Several attempts have been conducted to improve the mechanical properties of mineral trioxide aggregate (MTA), including the addition of various nanoparticle materials such as silver and titania. The smaller the added material, the higher the material’s ability to fill the cavity of MTA, thus increasing the tensile strength of MTA after hydration. In this study, the effect of silver nanoparticles (AgNP) concentration and titania (TiO2) mass variation on the tensile strength of MTA was investigated. The ratio of MTA mass to AgNP volume used was 1 g to 330 μL, while TiO2 was added to MTA powder in a solid-solid state with a mass variation. The results show that the addition of AgNP and TiO2 to MTA powder can significantly increase the tensile strength of MTA from 0.404±0.125 to 1.044±0.021 and 1.378±0.391 MPa for 1.5% Ag and 0.5% TiO2, respectively.

This research focuses on the batch adsorption process, then looks for kinetic models and Freundlich model adsorption isotherms. In the process of adsorbing the heavy metal Pb, humic acid from goat dung has the potential to be employed as a promising adsorbent since it offers benefits, including being economical, being able to work accurately, quickly, sensitively, selectively, and helping to maintain public health. Parameters for testing humic acid from goat dung as an adsorbent for heavy metal Pb were determined by optimizing pH test variations, contact time, and concentration of Pb solution. Humic acid from goat manure could work optimally to absorb heavy metal Pb at pH 5, contact time 30 minutes, and metal concentration Pb 20 ppm with an adsorption capacity of 19.784 mg/g. Data modeling revealed that the adsorption process followed a pseudo-second-order kinetics model with the acquisition value of R² = 0.9595 and the Freundlich isotherm with the acquisition value of R² = 0.9166.

White mineral trioxide aggregate (WMTA) was successfully synthesized using silica from rice husk ash (RHA) and precipitate calcium carbonate (PCC) from limestone. Silica was synthesized from rice husk ash by the sol-gel method with the help of a strong base NaOH to obtain sodium silicate solution. In contrast, PCC in the calcite structure was extracted from limestone by a carbonation method. The limestone powder sample was calcined at 900 °C for 3 hours, dissolved in 0.8 M nitric acid solution, and was followed by carbonation for 60 minutes. The synthesis of WMTA was carried out by mixing silica, PCC, bismuth oxide, aluminum oxide, NH3 solution catalysts and treating the mixture thermally at 950 °C for 3 hours. Products were characterized by Fourtier-Transform Infrared (FTIR) spectroscopy, X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). The results showed that the RHA silica had an amorphous phase that peaked at 2θ= 22°, but the background intensity was irregular. The PCC obtained through isolation from limestone is predominantly calcite structure. WMTA has been successfully synthesized by thermal treatment at 950 °C using NH3 solution catalyst, as evidenced by the presence of tricalcium silicate (C3S), dicalcium silicate (C2S), tricalcium aluminate (C3A), and Bi2O3.