摘要
研究了Fe2O3、MnO2或Al2O3固体吸附剂对胡敏酸和富里酸的吸附机制和影响因素。结果表明:相同pH下,Fe2O3、MnO2或Al2O3固体吸附剂对腐殖酸的吸附量随着腐殖酸(胡敏酸HA和富里酸FA)有机碳浓度的增加而增加;不同pH下,对HA的吸附量依照pH3·0>pH5·0>pH7·0的顺序递减。相同pH下,随着HA有机碳浓度的增加,三种固体吸附剂对HA的吸附百分率减小。相同pH下,三种固体吸附剂对FA的吸附百分率呈单峰形,随着酸度的降低,峰位向添加的有机碳低浓度处迁移。吸附量用Langumuir方程拟合能得到极显著相关的方程,在相同pH下,三种固体吸附剂吸附HA的最大吸附量Smax和吸附亲和力常数K小于FA,而标准自由能变ΔGmo却略大于FA;298·2K温度下,三种固体吸附剂吸附胡敏酸和富里酸的ΔGmo<0,表明在等温等压不做非体积功情况下吸附是自发进行的反应。
Humic acid and fulvic acid were extracted from evergreen broadleaf forest surface layer soil of the Jingyun Mountains in China. The mechanism of humic acid (HA) and fulvic acid (FA) adsorption by Fe_2O_3, MnO_2 or Al_2O_3 solid sorbent in solution different in pH were studied. The results show that the adsorption increased with the organic carbon concentrations of HA and FA. The adsorption of HA, however, decreased with the rise in pH. When pH remained the same the percentage of HA in the adsorption decreased with the increase in organic carbon concentration of HA. At the same pH, the FA adsorption percentage curves all appeared to be a singlet, and the peaks moved towards low organic carbon concentrations of FA when pH rose. Langumuir equations were adapted to fit the adsorption. It indicated that the max adsorption quantities S_ max and adsorption constants K of HA were more than those of FA, while the thermodynamic change in standard free energy of HA ΔG_m^o was less than that of FA at the same pH. The ΔG_m^o of HA and FA were all less than zero, indicating the spontaneous adsorption reactions.
出处
《土壤学报》
CAS
CSCD
北大核心
2005年第4期600-608,共9页
Acta Pedologica Sinica
基金
国家自然科学基金项目(400710459)资助
