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Corresponding Author
Neneng Windayani
Institutions
Department of Chemistry Education, UIN Sunan Gunung Djati Bandung
Jl. A. H. Nasution No. 105, Bandung 40614, Indonesia
a)E-mail: nenengwinda.ftk[at]uinsgd.ac.id
Abstract
This study aims to obtain an optimum combination formulation of cera alba in the manufacture of lip balm with natural material collorant in accordance with SNI. The experimental method used was maceration of natural products with n-hexane solvents and concentrated with a rotary evaporator to find a dark yellow paste. Furthermore, making lip balm with various formulations of 2 gr cera alba, 2.5 gr, 3 gr and without cera alba in 10 gr shea butter with additives of orange and stawbery essence and natural coloring agent from carrots. The stability of lip blam the homogeneity test was carried out, the stability test carried out for 20 days at room temperature by observing changes in color, odor, and dosage form, pH test, topical test, and irritation test. The experimental results showed that all lip balm preparations were homogeneous, had a pH of 5-5,5 and did not cause skin irritation after 10 minutes of applying to the skin.
Keywords
Lip balm formulation, natural coloring agent, carrot extract
Topic
Chemistry
Corresponding Author
Saprizal Hadisaputra
Institutions
a) Chemistry Education Division, Faculty of Science Education, University of Mataram.
b) Department of Chemistry, Faculty of Mathematics and Natural Science, University of Mataram.
Abstract
The efficiency of ethyl-p-methoxycinnamate and its derivatives as corrosion inhibitors of iron corrosion in acid environment has been studied to find the relationship between molecular structure parameters with the efficiency of corrosion inhibition. The MP2 perturbation theory was applied to calculate molecular structure and electronic parameters. Computational and experimental corrosion inhibition efficiency show that the electronic properties of molecules, including the orbital molecular frontier energy (HOMO and LUMO energy), ionization potential, electron affinity, electronegativity, softness, hardness, number of electron transfer from inhibitor to metal, and interaction energy have a strong relationship with inhibition performance. Furthermore, Fukui function obtained from natural bond orbital analysis was employed to study the interactions between inhibitors with iron metal in more detail. The presence of heteroatom and electron donor groups within the frameworks of inhibitors has a significant effect on corrosion inhibition performance.
Keywords
ab initio, corrosion inhibition, ethyl-p-methoxycinnamate, inhibitor
Topic
Chemistry
Corresponding Author
Siti Oryza Sativa
Institutions
Laboratory of Analytical Chemistry, Department of Chemistry, Bandung Institute of Technology, Bandung 40132, Indonesia1, Analytical Chemistry Research Division, Bandung Institute of Technology, Bandung 40132, Indonesia2, Department of Chemistry, Science and Technology Faculty, UIN Walisongo, Semarang3, Research Unit for Clean Technology Indonesian Institute of Science, Jl. Cisitu Sangkuriang, Bandung 40135, Indonesia4Technology, Bandung 40132, Indonesia
zulfikarmuhammadali[at]gmail.com
Abstract
Peat water source could be found in many lowland and marshy areas in Indonesia such as in Sumatra, Kalimantan, and Papua. This type of water could be a problem for resident living around it as fresh water is one of the basic needs for human being. It formed from decayed of plants, animals, and microbes. The main component of peat water is humic acid which is a complex of organic compound and natural polymer. One of the potential process to treat humic acid is by using photocatalytic degradation method. This research aims to conduct activity of PVDF-TiO2/ZnO/CoO nanofiber photocatalyst for degradation of humic acid solution. Photocatalytic activities was studied inside photoreactor with artificial UV radiation with 254 nm wavelength. The percentage of degradation was determined by measuring humic acid solution before and after degradation using UV-Vis spectrophotometer with maximum lambda in 219 nm. Study of kinetic for photocatalytic reaction was calculated with rate constant 4,29 x 10-5 min-1 ppm-1 and the kinetic of photodegradation on this research was pseudo second order kinetic model.
Keywords
nanofiber, photocatalyst, photocatalytic activity, TiO2, humic acid
Topic
Chemistry
Corresponding Author
Galuh Yuliani
Institutions
Chemistry Department, Universitas Pendidikan Indonesia, Jalan Dr. Setiabudi 229 Bandung 40154, West Java, Indonesia
Abstract
Coal bottom ash (CBA) waste generated from coal-based industries has been increasing at an alarming rate causing huge problems in its recycling and disposal process. On the other hand, CBA is potentially used as raw material in zeolite manufactures due to its high SiO2 and Al2O3 contents. We report the conversion of CBA into zeolites-like material via a low temperature method of 90°C for 24 h using NaOH solution. The synthetic zeolite was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and BET surface area measurement. The study of its adsorption-desorption properties was also conducted using ammonium solution. FTIR spectra confirmed characteristic zeolite peaks at 980-1170 cm-1, 740.6 cm-1, 439.7 cm-1, 559.3 cm-1 for Si-O, Al-O and Si-O-Al absorptions, respectively. XRD results indicated the formation of sodium aluminosilicate hidrate belong to the zeolite structure group at NaOH 5M ratio of 1:8. XRF results also indicated the domination of Al2O3 and SiO2 in the zeolite composition. BET analysis resulted the surface area of zeolite was 60.38 m2/g, markedly increased from the initial surface area of CBA of 0.598 m2/g. The maximum adsorption capacity for ammonium ions were 85.22 mg/g and the adsorption data fitted the Freundlich isotherm model. Meanwhile, the desorption study indicated that the ammonium leached rapidly in the first 3 h followed by a plateu in the next 71 h.
Keywords
bottom ash; zeolite; adsorption; desorption; ammonium
Topic
Chemistry
Corresponding Author
Neneng Windayani
Institutions
1 Prodi Pendiidkan Biologi, 2Prodi Pendidikan Kimia, Fakultas Tarbiyah dan Keguruan, UIN Sunan Gunung Djati Bandung Jl. A.H. Nasution No. 105, Bandung 40614, Indonesia
a)E-mail: nenengwinda.ftk[at]uinsgd.ac.id
Abstract
In this study, the nutritional composition of milk kefir cream and hunger resistance on its use as a menu of pre-dawn meal were examined. The pre-experimental design of intact group comparison was used on 34 research subjects. The experimental group (n = 17) treated pre-dawn meal using milk kefir cream and cereal while the control group used a complete per-dawn meal menu. The time of preparation, the implementation of the meal and hunger resistance were calculated and recorded. Based on the results of the study, in terms of methods, consuming 250 mL of milk kefir cream and cereal only takes about 7.9 minutes with a hunger resistance of up to 9.4 hours. With this composition and method, it is suggested that the results of this study can be useful to be an effective alternative of pre-dawn meal both in Ramadan and other Sunnah fasts.
Keywords
pre-dawn meal, milk kefir, fasting, glycemic index
Topic
Chemistry
Corresponding Author
Afrizal Afrizal
Institutions
Department of Chemistry Universitas Negeri Jakarta
Abstract
The blending process of cholesterol acrylate and ITO nanoparticle was performed using UV curing technique at various the concentration of ITO nanoparticles. In this research using variation concentration of ITO nanoparticles. Polymer Cho-ITO nanoparticles have succeeded in becoming a composite. Pattern of X Ray Diffraction of Cholesteryl acrylate-Indium Tin Oxide nanoparticle (Cho-ITO) at ITO 10% w/w showed peak for Cholesteryl acrylate in 2θ at 2,6782; 5,2275; dan 15,8050 with value of d spacing (001) was 32,96 Å. For ITO in 2θ at 30,6244o; 35,5105; 45,6814; 51,0400; dan 60,6473. therefore pattern of XRD of Cho-ITO at ITO 20% w/w showed peak for Cholesteryl acrylate in 2θ at 2,6372; 5,2022; dan 15,7867 dengan nilai d spacing bidang (001) sebesar 40,09 Å. For ITO in 2θ at 30,5685; 35,4428; 41,8550; 50,9846; 60,6252. increasing value of d spacing for (001), that d spacing for cholesteryl acrylate 32,60 Å when added was by ITO 10% w/w d spacing increase untuil 32,96 Å. When added ITO 20% w/w value of d spacing until 40,09 Å. This phenomenon explained that ITO nanopartikel filled space in crystalline at polymer of cholesteryl acrylate.
Keywords
XRD pattern of polymer Cholesteryl acrylate-ITO, ITO nanoparticle, Composite, Photopolymerization, UV light
Topic
Chemistry
Corresponding Author
Maria Paristiowati
Institutions
a) Department of Chemistry Education, Faculty of Mathematics and Natural Sciences, Universitas Negeri Jakarta, Jakarta 13220, Indonesia
* maria.paristiowati[at]unj.ac.id
Abstract
This study aims to analyze the profile of technological pedagogical and content knowledge (TPACK) chemistry teachers at one of the schools in Jakarta. The criteria for the teachers analyzed are professional teachers who have been certified and have more than 20 years of teaching experience. The method used in this study is a qualitative descriptive research method. The data sources were collected through the TPACK questionnaire referring to the Schmid instrument (2009), lesson plan analysis, observation of the learning process, and interviews. The results show that chemistry teachers can apply learning methods that vary each meeting according to the characteristics of acid-base material. The teacher also utilizes technology information & communication (ICT) based learning media to simplify and clarify material delivery. It can be concluded that teachers have pedagogical content knowledge (PCK) and technological content knowledge (TCK). The use of ICT media such as interactive power points, videos and mobile phones to support selected learning methods, shows that teachers are also competent in technological pedagogical knowledge (TPK). The results of the study concluded that the teacher had integrated all TPACK components into acid-base learning.
Keywords
Technological pedagogical and content knowledge; chemistry teacher profiles;
Topic
Chemistry
Corresponding Author
Neneng Siti Silfi Ambarwati
Institutions
1Department of Cosmetology, Faculty of Engineering, Universitas Negeri Jakarta, Jl. Rawamangun Muka, East Jakarta, 13220, Indonesia
2Department of Phytochemistry, Faculty of Pharmacy, Universitas Indonesia, UI Depok Campus, Depok, 16424, Indonesia
3 Department of Pharmacognosy, Faculty of Pharmacy, Universitas Pancasila, Jl. Srengseng Sawah, Jagakarsa, Kota Jakarta Selatan, Daerah Khusus Ibukota Jakarta, 12640, Indonesia.
Abstract
Background. Elastase is a proteinase enzyme that can reduce elastin by dividing specific peptide bonds. Therefore, the inhibition of elastase activity in the dermis layer can be used to maintain skin elasticity. Materials that can inhibit elastase activity can be a cosmetic ingredient in dealing with skin aging. Increased desire to maintain healthy skin without chemicals, encourages the use of materials from natural sources such as plants from Indonesia, a country that has a high biodiversity, including Garcinia latissima from the Clusiaceae family. Purpose. The purpose of this study is to know G. latissima has the activity as an inhibitor of elastase enzyme or not. Methods. Plant extraction was carried out using maceration successively methods. The inhibition activity of elastase enzyme was carried out by measuring the kinetic enzyme N-succ (Ala) 3-Nitroanilide conversion to p-nitroaniline (substrate) spectrophotometry at 405 nm and using porcine pancreatic elastase (PPE) as an enzyme. Results. The results showed that the G. latissima methanol and ethyl acetate extract were active as elastase enzyme inhibitors. Conslusion. G. latissima extract can maintain skin elasticity.
Keywords
Garcinia latissima Miq., elastase enzyme, maceration succesively
Topic
Chemistry
Corresponding Author
Sri wahyu Kurnia
Institutions
Department Of Chemistry, Faculty of Mathematic and Natural Science, University of Bengkulu, Jl. WR. Supratman, Bengkulu 38371, Indonesia
email = morina[at]unib.ac.id; morinaadfa[at]yahoo.com
Abstract
The aims of this reseach were to determine the antibacterial activity of methanol extract from sambang darah (Excoecaria cochichinensis L.) leaves againts to the growth of the Staphylococcus epidermidis acne bacteria and to determine the most effective concentration of the tested samples. Antibacterial test was performed by variation concentrations of extract 2 mg/mL, 4 mg/mL, 6 mg/mL, 16 mg/mL, 32 mg/mL, and 64 mg/mL, antibiotic clindamycin as positive controls, and DMSO as negative control. The antibacterial activity of methanol extract from sambang darah (Excoecaria cochichinensis L.) leaves showed that the Staphylococcus epidermidis growth inhibitory was increased when the concentration of methanol extract from sambang darah (Excoecaria cochichinensis L.) leaves increased. A concentration of 64 mg/mL indicated the highest inhibition zone (12.94 mm). Based on Porce et al., (2003) the average of inhibition zone of 64 mg/mL concentration was summarized as moderate category that can inhibit the growth of Staphylococcus epidermidis bacteria.
Keywords
Antibacterial, Excoecaria cochichinensis L., Staphylococcus epidermidis
Topic
Chemistry
Corresponding Author
Aika Latifah Alawiyah
Institutions
a). Program Studi Kimia, Fakultas MIPA, Universitas Garut
Jl. Jati 42B, Tarogong Garut, Indonesia 55141
*aikalatifah[at]uniga.co.id
b). Program Studi Farmasi, Fakultas MIPA, Universitas Garut
Jl. Jati 42B, Tarogong Garut, Indonesia 55141
c). Program Studi Kimia, Fakultas MIPA, Universitas Pendidikan Indonesia
Jl. Dr. Setiabudi No. 229, Bandung, Indonesia 40153
Abstract
Secondary metabolites of Syzygium aromaticum (L.) leaves essensial oil have been identified as antioxidants. This study aimed to determine the volatile compounds of Syzygium aromaticum (L.) leaves essential oil and antioxidant activity. Fresh Syzygium aromaticum (L.) leaves were extracted by steam distillation. Identification of volatile compounds was done by Gas Chromatography Mass Spectroscopy (GC-MS). DPPH assay was used to evaluated an antioxidant activity of samples. Volatile compounds of Syzygium aromaticum (L.) leaves essential oil resulted 15 compounds. The resulted of DPPH assay showed very strong antioxidant.
Keywords
Antioxidants, Clove, Essential oil,
Topic
Chemistry
Corresponding Author
Asmiyenti Djaliasrin Djalil
Institutions
Faculty of Pharmacy, Universitas Muhammadiyah Purwokerto
Jl. Raya Dukuhwaluh, PO. Box 202 Purwokerto 53182, Indonesia *asmiyentidjaliasrindjalil[at]ump.ac.id
Abstract
Exposure the ultraviolet (UV) radiation results in a photo-oxidative reaction that reduces the antioxidant defense system and increases the formation of reactive oxygen species (ROS) on the skin. Antioxidant creams protect the skin from adverse effects of UV which cause the initial signs of aging. Several creams containing 0.02 (F1); 0.2 (F2); and 2% of virgin olive oil (VOO) or virgin coconut oil (VCO) were prepared. Antioxidant activities of VOO, VCO, and their creams were evaluated by DPPH radical scavenging assay. The results showed that the oils and formulations have antioxidant activities. The IC50 value of VOO, F1, F2, and F3 of VOO were 31.7±0.1; 176.3±5.9; 111.9±4.7; 90.4±5.5 µg/mL, respectively. Furthermore, The IC50 value of VCO, F1, F2, and F3 of VCO were 44.7±2.0; 62.56±1.8; 53.56±1.7; 47.14±1.7 µg/mL, respectively. The formulation of antioxidant cream containing VOO meets the requirement of stability and physical properties. Meanwhile, the formulation of antioxidant cream containing VCO meets the requirement of stability and some physical properties, except for pH value.
Keywords
Antioxidant cream; Virgin olive oil; Virgin coconut oil
Topic
Chemistry
Corresponding Author
RINI SETIATI
Institutions
1Petroleum Engineering, FTKE, Universitas Trisakti, Jakarta, Indonesia
2 Petroleum Engineering, FTTM, Institut Teknologi Bandung, Bandung, Indonesia
3,4 Chemistry, FMIPA, Institut Teknologi Bandung, Bandung, Indonesia
Abstract
Green chemical is the designing of products and processes that minimize the use and generation of hazardous substances. Synthesis of Sodium Lignosulfonate (SLS) Surfactant can be processed from bagasse, waste of sugar cane. The aim of this study is to show that sodium lignosulfonate surfactant (SLS) can be made from bagasse using the Microwave-Assisted Organic Synthesis (MAOS) with the concept of green chemistry. Bagasse processing becomes SLS with hydrolysis and sulfonation process using microwave radiation. The process is closed system, for 1 hour, with a microwave power of 300 watts at 80oC. The process is using Microwave-Assisted Organic Synthesis (MAOS) which is equipped with chemical flask and condenser. Reagents are used fairly in small concentrations, 2% NaOH and 0.1 M sodium bisulfite. The result of synthesized SLS from bagasse is brown powder. The synthesized SLS product using Microwave-Assisted Organic Synthesis has been tested with Fourier Transform Infra Red (FTIR), consisting of Alkene, Sulfonate, Carboxylic Acids and Ester. This composition is similar to the composition of the commercial SLS standard which petroleum based, so it qualifies for surfactant injection in the EOR process. Green Chemical concepts can be applied in the Synthesis of Sodium Lignosulfonate Surfactant using Microwave Assisted Organic Synthesis.
Keywords
bagasse, green chemical, microwave, synthesized surfactant
Topic
Chemistry
Corresponding Author
Santhy Wyantuti
Institutions
1 Department of Chemistry, Faculty of Mathematics and Science, University of Padjadjaran Jalan Raya Bandung Sumedang KM.21, West Java, Indonesia
2 Graduate School of Science Education, University of Bengkulu, Indonesia
Abstract
Middle group rare earth elements, such as Gadolinium, have an important role in a variety of applications, mostly used in high-tech industries because they have good mechanical strength. However, the rare earth elements of this middle group are difficult in their analysis because each element has almost the same physical and chemical properties. Gadolinium is one of the rare earth elements that has high paramagnetic properties. The purpose of this study was to determine the gadolinium content by differential pulse voltammetry using an experimental design. Plackett-Burman experimental design was used to obtain selected factors that have positive results to the method. A total of 11 factors that have the potential as the main influence in this study were selected at the highest (+) and lowest (-) levels, and then measured 12 times according to the Plackett-Burman experimental design. Furthermore, an optimization was carried out with the Box-Behnken experimental design by performing 15 measurements to obtain the optimum conditions for each factor. Response data was processed and obtained factors with optimum conditions, deposition potential of -2.0 V, modulation of amplitude of 0.1 V and deposition time of 120 seconds. The detection limit and the quantitation limit were 3.97 mg / L and 10.71 mg / L, respectively. The recovery of Gadolinium was 95% that is satisfactory.
Keywords
Box-Behnken, differential pulse voltammetry, gadolinium, Plackett-Burman, rare earth elements.
Topic
Chemistry
Corresponding Author
Ida Farida
Institutions
Program Studi Pendidikan Kimia
UIN Sunan Gunung Djati Bandung
Abstract
Crane equipment with hydraulic power is widely used to lift heavy loads at construction sites. The working principle of hydraulic cranes that utilizes the nature of the pressure of the liquid in the hydraulic pump according to Pascals Law. The working principle of the hydraulic pump has been applied to design a solution of electrical conductivity test equipment. The hydraulic system of a large device has been modified using tools and materials that are easily available in everyday life. The design of the electrical conductivity test equipment is composed of: a hydraulic pump made from used injection hydraulic hose and hydraulic fluid. When the hydraulic pump is given pressure, the fluid (colored liquid) will continue the pressure through the hydraulic hose to the hydraulic working cylinder, so that the crane connected to the two electrodes can move. As a current source, Powerbank circuits are used with a USB (Universal Seral Bus) cable and 5 Watt LED lights for conductivity indicators. Miniature props with hydraulic working principles are expected to provide new experiences in the electrical conductivity tests of solutions so that the chemical learning process is more fun for students.
Keywords
hydraulic cranes, conductivity tester, Chemistry learning.
Topic
Chemistry
Corresponding Author
Ella Fitriani
Institutions
Universitas Negeri Jakarta, Chemistry Education Department, Faculty of Mathematics and Natural Sciences, Jalan Rawamangun Muka 13220, Jakarta, Indonesia
Abstract
There are difficulties for first-year chemistry students to adapt to chemistry laboratory activity since they are lack of experience in their school. As a result, it affected their confidence and even their safety in the laboratory. One of the very basic skills in chemistry laboratory is the titration. This multi-year study aims to design and develop chemistry pre-laboratory demonstration videos to make students familiar with the skills before they start the laboratory activity. The data were collected by questionnaire, documentation, and interview. Based on the evaluation of users and experts, usability and feasibility of the videos were categorized very high. Moreover, corrections and suggestions are implemented to improve the chemistry pre-laboratory demonstration videos quality.
Keywords
pre-laboratory; demonstration video; titration; basic chemistry
Topic
Chemistry
Corresponding Author
Astrie Kusuma Dewi
Institutions
a* Politeknik Energi dan Mineral Akamigas,Jalan Gajah Mada No.38, Cepu, Blora, Jawa Tengah, Indonesia – 18513
b Department of Materials Science and Technology, Faculty of Engineering, Gifu University, Gifu 501-1193, Japan
*e-mail address : pusparatu[at]esdm.go.id
Abstract
Catalytic Isomerization of n-hexane over Beta (BEA) zeolite synthesized by dry gel conversion (DGC) and hydrothermal (HTS) methods were studied. The isomerization was influenced by types of synthesized methods, and combined selectivity for branched alkanes (2- and 3-methylpentanes, 2,2-dimethylbutane, 2-, and 3-methylbutanes, 2,2-dimethylpropane, and 2-methylpropane) decreased in the order: BEA (DGC) > BEA (HTS). BEA synthesized by DGC had the highest activity and selectivity for the isomerization, and BEA Synthesized by HTS has the highest activity for cracking to lower alkanes and alkenes. These differences are ascribed to the difference of surface area, pore volume, acid properties, and reaction parameters.
Keywords
isomerization, hexane, branched alkane, zeolite; Hydtrothermal ; Dry-Gel Conversion ; BEA
Topic
Chemistry
Corresponding Author
Muhamad Ariq Al Badar
Institutions
Department of Chemical Engineering, Politeknik Negeri Bandung
Jl. Gegerkalong Hilir, Bandung 40559, Indonesia
*haryadi[at]polban.ac.id
Abstract
The growth of the textile industry in Indonesia brings harm to the environment as disposal of wastewater to the river bodies still contains dangerous dyes. This affects the life of aquatic biota and the health of surrounding communities that use river water for domestic needs. To overcome this problem, N-doped Carbon Nanodots (N-doped CNDs) as photocatalysts can be used as an alternative in degrading Methylene Blue through photocatalytic process. N-doped CNDs from molasses have been successfully synthesized using H2O2 followed by the Microwave-Assisted Extraction (MAE) method. The synthesized N-doped CNDs possess average particle size of 1.5 nm observed by TEM. The properties of N-doped CNDs emit blue fluorescence under UV light 365 nm and show peak absorption at wavelength of 220 nm. Vibration peaks of OH, C-H, C = O, N-H, C-N functional groups are observed by FTIR at wavenumbers 3246.94 cm-1, 2929.06 cm-1, 1656.08 cm-1, 1590.27 cm-1 and 1036.98 cm-1 respectively. The success of nitrogen doping within CNDs is proven by FTIR analysis showing an increase of absorbance of C-N and N-H groups of N-doped CNDs. The potential of N-doped CNDs as photocatalysts for the degradation of methylene blue became the object of this study. The results showed that the degradation efficiency of methylene blue using 3 mL N-doped CNDs at pH 10 exhibited the most optimal degradation efficiency. Under these conditions, the degradation efficiency resulting from the use of 254 nm 11 W UV lamps and 14.5 W Philips LED lamps in 270 minutes is 96.8% and 97.2% consecutively.
Keywords
Methylene Blue; N-doped Carbon Nanodots; Molasses; Photocatalysts
Topic
Chemistry
Corresponding Author
Ni Made Defy Janurianti
Institutions
1 Food Science and Technology Department, Faculty of Agriculture, Warmadewa University, Indonesia
2 Agrotechnology Department, Faculty of Agriculture, Warmadewa University, Indonesia
Abstract
This research aims to know the old fermentation influence the chemical changes during storage on coconut oil. Coconut oil is made with fermented pineapple extract as much as 15%. This study is a Randomized Design with factorial experiment complete consisting of two factors. There are factor long fermentation and long storage The observed variables against the coconut oil include objective observations i.e. water content, free fatty acids, peroxide, levels of dirt and acid number. The characteristics of coconut oil during storage tend to change but still meet Indonesian National Standard No. 01-2902-1999. From the results of research on the long fermentation 12% with prolonged storage 0 weeks gives the characteristics of the best oils than any other treatment that is the average value of water content, the level of dirt, free fatty acids, peroxide and acid number respectively i.e. 0.17%, 1.56%, 0.53%, 1.45% and 2.20%. During the storage of chemical changes tend to occur on coconut oil. The value of the average water content, the level of dirt, free fatty acids, peroxide and acid number highest obtained on treatment of fermentation 36 hours and long storage of 3 weeks in a row with a value of 0.50%, 3.70%, 0.85%, 2.51% and 4.38%.
Keywords
Coconut Oil, Pineapple Extract, Fermentation, Storage
Topic
Chemistry
Corresponding Author
Wilda Naily
Institutions
a) Doctor of Environmental Science, Postgraduate School, Padjadjaran University
Jl Dipatiukur, Bandung 40132, Indonesia
*wilda.naily[at]gmail.com
b) Research Center for Geotechnologi LIPI
Jl Cisitu Sangkuriang, Bandung 40135, Indonesia
Abstract
Groundwater provides an overview of environmental conditions in an area. Chemical analysis of groundwater will provide information about the origin and quality of groundwater as a basis for groundwater utilization. In this paper, analysis is carried out by determining the water types of unconfined groundwater. Unconfined groundwater sample were taken from Southern Bandung. Measurement of major ion (sodium, potassium, magnesium, calsium, chloride, sulfate and bicarbonate), also pH and electrical conductivity were carried out in 16 groundwater samples. Paper discusses a) the classification of groundwater types determined by Kurlov method, b) the correlation of chemical properties in groundwater determined by Stiff method. Result showed that unconfined groundwater in Southern Bandung was dominated by calcium cations and bicarbonate anions, and water type were dominated by calcium – alkali – bicarbonate – chloride. Correlation of chemical properties in groundwater is seen in several location which show groundwater in the same flow and is fresh.
Keywords
Groundwater, Water type, Major ion, Calcium, Bicarbonate
Topic
Chemistry
Corresponding Author
Yuli Rahmawati
Institutions
(a) Universitas Negeri Jakarta
Jl Rawamangun Muka, Jakarta Timur
*yrahmawati[at]unj.ac.id
(b) Universitas Halu Oleo
Jalan Kampus Bumi Tridharma, Andunohu, Kambu, Kendari, Sulawesi Tenggara
Abstract
This study aimed to analyse the students- cognitive structure on the concept of oxidation reduction by employing learning cycle 8E model. The participants of 32 students in year-10 were involved in the study. The data was collected by drawing writing technique presented through student worksheets, interview, observations, and reflective journal. The learning cycle 8E was applied which consist of engage, explore, e-search, elaborate, exchange, extend, evaluate and explain stages. Data analysis consists of data reduction, data presentation, and conclusion. Students- cognitive structure was divided into three categories which are an understanding, misconception and no understanding. Categories of understanding were found in the concept of redox, oxidizing agents and acid-base nomenclature and transitions. Students- misconception categories were found in redox applications and polyatomic. Students faced the challenges in understanding the oxidation number and binary nomenclature. The results showed that misconceptions were decreased through the implementation of the learning cycle 8E. Learning cycle 8E also has implications on students- critical thinking, collaboration, and empathy communication skills.
Keywords
learning cycle 8E model, drawing writing technique, reduction oxidation drawing writing technique, cognitive structure, misconceptions
Topic
Chemistry
Corresponding Author
Tritiyatma Hadinugrahaningsih
Institutions
Universitas Negeri Jakarta, Chemistry Education Department, Faculty of Mathematics and Natural Sciences, Jalan Rawamangun Muka 13220, Jakarta, Indonesia
Abstract
This research aimed to develop the chemistry students- soft skills students through acid-base learning by integrating Think Pair Square (TPSq) in socio critical and problem-oriented approach. The study involved 36 secondaty school students in year-11. The qualitative research methodology with interview, observation, and reflective journal were employed to understand the process and engage the participants. The issues of 1000mg vitamin C, “kangen water”, and infused water in relation to acid-base concept water were used to encourage students- critical thinking in solve the problems. The results showed that students engaged and motivated in meaningful chemistry learning experiences, meanwhile the teacher were challenged in the role as facilitator. The students- soft skills of collaboration and communication skills, critical and creative thinking skills were stimulated within the process. The students have learnt to reflect on their own values during debate in solving the problems. Finally, the learning experiences have challenges both students and teacher in reflecting on their roles to create challenging academic environment.
Keywords
Socio Critical and Problem Oriented, acid base, think pair square (TPSq), soft skills
Topic
Chemistry
Corresponding Author
ARI SYAHIDUL SHIDIQ
Institutions
(a)Departemen Pendidikan IPA, Sekolah Pascasarjana, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudi no 229, 40154, Bandung, Indonesia
(b) Program Pendidikan Kimia, Universitas Sebelas Maret, Jl. Ir. Sutami No. 36A, Kentingan, 57126, Surakarta, Indonesia
Abstract
Identifying students learning difficulties and finding the effective ways of addressing them have been the two of major concerns in chemistry education. The aims of this study were to identify students learning difficulties in hydrolysis. A formative assessment post-test was administered to 151 students in grade 11 using testlet instrument to find out their learning difficulties. Its findings could provide the teachers with sufficiently valuable information required in order to adapt their teaching methods to the students needs for chemistry sustainable curriculum development. The instrument contained 30 items distributed across three themes: scientific reasoning, numeracy and scientific language literacy. The results indicated that the students held learning difficulties on numeracy. The students had difficulties in controlling and interpreting the data. The possible uses of teaching methods, targeted remedial teaching and testing using testlet instrument for addressing students learning difficulties were discussed
Keywords
sustainable development education, pre-service chemistry teacher, hydrolysis
Topic
Chemistry
Corresponding Author
Enung Siti Nurhidayah
Institutions
1Master Program in Computational Science, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl.Ganesha No. 10, Bandung, West Java, 40132, Indonesia
2Division of Analytical Chemistry, Department of Chemistry, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha No. 10, Bandung, West Java, 40132, Indonesia
3Department of Chemistry Education, UIN Sunan Gunung Djati Bandung, Jl. Cimincrang, Cimenerang, Panyileukan, Bandung, West Java, 40292, Indonesia
4Division of Physical and Inorganic Chemistry, Department of Chemistry, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha No. 10, Bandung, West Java, 40132, Indonesia
*corresponding author: atthar[at]compscience.itb.ac.id
Abstract
NBO and RDG analysis of inclusion complex between R/S-omeprazole (OMZ) enantiomer and β-cyclodextrin (CYD) have been carried out to elucidate the interaction between them in order to understand the performance of β-cyclodextrin for the separation of omeprazole enantiomer. NBO analysis results showed that the inclusion complex of R-omeprazole with β-cyclodextrin is more stable than the inclusion complex of S-omeprazole with β-cyclodextrin, in which the total value of the stabilization energy (E(2)) caused by hydrogen bonding in the inclusion complex of R-omeprazole with β-cyclodextrin is 150.22 kcal/mol and in the inclusion complex of S-omeprazole with β-cyclodextrin is 115.62 kcal/mol. From RDG analysis results, beside hydrogen bonding, there are also Van der Waals interaction and steric effect on the interaction between omeprazole enantiomer and β-cyclodextrin.
Keywords
NBO, RDG, inclusion complex, enantiomer, omeprazole, β-cyclodextrin.
Topic
Chemistry
Corresponding Author
Meibi Lestari Gusti Pratama
Institutions
Departement of Chemistry, Faculty of Mathematics and Natural Sciences, University of Bengkulu
Jl. W.R Supratman Kandang Limun 38371 A Bengkulu, Indonesia
Abstract
SnO2 nanoparticles are the materials that have many advantages physically and chemically, therefore they have been applied in many fields such as photocatalysts, gas sensors, dye sensitized solar cells (DSSCs) and lithium batteries which were all strongly influenced by the morphology, especially the formation of aggregates. This aggregates can be reduced by using the capping agents such as synthetic and natural compounds using the hydrothermal reaction. In this research, SnO2 nanoparticles were synthesized by green hydrothermal synthesis at relatively low temperatures using sucrose as the capping agent to reduce the aggregate formation. The effect of sucrose concentration as the capping agent on the SnO2 nanoparticles properties was examined using X-Ray Difraction (XRD) and Scanning Electron Microscope (SEM). The XRD pattern obtained, showed that the variation of sucrose concentration give a significant effect on the SnO2 nanoparticles properties. While the SEM analysis also showed that the sucrose concentration greatly affects the aggregates formation and the porosity of SnO2 nanoparticles. This result shows that the optimization of sucrose concentration in green synthesis of SnO2 nanoparticles could be used as an alternative way to control the crystallinity and morphology of SnO2 nanoparticles.
Keywords
Nanoparticles, SnO2, Capping agent, Sucrose.
Topic
Chemistry
Corresponding Author
Yuli Rahmawati
Institutions
a Universitas Negeri Jakarta
Jl Rawamangun Muka, Jakarta Timur, Indonesia
*yrahmawati[at]unj.ac.id
b. Universitas Halu Oleo
Jalan Kampus Bumi Tridharma, Andunohu, Kambu, Kendari, Sulawesi Tenggara
Abstract
This study aimed to develop critical thinking skills through Culturally Responsive Teaching (CRT) approach and ethnochemistry of Tegal culture. The teaching approach is focusing on exploring the culture and local wisdom in Tegal Culture especially in Acid-Base such as Jamasan Tradition, Nginang, and Moci from chemistry perspectives integrated into CRT. The study employed the teaching model which consists of five phases of self-identification, cultural understanding, collaboration, critical reflections, and transformative construction. The study involved 35 students of year 11 in secondary school in Balapulang Tegal. The qualitative methodology approach has been employed with observation, interviews, critical thinking test, and reflective journals as data collection. The results showed that the integration of ethnochemistry in CRT approach has engaged students in developing their critical thinking skills in developing a conclusion, making the connection, conceptual understanding, and interpretation with the critical thinking skills test shows 40% students have reached level 3 (Satisfactory). In addition to the students engaged in the cultural identity empowerment, meaningful chemistry learning experiences, and team working. The students have been challenged in developing their critical thinking skills.
Keywords
chemistry learning, culturally responsive teaching, ethnochemistry, critical thinking skills, acid-base
Topic
Chemistry
Corresponding Author
Arif Rahman
Institutions
Universitas Negeri Jakarta
Abstract
A Novel catalyst prepared from Indonesia bauxite was used as a catalyst for photo fenton degradation of methyl orange solution. This catalyst is more cheaper than Nafion-based catalyst and more greener than other synthesized catalysts. It is easily prepared from Indonesian natural resources. X-ray diffraction measurements provide structure and mineral compostion of bauxite, while XRF provides information on the composition of Fe by 18% by weight of bauxite mass. The presence of large amounts of Fe in bauxite acts as a catalyst in the decomposition of metyl orange. Testing of photo fenton activity to decompose metyl orange showed that indonesian bauxite had high catalytic activity, was able to decompose 99.4% metyl orange within 40 minutes on irradiation using an 8Watt UVC radiation source
Keywords
catalyst, photo fenton, bauxite
Topic
Chemistry
Corresponding Author
Sari Sari
Institutions
1,2,3 Prodi Pendidikan Kimia Universitas Islam Negeri Sunan Gunung Djati Jl. A.H. Nasution No. 105, Bandung 40614, Indonesia
Abstract
This study uses the stages of the Research Based Design method to produce an educational game oriented to chemical literacy on petroleum material. This research is driven by the importance of a visual learning media in order to improve the ability of chemical literacy in petroleum material so that students can connect between knowledge of concepts and phenomena that occur. The aim of the study is to describe the appearance of educational games oriented to chemical literacy on petroleum material. Based on the results of the study, it is obtained that the chemical literacy oriented educational game products in the form of chemical monopolies and chemical energy ladders which have characteristics such as game rules that modify the monopoly and snake ladders games equipped with questions oriented to chemical literacy, obstacles in the games show the levels of difficulty and levels of thinking as well as different visualizations that illustrate the context and application of petroleum.
Keywords
educational games, chemical literacy,petroleum material
Topic
Chemistry
Corresponding Author
Florentina Maria Titin Supriyanti
Institutions
Chemistry Study Program
Department of Chemistry Education
UPI
Abstract
The research aims to investigate the antioxidant activity and physico-chemicals characteristics of yogurt powder fortified by peel of super red dragon (Hylocereus costaricensis) fruit. Methods include of making super red dragon fruit peel powder, making yogurt, fortification of yogurt using super red dragon fruit peel powder and freeze drying. The analysis consist of antioxidant activity with the DPPH method and Physico-chemicals characteristics includes water content by gravimetric method, ash content by ashing method and pH by potentiometric method. Produced yogurt without fortification (F0) and three fortified yogurt variants F1, F2 and F3 with 10%; 20%; 30% successive fortification. The super red dragon fruit peels had antioxidant activity 93.08% ± 2.51; powdered yogurt before fortification 15.86% ± 3.39 while F1, F2 and F3 fortified powdered yogurt were 63.69% ± 1.70 ; 76.33% ± 2.79 and 92.67% ± 1.61 respectively. The water content of powdered yogurt before fortification were greater than fortified yogurt. The ash content of yogurt before fortification and fortified powdered yogurt are greater than the value of standard ash content. The pH value of yogurt powder before fortification and fortified yogurt is in the pH range of yogurt.
Keywords
Antioxidant activity, super red dragon fruit peel, yogurt powder
Topic
Chemistry
Corresponding Author
ARI SYAHIDUL SHIDIQ
Institutions
1Departemen Pendidikan IPA, Sekolah Pascasarjana, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudi no 229, 40154, Bandung, Indonesia
Abstract
Spectroscopy is part of modern chemistry, which allows chemists to study the structure and properties of atoms and molecules. Unfortunately, many pre-service chemistry teachers are not usually introduced to the basic principles behind this technique. The study aims to develop simple and low-cost spectrophotometers. Project-based learning was used in this study. The experiments fit well into an analytical chemistry course and take a standard (1 h) lab period. Low-cost spectrophotometers made by pre-service chemistry teacher have a fairly good sensitivity compared to modern spectrophotometers. Pre-service chemistry teachers have better knowledge about the spectroscopy, and the basic principles of the instrument after developing Low-cost spectrophotometers. In addition, the project activities also enhance the creative thinking skills of the pre-service chemistry teacher
Keywords
Laboratory tool, Spectroscopy, spectrophotometers
Topic
Chemistry
Corresponding Author
Yuli Rahmawati
Institutions
a. Universitas Negeri Jakarta
Jl Rawamangun Muka, Jakarta Timur
*yrahmawati[at]unj.ac.id
b. Universitas Halu Oleo
Jalan Kampus Bumi Tridharma, Andunohu, Kambu, Kendari, Sulawesi Tenggara
Abstract
The paper portrays the integration of Science, Technology, Art, Engineering, and Mathematics (STEAM) project in chemistry learning of electrolyte non-electrolyte solutions for developing 21st-century skills. The participant of the thirty-two of year-10 students has engaged in the study. The research employed qualitative research with multiple data collection of semi-structured interviews, classroom observations, reflective journals, and documentation were guided by the 21st-century skills rubric. In addition to the project has been assessed with the criteria of project development, STEAM integration, and product quality. Students designed an innovation project with the integration of STEAM in developing the building miniature by using the nature electrolyte solution sources, such as lemon, lime, apples, and salt water. Students created posters and video projects and presented in the project exhibition. Students are able to integrate their knowledge from various fields to solve problems and create new innovations. The students have developed the 21st-century skills of collaboration, communication, critical thinking, creativity and innovation besides using the technology as a tool for learning. The engaging learning environment has encouraged students to develop their skills and chemistry conceptual understanding.
Keywords
chemistry learning, STEAM, 21st-century skills, electrolyte non-electrolyte solutions
Topic
Chemistry
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