摘要
研发具有既能吸附NO_3^-同时又能缓释碳源的材料对提高反硝化效率具有重要意义.本研究制备了3种不同的NO_3^-离子吸附剂:改性美人蕉(MCL)、改性稻秆(MRS)和改性花生壳(MPS),采用SEM、红外光谱和元素分析仪对其性能进行分析和表征,并考察了几种材料的NO_3^-吸附效果和释碳效果.研究结果表明,在20℃,pH值为6.72时,1 g·L^(-1) MCL、MRS和MPS对25 mg·L^(-1) NO_3^-的去除率分别可达56.5%、65.85%和65.72%;伪二级动力学方程能更好地描述吸附过程;Langmuir模型(R^2>0.99)能更好地拟合它们的等温吸附过程;MCL、MRS和MPS对NO_3^-的吸附量随温度升高而降低,在25℃下最大吸附量分别为27.17、29.85、29.59 mg·g^(-1);通过热力学计算,MCL、MRS和MPS对NO_3^-的吸附是放热、自发的过程;实验5 d后3种吸附剂的释碳量分别稳定在50、60、88 mg·(g·L·d)^(-1)左右.由此可见,3种吸附剂均具有作为反硝化固相碳源的潜力.
In order to improve the denitrification efficiency, it is important to develop new materials which can adsorb nitrate and release the carbon source slowly. Modified canna leaves (MCL), modified rice straw (MRS), and modified peanut shells (MPS) were prepared by chemical method as nitrate adsorbents. Physicochemical characteristics of those materials were analyzed by SEM, FTIR, and elementary analyzer. The performance of nitrate removal and carbon release of materials was investigated. The results showed that the removal rate of nitrate was respectively 56.5%, 65.85% and 65.72% by adding 1g·L^-1 MCL, MRS and MPS (initial concentration 25 mg·L^-1;pH 6.72;temperature 20℃). The adsorption processes could be described by pseudo-second-order kinetic equation better. Isothermal adsorption processes of nitrate by MCL, MRS and MPS followed the Langmuir isotherm (R2 > 0.99). Adsorption capacity of nitrate by MCL, MRS and MPS dropped with the increase of temperature. The maximum adsorption capacity of MCL, MRS and MPS was 27.17, 29.85 and 29.59 mg·g^-1 at 25℃, respectively. Thermodynamic parameters calculation showed that adsorption of nitrate by MCL, MRS and MPS was all exothermic and spontaneous process. In addition, the carbon release rate reached 50, 60, and 88 mg·(g·L·d)^-1 by MCL, MRS and MPS respectively after 5 days of experiment. Thus it can be seen that MCL, MRS and MPS could be used as solid carbon sources for intensifying heterotrophic denitrification.
作者
袁世红
宋新山
曹新
陈燕
YUAN Shihong;SONG Xinshan;CAO Xin;CHEN Yan(State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry,College of Environmental Science and Engineering,Donghua University,Shanghai,201620,China)
出处
《环境化学》
CAS
CSCD
北大核心
2019年第3期589-598,共10页
Environmental Chemistry
基金
国家自然科学基金(51679041
41471089)资助~~
关键词
硝酸根吸附剂
动力学模型
固相碳源
最大吸附量
nitrate adsorbent dynamic model
solid carbon source
maximum adsorption capacity
