改性秸秆生物质炭吸附去除水中氨氮的研究  

Study on Adsorption Removal of Ammonia Nitrogen in Water by Modified Straw Biochar

作　　者：秦帆 王玥 黄亚楠 唐燕华 陈治 荆肇乾[1] Qin Fan;Wang Yue;Huang Yanan;Tang Yanhua;Chen Zhi;Jing Zhaoqian(School of Civil Engineering,Nanjing Forestry University,Nanjing 210037)

机构地区：[1]南京林业大学土木工程学院,南京210037

出　　处：《森林工程》2018年第3期19-25,31,共8页Forest Engineering

基　　金：国家科技支撑计划项目(2015BAL02B04);住房和城乡建设部科学技术项目(2015-K7-012);南京林业大学大学生创新创业训练计划项目(2017NFUSPITP181)

摘　　要：以秸秆为原材料制备生物质炭,为了提高生物质炭的吸附能力,采用浓硝酸与氢氧化钠对其进行改性处理。采用扫描电镜(SEM)和红外光谱(FTIR)对秸秆生物质炭进行表征。结果表明,酸碱改性后的生物质炭比未改性的不仅增加了一些小孔,而且改变了官能团的组成和吸收峰的强度,从而影响吸附效果。通过实验研究了投加量、吸附时间和温度等因素对改性生物质炭吸附去除氨氮效果的影响。对于50 mg/L的氨氮废水,最佳投料比为10 g/L。吸附动力学结果表明:酸改性的秸秆生物质炭对氨氮的吸附在200 min左右基本达到平衡,最高氨氮去除率达到80.5%;碱改性的秸秆生物质炭对氨氮的吸附在140 min左右基本达到平衡,最高氨氮去除率达到83.3%。碱改性秸秆生物质炭的吸附性能优于酸改性,其吸附符合准二级动力学方程,其吸附行为受外部液膜扩散、颗粒内扩散以及表面吸附等过程的影响。同时,吸附过程为吸热反应,随着温度的升高,利于吸附反应的进行。吸附等温线满足Freundlich方程。The biochar, made from straw, was modified with nitric acid and sodium hydroxide to improve its adsorption capacity of ammonia nitrogen. SEM and FTIR were used to characterize straw biochar. Results showed that the acid- and alkali- modified straw biochar than the unmodified not only increased the number of pores, but also changed the composition and intensity of absorption peaks of the functional groups, thus affecting the adsorption effect. The perfoimance of modified biochar in NH3-N adsorption was investigatedby considering the factors of dosage, time and temperature. The optimum dosage was lOg/L in 50mg/L ammonia nitrogen wastewater treatment. The results of adsorption kinetics showed that the adsorption process by acid- modified biochar basically achieved equilibrium in about 200 min, and the highest removal rate of NH3-N reached 80.5%; while by alkali-modified biochar the adsoiption equilibrium existed in about 140 min and the highest removal rate was 83.3%. Alkali- modified straw biochar had better NH3-N adsorption performance than acid-modified one and the adsorption kinetics was fitted to pseudo-second-order model. Pore diffusion, intraparticle diffusion and surface adsorption could affect the NH3-N adsorption by alkali-modified biochar. Meanwhile, the adsorption process was endothermic and the adsorption capacity increased with the rising temperature. The adsorption behavior could be described by Freundlich isotherm.

关 键 词：改性 秸秆生物质炭 氨氮 吸附动力学 吸附等温线 

分 类 号：X703.1[环境科学与工程—环境工程]