Improving the antibacterial activity to avoid infections and keeping the biocompatibility at a safe level of HAp-based materials is highly important for biomedical applications. In this work, we investigate the antibacterial activity of 2.5Ag/2.5Mg co-doped HAp and 2.5Ag/2.5Zn co-doped HAp toward Escherichia coli bacteria. Moreover, their biocompatibility for osteoblastic cells (MC3T3-E1 cells) was also evaluated. The physical properties were characterized with necessary characterization tools such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Brunauer–Emmett–Teller. Both 2.5Ag/2.5Mg and 2.5Ag/2.5Zn co-doped HAp consist of hydroxyapatite (HAp) and beta calcium triphosphate (β-TCP) phases. The antibacterial test reveals that 2.5Ag/2.5Mg co-doped HAp or 2.5Ag/2.5Zn co-doped HAp has an outstanding antibacterial activity with a killing rate of 99 ± 1%. More importantly, the cell viability for osteoblast cells with 2.5Ag/2.5Mg and 2.5Ag/2.5Zn co-doped HAp promotes the proliferation much more effectively than 2.5Ag-doped HAp or 5Ag-doped HAp.

Synthesis of silica gel base on Mount Sinabung's volcanic ash taken from different villages, was carried out. The purposes of this research are to synthesis and characterized by silica gel which was generated base on ash. The method of this research is a sol-gel method. T h e silica gel w as characterized by Fourier Transform Infra Red (FTIR), X-Ray Diffraction (XRD), and Barret Emmet Teller (BET) respectively. The silica gel consists of Si-O-Si and Si-OH groups. XRD data also shows that silica is amorphous. BET data show that the surface area of silica gel is 374.994 m²/g. A fix bed Column of silica gel was used for the removal of Cd(II). The adsorption column used has a diameter of 1.7cm and is filled with 0.5g of silica. the optimum adsorption capacity is: flow rate 4mL / min (21,194 mg / g). The initial optimum concentration is 24 ppm (21.632 mg / g). The optimum pH is pH 6, (21.848 mg / g). The experiment result showed silica adsorbent effective for removal Cadmium

Hydroxyapatite has been synthesized as a bone graft material by analyzing the membrane made according to the cytotoxicity test and bending test. The method used is dry ball milling. Cytotoxicity testing was carried out by making isolated osteoblast cells cultured in a 75 cm2 cell flask containing a minimum of essential media. Based on the cytotoxicity test, it was found that hydroxyapatite is not toxic with cell viability above 60% (non-toxic requirements ISO 10993-5). From the variation of the hydroxyapatite mixture used, the average cell viability was (100.48 ± 11.98)%. A mixture of 2.5% Ag and 5% Ag with hydroxyapatite also provides good viability, which is above 60%, which means it is not toxic. The results of the analysis of the bending test and the compressive test showed that the larger the hydroxyapatite mixture, the lower the bending and compressive test results. The maximum bending test on a 10% mixture is 22.1 M.Pa and the compressive test on a 5% mixture is 16 °ShD.

Adsorpsi logam berat Pb (II) oleh adsorben berbasis silika dari abu vulkanik gunung Sinabung dengan sistem batch meliputi: jumlah adsorben, waktu kontak, pH dan konsentrasi telah dilakukan.hasil menunjukakan bahwa massa silika optimum diperoleh 0,25 g dengan Pb (II) yang teradsorpsi 9,8801x10-6 mol/g. Waktu kontak optimum 40 menit dengan jumlah Pb (II) yang teradsorpsi 9.9091x10-6 mol/g. pH optimum adsorpsi adalah pH 7 dengan jumlah Pb (II) yang teradsorpsi 9,5845x10-6 mol/g. Konsentrasi optimumnya adalah 110 ppm dengan jumlah Pb (II) yang teradsorpsi 2.3103x10-5 mol/g.

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