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

摘要

To decrease ratio of the organic compounds in permeate water during micro-polluted surface waterultrafiltration process, UV/TiO2 photocatalytic oxidation was employed as ceramic membraneultrafiltration (CMU) pretreatment by elevation of the level of effluent quality. Initially, the catalyticactivity between new and recycled TiO2 was estimated by the degradation of CODMn. The dataillustrate that the photocatalytic efficiency exhibits no crucial distinction of activity between unusedand used titanium dioxide after decomposition. Secondarily, the decomposition of organic matter wasexplored through UV/TiO2-CMU cycling test. The results illuminate that the concentration of CODMnduring the UV/TiO2-CMU coupling technology is higher than the CMU technique. Conversely, the proportionof UV254 in the yield of UV/TiO2-CMU is lower than CMU. This phenomenon is ascribed to the lowmolecular weight organic matter, which is formed from macromolecule organic matter under incompletephotocatalytic dissociation. This micromolecule substance can easily penetrate membrane poresincurring the rising of CODMn in UV/TiO2-CMU hybrid system. Concurrently, this intermediate product isinsensitive to ultraviolet light, diminishing the content of UV254. Subsequently, parameters such as thereflux ratio, concentration of TiO2, aeration rate, transmembrane pressure, and crossflow velocity thataffected 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 theresponse value. Optimal outcomes are attained at a reflux ratio of 85%, 0.5 g/L additional TiO2, anaeration rate of 5 L/min, a transmembrane pressure of 0.05 MPa, and a crossflow velocity of 1.0 m/s.