Enhanced Effluent Quality of Ceramic Membrane Ultrafiltration Combined with UV/TiO2 Photocatalysis

• Published in: Nature environment and pollution technology 2017-09, Vol.16 (3), p.695
• Main Authors: Zhen, Zhou, Jilun, Yao, Xing, Zhang, Zhaoxia, Ding, Meimei, Zuo
• Format: Article
• Language: English
• Subjects: Aeration; Catalysis; Catalytic activity; Chemical industry; Coupling (molecular); Decomposition; Effluents; Engineering; Environmental engineering; Environmental science; Hybrid systems; Light; Membrane separation; Molecular weight; Organic compounds; Organic matter; Oxidation; Photocatalysis; Photooxidation; Pollutants; Pressure; Pretreatment; Surface water; Titanium; Titanium dioxide; Ultrafiltration; Ultraviolet radiation; Velocity; Water pollution; Water quality; Water treatment
• ISSN: 0972-6268; 2395-3454

To decrease ratio of the organic compounds in permeate water during micro-polluted surface water ultrafiltration process, UV/TiO2 photocatalytic oxidation was employed as ceramic membrane ultrafiltration (CMU) pretreatment by elevation of the level of effluent quality. Initially, the catalytic activity between new and recycled TiO2 was estimated by the degradation of CODMn. The data illustrate that the photocatalytic efficiency exhibits no crucial distinction of activity between unused and used titanium dioxide after decomposition. Secondarily, the decomposition of organic matter was explored through UV/TiO2-CMU cycling test. The results illuminate that the concentration of CODMn during the UV/TiO2-CMU coupling technology is higher than the CMU technique. Conversely, the proportion of UV254 in the yield of UV/TiO2-CMU is lower than CMU. This phenomenon is ascribed to the low molecular weight organic matter, which is formed from macromolecule organic matter under incomplete photocatalytic dissociation. This micromolecule substance can easily penetrate membrane pores incurring the rising of CODMn in UV/TiO2-CMU hybrid system. Concurrently, this intermediate product is insensitive to ultraviolet light, diminishing the content of UV254. Subsequently, parameters such as the reflux ratio, concentration of TiO2, aeration rate, transmembrane pressure, and crossflow velocity that affected water quality in the hybrid process were investigated by single-factor experiments. Meanwhile, the main variables were optimized by orthogonal methodology using the removal of CODMn as the response value. Optimal outcomes are attained at a reflux ratio of 85%, 0.5 g/L additional TiO2, an aeration rate of 5 L/min, a transmembrane pressure of 0.05 MPa, and a crossflow velocity of 1.0 m/s.