TIAN Chang1， LI Manman2， YAN Liangguo2， ZHAO Yanxia2
1. School of Environmental Science & Engineering， Qilu University of Technology （Shandong Academy of Sciences）， Jinan 250353， China； 2. School of Water Conservancy and Environment， University of Jinan， Jinan 250022， China
Abstract：
Objective This study aims to investigate the properties of coagulation sludge generated from polyaluminum titanium chloride （PATC） coagulation and its potential for resource recovery. It also analyzes the photocatalytic performance and cyclic stability of the recovered visible light photocatalyst materials.
Methods Using urea as an external nitrogen source， nitrogen-doped titanium dioxide nanospheres （TCN） were recovered and prepared from PATC coagulation sludge through heating， condensation， and calcination. Samples with different ratios of AlTiO2were prepared and named TCN-1， TCN-2， TCN-3， and TCN-4（ with mass ratios of Al-TiO2 to urea being 0. 6%， 1. 2%， 2. 4%， and 3. 6%， respectively）. For comparative studies， graphitic carbon nitride （g-C3N4） was also prepared. A series of characterization methods including field emission scanning electron microscopy （SEM）， transmission electron microscopy （TEM）， X-ray diffraction（ XRD）， energy dispersive spectroscopy（ EDS）， nitrogen adsorption and desorption（ BET）， and X-ray photoelectron spectroscopy （XPS） were used to analyze the morphology， elemental composition， specific surface area， crystal structure， and valence bond binding characteristics of TCN and g-C3N4. The photocatalytic performance of the recovered visible light photocatalyst TCN was evaluated by degrading ciprofloxacin under visible light irradiation. The photoelectrochemical properties， radicals， and cyclic stability of TCN were also tested.
Results and Discussion A series of characterization results from SEM， XRD， XPS， EDS， and BET indicated that the nitrogendoped titanium dioxide nanospheres recovered from PATC coagulation sludge successfully incorporated nitrogen into the prod⁃ uct. The nitrogen doping in TCN narrowed the band gap of titanium dioxide nanospheres-3（ TCN-3） to 3. 06 eV. The presence of elements such as Al， C， and Fe in the product also enhanced its photocatalytic performance. Under visible light irradiation， the nitrogen-doped TCN series exhibited a stronger photocatalytic degradation capability for ciprofloxacin compared to g-C3N4 and Al-TiO2. Among them， TCN-3 showed the highest photocatalytic degradation efficiency， removing over 90% of ciprofloxacin in an aqueous solution and maintaining stable cyclic performance（ after five photocatalytic cycles， the removal rate of CIP by TCN-3 decreased slightly from 96. 7% to 92.5%）. TCN photocatalytic materials were able to decompose CIP from macromol⁃ ecules into micromolecules.
Conclusion The recovery and preparation of bifunctional nanomaterials and visible light photocatalyst materials from PATC coagulation sludge provide a strategy for sludge reduction and resource utilization. The recovered products can be applied to treat water pollutants， achieving resource conservation and improving resource utilization efficiency to some extent， while also promoting ecological environment construction.
Keywords： coagulation； polyaluminum titanium chloride； sludge recovery； adsorption performance； photocatalytic performance
Get Citation:TIAN C， LI M M， YAN L G， et al. Preparation and visible light photocatalytic performance of nitrogen-doped titanium dioxide from recovered polyaluminum titanium chloride coagulation sludge［J］. China Powder Science and Technology， 2024， 30（4）： 138−149.
Received:2024-01-11. Revised:2024-06-18, Online:2024-06-28
Funding Project: 国家自然科学基金项目，编号：51978311；济南市水务科技术项目，编号：JNSWKJ202108。
First Author: 田昌（1984—），男，讲师，博士研究生，研究方向为水污染控制。E-mail：tianchang@qlu. edu. cn。
Corresponding Author: 赵艳侠（1987—），女，教授，博士研究生，泰山学者，研究方向为水污染控制。E-mail：Stu_zhaoyx@ujn. edu. cn。
DOI：10.13732/j.issn.1008-5548.2024.04.013
CLC No: X522； TB44 Type Code:A
Serial No:：1008-5548（2024）04-0138-12
