No abstract

Biodiesel production from Castor (Ricinus communis) oil was carried out through transesterification using heterogeneous KOH/zeolite catalyst. The aim of this study was to determine the optimum condition of the reaction. The synthesis of the catalyst was initiated through chemical activation of zeolite, followed by the synthesis of KOH/zeolite through ultrasound-assisted method and calcination at 450 o C. Transesterification of castor oil was performed at a temperature of 55, 60 and 65 o C; 5, 6, 7 h contact times; and 50, 60, 70% of catalyst concentration. The result of XRD analysis on natural zeolite indicated the zeolite belong the group mordenite. The addition of KOH to the activated zeolite gave rise to new peaks at 2θ: 31, 36, and 38. In addition, the data from XRF analysis indicated there is an increase of potassium (K) amount in KOH/zeolite compared to the activated one. Based on the GC-MS data of biodiesel produced through transesterification, the optimum yield of methyl ricinoleate was achieved at 55 o C, 7 h contact time and 70 % catalyst concentration. A number of physical properties such as water content and density are reported to have not yet met the SNI standard.

corn stalks are effective adsorbent for methylene blue (MB) and malachite green (MG). In this research, we modified corn stalks used citric acid .The adsorption process of MB and MG by corn stalks illustrates the suitability of pseudo second-order. The Langmuir isotherm is also describe in the data on adsorption of MG. MB and MG adsorption on corn stalks was confirmed by infra-red (IR) spectroscopy and showed that the intensity peak 1734 cm−1 decreases. It indicated that the interaction between adsorbent and adsorbate involved the ester functional group.

TiO 2 Anatase activities should be increased from the UV to the visible light photocatalytic activity of TiO 2 to increase anatas. One efforts to optimize TiO 2 anatase activity is doping by using dopant vanadium(V). Synthesis method which is used in this research is a solid reaction method. The steps being taken in this methods include grinding and heating at high temperatures. Dopant concentrations of vanadium(V) which are used in the research was 0.3%, 0.5% and 0.7%. and the characterization used is X-ray diffraction and UV-Vis Diffuse Reflectance Spectroscopy. The result shows that there are a changing of particle size, band gap energy, and absorption of TiO 2 anatas wavelength because of dopan vanadium(V) addition. While TiO 2 's structure does not change. The crystal sizes of each TiO 2 without doping, V-TiO 2 0,3%, 0,5% and 0,7% are 53.21 nm, 47.67 nm, 79.65 nm dan 68.99 nm. Band gap energy of each TiO 2 without doping, V-TiO 2 0,3%, 0,5% dan 0,7% are 3.309 eV, 3.279 eV, 3.270 eV and 3.259 eV. While wavelength absorption of each TiO 2 without doping, V-TiO 2 0,3%, 0,5% and 0,7% are 374.9 nm, 378.4 nm, 379.5 nm and 380.8 nm.Keywords: Synthesis, titanium dioxide, vanadium(V), solid state method Abstrak Aktifitas TiO 2 anatas perlu ditingkatkan dari daerah sinar UV ke daerah sinar tampak untuk meningkatkan aktifitas fotokatalis TiO 2 anatas. Salah satu upaya untuk meningkatkan aktifitas fotokatalis TiO 2 anatas tersebut adalah dengan doping mengunakan dopan vanadium(V). Penelitian ini bertujuan untuk mengetahui pengaruh penambahan dopan vanadium(V) terhadap struktur, ukuran kristal, energi band gap dan serapan panjang gelombang TiO 2 Anatas. Metode sintesis yang digunakan dalam penelitian ini adalah metode reaksi padatan. Tahapan yang dilakukan dalam metode meliputi penggerusan dan pemanasan pada suhu tinggi. Konsentrasi dopan vanadium(V) yang digunakan dalam penelitian adalah 0,3%, 0,5% dan 0,7% dan karakterisasi yang digunakan adalah difraksi sinar-X dan UV-Vis diffuse reflectance spectroscopy. Hasil dari penelitian ini menunjukkan bahwa terjadi perubahan terhadap ukuran kristal, energi band gap dan serapan panjang gelombang TiO 2 anatas akibat penambaan dopan vanadium(V). Sedangkan struktur TiO 2 anatas tidak mengalami perubahan. Ukuran kristal masing-masing TiO 2 tanpa doping, V-TiO 2 0,3%, 0,5% dan 0,7% adalah sebesar 53.21 nm, 47,67 nm, 79,65 nm dan 68,99 nm. Energi band gap masing-masing TiO 2 tanpa doping, V-TiO 2 0,3%, 0,5% dan 0,7% adalah 3,309 eV, 3,279 eV, 3,270 eV dam 3,259 eV. Sedangkan serapan panjang gelombang masing TiO 2 tanpa doping, V-TiO 2 0,3%, 0,5% dan 0,7% adalah 374,9 nm, 378,4 nm, 379,5 nm dan 380,8 nm.

In this article, the copper and lead adsorption process using Indonesian Natural Zeolite (INZ) is studied as an adsorbent. INZ samples were obtained from Sumbermanjing Wetan, Malang district, East Java. The influence of activating acid concentration and different types of acid on the removal of copper and lead were evaluated. The activated INZ was used for adsorption of Cu and Pb from chemistry laboratory wastewater of State Islamic University of Maulana Malik Ibrahim Malang. INZ were characterized by X-ray diffraction and X-ray fluorescence spectroscopy. Characterization using XRD indicated that the activation does not affect structural changes and the diffraction pattern showed that INZ had a mordenite phase. The XRF spectra showed that increasing concentration of the activating acid simultaneously reduces undesired metal content in INZ. Determination of Cu and Pb content using Atomic Absorption Spectroscopy on wastewater showed that increasing concentration of the activating acid decreases the concentration of Cu and Pb in wastewater. The removal of Cu and Pb using INZ activated by HCl reached 61.56 % and 71 % respectively, while the removal of Cu and Pb using INZ activated by H2SO4 reached 32.86 % and 73.14 % respectively.