The research on the use of coconut husk as a solid catalyst for transesterification reaction of Cerbera manghas oil into biodiesel has been done. The aim of this study is to investigate the performance of coconut husk ash for biodiesel production from Cerbera manghas seed oil. Coconut husk is prepared by burning in air to obtain potassium oxide as active phase. The coconut husk is analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD spectrum shows that the peak characteristics of potassium oxide can be observed in the diffractogram. The particle size of the catalyst ranging from 1 - 3 μm with pentagonal structure. The coconut husk ash solid catalyst is used in the transesterification reaction of Cerbera manghas oil in a batch reactor. Biodiesel yield of 88.6% can be achieved over coconut husk ash catalyst, using a 10 wt.% of catalyst, reaction temperature at 3 hours, and a methanol-to-oil ratio of 6: 1. This solid catalyst can be separated easily from the reaction system and not soluble in methanol or methyl esters. The coconut husk ash catalyst is high potential to be developed as one of the solid catalysts to convert Cerbera manghas oil to biodiesel.

No abstract

A novel magnetic solid base catalyst consisting of an MgFe 2 O 4 -MgO nanocomposite was successfully prepared by synthesizing magnesium ferrite (MgFe 2 O 4 ) as the catalyst support, and it was employed in an esterification reaction for the production of biodiesel. MgFe 2 O 4 was synthesized by a ball-milling mechanochemical method at various furnace temperatures (350°C, 550°C and 750°C), and the best results were obtained at 750°C. The results of TEM revealed an average size of 39 nm. A nanocomposite of MgFe 2 O 4 -MgO was successfully synthesized in this study, as confirmed by Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy-energy dispersive x-ray (SEM-EDX) and transmission electron microscopy (TEM) characterization. The results of the FTIR characterization revealed peaks with wavenumbers corresponding to Mg-O and Fe-O bonds in the range of 500-900 cm -1 , SEM mapping showed that MgO was distributed on the surface of the MgFe 2 O 4 catalyst support, and the MgFe 2 O 4 -MgO average size was found to be 50 nm by TEM. The influence of MgO on MgFe 2 O 4 was determined by varying the molar ratio of MgFe 2 O 4 to MgO from 1: 1, 1: 2 and 1: 3 and by studying the catalytic activity in the esterification of oleic acid to biodiesel. The best MgFe 2 O 4 -MgO nanocomposite have a molar ratio of 1: 2 and gave a percent conversion of 96.089%. Impregnating MgFe 2 O 4 with MgO increased the number of basic active sites, thereby increasing the catalytic activity. This type of nanocomposite is a promising new material for future catalysts.

Salmonella typhi adalah bakteri penyebab demam tifoid. Penyakit ini menyerang hampir di semua negara, terutama di negara-negara berkembang seperti Indonesia. Penyakit demam tifoid ini dapat tertular lewat makanan atau minuman yang terkontaminasi oleh feses atau urin dari orang yang terinfeksi. Di Indonesia kloramfenikol masih merupakan obat pilihan utama untuk mengobati demam tifoid. Namun banyak dilaporkan adanya resistensi S. typhi terhadap antibiotik kloramfenikol.Oleh karena itu, mulai dikembangkan penelitian untuk meminimalisir efek samping dari penggunaan antibiotik. Salah satunya adalah dengan pengembangan antimikroba yang berasal dari bahan alam. Salah satu tanaman yang dapat dimanfaatkan sebagai obat tradisional adalah tanaman pepaya (Carica papaya L  memiliki nilai medis yang tinggi dan efek antibakteri . Adapun tanaman lain yang dapat di jadikan obat adalah mentimun (Cucumis sativus) dimana memiliki senyawa aktif yang berperan sebagai antifungi dan antibakteri. Mengetahui perbedaan daya antibakteri antara buah pepaya (Carica papaya L.) dan mentimun (Cucumis sativus L.)  terhadap bakteri Salmonella thypi. Jenis penelitian yang dilakukan adalah penelitian eksperimental labatorium dengan metode yang digunakan pada penelitian ini adalah metode disc diffution. Zona hambat yang dihasilkan oleh ekstrak buah pepaya pada dua replikasi yaitu rata-rata diameter sebesar 0 mm dan 7 mm dan zona hambat yang dihasilkan oleh ekstrak buah mentimun untuk dua replikasi yaitu rata-rata diameter sebesar 0 mm dan 16,7 mm. Ekstrak buah mentimun  dengan konsentrasi 100% lebih efektif karena memiliki daerah hambat yang lebih besar jika dibandingkan dengan ekstrak buah pepaya dengan konsentrasi 100%.