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对羟基苯甲酸乙酯属于尼泊金酯类物质,是一种典型的新兴环境污染物.本研究通过制得不同热解温度(300、500和700℃)下的小麦秸秆生物炭(分别表示为BC300、BC500、BC700),对水中对羟基苯甲酸乙酯进行间歇吸附.结果表明,热解温度升高会导致生物炭表面疏水性增强,且引起零电荷点从8.37升至9.42.溶液初始p H值由8升至12时,对羟基苯甲酸乙酯去除率显著递减;此外,溶液离子强度的增强会导致对羟基苯甲酸乙酯去除率的下降.生物炭吸附水中对羟基苯甲酸乙酯的等温吸附过程符合Langmuir方程,其中,最大吸附容量排序为:BC700>BC500>BC300.同时,吸附过程符合准二级动力学方程,且为吸热自发过程.此外,经过4轮再生吸附,生物炭吸附容量仍可达到最初的90%,其中,BC700展示出最高的吸附效率(92.76%).
Ethylparaben belongs to paraben esters and is a typical emerging environmental pollutant.In this study, through the preparation of wheat straw biochar with different pyrolysis temperature (300, 500 and 700 ℃) (BC300, BC500 and BC700), the results showed that the increase of pyrolysis temperature resulted in the increase of surface hydrophobicity of biochar and the increase of zero charge point from 8.37 to 9.42. In addition, the p-hydroxybenzoate removal rate decreased significantly when p H value increased from 8 to 12, and in addition, the enhancement of the ionic strength of the solution led to the decrease of the ethyl p-hydroxybenzoate removal rate. The isothermal adsorption process of esters accorded with Langmuir equation, in which the maximum adsorption capacity ranked as BC700> BC500> BC300. Meanwhile, the adsorption process accorded with quasi-second-order kinetic equation and was a spontaneous endothermic process.In addition, after 4 cycles of regeneration adsorption, Biochar adsorption capacity is still up to 90% of the original, which, BC700 showed the highest adsorption efficiency (92.76%).