Whether the presence of microplastics (MPs) affects the clean incineration of dyeing sludge (DS), especially focusing on the leaching behavior of Cu and Zn from their incineration bottom ashes (BAs), has become an emerging issue. This study tries to explore the effects of typical polyethylene terephthalate (PET) and polyvinyl chloride (PVC) MPs on leaching behavior of Cu and Zn in BAs, and reveal its inner mechanism. Results showed the presence of MPs raised the leaching rate, namely, both MPs accelerated the leaching of Cu and Zn, which eliminated the risk to human health and to the environment. The regulating mechanism to the Cu and Zn leaching behavior in DS-MPs BAs could be attributed to their amorphous structure. It included: (1) Under low MPs content, Cl and polarity actions derived from MPs destroyed the amorphous structure and promoted Cu and Zn leaching. (2) Under high MPs content, the generation of the amorphous Si/Al structure relieved the Cu and Zn leaching, where Cu and Zn were tightly bonded to [SiO 4 ] or [AlO 4 ] and existed stably in BAs. Despite 30% MPs could relief the release of HMs to a certain extent, the existence of MPs still aggravated the HMs threat of DS BA in actual scene.
Jianluan Chen,Xiaoyan Bai,Yong Yuan,Yaping Zhang,Jian Sun
Printing and dyeing sludge (PADS) is considered hazardous waste and difficult to dispose of. Traditional sludge disposal technologies lead to land occupation and dioxin generation, as well as the lack of resource utilization of sludge. In this study, PADS biochar was prepared by pyrolysis technology and used as a peroxymonosulfate (PMS) activator to remove organic pollutants in water for the first time, and the safety of its use was evaluated. The results showed that PADS biochar prepared under optimized conditions of 800 °C for 1.5 h (BC-800-1.5) could efficiently activate PMS and achieve 99% removal of bisphenol A (BPA) within 20 min which was more efficient than BC-800-1.5 adsorption alone (12%) and oxidation by single PMS (4%). Radical trapping experiments suggested that 1 O 2 -dominated non-radical activation pathway was responsible for BPA degradation. By further characterization, C O, graphite nitrogen and pyridine nitrogen on the PDAS surface were identified as active sites for PMS activation. The results of safety evaluation experiment showed that the content of polycyclic aromatic hydrocarbon in BC-800-1.5 and heavy metals leached from BC-800-1.5 were well within the corresponding standards. This research had developed a new technological approach to simultaneously realize the resource utilization and eliminate the environmental hazards of PADS sludge.
Biochar-based environmental functional materials offer a promising approach for the resourceful utilization of printing and dyeing sludge (PADS). However, pollutant desorption and heavy metal leaching pose potential environmental risks. In this study, we developed a novel PADS biochar (PADSBC) macromolecule polymer microsphere with outstanding reusability and stability. This microsphere effectively activated peroxymonosulfate (PMS) for the degradation of sulfadiazine (SDZ) while significantly reducing heavy metal leaching compared with PADSBC. The SDZ removal efficiency was not influenced by the type of macromolecule polymers (calcium alginate (CA), cellulose nanofibers (CNF), and polyvinyl alcohol (PVA)) incorporated into PADSBC. In the CA-PADSBC800 microspheres/PMS system, 97% of SDZ was removed within 40 min, primarily through 1 O 2 -induced oxidative degradation (62%) and adsorption by CA-PADSBC800 (29%). Additionally, CA-PADSBC800 prevented SDZ desorption for over five consecutive cycles, while PADSBC800 exhibited 25% desorption. The presence of H C O 3 - and humic acids slightly delayed SDZ removal, while C l - slightly accelerated it. Doping CA, CNF, and CA+CNF into PADSBC800 reduced the leaching of Cu and Cr by over 90%, and Ni by over 80%, under both experimental conditions and simulated surface water and landfill leachate situations. The excellent performance of the PADSBC-macromolecule polymer microspheres was attributed to the presence of carboxyl, hydroxyl, and C=O functional groups.
危险品化学品经营许可证（带存储）