No abstract

Learning media is an important component in the learning process. Technology and computer-based media is one of the media needed. It aims to attract students to learn chemistry material, especially material that need more efforts to understand. This research aims to develop android-based chemistry learning media for experimenting by using simulation models in Senior High School 2 Palangka Raya. The methods of this study are a research and development (R & D) by Alessi and Trollip. Product testing consists of an alpha test and a beta test to determine the level of product feasibility and test the effectiveness of products on student learning outcomes. The instruments that used to collect data were observation sheet, interview guidelines, scoring questionnaires, and test. The data that have been collected were analysed by qualitative descriptive technique. The results of this study can be concluded: 1) Learning media is very good. 2) Learning material is very good. 3) The individual test result is very good. 4) The small group test result is very good. 5) The final product trial result is very good. The android-based chemistry learning media produced is worthy to be used and effectively used in upper class students and middle class students, but it is not yet effective to be used in lower class students.

Torrefaction was thermochemical processes to make biomass a fuel that had better properties, such as increased carbon content and calorific value. It was a temperature-sensitive process that was effective between 200 °C and 300 °C in an inert environment with a residence time of 20-60 minutes. Palm kernel shell was one of the biomass that has the potential to be used as fuel, where its availability was abundant and has good physical properties. In this study of palm kernel shell torrefaction was carried out from 0.5 cm sieve with three variations in temperature and residence time follows 250 °C - 300 °C and 20-40 minutes. The results obtained were the increase in temperature and holding time causes an increase in the calorific value but relatively on energy yield because of a large mass loss at a temperature of 300 °C. The optimum process for torrefaction of palm kernel shell according to calorific value and energy yield was 275 °C with residence time 20 minutes.

Clay is a natural material from crystalline silicate with layered structures, has high cation exchange capacity, and large surface area. These advantages can be used as an adsorbent for the removal of contaminants in aqueous solutions, such as heavy metals and dyes. In Indonesia, clays from Java, Sulawesi, and Sumatra islands have been used as adsorbent, furniture, and construction materials. Due to limited information about basic characteristics of clay from Kalimantan, this clay has not been utilized well. Therefore, natural clay from Kalimantan, especially in Central Kalimantan, was used as adsorbent of cationic dyes in this present study. However, the clay has difficulty for separating the solid phase from aqueous solution after adsorption process. To solve this problem, combining clay with magnetic material was opted. The objectives of this study are to synthesize the magnetic composite material from natural clay by coprecipitation method and to characterize the synthesized magnetic composite material using an x-ray diffraction method, transmission electron microscopy, and vibrating sample magnetometer. The adsorption properties of the synthesized magnetic composite material were evaluated using rhodamine B and methylene blue dyes in aqueous solution. Before magnetic composite material was synthesized, the clay was previously being activated for removing impurities. The magnetic material formed in the structure of clay had magnetite with particle size of 2.75 nm and the magnetization value of 24.91emu/g. The adsorption capacities of natural clay, activated clay, and magnetic composite of clay in rhodamine B were 34.29, 76.27, and 81.46 mg/g, respectively, while in methylene blue were 30.25, 83.92, and 133.90 mg/g, respectively. These results suggested that magnetic composite of clay can increase the adsorption capacities against dyes and accelerate the separation of the adsorbent solid phase from aqueous solution with largest adsorption capacity on methylene blue dye.

Salah satu cara pengolahan air yang sederhana dan ramah lingkungan adalah melalui proses penyaringan dengan instalasi penyaringan air sederhana (IPAS) menggunakan bahan alam. Bahan alam yang dapat digunakan sebagai filter dalam instalasi penjernihan air sederhana adalah pasir silika dan lempung alam yang diaktivasi. Pengambilan sampel sungai akan dilakukan di DAS (Daerah Aliran Sungai) Kahayan Kalimantan Tengah. Sampling air akan dilakukan pada saat musim kemarau sehingga tidak ada pengaruh pengenceran. Filter pasir silika dan kerikil diperoleh dari toko penjual ikan hias yaitu pasir ukuran halus dan kasar. Filter lempung mangan dapat dibuat dengan menggunakan lempung alam yang perlakukan dengan MnCl2 dan KMnO4. Hasil pengujian menunjukkan filter lempung mangan dan arang aktif mampu menyaring zat-zat berbahaya yang terlarut dalam air, menghilangkan bau dan menjernihkan air sungai kahayan yang keruh. Air sungai kahayan yang sebelum dilakukan penjernihan memiliki nilai pH 5,5, kandungan Fe 2,16 mg/L, total padatan tersuspensi (TSS) 258 mg/L, total padatan terlarut 30 mg/L, kekeruhan 140 NTU dan sangat bau. Setelah dilakukan penjernihan dengan instalasi penjernihan air, penjernihan memiliki nilai pH 6,5, kandungan Fe 0,7 mg/L, total padatan tersuspensi (TSS) 134 mg/L, total padatan terlarut 32 mg/L, kekeruhan 35,3 NTU dan tidak berbau. Hasil penjernihan air ini cukup layak digunanakan sebagai air bersih karena nilai pH, kandungan Fe, TDS, TSS, kekeruhan dan bau sesuai dengan syarat air bersih menurut Permenkes RI No: 416/MENKES/PER/IX/1990.