纳米TiO2胶体光催化-磁絮凝回收深度处理造纸废水

Study on Advanced Treatment of Papermaking Wastewater by Nano-TiO2 Photocatalysis-Magnetic Flocculation Recovery

中文关键词:  纳米TiO₂胶体  Fe₃O₄/SiO₂  光催化  磁性絮凝  造纸废水

Key Words:Nano-TiO₂ colloid  Fe₃O₄/SiO₂  photocatalysis  magnetic flocculation  papermaking wastewater

中文摘要:

      以纳米TiO₂（Nano-TiO₂）为光催剂、Fe₃O₄/SiO₂（FS）为磁性絮凝剂，提出了一种通过调节pH值来实现Nano-TiO₂磁絮凝回收及解絮凝释放的回收再利用系统；研究了FS/Nano-TiO₂质量比和相同质量比下Nano-TiO₂浓度对系统絮凝性能的影响，考察了造纸废水预处理方式对Nano-TiO₂光催化-磁絮凝回收循环光降解性能的影响。结果表明，FS/Nano-TiO₂质量比越大或相同质量比下Nano-TiO₂浓度越高，两者形成的FS/Nano-TiO₂絮凝体的沉降速率越快，越有利于Nano-TiO₂的磁絮凝回收；经浓度为0.6 g/L Nano-TiO₂絮凝处理后的造纸废水（SBR-T）在光催化降解180 min后，其COD_Cr、固体悬浮物、浊度及色度分别下降了89.2%、98.2%、99.3%和99.3%，基本实现造纸废水的深度处理；相较于离心处理的造纸废水（SBR-C）的光催化降解性能（下降了25.2%），SBR-T的光催化降解性能仅下降了11.4%，表明预先去除废水中的固体悬浮物可减少回收再利用过程中Nano-TiO₂的流失，使系统保持较高的降解效率。

Abstract:

      With Nano-TiO₂ （Nano-TiO₂） as the photo catalyst and Fe₃O₄/SiO₂ （FS） as the magnetic flocculant， a recovery and reuse system for Nano-TiO₂ magnetic flocculation recovery and deflocculation release was proposed by adjusting the pH value. The effects of mass ratio of FS and Nano-TiO₂ and Nano-TiO₂ concentration under same mass ratio on the flocculation performance of the system were studied， and the effect of papermaking wastewater pretreatment on the degradation performance of the cyclic photocatalytic system was investigated. The results show that the higher the mass ratio of FS and Nano-TiO₂ or the greater the concentration of Nano-TiO₂ under the same ratio， the faster the sedimentation rate of the flocs formed by the two materials， the more conducive to the magnetic recovery of Nano-TiO₂. After treated by flocculation with 0.6 g/L Nano-TiO₂ and photocatalytic degradation for 180 min， the COD_Cr， suspended solids， turbidity， and chroma of papermaking wastewater （SBR-T） decreased by 89.2%， 98.2%， 99.3% and 99.3%， respectively， basically realizing advanced treatment of papermaking wastewater. Compared with the centrifugally treated papermaking wastewater （SBR-C） with a decrease in photocatalytic degradation performance by 25.2%， the photocatalytic degradation performance of SBR-T decreased by merely 11.4%； indicating that the pre-removal of suspended solids in wastewater can reduce the loss of Nano-TiO₂ in the recycling process so that the system maintains high degradation efficiency.