Sonophotocatalytic mineralization of Norflurazon in aqueous environment

Norflurazon (4-chloro-5-(methylamino)-2-[3- trifluoromethyl)phenyl]pyridazin-3(2H)-one; C12H9ClF3N3O) is an excellent weed controlling agent being practiced in the agricultural lands. The excessive addition or the undissolved Norflurazon (maximum solubility 28 mg/L at 25 C) enters into the aquatic environment and causes the adverse effects associated with its high concentration. To avoid the perilous effects, visible light assisted photocatalysis set-up coupled with the 42 kHz ultrasound producing bath type sonicator is used to completely mineralize the Norflurazon. TiO2, ZnO and gold loaded zinc oxide nanocatalysts were utilized to study the mineralization of Norflurazon. AueZnO shows the greater efficiency for the sonophotocatalytic removal of Norflurazon among the various nanocatalysts employed to study the mineralization. The order of Norflurazon mineralization was sonophotocatalysis > sonocatalysis > photocatalysis. The additive effect was achieved for the sonophotocatalytic degradation. The high performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometric (LCMS) analyses were employed to identify the various intermediates produced during the mineralization. The identification of four pseudo molecular ions and various intermediates using the LCMS analysis evidently suggests the sonophotocatalytic degradation was preceded in various decay pathways. A suitable mechanism has been proposed for the sonophotocatalytic mineralization of Norflurazo

Recent Advances in Hydrogen Production Using MXenes-based Metal Sulfide Photocatalysts

At present, the composition and crystalline structure of transition metal nitrides or carbides (MXenes) and their derivatives are continuously expanding due to their unique physicochemical properties, especially in the photocatalytic field. Advances over the past four years have led to improved preparation of new MAX phases, resulting in new MXenes with excellent photo-thermal effect, considerable specific surface area, long-term stability and optimum activity. Since MXenes have good electrical conductivity and their bandgap is adjustable under the visible light range, this group is one of the best promising candidates for hydrogen production from photo-splitting of water as an environment-friendly method of converting sunlight to chemical energy. Progress in noble metal-free photocatalyst associated with more understanding of the fundamental mechanism of photocatalysis has enabled a proper choice of cocatalyst with better efficiency. In this study, the photocatalytic production of hydrogen through MXens as a support and co-catalyst on metal sulfide is summarized and discussed. Recent advances in the design and synthesis of MXenes-based metal sulfide nanocomposites to increase the efficiency of photocatalytic hydrogen production are then highlighted. Finally, the challenges and future prospects for the development of MXenes-based metal sulfide composites are outlined

Ultra-small Ni@NiFe2O4/TiO2 magnetic nanocomposites activated peroxymonosulphate for solar light-driven photocatalytic mineralization of Simazine

In the heterogeneous photocatalytic degradation of environmental contaminants the recovery, reuse of employed nanocatalyst was crucial and it is essentially required for the scale up applications. Besides, designing a magnetic material with heterojunction that can effectively oxidize the toxic organic contaminants to non-toxic substance under different reaction conditions including direct solar light irradiation remains a challenge. Considering the above facts, herein, we tailored heterojunction between the magnetic materials and non-magnetic materials with ultra-small Ni nanoparticles modified NiFe2O4/TiO2 nanostructures (Ni@NiFe2O4/TiO2 magnetic nanocomposites) through a simple sonochemical route. The Raman phonons at ∼ 540 cm−1 consistent to nickel metal nanoparticles and the spinel ferrites crystal structure confirmed the formation of Ni@NiFe2O4/TiO2 magnetic nanocomposites. The reduced optical bandgap of the resulting nanocomposites indicated the effective absorption of direct solar light irradiation when compared to the bare TiO2. Thus in-turn, enhanced the photocatalytic efficiency of simazine degradation in the presence of Ni@NiFe2O4/TiO2 magnetic nanocomposites (k´= 11.0 × 10–4 s−1) and augmented the activation of peroxymonosulphate (PMS) in the presence of Ni@NiFe2O4/TiO2 magnetic nanocomposites (k´= 32.5 × 10–4 s−1). Ni@NiFe2O4/TiO2 +PMS exhibited 3 folds enhanced efficiency in the presence of sunlight. The as-prepared NiFe2O4/TiO2 magnetic nanocatalysts were more stable and the efficiency of simazine oxidation was approximately same for the continuous five cycles at the optimized experimental conditions. The Ni@NiFe2O4/TiO2 magnetic nanocomposites preparation and the activation of PMS may promise the applications in an efficient wastewater treatment