Synthesis, characterization, and evaluation of ZrSiO4/Fe2O3 adsorbent for methylene blue removal in aqueous solutions

Methylene blue dyes are widely used in textile, batik, plastic, paper, and many other industries. The remain of methylene blue dyes in the textile waste is hazardous for health and the environment. Therefore, it takes effort to deal with it. One of the efforts is the process of adsorption using adsorbents. In this study, the adsorbent ZrSiO4/Fe2O3 was synthesized using the coprecipitation method using NaOH as precipitant. Either ZrSiO4 or Fe2O3 was synthesized from Indonesia mineral local zircon sand and jarosites, respectively. The composites of ZrSiO4/Fe2O3 were prepared in %mole variation, which is 75:25; 50:50; and 25:75. All obtained composites were then characterized using X-Ray Diffraction (XRD). The XRD analysis showed that the crystal structure formed was tetragonal for ZrSiO4 and hexagonal for Fe2O3 (also known as α-Fe2O3). Evaluation toward isotherm adsorption and kinetic adsorption showed that the adsorption of MB using ZrSiO4/Fe2O3 follows the Langmuir isotherm model and pseudo-second-order model, respectively.

THE EFFECT OF PH AND CALCINATION TEMPERATURE ON THE ZrO2 PHASE FORMATION FROM NATURAL ZIRCON SAND OF KERENG PANGI

In this research ZrO2 has been synthesized from Kereng Pangi zircon sand in Central Kalimantan through alkali fusion-coprecipitation method. Firstly, zircon sand (ZrSiO4) was purified to reduce impurities by magnetic separation, cleaned using an ultrasonic cleaner, soaked/leached with HCl 2 M for 12 hours and leached with HCl at 60 ºC for 3 hours. Secondly, alkali fusion was done with KOH as an alkali. This product was then washed by water and dried before leached with HCl 30% at 90 ºC for 30 minutes to precipitate and seperate Silica from Zircon. ZrO2 filtrate (ZrOCl2) precipitated with NH4OH at pH 4, pH 7, and pH 10 forms Zr(OH)4 gel. Zr(OH)4 gel was dried and characterized by DTA-TGA, which was then followed by calcination based on DTA TGA results at temperature ranges of 550 ºC - 700 ºC to produce ZrO2. XRD results show that single tetragonal phase of ZrO2 is formed in all variations of pH precipitation and calcination temperature. An analysis using MAUD software show that crystal size reduces as the increase in precipitation of pH. The crystal size results are 110 nm, 66 nm and 48 nm at pH 4, pH 7 dan pH 10 at 700 ºC, respectively. Moreover, XRF results show that ZrO2 with purity is at around 95.8 % at pH 4 and 96.3 % at pH 7 and pH 10.

Friction Stir Processing of Hybrid Al-Si Alloy Metal Matrix Composite

Metal matrix composites are an important class of material that is developing rapidly to fulfil the diversified engineering requirements. The metal matrix composites are attractive owing to superior properties as compared to monolithic material. Their properties are dependent on various factors and fabrication techniques. The metal matrix composites are associated with several issues which hinder their full potential. In the present study friction stir processing is applied on the metal matrix composite as a post-processing operation. The friction stir processing offers many advantages owing to the solid-state nature of the processing. Stir cast metal matrix composites are prepared by using zircon sand particles of 50 µm in the matrix of LM13 aluminium alloy. The friction stir processing is applied on the metal matrix plates at a constant rotational speed and traverse speed of 1400 rpm and 63 mm/min, respectively. Multiple passes of friction stir processing are applied to elucidate the effect of the number of passes on microstructural modification. Microstructural examination showed a significant improvement in eutectic silicon morphology and distribution of zircon sand particles. A more than 5 times reduction as compared to the initial size was observed in the zircon sand particles after four passes of friction stir processing. The processed metal matrix composite also exhibits improvement in tensile strength and hardness.

Elevated Temperature Effects on the Properties of Self Compacting Mortar Containing Nano Materials and Zircon Sand

The present research work tries to assess the performance of self compacting mortar containing zircon sand as substitute for river aggregate in combination with nano alumina and nano silica as additive for cement. The fresh state results as observed through slump cone and mini V funnel showed positive effects of zircon sand balancing the negative effect of nano particles addition on workability. The mechanical properties, durability and microstructure of the mortar were assessed by conducting experiments at normal temperature and after subjecting to temperatures of 2000C, 4000C, 6000C and 8000C. The results indicate that addition of nano alumina and nano silica contributed towards the mechanical strength enhancement at elevated temperatures in combination with zircon sand which is a very good refractory material. The durability of the self compacting mortar at elevated temperatures enhanced due to the combined action of nano materials and zircon sand which is evident through microstructure analysis.