Papers by Keyword: Carbon Tetrachloride

Abstract: Malaysian ilmenite from “amang” or tin mining waste is well known for its physical and chemical complexity, making it difficult to be treated conventionally. With knowledge of ilmenite is rich in titania and iron, extractive efforts were made in order to segregate and recover the components of ilmenite, with major interest being the removal and retrieval of titanium. In this study, the extent of chlorination execution is observed by means of weight loss studies under various parameters, with an aim of successful chlorination at lower temperatures. At 723 K, chlorination trials were done using gaseous hydrogen chloride (gHCl), carbon monoxide-chlorine gas mixtures (gCO-Cl) and gaseous carbon tetrachloride (gCT). It was clearly seen that at such a relatively low temperature, only gCT was able to obtain a good chlorination degree, with up to 90% chlorination of –45+37 μm ilmenite particles were observed after 1 hour of reaction. With similar size fraction and time, hydrogen chloride was only able to give approximately 6% of chlorination while the mixture of carbon monoxide and chlorine was seen incapable of giving anything higher than a 6% reaction. Initial observation suggests that the chlorination of ilmenite by carbon tetrachloride physically resembles the core shrinking model, although proper kinetic studies needs to be done to confirm this. Changes in various parameter values are seen to be quite sensitive to the overall ilmenite chlorination (via gCT) process. This study have shown that gCT presents an interesting route for the chlorination of complex ores such as ilmenite.

Abstract: Saponins from Rhizoma Panacis Majoris (SRPM), the bioactive component in Rhizoma Panacis Majoris, have been used extensively as a remedy for liver injury diseases and achieved good clinical efficacy, but the underlying mechanisms remain poorly understood. The goal of our present study was to further confirm SRPM hepatoprotective effect, and evaluate that whether SRPM attenuate oxidative stress and fibrosis in carbon tetrachloride (CCl₄)-induced hepatic injury, based on these results, investigate the probable mechanisms involved. At first, the separation and purification of SRPM were studied. And then, in the animal experiment, the male Sprague-Dawley rats were randomly divided into control, model, l-SRPM and h-SRPM group. Hepatic fibrosis model were made according to our previous studies reported. At the same time, the experimental rats were treated respectively with relative drugs, once a day for 8 weeks. Hepatoprotective effects of SRPM were evaluated by liver function, total antioxidant capacity and total-superoxide dismutase, histopathological observations and the hepatic fibrosis relative gene expressions. In the study, we found that SRPM significantly improved liver function, serum antioxidation level, reversed the upregulated α-SMA and TIMP1 mRNA expressions, and further increased the MMP1 mRNA expression. Our studies indicated that SRPM exerted beneficially hepatoprotective effects on the CCl₄ induced hepatic fibrosis, mainly enhancing liver tissue antioxidant capacity, reducing the lipid peroxidation of hepatocyte membranes, and then alleviating hepatic fibrosis and hepatic cell death.

Abstract: To analysis the main component of Laetiporus sulphureus primary separation product (LSPSP) and observe the hepatoprotective effect of LSPSP. Silica column and HPLC was adopted to isolate main constituents from LSPSP. The main components were analyzed and identified by HPLC and HNMR. And then its hepatoprotective effect was evaluated, we used Sprague-Dawley rats as experimental rats, and made hepatic fibrosis models induced by carbon tetrachloride (CCl₄).The hepatoprotective effects of SPSP on hepatic fibrosis of rats were evaluated by content of AST and ALT, levels of liver cell injury and degree of liver fibrosis. In the study, we found that LSPSP mainly contains eburicoic acid and trametenolic acid B. After treatment with LSPSP, the levels of serum AST and ALT significantly decreased, alleviated liver cell damage, reduced the collagen deposition in the liver tissue, and then inhibited liver fibrosis. Our studies indicated that LSPSP main components areeburicoic acid and trametenolic acid B, it exerted beneficially hepatoprotective effects on the CCl₄ induced hepatic fibrosis.

Abstract: Volatile Organic Compounds (VOCs) are highly reactive, often mixed with interfering gases and more importantly, their vapours in the gaseous form respond to the gas sensor devices. Oxide semiconductor based thin film gas sensors play vital role in detecting, monitoring and controlling the presence of hazardous and harmful gases in the environment at very low concentration and hence are tested for the detection of harmful or industrially important VOCs. The demand of sensitive as well stable gas/vapour sensors for direct sensing application has increased the importance of In₂O₃:SnO₂ based semiconductor materials. The paper presents the fabrication aspects of thin film gas sensors based on x1In₂O₃:x2SnO₂ compound and also their application for the detection of some important volatile organic compounds. Thin films of x1In₂O₃:x2SnO₂ were deposited using Thermal Evaporation technique and under the optimized fabrication conditions, the vapour sensors were prepared and mounted on the proper contact jig. Their response to the presence of Volatile Organic Compounds like CCl₄ was examined. The stability, the sensitivity and the response time of the sensors were studied for the different concentrations of test vapours.

Abstract: Through the method of the static tests, the removal rate of aqueous carbon tetrachloride onto a new TCAS-loaded resin was researched. This TCAS-loaded resin was made of a novel supramolecular acceptor compound named thiacalix [arenetetrasulfonate (TCAS) and anion exchange resin, and the adsorption mechanism was discussed preliminarily. The results of adsorption indicated that the pH value was an important factor for the removal of carbon tetrachloride and it would be better for the adsorption if the pH value was greater than 6. The operating temperature should be controlled in 5 to 15°C for the adsorption of carbon tetrachloride onto TCAS-loaded resin while the removal rate decreased with the temperature increasing and the best time for reaction was 40min. The removal rate of carbon tetrachloride in aqueous solution was better when 25mL aqueous solution of carbon tetrachloride (1.0mg/L) was adsorbed by 0.5g TCAS-loaded resin. The carbon tetrachloride can be resolving and TCAS-loaded resin can be reused.

Abstract: This work explores an estimation of adsorptive surface coverage for carbon tetrachloride onto different carbon nanofibers (CNFs). Two kinds of CNFs with various pore characteristics are fabricated by template-based and thermal chemical vapor deposition methods, respectively. The pore size distributions of these carbons, determined according to the density functional theory model, are found to vary with synthesis methods. The results of adsorption experiments show that CCl4 adsorption isotherms of these CNFs are of Langmuir-type model during the restricted pressure of 0–0.2 atm at 30°C. The surface coverage capable of adsorbing CCl4 molecules onto the CNFs can be determined based on the monolayer adsorption model. Interestingly, the CCl4 capacity of these CNFs does not proportionally increase with their specific surface area, and the CNFs with more micropore fraction facilitate the adsorptive surface coverage. This finding attributes to a fact that micropores in the CNFs have stronger adsorption energies, thus, become a major provider for carbon tetrachloride adsorption.