ZnO Zeolite Nanocomposite for Photocatalytic Elimination of Benzophenone and Caffeine

Novel visible-light-active P-g-CN-based α-Bi2O3/WO3 ternary photocatalysts with a dual Z-scheme heterostructure for the efficient decomposition of refractory ultraviolet filters and environmental hormones: Benzophenones

The ubiquitous and refractory benzophenone (BP)-type ultraviolet filters, which are also endocrine disruptors, were commonly detected in the aquatic matrix and could not be efficiently removed by conventional wastewater treatment processes, thus causing extensive concern. Herein, a novel ternary nanocomposite, P-g-CN/α-Bi2O3/WO3 (P-gBW), was successfully fabricated by mixing cocalcinated components and applied to the decomposition of BP-type ultraviolet filters. The dual-Z-scheme heterostructure of P-gBW enhances visible-light absorption, efficiently facilitates separation and mobility, and prolongs the lifetime of photoinduced charge carriers via double charge transfer mechanisms. The optimum 95 wt% P-gBW exhibited excellent photocatalytic activity, degrading 96% 4-hydroxy benzophenone (4HBP) within 150 min and 93% 2,2',4,4'-tetrahydroxybenzophenone (BP-2) within 100 min under visible-light illumination, respectively. The pseudo-first-order rate constant of 4HBP (1.15 h-1) was 6.8-, 3.1-, 3.3- and 2.2-fold higher than those of WO3, P-g-CN, α-Bi2O3, and P-g-CN/α-Bi2O3, respectively, while that of BP-2 (1.71 h-1) was 5.2-, 2.2-, 3.2- and 1.5-fold higher, respectively. The improved photocatalytic degradation was attributed to efficient photoinduced charge carrier separation and migration and prevented the recombination of electron holes, as verified by photoluminescence, transient photocurrent response, and electrochemical impedance spectroscopy. Trapping experiments, electron paramagnetic resonance, and band energy position indicated an efficient dual-Z-scheme heterostructure.

Response Surface Methodology (RSM) modelling for the photocatalytic optimization study of benzophenone removal using CuWO4/NiO nanocomposite

Emerging contaminants are posing a new water quality challenge, worldwide. The majority of pharmaceutical and personal care products used by us have been regarded as emerging contaminants. Benzophenone is one such chemical found in personal care products, specially in sunscreen creams as an UV-filter. Copper tungstate/nickel oxide (CuWO4/NiO) nanocomposite with visible (LED) light irradiation has been investigated in degradation of benzophenone, in the present study. The co-precipitation approach was used to produce the aforementioned nanocomposite. XRD, FTIR, FESEM, EDX, Zeta potential, and UV-Vis spectroscopy illustrated the structure, morphology, and other catalytic features. Response surface methodology (RSM) was used to optimize and simulate the photodegradation of benzophenone. Herein, catalyst dose, pH, initial pollutant concentration, and contact time were considered as the independent factor in the design of experiment (DoE) using RSM with percentage degradation as the dependent factor or as a response. The CuWO4/NiO nanocomposite demonstrated high photocatalytic performance of 91.93% at pH = 11 with a pollutant concentration of 0.5 mg/L and a catalyst dose of 5 mg within 8 h under ideal circumstances. The RSM model was determined to be the most convincible with an R2 value of 0.99 and a probability value (P-value) of 0.0033, respectively, with a agreeable projected and actual values. As a result, it is envisioned that this study may provide new avenue for developing a strategy to target such emerging contaminants.