Papers by Keyword: Decontamination

Abstract: This paper demonstrates the feasibility of ensuring radiation safety of solid substances that comprise environmental objects and have surfaces contaminated with radioactive substances. The identified problem is solved by utilizing the natural property of anti-radiation self-protection. To reintroduce structures and buildings contaminated with radionuclides into economic circulation, it is recommended to dismantle them, grind the materials, and mix the resulting mass. The proposed method is made possible by transforming the surface contamination of these objects into a uniform distribution of radionuclides throughout the mass of the contaminated substance. This uniform distribution will remain consistent in products made from the received raw materials. By implementing this approach, it is feasible to reintroduce large volumes of radioactively contaminated materials into the economic cycle and dispose of them in contaminated areas.

Abstract: This article shows the analysis of the efficiency of the pomegranate husks like an adsorbent agent in aqueous solutions contaminate with mercury (II). The contaminated with mercury (II). The variables of this experiment were: the initial concentration of mercury (II) in water, quantity of adsorbent material 50 ml of contaminate solution with Hg (2 and 4 grams), size of the particle of pomegranate husk and contact time between adsorbate and adsorbent (60 minutes). In this process the pomegranate husks were dehydrated at temperature between 30 °C and 50 °C. The results obtained at the end of the investigation show that the pomegranate husks have the capacity to decontaminate mercury (II) from contaminated water at a level of 1 ppm quantity accepted by the World Health Organization (WHO, 2003). This is an alternative method, environmentally friendly and sustainable to eliminate pollutant agents from water such as mercury (II).

Abstract: This article aims to investigate the effectiveness of Sargassum in eliminating mercury in wastewater. The most toxic form of mercury is the methyl mercury, as 90% is absorbed in the body, and mercury chloride only by 2%. Current cleaning methods can be very expensive. Some adverse effects of methyl mercury include, mainly, damage to the brain and kidneys, but it can also cause nervous system disorders. The percentage of Mercury adsorbed by sargassum was analyzed, varying contact times, sargassum concentrations and particle size in microns. Several processes were used, as 4 kilos of sargassum were washed with detergent and water, dehydration techniques were applied to dry the product inside a drying oven, and pulverization was also implemented to obtain 1800 g in different particle sizes (from 100 microns to 300 microns) of product. Subsequently, solutions were prepared with concentrations of Mercury ranging from 10 to 100 ppb. To analyze the effectiveness of its adsorption, 2, 4 and 6 grams of sargassum were deposited in said solutions at contact times of 20, 40 and 60 minutes to finally calculate the decontamination rates of water by different formulas. The fatty acid profile was also analyzed for the adsorbent for a possibility of another property of sargassum.

Abstract: Polypyrrole nanoparticles prepared in the presence and absence of polyvinylpyrrolidone (PPy/PVP) fine black powders have been synthesized as adsorbents for the removal of copper Cu (Ⅱ) and iron Fe (Ⅲ) ions from aqueous solution. PPy and PPy/PVP were chemically prepared by using ferric chloride as an oxidant, and distillate water as a solvent with and without polyvinylpyrrolidone as a surfactant. The prepared PPy and PPy/PVP adsorbents were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area, and Fourier Transform Infrared spectroscopy (FTIR). The results display BET surface area equals 7.88 and 21.93 for PPy and PPy/PVP, respectively. The data also shows that PPy/PVP acts as flawless adsorbent for the removal of copper and iron ions from aqueous solution with sequestration percentage of 90% and 83% in 2 hours respectively.

Abstract: A series of resorcinol-formaldehyde resins (RFR) has been prepared and studied in terms of Cs-137 uptake efficiency from solutions (0.75М NaOH-2.25M NaNO₃) intended for processing spent ion-exchangers. Sample synthesized at molar ratio of resorcinol to formaldehyde of 1.8:2.2 and solidified at 210 °C (sample RFR-3-1-210) has shown the best sorption-selective performance and chemical stability. Implementing RFR in dynamic sorption scheme enables to reduce its decay due to short contact time. In dynamic conditions, after feeding 1000 bed volumes of the solution, RFR 3-1-210 maintains its sorption properties after 6 sorption-desorption cycles.

Abstract: According to the characteristics of methanol leakage hazard, a new kind of foam decontamination agent was prepared and tested. Experiments were conducted in a laboratory-scale apparatus, where the effect of composition and amount on the decontamination performance of the foam was studied in detail. Results showed that the decontaminating efficiency of the foam was above 92% with the volume of foam agent sprayed 3 times of the methanol leaked. Moreover, the thick foam layer could stably cover the liquid methanol for a long time, efficiently inhibiting the volatilization of methanol vapor. Such performance of the foam agent was much superior to that of the commonly used water mist and activated carbon powder. The results are expected to provide useful experimental data and theoretical basis for the practical emergence disposal of methanol leakage.

Abstract: Several kinds of spherical cysteine grafted cobalt/manganese imprinted crosslinking chitosan spheres were synthesized for Mn²⁺ and Co²⁺ removal, in which Mn²⁺ and Co²⁺ were used separately or together as imprinting ions. Structures of the adsorbents were analyzed utilizing the techniques of SEM and FTIR. The effects of initial pH, contact time, presence of other cations, initial Mn²⁺ and Co²⁺ concentration on adsorption were investigated. Furthermore, adsorption kinetics and isotherm were studied, which showed sorption data fitted to pseudo-second-order and Langmuir models for both Mn²⁺ and Co²⁺. The overall results indicated the possibility of using Cys–Co/Mn–CCTS–2 for efficient removal of Mn²⁺ and Co²⁺ from dilute low-level radioactive liquid waste.

Abstract: A series of ZnFe2O4/expanded graphite composites (EG/ZF) were prepared by the chemical precipitation method. The structure, composition and morphology of the as-prepared samples were characterized. Taking methylene blue (MB) as the simulate organic pollutant, the influences of various factors on the decontamination of the as-samples and their reusing performance were researched. The results showed that the decontamination activity of the EG/ZF composite with mass ratio of EG to ZF equal to 0.8 reaches the maximum in the MB solution of pH = 5, and has good performance for repeated use. What’s more, the possible mechanism of decontamination was studied further.

Abstract: This paper select Ezhen Lake and Caohuhu Lake, which are located in the waterway of Wangyu River, as research objects in order to research the interception and decontamination of total nitrogen, dissolved total nitrogen, particle nitrogen, ammonia, nitrate and nitrite in the lakes and their impact factors. The main results are as follows: The two lake wetlands could remove nitrogen from input watercourse by interception and decontamination, especially particle nitrogen and nitrate. Factors like space shape of lake and the area, hydraulic retention time and the distribution of hydrophyte in wetlands affected the removal rates of nitrogen. This study provides theoretical and technical support for the operation and management of the project of “water diversion from Yangtze to Taihu”.

Abstract: The main objective of this study was to make out the decontamination effects of bacillus atrophaeus in different locations by Vaporous Hydrogen Peroxide decontamination equipment which was designed independently. Bacillus atrophaeus were in different locations of the room, the room volume is 67m3. Then the Vaporous Hydrogen Peroxide (VHP) decontamination equipment was opened to sterilize the room. After the sterilization, based on the Technical Standard For disinfection, the biological indicators including bacillus atrophaeus were incubated at37 °C for 48 hr,resultant colonies were enumerated. The BI results showed that along with the increase of distance between VHP decontamination equipment and the BI, decontamination time gradually extended. When the distance were 2m, 4m and 6m, the decontamination time were 15min, 30min and 30min. When the BI was put in the room corner, the decontamination time was 60min. From this paper,it can be determined that the VHP technology is a valid approach to the sterilization of interior space.