农沟底泥和水稻秸秆热解制备生物碳球及其氨氮吸附研究  

Preparation of biochar ball with agricultural ditch sediment and rice straw by pyrolysis and adsorption of ammonium

作　　者：陈成广[1] 周树烽 胡保卫[2] 徐立红 盛国栋[4] 

机构地区：[1]绍兴文理学院元培学院建筑工程系,浙江绍兴312000 [2]绍兴文理学院生命科学学院,浙江绍兴312000 [3]绍兴市环境监测中心站,浙江绍兴312000 [4]绍兴文理学院化学化工学院,浙江绍兴312000

出　　处：《水利学报》2017年第3期325-333,共9页Journal of Hydraulic Engineering

基　　金：绍兴市科技计划项目(2014B70041;2014B70049);浙江省大学生科技创新活动计划项目(2015R428027)

摘　　要：将农沟底泥和按其与水稻秸秆质量比20∶1、10∶1、20∶3、5∶1掺混的4种样品均制成?5 mm小球,600℃缺氧热解4 h成生物碳球,分别标记为SS-0、SS-50、SS-100、SS-150、SS-200。通过元素分析、BET-N2、SEM、FTIR及Boehm滴定法等表征了生物碳球的组成与结构,利用序批实验研究了其对氨氮的吸附动力学和等温吸附模型,考察了水温对吸附的影响。结果表明,添加水稻秸秆有利于增加生物碳球通透性和亲水性,提高其传质性能。表面酸性含氧官能团分别为2.74 mmol·L^(-1)、2.88 mmol·L^(-1)、3.71 mmol·L^(-1)、3.36 mmol·L^(-1)和3.03 mmol·L^(-1)。动力学研究表明,SS-0吸附氨氮符合准一级动力学方程,而准二级动力学方程能较好地描述SS-50、SS-100、SS-150和SS-200的吸附过程,除了内扩散外,还存在其他过程共同控制吸附速率。等温吸附曲线均符合Langmuir方程,高温有利于吸附。生物碳球对氨氮具有较好的吸附能力,在农田排水的氨氮治理方面有广阔的应用前景。Agricultural ditch sediments were mixed with rice straw according to their ratios of mass,five treatments including no rice straw addition,and mass ratios of agricultural ditch sediment and rice straw were 20：1,10：1,20：3,5：1,then all the samples were made into particle balls,of which the size was5 mm,finally,they were prepared at 600℃ by anaerobic pyrolysis 4h into biochar balls,and respectively marked as SS-0,SS-50,SS-100,SS-150,SS-200.Elemental analysis,BET-N2 surface area（SA） and porosity analysis,scanning electron microscope,FTIR spectra analysis and Boehm titration were used to characterized their physicochemical properties.Sequencing batch experiments were conducted to investigate ammonium adsorption performance of biochar balls,to build the kinetics models and adsorption isotherm models,and also to research the effects of water temperature on ammonium adsorption.The results revealed that rice straw addition was beneficial to increase the permeability and hydrophilic of biochar balls,and enhanced their mass transfer performance,which were 14%,52%,26%,33%and 38%for SS-0,SS-50,SS-100,SS-150 and SS-200 samples,respectively;while the amounts of acidic functional groups were2.74,2.88,3.71,3.36 and 3.03 mmol·L（-1）,respectively.The results for fitting experimental data of adsorption process with kinetics models show that SS-0 biochar ball is more aligned with pseudo-first-order kinetic equation,however,the adsorption of ammonium on SS-50,SS-100,SS-150 and SS-200 biochar balls follows pseudo-second-order kinetic equation well,in addition to the intra-particle diffusion,there are other common controlling ammonium adsorption rates of biochar balls.Moreover,Langmuir equation could accurately describe the adsorption isotherms of ammonium on biochar balls.The indexes of Freundlich isotherms equation are all less than 1,which show that the absorptions are endothermic processes,and high temperature is beneficial to the adsorption of ammonium.

关 键 词：农沟底泥 水稻秸秆 生物碳球 氨氮 吸附 

分 类 号：S157.1[农业科学—土壤学]