CHARACTERISTIC OF XONOTLITE SYNTHESIZED BY HYDROTHERMAL REACTION USING RICE HUSK ASH AND ITS APPLICATION TO ABSORB CHROME (III) SOLUTION

In this paper, we report on synthesizing xonotlite, calcium silicate hydrate (CSH), via a hydrothermal reaction using rice husk from the Mekong Delta, Vietnam. The rice husks were burnt at 1000 °C for 3 h. Grey rice husk ash was collected, then mixed with Ca(OH)2 at a Ca/Si molar ratio of 1 : 1. This was followed by a hydrothermal reaction at 180 °C for 24 h and 48 h to obtain the xonotlite mineral. Before and after adsorption, 3-mm xonotlite pellets were thoroughly characterized using X-ray diffractometry (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and ultraviolet-visible (UV-VIS) spectroscopy. This material has potential application in chromium(III) removal during a chrome-plating process. The adsorption efficiency of the 3-mm pellet samples reached more than 76 % after 12 h.

Study of removal Chrome (III) using Calcium Silicate Hydrate (CSH) synthesized from rice hush and CaO by hydrothermal method

The Calcium Silicate Hydrate (CSH) family mineral such as Xonotlite (X), Tobermorite (T) was synthesized by hydrothermal method using rice hush and CaO as the Si and Ca supplier. The rice hush (RH) was burnt inside the furnace at 500oC for 2hrs to obtain the rice hush ash (RHA), then mixing with CaO with the Ca/Si 1.0, and hydrothermal treatment at 110oC for 24h to obtain Xonotlite and Tobermorite mineral with micropore structure (coded as CSH-110/24). The CSH 110/24 samples were used to remove Chrome (III) in 2,4 and 6 hours, with fast removal phenomena. This research can be applied in metallurgy industry such as removal Chrome (III) during the Chrome-coating process.

Simulation of Cr-III dispersion in the High Bogotá River Basin using the WASP model

The Bogotá River is the major river in Cundinamarca because it crosses the entire region from north to south. Industries from different economic activities have been established in the river, especially tanneries. Nevertheless, the current and traditional tanning process requires a large volume of water and generates tremendous environmental problems due to the chemical composition of dumpings that are discharged in the river. Chrome III (Cr III) is a persistent pollutant that represents a huge health public problematic because it can transform into Chrome VI, which is very harmful to the environment and people. Simulations carried out with this pollutant can help to establish a degree of pollution and monitoring and treatment spots in the river. For this reason, we aimed to simulate Cr III in a defined stretch of approximately 8 km along from Villapinzón. WASP model was chosen to simulate this pollutant with the study conditions, based on its software properties and similarities with previous studies. From our results, eight mixing zones were identified in the simulated stretch, which constitutes key points for water uptake for treatment and further applications. Dispersive coefficient, flow, and system geometry were identified as the main factors in the simulation. WASP efficiently simulated the system because observed and obtained data reached an index of agreement (IOA) of 0.975, which is higher than the criterium established for simulation. Experimental data can improve simulations to further understand the degree of pollution in the river.

EFFECT OF SELENIUM-CHROME-LIPID SUBSTANCE FROM CHLORELLA VULGARIS BIEJ. ON OXIDATIVE STATUS OF RATS

By incubation unicellular alga Chlorella vulgaris Biej. in aquaculture with sodium selenite and chrome (III) sulphate there was received and allocated stable lipid and selenium, chrome-lipid substance and studied their effects on oxidative status in healthy rats experiment. Putting substances at a dose of 1.85 mсg of selenium, chrome 1.1 mcg and 0.5 mg lipid per 1 ml of 1 % aqueous starch slurry body in healthy rats every day for 14 days suppressed prooxidative processes activated antioxidant status by glutation system by reduction of catalase and superoxidedismutase activity partly in experimental animals in the liver and in blood serum.