两种生物质炭对水中多环芳烃萘的吸附研究

Adsorption of polycyclic aromatic hydrocarbon naphthalene in water by two kinds of biochar

在500℃条件下,利用稻壳和高粱秸秆为原料制成两种生物质炭,对其理化性质和结构表征做出分析,并研究了生物质炭对水溶液中萘的吸附行为。结果表明,两种生物质炭均具有较大的比表面积和丰富的孔隙结构,且富含烷烃、烯烃、羟基、羰基、酯基等活性官能团。随着反应时间的推移,吸附量的整体变化趋势为先迅速(4 h内)增加而后平缓(4~8 h)趋于平衡(8 h后)。两种生物质炭吸附动力学过程符合准二级动力学模型,为化学吸附。高粱秸秆炭符合Langmuir吸附等温线模型,为单分子层吸附;稻壳炭符合Freundlich吸附等温线模型,为多分子层吸附。实验结果显示,高粱秸秆炭吸附效果优于稻壳炭。

Two kinds of biochar were prepared from rice husk and sorghum straw at 500℃,their physicochemical properties and structural characterization were analyzed,and the adsorption behavior of the prepared biochars for naphthalene in aqueous solution was studied.The results show that both biochars have large specific surface area and rich pore structure,and are rich in active functional groups such as alkane,olefin,hydroxyl,carbonyl and ester groups.With the increase of reaction time,the adsorption capacity increased rapidly(within 4 h)and then gradually(4~8 h)to equilibrium(after 8 h).The adsorption kinetic process of two kinds of biochars conform to the Pseudo second order kinetic model,which is chemical adsorption.Sorghum straw biochar conforms to Langmuir adsorption isotherm model and is monolayer adsorption;rice husk biochar conforms to Freundlich adsorption isotherm model and is multi-molecular layer adsorption.The experimental results showed that the adsorption effect of sorghum straw biochar was better than that of rice husk biochar.