Biological macromolecule chitosan grafted co-polymeric composite: bio-adsorption probe on cationic dyes

Chitosan biological macromolecule is a versatile polymer; chemical modification has been carried out that lead to the formation of chitosan grafted polymers composites (Chito-g-PC). We proposed synthesis of six various Chito-g-PC as sorbents for toxic dyes. A novel graft copolymerization method based on radical polymerization with vinyl monomer like acrylic acid, acrylamide, N-isopropylacrylamide, methacrylic acid and polyacrylonitrile were utilized in order to address the large amount of swelling at four different pH buffers solution. The effect of initiator and monomer concentration, time and temperature on % grafting and % grafting efficiency were performed. Comparative characterization of Chito and Chito-g-PC were evaluated by SEM, XRD and FTIR, as well as solubility characteristics of the composites were determined by various pH buffer solution. Cationic toxic dyes Malachite green (MG) and Methylene blue (MB) were selected as the sorbet, and Chito-g-PC were used as biosorbents. Thermodynamic analysis showed that the sorption process was spontaneous and endothermic with an increased randomness. The sorption experiments were realized with six different Chito-g-PC for MG and MB at various pH.

Pengembangan LKPD Berbasis Model ARCS Pada Pokok Bahasan Kesetimbangan Ion dan pH Larutan Penyangga

This study aims to develop student worksheets based on the ARCS model on ionic equilibrium and pH of the buffer solution subject, determining the validity of student worksheets of the aspects of content, ARCS characteristics, language, presentation, graphics and find out user responses through student worksheets based on ARCS models on ionic equilibrium and pH buffer solution subject. This research is a Research and Development (R&D) with a 4-D development model. The object of this research is student worksheets based on the ARCS model. The data collection instruments were in the form of validation sheets given to three validators and user questionnaires given to teachers and students. After two revisions, the validity results obtained in the aspects of content, ARCS characteristics, language, presentation and graphics, respectively, namely 93.75%, 93.75%, 98.33%, 97.92% and 98%. the average score was 96.33% that comes to valid criteria. student worksheets which was valid by the validator tested one by one on 3 students who had studied the ion balance and pH of the buffer solution. Furthermore, asking for response to 3 chemistry teachers and 20 students resulted the teacher’s response and resultied a student response 91.07% and 79.73% that comes to very good criteria. Based on the results of the data analysis, it concluded that student worksheets based on the ARCS model was valid and can be used during high school chemistry lessons on the ion balance and pH of buffer solution subject.

PENERAPAN MODEL PEMBELAJARAN KOOPERATIF FORMULATE SHARE LISTEN CREATE (FSLC) UNTUK MENINGKATKAN PRESTASI BELAJAR PESERTA DIDIK PADA POKOK BAHASAN KESETIMBANGAN ION DAN PH LARUTAN PENYANGGA

The research is aimed to improve student learning achievement on the subject of equilibrium ion and pH buffer solution in class XI MIA SMAN 1 Pekanbaru. This type of research is an experimental study with a pretest-posttest design. The research was conducted at SMAN 1 Pekanbaru. The sample study was included class XI MIA 6 as an experimental class and class XI MIA 5 as a control class. The experimental class was applied the cooperative learning model FSLC. The data analysis technique used is the t-test. Based on the results of the data analysis test, tcount> ttable is 1.78> 1.67, meaning that the application of cooperative learning model FSLC can improve student learning achievement on the subject of equilibrium ion and pH buffer solution in class XI MIA of SMA Negeri 1 Pekanbaru.

Alkaline Hydrolysis and Dyeing Characteristics of Sea-Island-Type Ultramicrofibers of PET Tricot Fabrics with Black Disperse Dye

In this study, we investigated conditions for the alkaline hydrolysis and black-disperse dyeing of sea-island-type polyethylene terephthalate (PET) ultramicrofiber tricot fabric. We examined the weight loss ratios and tensile strengths according to the NaOH content (10–30% on mass of fabric (omf)) during treatment; the optimal conditions used 25% omf NaOH for 30 min at 100 °C for an average weight loss ratio of 23.47%. By scanning electron microscope (SEM) analysis, the ‘sea’ components are extracted with increasing NaOH concentration until 25% omf NaOH, and damage of the ‘island’ components above 25% omf NaOH leads to a reduction in tensile strength. The dyeing conditions, including temperature (95–135 °C), time (20–60 min), pH buffer solution concentration (1–9 g/L), and contents of dispersant (1–9 g/L) and UV-absorbent (5–25% omf) were also explored. The optimal dyeing conditions were established as a dye concentration of 8% omf with 1 g/L dispersant, 1 g/L pH buffer solution concentration, and 10% omf UV-absorbent at 135 °C for 40 min at a 1:10 goods-to-liquor ratio. The rubbing colorfastness values for the fabrics dyed with the black disperse dye spanned four grades under dry and wet conditions. The light colorfastness values of the dyed fabrics were good to excellent in the range of 4–5 grades.

PENGARUH VARIASI LARUTAN pH BUFFER TERHADAP KARAKTERISTIK EKSTRAK ALGA MERAH (Gracilaria sp.) SEBAGAI PEWARNA

Gracilaria sp. is one type of red algae containing phycoerytrin pigment. Phycoerytrin pigment can be used as a natural dye to replace synthesis dyes. Phycoerytrin is widely used as a natural dye for foods and cosmetics. The purpose of this research was 1) to determine the effect of variations pH buffer solution on the characteristics of red algae extract (Gracilaria sp.), 2) to determine the best pH buffer solution used to produce red algae extract (Gracilaria sp.). This study used a factorial Randomized Block Design with group variation of pH buffer. The treatment of materials with solvent variation of pH buffer consist of 8 level, namely: 3, 4, 5, 6, 7, 8, 9 and 10. Each treatment are grouped into two time-based implementation. The results showed that each treatment of pH buffer variation significantly affected the yield, the degree of phycoerytrin pigment, brightness (L *), redness (a *) and yellowish (b *). Buffer pH 7 produced the best extracts in red algae (Gracilaria sp.) with a yield of 0.6030%, pigment production 0.933 mg/g, brightness value 18.650 L *, redness value 24.470 a * and yellowish value 10.135 b *. Keywords: Gracilaria sp., phycoerytrin, pH Buffer, extract characteristic.

Miskonsepsi materi larutan penyangga

Penelitian ini bertujuan untuk mengetahui miskonsepsi materi larutan penyangga, persentase miskonsepsi pada setiap indikator materi larutan penyangga, dan penyebab terjadinya miskonsepsi materi larutan penyangga pada siswa SMA Negeri 2 Mataram. Penelitian ini merupakan penelitian deskriptif kualitatif yang melibatkan 80 siswa kelas XI IPA 4 dan XI IPA 5 SMA Negeri 2 Mataram sebagai sampel dalam penelitian yang ditentukan secara purposive sampling. Instrumen yang digunakan untuk menganalisis miskonsepsi larutan penyangga yaitu instrumen multiple choice two tier diagnostic. Instrumen di validasi oleh expert judgment dan validasi empirik oleh 38 siswa kelas XII IPA 2 SMA Negeri 2 Mataram.. Hasil analisis miskonsepsi larutan penyangga menggunakan instrumen two-tier multiple choice diagnostic menunjukkan bahwa terjadi miskonsepi sebesar 47%, memahami konsep sebesar 37%, dan tidak memahami konsep sebesar 16%. Miskonsepsi terbanyak terjadi pada indikator konsep perhitungan pH larutan penyangga pada penambahan sedikit asam atau basa sejumLah 4 soal yaitu dengan rata-rata 64,08%. Miskonsepsi larutan penyangga terjadi karena guru kurang menekankan materi konsep, khususnya pada indikator larutan penyangga pada kehidupan sehari-hari, bahasa buku teks kimia yang terlalu sulit, dan siswa sendiri yang kurang fokus saat proses pembelajaran. Misconceptions on buffer solution AbstractThis study aims to determine the misconception on buffer solution, the percentage of misconceptions on each indicator, and the cause of the misconception of the student of SMA Negeri 2 Mataram.This research is a qualitative descriptive study involving 80 students of class XI of physics study (IPA) 4 and XI 5 of SMAN 2 Mataram as samples determined by purposive sampling. The instrument used to analyze the misconceptions of the buffer solution is two-tier instrument diagnostic multiple choice. The instrument is validated by expert judgment and empirical validation by 38 students of class XII physic study (IPA) 2 SMA Negeri 2 Mataram. The results of the data analysis showed that there is 47% misconceptions, 37% understand and as many as 16% do not understand concept. Misconceptions occurred in the calculation of the indicator concept pH buffer solution in the addition of a small amount of acid or base in an average of 64.08%. The misconception of the buffer solution occurred because the teachers did not emphasize the concept of matter, particularly on indicators of the buffer solution in everyday life, the language of chemistry textbooks that are too difficult, and the students themselves are less focused during the learning process.

FORMULATION AND EVALUATION OF NANOSUSPENSION OF VALSARTAN

Objective: The objective of the present research work was to formulate and evaluate Valsartan nanosuspension by nanoprecipitation ultra sonication method using different polymers to enhance solubility and bioavailability of the poorly water-soluble drug.Methods: Formulation of nanosuspension of valsartan by nanoprecipitation technique was used. The nanosuspension formulations were prepared using different polymers such as hydroxyl propyl methyl cellulose E50, polyvinyl pyrollidone k-30, polyethene glycol 6000 and sodium lauryl sulphate was used as the surfactant.Results: The formulation of nanosuspension was formed clear and no sedimentation was seen on further shaking. The nanosuspension formulations were Valsatan shows maximum solubility in HPMC as a non-volatile solvent. All the Preformulation parameters were evaluated such as organoleptic characterization of drug sample, melting point, pH, partition coefficient, identification of drug samples by using UV spectroscopy and FTIR analytical method, preparation of calibration curves, solubility studies of drug sample like qualitative, quantitative and pH dependent solubility of drug in different pH buffer solution. The viscosity of the dispersion medium was more in F10.895 mPa-s and F2 0.894 mPa-s than the other formulations. The particle size distribution of the nanosuspension with zeta potential found to be negative mv. Fourier transform infrared spectroscopy indicated that there was no possible interaction between drug and polymer.Conclusion: From this study, it was concluded that in recent advances in novel drug delivery system aims to enhance safety and efficacy of drug molecule by formulating a convenient dosage form for administration and to achieve better patient compliance, one such approach is nanosuspension.

Analisis Miskonsepsi Siswa Kelas XI SMA Negeri 1 Banawa Tengah Pada Pembelajaran Larutan Penyangga Dengan CRI (Certainty of Response Index)

The aim of this study is to analyze misconception of student in class XI SMA Negeri 1 Banawa Tengah on the buffer material. The type of this research is a description where the subject of research is 41 student. The instrument used was a multiple choice test with reasoned (CRI). It consists of 13 items which was accompanied by questionnaries. The results were obtained information that the students have misconceptions on subconcepts calculate pH buffer solution and way of working buffer solution, with amount of 37 students (46%). students at least experienced a misunderstanding on the component subconcepts buffer solution and way of working buffer solution with amount 17 student (21%). Furthermore, causes of student misconception is due to the lack of interest of student in the buffer solution material (22%), praconception and less understanding of the concept (80%), textbook of student (34%), and model of learning (57%). The result of this study shows that most of students in class XI SMA Negeri Banawa Tengah have misconception on the buffer material.