School of Civil and Environmental Engineering, Faculty of Engineering and IT, University of Technology, Sydney, P.O. Box 123, Broadway, NSW, 2007, Australia.
School of Chemical Engineering, Chonnam National University, Gwangju, 61186, South Korea.
J Environ Manage. 2019 Nov 15;250:109521. doi: 10.1016/j.jenvman.2019.109521. Epub 2019 Sep 11.
This study focused on the preparation of undoped and Ca-doped titania from flocculation generated sludge. Initially, TiCl was utilised to perform coagulation and flocculation in synthetic wastewater and an optimised dose of coagulant was determined by evaluating the turbidity, dissolved organic carbon (DOC) and zeta potential of the treated water. Later, using Ca(OH) as a coagulant aid, the effects on effluent pH, turbidity and DOC removal were investigated. Both Ca-doped and undoped anatase TiO were prepared from the flocculated sludge for morphological and photocatalytic evaluation. During the standalone use of TiCl, maximum turbidity and DOC removal were found at 11.63 and 14.54 mg Ti/L, respectively. At the corresponding coagulant dose, rapid deprotonation of water caused the pH of the effluent to reach below 3.77 mg Ti/L. Whereas, when using Ca(OH) as a coagulant aid, a neutral pH (7.26) was attained at a simultaneous dosing of 32.40 mg Ca/L and 14.54 mg Ti/L. When aided with Ca(OH), the turbidity removal was further increased by 54.28% and the DOC removal was somewhat similar to the standalone use of TiCl. TiO was prepared by incinerating the collected sludge at 600 °C for 2 h. Both XRD and SEM analysis were conducted to observe the morphology of the prepared titania. The XRD pattern of the TiO showed only an anatase phase along with the presence of a high atomic proportion of Ca (4.14%). Consequently, a high amount of Ca atoms inhibited the level of TiO phase and no obvious presence of CaO was observed. The prepared Ca-doped TiO at the optimised dose of Ca(OH) was found to be inferior to the undoped TiO during the photodegradation of acetaldehyde. However, a reduced dose of Ca(OH) (<15 mg Ca/L) exhibited a substantial increase in photoactivity under UV irradiance.
本研究聚焦于从絮凝生成的污泥中制备未掺杂和掺钙的二氧化钛。首先，使用 TiCl 进行合成废水中的混凝和絮凝，并通过评估处理水的浊度、溶解有机碳（DOC）和 ζ 电位来确定最佳投药量。随后，使用 Ca(OH)2 作为助凝剂，考察了其对出水 pH 值、浊度和 DOC 去除率的影响。通过对絮凝污泥进行处理，制备了掺钙和未掺钙锐钛矿型 TiO2，以进行形貌和光催化评估。在单独使用 TiCl 时，最大浊度和 DOC 去除率分别为 11.63 和 14.54 mg Ti/L。在相应的投药量下，快速的水去质子化作用使出水 pH 值降至 3.77 mg Ti/L 以下。而当使用 Ca(OH)2 作为助凝剂时，在同时投加 32.40 mg Ca/L 和 14.54 mg Ti/L 时，可达到中性 pH（7.26）。当与 Ca(OH)2 一起使用时，浊度去除率进一步提高了 54.28%，DOC 去除率与单独使用 TiCl 时相似。通过在 600°C 下煅烧收集的污泥 2 小时来制备 TiO2。进行 XRD 和 SEM 分析以观察制备的 TiO2 的形貌。TiO2 的 XRD 图谱仅显示锐钛矿相，同时存在高比例的 Ca（4.14%）。因此，大量的 Ca 原子抑制了 TiO2 相的水平，并且没有观察到明显的 CaO 存在。在优化的 Ca(OH)2 投加量下制备的掺钙 TiO2 在光降解乙醛时劣于未掺钙 TiO2。然而，在紫外光照射下，较低剂量的 Ca(OH)2（<15 mg Ca/L）显著提高了光活性。
