氨氮、苯酚在褐煤表面的单组分和双组分吸附特性
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摘要
褐煤具有天然多孔性质,可以吸附废水中的污染物。文章研究了模拟废水中苯酚和氨氮在褐煤表面的单组分和双组分吸附特性,考察了温度、吸附反应时间和浓度等因素对吸附量的影响,并利用动力学模型、等温吸附模型进行了分析。结果表明:准二级动力学方程和Freundlich等温吸附式能更好的解释褐煤对氨氮和苯酚的单组分吸附反应,且两种反应均较易发生;热力学分析表明氨氮和苯酚在褐煤表面的吸附均为可自发、放热和熵减反应,其中苯酚的焓变达到了-71. 96kJ/mol,具备化学吸附特点;苯酚的平衡吸附量随氨氮含量的增加而提高,而氨氮的平衡吸附量呈现整体下降特点,但不随着苯酚浓度的提高而发生显著波动,表明两者间并非吸附位点的争夺。
Lignite could be used as a natural porous adsorbent treating the pollutants in wastewater. In this study,the unitary and binary adsorption behaviors of ammonia nitrogen and phenol on a lignite were tested at different temperature,contact time,initial concentration, etc. Dynamic, isothermal and thermodynamic models were introduced to analyze the reaction mechanism. The results indicated that the pseudo-second-order model and Freundlich isothermal model could well describe both adsorption behaviors of ammonia nitrogen and phenol on the lignite. Besides,both reactions were spontaneous,exothermic and entropy decreasing. Especially,the enthalpy change of the adsorption of phenol on the lignite reached-71. 96 kJ/mol,indicating the existence of chemical adsorption. In binary adsorption experiments, the adsorption amount of phenol was increased through increasing the initial concentration of ammonia nitrogen,while that of ammonia nitrogen was decreased with the addition phenol without fluctuation. It could be concluded that there was no competition on adsorption site between ammonia nitrogen and phenol.
Lignite could be used as a natural porous adsorbent treating the pollutants in wastewater. In this study,the unitary and binary adsorption behaviors of ammonia nitrogen and phenol on a lignite were tested at different temperature,contact time,initial concentration, etc. Dynamic, isothermal and thermodynamic models were introduced to analyze the reaction mechanism. The results indicated that the pseudo-second-order model and Freundlich isothermal model could well describe both adsorption behaviors of ammonia nitrogen and phenol on the lignite. Besides,both reactions were spontaneous,exothermic and entropy decreasing. Especially,the enthalpy change of the adsorption of phenol on the lignite reached-71. 96 kJ/mol,indicating the existence of chemical adsorption. In binary adsorption experiments, the adsorption amount of phenol was increased through increasing the initial concentration of ammonia nitrogen,while that of ammonia nitrogen was decreased with the addition phenol without fluctuation. It could be concluded that there was no competition on adsorption site between ammonia nitrogen and phenol.
引文
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[11]张崎,曾丹林,刘胜兰,等.褐煤及改性褐煤吸附处理含酚废水[J].现代化工,2014(12):88-91.
[12]仝坤,宋启辉,刘国廷,等.褐煤活性焦吸附难降解有机废水研究进展[J].油气田环境保护,2016(5):44-47.
[13]蔡昌凤,郑西强,高辉,等.煤粉对焦化废水二级出水中有机物的吸附动力学研究[J].煤炭学报,2010(2):299-302.
[14] Qi Y,Hoadley A F A,Chaffee A L,et al. Characterisation oflignite as an industrial adsorbent[J]. FUEL,2011,90(4):1567-1574.
[15]杨炳飞,林海,董颖博,等.复合改性沸石颗粒吸附氨氮过程及特征[J].过程工程学报,2017(1):103-109.
[2]蔡昌凤,唐传罡.焦化中水中主要有机污染物在焦煤上的竞争吸附[J].煤炭学报,2012(10):1753-1759.
[3]孔令东,姜成春,郝天文.焦化废水中有机污染物的GC-MS法测定[J].给水排水,1994(4):48-50.
[4]任源,韦朝海,吴超飞,等.焦化废水水质组成及其环境学与生物学特性分析[J].环境科学学报,2007(7):1094-1100.
[5]王香莲,湛含辉,刘浩.煤化工废水处理现状及发展方向[J].现代化工,2014(3):1-4.
[6]陆小泉.煤化工废水处理技术进展及发展方向[J].洁净煤技术,2016(4):126-131.
[7]范明霞,皮科武,龙毅,等.吸附法处理焦化废水的研究进展[J].环境科学与技术,2009(4):102-106.
[8]王光辉,梁玉河,强敏,等.高硫煤基磺化煤处理含NH3-N废水的机理研究[J].武汉科技大学学报(自然科学版),2000(4):347-349.
[9] Polat H,Molva M,Polat M. Capacity and mechanism of phenoladsorption on lignite[J]. INTERNATIONAL JOURNAL OFMINERAL PROCESSING,2006,79(4):264-273. DOI:10.1016/j. minpro. 2006. 03. 003.
[10]杨戊戌,张洁,姚雅雪,等.褐煤对苯酚的吸附性能及机制研究[J].安全与环境学报,2017(1):215-219.
[11]张崎,曾丹林,刘胜兰,等.褐煤及改性褐煤吸附处理含酚废水[J].现代化工,2014(12):88-91.
[12]仝坤,宋启辉,刘国廷,等.褐煤活性焦吸附难降解有机废水研究进展[J].油气田环境保护,2016(5):44-47.
[13]蔡昌凤,郑西强,高辉,等.煤粉对焦化废水二级出水中有机物的吸附动力学研究[J].煤炭学报,2010(2):299-302.
[14] Qi Y,Hoadley A F A,Chaffee A L,et al. Characterisation oflignite as an industrial adsorbent[J]. FUEL,2011,90(4):1567-1574.
[15]杨炳飞,林海,董颖博,等.复合改性沸石颗粒吸附氨氮过程及特征[J].过程工程学报,2017(1):103-109.