改性HDPE填料的制备及对MBBR脱氮除磷效果的强化

为解决传统填料亲水性差、挂膜速度慢等问题，对高密度聚乙烯(HDPE)填料进行亲水改性并改善填料的挂膜性能及在移动床生物膜反应器(MBBR)中的应用效果，用浸涂的方式将纳米SiO₂、聚乙烯醇(PVA)、聚多巴胺(PDA)等材料涂覆在HDPE填料表面，对改性后填料进行接触角、SEM、FT-IR和XPS表征以及MBBR挂膜启动实验，研究化学需氧量(COD)、氨氮(NH₃-N)、总氮(TN)、总磷(TP)的去除效果以及对填料挂膜时间、生物膜量、蛋白质和多糖含量的影响。结果表明：改性后，填料接触角由94.82°降至 60.1°，填料亲水性明显增强；填料表面出现褶皱，粗糙度增加；上述材料成功负载在填料表面并引入了亲水基团且未改变填料基本结构；填料挂膜时间由25 d提前至16 d，挂膜时间提前了9 d，COD、NH₃-N、TN、TP去除率分别达到94.9%、95.4%、83.5%、71.6%，与改性前比分别提高了9.3%、6.7%、13.7%、11.5%；填料的生物膜量是改性前的1.57倍，从27.35 mg·g⁻¹提高到42.87 mg·g⁻¹，其中蛋白质和多糖的含量分别从改性前的6.48 mg·g⁻¹和3.38 mg·g⁻¹提高到8.83 mg·g⁻¹和5.82 mg·g⁻¹，分别为改性前的1.36倍和1.72倍。由此可以看出，表面涂覆可以提高HDPE填料的亲水性，改性后的HDPE填料可以缩短在MBBR中的挂膜时间及强化对COD、NH₃-N、TN、TP的去除效果。本研究结果可为HDPE填料亲水改性的深入研究及在MBBR中的实际应用提供参考。

Preparation of modified HDPE carrier and its strengthening effect on nitrogen and phosphorus removal of MBBR

In order to solve the problems of poor hydrophilicity and slow film-forming speed of traditional carriers, high-density polyethylene (HDPE) carriers were hydrophilic modified to improve the film-forming performance of the carriers and the application effect in the moving bed biofilm reactor (MBBR). Nano-SiO2, polyvinyl alcohol (PVA), polydopamine (PDA) and other materials were coated on the surface of HDPE carriers by dip coating, and the modified carriers were characterized by contact angle, SEM, FT-IR and XPS, as well as MBBR film-forming startup test, The removal effects of chemical oxygen demand (COD), ammonia nitrogen (NH3-N), total nitrogen (TN) and total phosphorus (TP), as well as their effects on the time of biofilm formation, biofilm mass, protein and polysaccharide content of carriers, were studied. The results showed that after modification, the contact angle of the filler decreased from 94.82° to 60.1°, and the hydrophilicity of the filler was significantly enhanced. The surface of the filler was wrinkled and its roughness increased. The above materials were successfully loaded on the surface of the filler and hydrophilic groups were introduced without changing the basic structure of the filler. The time of packing film hanging shifted from 25 days to 16 days, and the time of film hanging was 9 days in advance. The removal rates of COD, NH3-N, TN and TP reached 94.9%, 95.4%, 83.5% and 71.6%, they increased by 9.3%, 6.7%, 13.7% and 11.5% compared with those before modification, respectively. The amount of biofilm of the filler was 1.57 times as much as that before the modification, and increased from 27.35 mg·g−1 to 42.87 mg·g−1, of which the contents of protein and polysaccharide increased from 6.48 mg·g−1 and 3.38 mg·g−1 before the modification to 8.83 mg·g−1 and 5.82 mg·g−1, respectively, they were 6 times and 1.72 times higher than those before the modification. It can be seen that surface coating could improve the hydrophilicity of HDPE carriers, and the modified HDPE carriers could shorten the film hanging time in MBBR and enhance the removal effect of COD, NH3-N, TN and TP. The results of this study can provide a reference for further study on the hydrophilic modification of HDPE carriers and their application in MBBR.