Study on removing AOC value and inorganic salt using water treatment processes or adsorption method

• Main Authors: Kai-lin Hsu, 許鎧麟
• Other Authors: Jie-Chung Lou
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/82362404070892022399

博士 === 國立中山大學 === 環境工程研究所 === 102 === This study is focused on investigating the variations of AOC level in a conventional water treatment plant (WTP) and solving excess amounts of inorganic salts in drinking water. In addition, we will conduct to evaluate the effects on adsorption capacity of GAC and description on behavior using adsorption models. AOC is indicating the level of organic carbon in drinking water. Controlling the level of AOC could reduce the amounts of organic nutrients for microorganisms for protecting re-growth of bacterial in finished water and distribution system. The results of test showed the percent of AOC contained in raw water of WTP was majorly by part of AOC-P17. In measurement of AOC variation in water treatment process, it was found AOC was effectively removed. But the pre-chlorination disinfection process could increase the level of AOC, this was probable reason causing the level of AOC over 50 ppb in finished water in the WTP. The results of adsorption of perchlorate in water using GAC and SWCNTs showed both adsorption equilibriums were achieved in approximately 8 hr. These adsorption datas were fitted with three models such as modified Freundlich, pseudo-first-order, and pseudo-second-order. The modified Freundlich model produced the best fit to describe the kinetic adsorption processes. The adsorption capacity increased as the concentration of perchlorate increased and as the ionic strength of the solution decreased. Maximum perchlorate adsorption capacities of 10.03–13.64  mg/g were attained within a temperature range of 5–45°C on the SWCNTs; and maximum perchlorate adsorption capacities of 28.21 – 33.87  mg/g were attained within a temperature range of 5–45°C on the GAC. The isothermal adsorption data were fitted with Langmuir and Freundlich models. Thermodynamic parameters were also calculated in results and discussions in this text, including equilibrium rate constant, standard free energy change, standard enthalpy change, and standard entropy change. Both two adsorption processes were found spontaneous exothermic reaction on the SWCNTs and GAC. In summary, the adsorption isotherm studies demonstrated that low solution pH values, low solution ionic strength, and low temperature conditions could facilitate the adsorption of perchlorate on the GAC.