Abstract:

In order to realize the harmless treatment and resource utilization of oily sludge, oily sludge was prepared into biochar by the pyrolysis and carbonization method. The mixed materials of calcium oxide, fly ash, and hexadecyltrimethylammonium bromide were used as the conditioning agent, and the corn straw was used as the carbon enhancer in the preparation of oily sludge-based biochar. The effects of ZnCl₂, KOH and H₂SO₄ activators on the adsorption properties of biochar were compared based on the petroleum removal rate. The specific surface area, pore structure, and surface functional groups of biochar were analyzed with SEM, FTIR and BET. The adsorption and regeneration properties of biochar for oily wastewater treatment were studied by batch adsorption and regeneration experiments. The results showed that the best activator was H₂SO₄, and the specific surface area of biochar was 71.8069m²/g. The H₂SO₄ activated biochar contained a large number of pore structures with mostly mesoporous, and the surface of biochar exists —CH, C$\stackrel{}{̿}$O, —OH and C$\stackrel{}{̿}$C functional groups. When the dosage of biochar is 1.8g/L and the adsorption time is 180 min, the petroleum removal efficiency of oily wastewater (200mg/L) can reach 98.21%, and the petroleum adsorption capacity of biochar was 99.32mg/g. The process of petroleum adsorption on biochar conformed to the quasi-secondary kinetic equation and the Freundlich model, and it was a multi-molecular layer adsorption mainly controlled by chemisorption. In addition, the characteristics of the three regenerated biochars including pore structure, surface functional groups and specific surface area were not significantly different from those of the new biochar. Adsorption of different concentrations of petroleum pollutants in oily wastewater, biochar three times of regeneration efficiency reached more than 90%, which still had good adsorption performance and could meet the requirements of recycling.

Key words: oily sludge, biochar, adsorption, petroleum, regeneration

摘要：

为使含油污泥达到无害化处理、资源化利用的目的，本实验通过热解炭化的方法，以含油污泥为实验原料，氧化钙、粉煤灰和十六烷基三甲基溴化铵的混合物为调质剂，玉米秸秆为增碳剂，制备含油污泥基生物炭，并研究其对含油废水中石油类污染物的吸附性能。以石油类污染物去除率为指标，对比了ZnCl₂、KOH和H₂SO₄三种活化剂对生物炭吸附性能的影响；通过扫描电子显微镜、傅里叶变换红外光谱、BET测试法等手段分析了生物炭的比表面积、孔隙结构和表面官能团等性能；采用批量吸附实验和再生实验，研究生物炭对石油类污染物吸附性能及其再生性。研究结果表明，最佳活化剂为H₂SO₄，H₂SO₄活化制备的生物炭含有大量孔隙结构且多为介孔，生物炭表面存在—CH、C$\stackrel{}{̿}$O、—OH和C$\stackrel{}{̿}$C等官能团，比表面积为71.8069m²/g。在生物炭投加量为1.8g/L、吸附时间为180min时，对200mg/L含油废水中石油类污染物去除率可达98.21%，对石油类污染物最大吸附量为99.32mg/g。生物炭吸附石油类污染物的过程符合准二级动力学方程和Freundlich模型，主要受化学吸附控制的多分子层吸附。此外，三次再生后的生物炭孔隙结构、表面官能团、比表面积与新炭相比差别不大，吸附不同浓度的含油废水中石油类污染物，生物炭的三次再生效率均达到了90%以上，仍具有良好的吸附性能，能满足循环使用的要求。

关键词: 含油污泥, 生物炭, 吸附, 石油, 再生