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Alotrop
Published by Universitas Bengkulu
Jurnal Alotrop adalah majalah ilmiah resmi yang diterbitkan oleh Program Studi Pendidikan Kimia Jurusan Pendidikan MIPA Fakultas Keguruan dan Ilmu Pendidikan Universitas Bengkulu, sebagai sumbangannya kepada pengembangan Ilmu Kimia dan Pendidikan Kimia yang diterbitkan dalam Bahasa Indonesia yang memuat hasil-hasil penelitian, telaah/tinjauan pustaka, kasus lapangan atau gagasan dalam bidang ilmu Kimia dan Pendidikan Kimia
Articles
30
Articles
PEMBUATAN DAN KARAKTERISASI METIL SELULOSA DARI BONGGOL DAN KULIT NANAS (Ananas comosus)

Rahmidar, Lena, Wahidiniawati, Seruni, Sudiarti, Tety

Alotrop Vol 2, No 1 (2018)
Publisher : FKIP University of Bengkulu

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Abstract

[MAKING AND CHARACTERIZATION OF CELLULOSE METHOD OF BONGGOL AND LEATHER LEATHER (Ananas comosus)] Wastes of core and  peel of pineapple are often not utilized properly, in fact the waste has nutritional content that can be useful. Carbohydrate content in the waste is large enough and allows to be utilized. The purpose of this research is for converting glucose into cellulose and synthesized into methylcellulose. The first stage is glucose from core and peel of pineapple converted into microbial cellulose with Acetobacter xylinum bacteria with the addition of nitrogen and carbon sources. The second stage is synthesis of methylcellulose with methylene chloride and the solvent aquadest/acetone. The dried microbial cellulose was firstly swelled with NaOH addition, then methylation by addition of solvent and methylene chloride and then refluxed at 50-60. Then methyl cellulose neutralized, washed and dried at 50.The FTIR results showed typical cellulose uptake for cellulose microbial pineapple core at wave number 3377.36 cm-1 for OH bonds and 2935.66 cm-1 for CH bonds and in cellulose microbialpineapple peel at wave number 3377.36 cm-1 for OH bonds and 2935.66 cm-1 for the CH bonds. The ratio OH/CH of methyl cellulose-acetone has a smaller value in the core and peel of pineapple concluded that acetone is more efficient to use as a solvent at the methylation. The substitution value of the core and peel of pineapple skin is estimated to below based on the solubility test results.

POTENSI AKTIVITAS ANTIOKSIDAN METABOLIT SEKUNDER DARI BAKTERI ENDOFIT PADA DAUN Moringa oleifera L

Yati, Susi Juni, Sumpono, Sumpono, Candra, I Nyoman

Alotrop Vol 2, No 1 (2018)
Publisher : FKIP University of Bengkulu

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Abstract

[POTENTIAL ANTIOXIDANT ACTIVITY OF SECONDARY METABOLITES FROM ENDOPHYTE BACTERIA ON Moringa oleifera L LEAF] This research aims to know the similarities between secondary compound metabolites produced by endophyte bacterial on host leaves and from  Moringa oleifera L (kelor) leaves as well as determine the magnitude of antioxidant activity compounds of secondary metabolites produced by bacterial endophyte. Based on the results of the test compound is secondary metabolite in both samples, for secondary metabolite compounds in the extract of the leaves of M. oleifera L. contains identified steroid compounds, flavonoids, saponins, tannins and phenolic compounds, while for metabolites secondary bacterial endophyte undetectable on the existence of any secondary metabolite compounds.For testing of antioxidants on endophyte bacterial extracts of leaves of M. oleifera L is done using the DPPH method, performed on variations of the concentration of 200, 400, 600, 800, and 1000 ppm with Ascorbic acid as a comparison. The results of the test get an IC50 of M. oleifera L leaf extract at 243.67 ppm, and supernatan extract from endophyte bacterial at 492 ppm. The IC50 values showed antioxidant activity in secondary metabolite compounds derived from extracts of the leaves of M. oleifera L which has an extreme antioxidant category. The amount of antioxidant activity for secondary metabolite compound extracts of bacterial endophyte on leaves of M. oleifera L category is feeble, and to extract the supernatan activity is weak compared to the value of the antioxidant activity of Ascorbic acid.

HUBUNGAN MINAT BELAJAR SISWA DENGAN PRESTASI BELAJAR SISWA PADA MATA PELAJARAN KIMIA DI SMA NEGERI 1 TEBAT KARAI DAN SMA NEGERI 1 KABUPATEN KEPAHIANG

Rozikin, Slamet, Amir, Hermansyah, Rohiat, Salastri

Alotrop Vol 2, No 1 (2018)
Publisher : FKIP University of Bengkulu

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Abstract

[RELATIONSHIP OF STUDENTS LEARNING ACHIEVEMENTS WITH STUDENTS LEARNING INTEREST IN THE    CHEMISTRY SUBJECTS AT SMA NEGERI 1 TEBAT KARAI AND SMA NEGERI 1 KEPAHIANG] This study aims to measure the significance of relationships of interest in learning chemistry with the result of chemical learning students in class X IPA residing in SMA Negeri 1 Tebat Karai and a in SMA Negeri 1 Kepahiang at 2016/2017 academic year.. The research is the correlation research. The population in this research is the whole  class  of X IPA grade in  SMAN 1 Tebat Karai and SMAN 1 Kepahiang at 2016/2017 academic year with total population 218 students who at was a total sample of research. Data collection techniques in the study used the instruments form of the interest in learning chemistry. Data analysis tested using correlation analysis, test validity, reliability, linear regression and hypothesis testing. Based on the analysis of the data obtained to the conclusion that there was a significant positive relationship between interest in study with the results of the study chemistry well in SMA Negeri 1 Tebat Karai and SMA Negeri 1 Kepahiang, indicated from the value of F test  is greater than F table (30.225 > 3.885) with contributions amounting to 76.4%  with the most significant influence indicator is an understanding of the concept of the learning materials with the value of the average correlation of 0,377, 14. From the results of research conducted obtained the conclusion that that interest in learning affects student learning results in class X SMA Negeri 1 Tebat Karai and SMA Negeri 1 Kepahiang. 

EKSPERIMEN KINETIKA ENZIM MENGGUNAKAN MODEL INKUIRI TERBIMBING UNTUK MENINGKATKAN KETRAMPILAN BERPIKIR KREATIF MAHASISWA

Amida, Nadia, Supriyanti, F.M. Titin, Liliasari, Liliasari

Alotrop Vol 2, No 1 (2018)
Publisher : FKIP University of Bengkulu

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Abstract

[EXPERIMENT OF ENZYME KINETICS USING GUIDED INQUIRY MODEL FOR ENHANCING CREATIVE THINGKING SKILLS] Purpose of this study was enhancing creative thinking skills of students using guided inquiry model through experiments of enzyme kinetics based on local materials. Method of this research was quasi-experimental methods, with pretest-posttest nonequivalent control group design. Subjects of this study were chemistry students enrolled in biochemistry lab course, consisted of 18 students in the experimental class and 19 students in control class. Instrument in this study were essay test that involves 3 indikators of creative thinking  skills (i.e. fluency, flexibility, and elaboration) and also student worksheets. The results showed that the experiments of kinetics enzyme  using guided inquiry model have been enhance creative thinking skills in medium category with a value of N-gain average of 0.66. Two indikators classified in the high category are fluency and elaborationwith the value of N-gain 0,71. Meanwhile, indikator of flexibility in the medium category with a value of N-gain 0,56.

PENENTUAN PARAMETER ADSORPSI SILIKA SINTETIK DARI CANGKANG KELAPA SAWIT TERHADAP KANDUNGAN AMMONIUM PADA LIMBAH CAIR TAHU

Karimullah, Rizki, Elvia, Rina, Amir, Hermansyah

Alotrop Vol 2, No 1 (2018)
Publisher : FKIP University of Bengkulu

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Abstract

[DETERMINATION OF SYNTHETIC SILICA ADSORPTION PARAMETERS OF OIL PALM SHELLS AGAINST THE CONTENT OF AMMONIUM ON LIQUID TOFU WASTE] This research aims to determine adsorption capacity of synthetic silica synthesized from Palm Oil (Elaeis guineensis Jacq) shells ashes against the content of Ammonium on tofu liquid waste . The shell sample soaked in a solution of HCl 10% for 2 hours, charred at a temperature of  300 °C for 3 hours ago ashed at 600 °C for 2 hours. Then ash soaked with HCl 1.2 M for 24 hours.  Taken 120 g of ash shells and then mixed right while heated with 160 mL 4 M NaOH. The residue obtained is heated at a temperature of 5000 °C  for 30 minutes, cooled to room temperature and retrieved the Na2SiO3 particle.The particle then  dissolved into 200 ml aquademin and settled at 12 hours, filtered and filtratnya ditetesi with HCL 1 M while stirring, until the white gel is formed and settled in the next 24 hours, filtered, and dried at a temperature of 120 °C for 2 hours, an silica powder obtained as result.  Ammonium Adsorption is done with mass variation 0125, 0.25, 0.5, 0.75, and 1 g silica as well as variations of the contact time of 15, 30, 60, 90, and 120 minutes. The results showed Ammonium adsorption at tofu liquid waste by silica synthesis from the Palm Oil shell ashes occurs with a maximum mass of 0.25 g and optimum contact time of 30 minutes with a capacity of adsorption of 2.581 mg/L and 3,154 mg/L as well as with adsorption efficiency at  61.9% and 76.8%.

PENERAPAN MODEL DISCOVERY LEARNING DENGAN MENGGUNAKAN MEDIA VIDEO UNTUK MENINGKATKAN AKTIVITAS BELAJAR DAN HASIL BELAJAR SISWA KELAS XI IPA 1 SMAN 1 KOTA BENGKULU

Medianty, Sitti Utami, Bahar, Amrul, Elvinawati, Elvinawati

Alotrop Vol 2, No 1 (2018)
Publisher : FKIP University of Bengkulu

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Abstract

[APPLICATION OF DISCOVERY LEARNING MODEL BY USING VIDEO MEDIA TO INCREASE LEARNING ACTIVITIES AND STUDENT LEARNING RESULT CLASS XI IPA 1 SMAN 1 BENGKULU CITY]. The research has goals to improve the activity and learning outcomes chemistry at XI IPA 1 class in SMA Negeri 1 Bengkulu that consist of 30 students: 23 girls and 7 boys. This study is research of class action on thermochemistry subjects by discovery learning model. This research consist three cycle on four stage: planning, action, absorption, and reflection. The data collected using test and non test that consist of post test and observation sheet of activity teacher and student. The data processed using quantitative simple analysis techniques: average score of observation sheet of activity teacher and student, average score, absorption percentage clasical, andclasssical learning completness percentage. From the reseult, we can conculded that chemistry learning process applying discovery learning model using video can improve activity and outcomes learning chemistry student. It can be see from the average score of students. In the first cycle is 69.33 in which the percentage of classical absorption is 86.67 and classical learning completeness is 66.67. The average score of the second cycle is 71,33 in which the percentage of classical absorption is 89.17 and classical learning completeness is 73.33. The students’ average score of the third cycle is 81.33 in which the percentage of classical absorption is 90.37 and classical learning completeness is 86.67. The teacher’s activities of the learning process in the first cycle get average score 26.5 and it is good category, the second cycle is 27.5 and it is good category, the third cycle is 30 and it is good category too. Meanwhile, the student’s activities in the first cycle get average score 22.5 and it is good category, the second cycle is 25 and it is a good category, the third cycle is 27 and it is good category.

PREPARASI DAN KARAKTERISASI MIKROKRISTALIN SELULOSA (MCC) BERBAHAN BAKU TANDAN KOSONG KELAPA SAWIT (TKKS)

Effendi, Fepri, Elvia, Rina, Amir, Hermansyah

Alotrop Vol 2, No 1 (2018)
Publisher : FKIP University of Bengkulu

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Abstract

[PREPARATION AND CHARACTERIZATION OF MICROCRYSTALLINE CELLULOSE (MCC) MADE FROM EMPTY PALM OIL BUNCHES (TKKS)] Empty Palm bunches (TKKS) is solid waste from industrial processing of oil palm (Elaeis guineensis Jacq) that have a high cellulose content.  This research aims to synthesize Microcrystalline Cellulose (MCC) from TKKS and determine the characteristics of the MCC produced. The manufacturing process begins with the MCC delignifikasi multistage pulping TKKS using mixed of 3.5% HNO3 and NaNO2 in temperatures of 90 ?C for 2 hours, followed by heating of a mixture of 2% NaOH and Na2SO3 2 % at temperature 50?C for 2 hours. The second stage of the lignification process is done using NaOH 17.5 %, followed by hydrolysis towards ?-Cellulose lignification results with heating in the aqueous solution of HCl at concentrations of 3, 3.5 and 4 M for 30, 45 and 60 minutes. From the results obtained from the hydrolysis of the optimum yield of 80.73 %, i.e., MCC that use concentration of HCl 3 M for 30 minutes.  MCC produced then analyzed using FTIR, XRD, and PSA. FTIR absorption for MCC results showed an of waves number on a 3375.43 cm-1 and 2899,01cm-1, indicating the presence of hydroxyl OH and CH.The results of the analysis with the PSA suggests that MCC has generated a measure of particle diameter 0.5281 µm. Using XRD analysis results that MCC has a degree of crystallinity of 86,79 %. And the results of testing the content of carbohydrates in MCC produced shows levels of carbohydrates of 88.36 %.

SINTESIS DAN KARAKTERISASI XEROGEL HASIL KOPRESIPITASI DARI PASIR PANTAI PANJANG BENGKULU

Meyori, Finni, Elvia, Rina, Candra, I Nyoman

Alotrop Vol 2, No 1 (2018)
Publisher : FKIP University of Bengkulu

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Abstract

[SYNTHESIS AND CHARACTERIZATION OF XEROGEL RESULTS OF COPRECIPITATION OF LONG BEACH BENGKULU BEACH].  This research aims to synthesize and characterization to  Xerogel which synthesizes from Pantai Panjang  sands Bengkulu. The method used for this study to synthesizes Xerogel is to use the coprecipitation method. Qualitative XRF test against raw sand  materials that were used show that the content of the element is the most significant element of Si. The first  stages of the synthesis of Xerogel is a purification of the sand sample..  Xerogel synthesis is carried out in two phases, namely the manufacture of aqueous solutions of Sodium Silicate and continued with the formation of a gel. The production of Sodium Silicate solution is done using the NaOH concentration at 5, 6 and 7 M.  Gel formation process is done by adding a solution of HCl 10 M into the solution of Sodium Silicate, followed by process of filtration, washing and drying in the oven. The results showed that the optimum conditions of synthesis of Xerogel   obtained  using 6 M NaOH  , with a yield obtained is amounting at 0.8%. The results of the test by XRD shows that the silica crystal structure  on Xerogel  are amorphous-shaped. SEM-EDS test results show that the acquired  Xerogel on research has a smooth texture and size is not homogeneous with the highest content of elements are the elements Si and O.  PSA test shows that particle size in Xerogel an average at 191.4 nm. 

POTENSI EKSTRAK METABOLIT SEKUNDER Eugenia uniflora L. SEBAGAI BAHAN PENGAWET TAHU

Tria, Genesis, Nurhamidah, Nurhamidah, Amir, Hermansyah

Alotrop Vol 2, No 1 (2018)
Publisher : FKIP University of Bengkulu

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Abstract

[POTENTIAL OF Eugenia uniflora L SECONDARY METABOLITES EXTRACT AS A TOFU PRESERVATIVE]. The purpose of this research is to know the secondary metabolite compounds from the Eugenia uniflora L (Dewandaru) fruit extracts , as well as to measure the potential of water extract from the fruit of E. uniflora L for the use in the tofu preserve as well as measure the impact of the addition of water extract of the fruit of E. uniflora L against moisture, pH, protein on tofu. The process of preserving test against tofu on the research done by soaking time at 2, 3 and 4 hour with each variation of the concentration of extract at  10, 15 and 20% as well as the observation time at 24 and 48 hours for each treatment.The result of the test water extract of the fruit of the phytochemical profile E. uniflora L showed the content of alkaloids, flavonoids, phenolic , saponins and steroid compounds. Test results from the granting of water extract from the fruit of E.uniflora L in the preserve of tofu with the variation of concentration and soaking time is proven to affect the value of water content, pH, and protein on tofu that was tested.The results of the research done indicate that the granting of a water extract of the fruit of E.uniflora L proven useful to be used as a natural preservative for tofu at 24 hours with a 20% concentration and a soaking time at 2 and 3 hours. From the results, it can be concluded that water extracts from the fruit of E.uniflora L. potential to be used as a natural preservative for tofu.

ANALISIS KEMAMPUAN BERPIKIR KRITIS MATA PELAJARAN KIMIA PADA SISWAKELAS XI IPA SMAN 1 KEPAHIANG

Yunita, Selly, Rohiat, Salastri, Amir, Hermansyah

Alotrop Vol 2, No 1 (2018)
Publisher : FKIP University of Bengkulu

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Abstract

[ANALYSIS OF THE CRITICAL THINKING ABILITY FROM CHEMICAL SUBJECTS IN STUDENTS OF CLASS XI IPA SMAN 1 KEPAHIANG] This research aims to know the critical thinking ability of students. Type of this research is descriptive research using quantitative methods. This research was carried out in SMA Negeri 1 Kepahiang on September 2 to 8 may in 2017. The population in this research is the entire class XI IPA are registered on the even-numbered school year 2016/2017 semester. As the samples are taken at class XI IPA 6 of 32 participants.  Data collection is done with the test in the form of reserved descriptions as much as 10 round the whole includes indicators of critical thinking from the taxonomy of Bloom that is level (C2) understand (C3), apply (C4), analyzing and evaluating (C5). Test results obtained from the analysis of results the percentage of students with the ability to answer a question of thinking very critically at 15,6%, quite critical at 53,2 %, and less critical at 31,2 %, with an average value of 61.81. From the average of the values obtained showed that students who have average value included in the category of being. Based on the analysis of the data collected can be inferred levels of critical thinking ability of the students in class XI IPA 6 SMA Negeri 1 Kepahiang at school 2016/2017 academic year can be grouped in a category group are of 53,2 %, middle , 15,6 %  at high group and 31,2 % at low groups. From the results, it can be concluded that overall students in grades at  XI IPA 6 SMA Negeri 1 Kepahiang even 2016/2017 academic year with the ability to enough think critically.