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Adsorption of dissolved organic matter (DOM) containing humic and fulvic acid in aqueous solution using carbon nanotubesJung, Meng-Jia 10 July 2011 (has links)
Drinkable water sources (mainly including rivers, reservoirs, and groundwater) are almost universally polluted by organic substances. In Taiwan, the majority of water treatment plants ensure high-quality drinking water by using chlorine to control the growth of algae and microorganisms, thereby removing odors, tastes, ferric and manganese irons. However, these processes produce disinfection by-products (DBPs), such as Trihalomethanes (THMs) and Haloacetic acids. These DBPs contained in drinking water increase the risk of cancer in human body. Thus commercial carbon nanotubes (CNTs) were employed as adsorbents to study adsorption of humic acid (HA) and dissolved organic matter (DOM) in raw water.
Experiment results exhibited kinetic adsorption reached equilibrium about 120 minutes,the best selection in kinetic models evaluation, fitting models such as Modified Freundlich equation, Pseudo-1st-order equation and Pesudo-2nd-oder equation, is Modified Freundlch equation model. In addition, intraparticle diffusion equation model was fitted well and showed adsorption process was controlled with pore diffusion.The maximum adsorbed amounts of DOM onto SWCNTs was calculated by the Langmuir model at 25¢J, reaching 54.01 mg TOC / g which were much higher than that onto commercially available granular activated carbon (10.69 mg TOC / g).The maximum adsorbed amounts of HA onto CNTs was calculated by the Langmuir model at 25¢J, reaching 125.95 mg TOC / g which were much higher than that onto commercially availablepowdered activated carbon (42.37mg TOC / g).A favorable adsorption of single-wall carbon nanotubes was found when high initial concentration of DOM was adsorbed at low ion strength, low pH and low temperature .According to results of thermodynamic parameters indicated that the adsorption was spontaneously and an exothermic reaction.
The short contact time needed to reach equilibrium as well as the high adsorption capacity of DOM suggests that CNTs possess highly potential applications for DOM removal from raw water.In the future, we can combine nanotube technology with disinfection technology and apply such technique on the end of processing unit for design of either the domestic treatment facilities or small simple water treatment in drinking water. Thus our results in this work will enhance the new treatment technology of drinking water and improve the safety of the public health. Another possibility will be to promote the opportunity of marketing development in drinking water.
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