Preparation of High-Porosity B-TiO2/C3N4 Composite Materials: Adsorption-Degradation Capacity and Photo-Regeneration Properties

Influencing Factors and Kinetics of Modified Shell Powder/La-Fe-TiO2 Photocatalytic Degradation of Pyridine Wastewater

Modified Shell Powder/La-Fe-TiO₂ (La-Fe-TiO₂@MSP) composites were fabricated using the sol-gel method and characterized by SEM, XRD, UV-vis DRS and photocurrent techniques, and their physicochemical and optical properties were analyzed. The effects of various factors on the photocatalytic degradation of pyridine and its reaction kinetics were investigated by batch experiments using pyridine, a typical nitrogen-containing heterocyclic compound in coal chemical wastewater, as the target removal species. The pyridine degradation rate of 80.23% was obtained for 800 mg/L composite solution by photocatalytic oxidation of 50 mg/L pyridine wastewater for 180 min at 35 °C, pH = 8 and light intensity of 560 W. The photocatalytic degradation performance was optimal. The quenching experiments determined that the active species of photodegradation were mainly hole and hydroxyl radicals, and the photocatalytic degradation mechanism was analyzed in this way.

Making Pb Adsorption-Saturated Attapulgite with Excellent Photocatalysis Properties through a Vulcanization Reaction and Its Application for MB Wastewater Degradation

Attapulgite (AT) is a clay mineral with rich reserves in China, and it has good adsorption activity for Pb-containing wastewater. However, as a hazardous waste, the treatment of Pb adsorption-saturated attapulgite was quite difficult. In this work, through a simple vulcanization reaction, the waste Pb adsorption-saturated attapulgite (AT@Pb) was transformed into composite materials (AT@PbS) with good photocatalytic performance. After comprehensive material characterization (including XRD, TEM, XPS, and UV-Vis), the photocatalytic degradation performance and mechanism of AT@PbS for methylene blue (MB) were investigated. The results revealed that AT@PbS was a composite material of attapulgite nanorods (500-600 nm) and nanosquare PbS particles (80-100 nm). Additionally, AT@PbS displayed good visible light absorption, improved photo-electric properties, excellent photodegradation performance for MB, and recycling stability. Moreover, the energy band range of AT@PbS was about -0.043 V to 1.367 V. The photo-generated holes and their derived hydroxyl radicals were the main active species for MB degradation. This work not only provides a new approach to construct the composite photocatalyst, but also demonstrates the possibility of the comprehensive utilization of heavy metal adsorbents for wastewater degradation.