Tianyu Chai

Synthesis of hollow lantern-like Eu(III)-doped g-C 3 N 4 with enhanced visible light photocatalytic perfomance for organic degradation

A series of hollow structure lantern-like Eu(III)-doped g-C3N4 (xEu-CN, x = 1, 2, 3) was firstly synthesized by heating a mixture of melamine, HNO3 and Eu2O3 at 500 °C for 2 h. The phase, morphology and optical properties of the serial xEu-CN samples were characterized by different techniques, including TEM, XRD, FT-IR, SEM, XPS, BET, UV-vis, PL, photocurrent, and EIS. The results indicated that Eu doping extraordinarily enhanced the photocatalytic activity of pure g-C3N4, and the 2Eu-CN exhibited the highest photocatalytic performance with a 98% (82%) degradation rate for RhB (TC), 6.03 (1.71)-fold of pure g-C3N4(CN). The higher photocatalytic efficiency is ascribed to the synergy effect of Eu(III) and the hollow structures, which led to a larger surface specific area, bandgap narrowing, enhanced light harvesting ability and efficient charge separation.

Use of anaerobic hydrolysis pretreatment to enhance ultrasonic disintegration of excess sludge

To improve the excess sludge disintegration efficiency, reduce the sludge disintegration cost, and increase sludge biodegradability, a combined pretreatment of anaerobic hydrolysis (AH) and ultrasonic treatment (UT) was proposed for excess sludge. Results showed that AH had an advantage in dissolving flocs, modifying sludge characteristics, and reducing the difficulty of sludge disintegration, whereas UT was advantageous in damaging cell walls, releasing intracellular substances, and decomposing macromolecular material. The combined AH-UT process was an efficient method for excess sludge pretreatment. The optimized solution involved AH for 3 days, followed by UT for 10 min. After treatment, chemical oxygen demand, protein, and peptidoglycan concentrations reached 3,949.5 mg O2/L, 752.5 mg/L and 619.1 mg/L, respectively. This work has great significance for further engineering applications, namely, reducing energy consumption, increasing the sludge disintegration rate, and improving the biochemical properties of sludge.

Filtration performance comparison of a metal membrane and an organic membrane in bioreactor

AbstractA metal membrane and a polyethersulfone (PES) membrane were compared in this study. The surface morphology, inherent resistance, and critical flux of the membranes were first investigated. The two membranes were then placed in an activated sludge reactor to treat municipal sewage. The two membranes showed similar removal efficiencies of chemical oxygen demand (COD), ammonia, and total nitrogen (TN). The average effluent COD removal efficiencies, effluent ammonia, and effluent TN removal efficiencies were approximately 94.00%, 0.19 mg/L, and 28.22%, respectively. The metal membrane showed lower inherent membrane resistance of 0.27 × 1011 m−1, higher critical flux of 0.7 m3/(m2 d), higher anti-fouling ability, and slower transmembrane pressure increasing rate compared with the PES membrane. The main fouling mechanism of the metal membrane was cake formation, whereas that of the PES membrane was pore blocking. The metal membrane was easy to recover after fouling. The results of the study suggest that...