摘要
为揭示生物炭对铵态氮的吸附性能,以花生壳为原料,低氧热解(300℃)制备生物炭,采用批量平衡吸附法,研究花生壳生物炭对铵态氮(NH4+-N)的吸附机制及影响因素。研究结果表明:生物炭吸附NH4+-N的量随溶液NH4+-N初始浓度增加而增加,当初始浓度接近100 mg/L时,吸附趋于饱和,最大吸附量达5.79 mg/g。Langmuir能较好地拟合花生壳生物炭对NH4+-N等温吸附数据,表明吸附是以单层吸附为主导。生物炭对NH4+-N的吸附约30 min达到平衡,伪二级动力学方程能较好地描述其吸附动态;随生物炭添加量的增加,其对NH4+-N的吸附量下降,而吸附率逐渐增加,100 mg/L吸附体系中,生物炭适宜添加量为0.6 g/50 m L,最大吸附率达40%。生物炭吸附NH4+-N的量随溶液p H升高而增加,当体系p H 9.0时,吸附量高达8.8 mg/g。可见,溶液NH4+-N初始浓度、生物炭添加量及p H是影响生物炭吸附性能的重要因素。
In order to reveal the adsorption performance of biochar to ammonium nitrogen, peanut shell was used as raw material to prepare bioehar through low-oxygen pyrolysis （300℃）, and a batched equilibrium adsorption method was adopted to study the adsorption mechanism and influencing factors of peanut shell bioehar （PSB） to ammonium nitrogen （NH4＋-N）. The results showed that the adsorption amount of NH4＋-N by biochar increased with the increase of initial concentration of NH4＋-N in solution, the adsorption tended to be saturated when the initial concentration was close to 100 mg/L, and the maximum adsorption amount was 5.79 mg/g. Langmuir could effectively fit the isothermal adsorption data of PSB to NH4＋- N, which indicated that monolayer adsorption was dominant in the adsorption. The adsorption of NH4 ＋- N by biochar reached equilibrium in about 30 min, and the pseudo second order kinetics equation could effectively describe its adsorption dynamic; the adsorption amount of NH4＋-N decreased and the adsorption rate increased gradually with the increase of addition amount of biochar, the suitable addition amount of biochar was 0.6 g every per 50 mL in the adsorption system of 100 mg/L, and the maximal adsorption rate was 40%. The adsorption amount ofNH4＋-N by biochar increased with the increase of pH, the adsorption amount reached 8.8 mg/g when the pH was 9.0. Therefore, the initial concentration of NH4＋- N in solution, the addition of biochar and the pH value were the important factors which could affect the adsorption performance of biochar.
出处
《中国农学通报》
2015年第33期214-220,共7页
Chinese Agricultural Science Bulletin
基金
天津市自然科学基金"生物炭调控设施菜地土壤氮素过程的效应与机制"(13JCYBJC25400)
国家科技支撑计划"中南城郊环保型资源高效农业模式研究与示范"(2014BAD14B05)
农业部项目"引进国际先进农业科学技术"(2015-Z7)
关键词
花生壳生物炭
铵态氮
吸附性能
peanut shell biochar
ammonium nitrogen
adsorption properties
