TiO2 is a semiconductor material with high chemical stability and low toxicity. It is widely used in the fields of catalysis, sensing, hydrogen production, optics and optoelectronics. However, TiO2 photocatalyst is sensitive to ultraviolet (UV) light; this is why its photocatalytic activity and quantum efficiency are reduced. To enhance the photocatalytic efficiency in the visible light range as well as to increase the number of the active sites on the crystal surface or inhibit the recombination rate of photogenerated electron–hole pairs electrons, various metal ions were used to modify TiO2. This review paper comprehensively summarizes the latest progress on the modification of TiO2 photocatalyst by a variety of metal ions. Lastly, the future prospects of the modification of TiO2 as a photocatalyst are proposed.

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In this work, polyvinylidene fluoride-boron carbide mixed matrix membranes were synthesized via phase inversion method. The synthesized membranes were characterized using field emission scanning electron microscopy, X-ray diffraction spectroscopy, energy dispersive spectroscopy, porosity, and contact angle. The mixed matrix membranes (0-5 wt.% of boron carbide) were tested for ultrafiltration of bovine serum albumin solution and photodegradation property using rhodamine B and methylene blue dyes. The morphological images reveal the existence of boron carbide particles on the surface of the membranes. Upon introduction of B 4 C particles, the performance of the membranes was improved: permeate flux increases from 163.13 to 351.15 L/m 2 h; bovine serum albumin rejection increased from 77.1% to 99.1%; relative flux reduction decreased from 45.58% to 16.06%; flux recovery ratio increased from 61.71% to 98.42%. Furthermore, maximum photodegradation yield was observed for membranes with 4 wt.% boron carbide particles with degradation efficiency of 96.7% and 96% for rhodamine B and methylene blue dyes, respectively. Furthermore, the rate constant of the optimum membrane was higher than the pristine membrane (about 2.05 and 2.26 times higher for rhodamine B and methylene blue dyes, respectively). Indeed, the mixed matrix membranes present a great prospect for the photodegradation of organic dyes.

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