,9938 ppm, dan 145,610 ppm. Perlakuan 25 ton/ha diperoleh hasil kadar berturut-turut sebesar 1,22%; 0,14%; 144,8662 ppm, dan 260,960 ppm. Perlakuan 60 ton/ha kadar berturut-turut sebesar 2,58%; 0,15%; 190,6140 ppm, dan 380,180 ppm. Hal tersebut menunjukkan bahwa takaran setara 60 ton/ha cukup untuk meningkatkan kandungan hara C, N, P, dan K tanah dalam waktu 4 minggu. Kata kunci: Blotong, tanah, C-organik, N, P, K ABSTRACT Blotong or filter cake is sugar cane sap dirt from the sugar-making process. However, blotong can be used as an organic fertilizer because the nutrient content in blotong is relatively high. For example, the contents of C, N, P, and K can be a source of nutrients and improve soil quality. This study aimed to determine the increase in nutrients C, N, P, and K in the soil after applying blotong fertilizer. There were methods used in this study, such as the Walkley and Black method for determining C nutrients, the Kjeldahl method for determining N nutrients, and the Bray I method for determining P and K nutrients. Fertilization treatment was carried out on a small scale, where who repaired the plantation soil in polybags measuring 50 cm x 50 cm. Fertilization is carried out for four weeks with varying doses of fertilizer equivalent to 0 tons/ha, 10 tons/ha, 25 tons/ha, and 60 tons/ha. The results showed that blotong fertilizer could increase the nutrient content of the plantation soil. Treatment of 0 ton/ha resulted in C, N, P, and K of 1.12%, 0.12%, 102.7588 ppm, and 101.320 ppm, respectively, while the 10 ton/ha treatment yielded 1.18%, 0.13%, 122.9938 ppm, and 145.610 ppm, respectively. Moreover, the 25 ton/ha treatment produced a grade of 1.22%, 0.14%, 144.8662 ppm, and 260.960 ppm, respectively, whereas the treatment of 60 tons/ha of 2.58%, 0.15%, 190.6140 ppm, and 380.180 ppm successively. These results showed that the equivalent dose of 60 tons/ha was sufficient to increase the contents of C, N, P, and K nutrients in the soil within four weeks. Keywords: blotong, soil, C-organic, N, P, K

EFEKTIVITAS EKSTRAK METANOL DAUN NANGKA (Artocarpus heterophyllus Lam.) SEBAGAI INHIBITOR ALAMI TERHADAP KOROSI PADA BAJA ST 37 DALAM MEDIA KOROSIF HCl Dwiyanti, D. A. B.; Suarya, P.; Suirta, I W.
Jurnal Kimia (Journal of Chemistry) Vol. 17, No.2, Juli 2023
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/JCHEM.2023.v17.i02.p11

Korosi merupakan salah satu masalah lingkungan yang sering ditemukan dan juga menjadi pusat perhatian masyarakat khususnya di bidang industri besi dan baja. Untuk melindungi baja dari serangan korosi, maka perlu adanya perlindungan dari inhibitor. Inhibitor korosi adalah bahan kimia yang ditambahkan ke dalam lingkungan korosif untuk mengurangi laju korosi. Sebagian besar inhibitor yang digunakan dalam aplikasi industri adalah inhibitor anorganik. Namun inhibitor ini memiliki dampak buruk bagi ekologis dan kesehatan. Oleh karena itu diperlukan inhibitor ramah lingkungan yang berasal dari bahan alam. Dalam penelitian ini digunakan inhibitor organik yaitu daun nangka. Penelitian ini bertujuan untuk mengetahui efektivitas ekstrak metanol daun nangka dalam menghambat laju korosi pada baja ST 37. Metode yang digunakan dalam menetukan laju korosi adalah metode kehilangan berat. Media uji korosi yaitu larutan HCl 1 M dengan variasi konsentrasi ekstrak daun nangka 0,2 ; 0,4 ; 0,6 ; 0,8, 1% dan variasi suhu 30, 40, 50, 60 ?C. Hasil uji fitokimia menunjukan bahwa ekstrak daun nangka positif mengandung senyawa alkaloid, flavonoid, fenolik, steroid, triterpenoid. Analisis FTIR menunjukkan ekstrak daun nangka memiliki gugus fungsi O-H, C=O, C=C aromatik, C-H aromatik serta mengandung senyawa alifatik golongan alkana yaitu C-H dan –CH3. Efisiensi inhibisi tertinggi yaitu 93,79% pada konsentrasi ekstrak daun nangka 1% dengan laju korosi baja 0,5682 ± 0,0067 mmpy. Sedangkan suhu optimal diperoleh pada suhu 30 ?C dengan efisiensi inhibisi tertinggi yaitu 91,63% dan laju korosi baja 0,7374 ± 0,0049 mmpy. Kata Kunci: baja ST 37, inhibitor, daun nangka, metode kehilangan berat ABSTRACT Corrosion is one of the environmental problems often found and also the center of public attention, especially in the iron and steel industries. To prevent the steel from corrosion, it is necessary to have protection from inhibitors. Corrosion inhibitors are chemicals added to a corrosive environment to reduce the rate of corrosion. Most of the inhibitors used in industrial applications are inorganic inhibitors, but these inhibitors have negative impacts on ecology and health. Therefore, we need environmentally friendly inhibitors derived from natural materials. In this study, organic inhibitors were used, namely jackfruit leaves. This study aimed to determine the effectiveness of methanol extract from jackfruit leaf in inhibiting the corrosion rate of ST 37 steel. The method used to determine the corrosion rate was the weight loss method. The corrosion test medium was 1 M HCl solution with various concentrations of jackfruit leaf extract of 0.2; 0.4; 0.6; 0.8: 1.0 %, and the temperature variations of 30, 40, 50, and 60 ?C. The results of the phytochemical test showed that jackfruit leaf extract positively contained alkaloids, flavonoids, phenolics, steroids, and triterpenoids. FTIR analysis showed that jackfruit leaf extract has the functional groups O-H, C=O, C=C aromatic, and C-H aromatic and contains aliphatic compounds of the alkane group, namely C-H and –CH3. The highest inhibition efficiency was 93.79% at a jackfruit leaf extract concentration of 1% with a steel corrosion rate of 0.5682 ± 0.0067 mmpy. Meanwhile, the optimum temperature obtained was at 30 ?C with the highest inhibition efficiency of 91.63% and the highest corrosion rate steel of 0.7374 ± 0.0049 mmpy. Keywords: inhibitor, jackfruit leaf, ST 37 steel, weight loss method.

USE OF BENTONITE-CHITOSAN MIXTURE AS AN AMMONIUM SULFATE CARRIER IN MANUFACTURING SLOW RELEASE FERTILIZER: - Tobing, Marta; Suarya, P.; Prayikaputri, P. U
Jurnal Ilmu Pendidikan Indonesia Vol 12 No 1 (2024): JURNAL ILMU PENDIDIKAN INDONESIA
Publisher : Program Magister Pendidikan IPA, Program Pascasarjana Universitas Cenderawasih

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31957/jipi.v12i1.3500

Nitrogen is a nutrient that is needed for the process plant growth, but nitrogen is easily carried away by water and evaporates, it causes farmers to fertilize excessively. This cause environmental pollution. The aim of this research is to make slow release fertilizer (SRF) with a bentonite-chitosan-ammonium sulfate formula to increase fertilization efficiency. Mixing was using the liquid-liquid method where 50 mL of 20% (NH4)SO4 was mixed with 20% bentonite-1% chitosan in a ratio of 10:0; 10:20; 20:20; 30:20; 40:20; 50:20. The highest total nitrogen content was obtained in SRF with a bentonite-chitosan ratio of 0:50 (3.94%) which was tested using the Kjeldahl method. Comparison of release tests on SRF and pure fertilizer was carried out every day for 6 days, SRF increased slowly, namely from 0.07%; 0.18%; 0.27%; 0.6%; 0.42%; 0.5%while in 20% (NH4)SO4 fertilizer there was a release of 0.07%; 0.18%; 0.27%; 0.6%; 0.42%; 0.5%%. Nitrogen release in SRF is slower than in ammonium sulfate fertilizer

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