Rapid reduction of real-time industry effluent using novel CuO/MIL composite

In this study, a series of novel metal organic framework based composite materials was synthesized using a facile combustion synthesis method. The synthesized materials were characterized using standard analytical techniques for crystallite size, surface functional groups, surface area, porosity, optical properties, and particle size. The increase in the amount of CuO in the composite material resulted decrease in surface area and pore volume. The band-gap energy of the synthesized composites reduced with increase in the amount of CuO. Among the composite, 0.9 CuO:0.1 MIL displayed least emission intensity indicating lower electron-hole recombination and thereby superior charge separation of the material. The increase in the amount of CuO NPs in the composite resulted in increase in the average particle size and decrease in the zeta potential. As an application, the NaBH₄-mediated reduction of Methyl orange dye was studied using the synthesized materials. The increased amount of CuO in the composite resulted in the higher activity of the material. Highest activity was observed with the composite containing 9:1 ratio of CuO and MIL, and this material was further used to investigate the reduction of methylene blue, Rhodamine B, 4-nitrophenol, 2-nitrophenol, and 2, 4-dichlorophenol. The material exhibited excellent activity for all the selected organic pollutants. Finally, the composite containing 9:1 ratio of CuO and MIL was employed for the reduction of a real-time industry effluent and the observed results were encouraging. The reusability aspect of the synthesized material was investigated. Based on the LC-MS analysis, a possible reduction mechanism is proposed.

Bi2S3@NH2-UiO-66-S composites modulated by covalent interfacial reactions boost photodegradation and the oxidative coupling of primary amines

The Bi₂S₃@NH₂-UiO-66-S heterostructures have been synthesized via covalent interfacial reactions, exhibiting excellent performance in the photodegradation of methylene and the oxidative coupling of primary amines compared to reported photocatalysts.

Adsorption of Sudan-IV contained in oily wastewater on lipophilic activated carbons: kinetic and isotherm modelling

Up to nine kinetic and fourteen isotherm adsorption models are employed to model the adsorption of Sudan IV, a lipophilic model pollutant present in a biphasic mixture of cyclohexane-water system to simulate oily wastewater. Six different modified activated carbons were used as adsorbents. The highest amount adsorbed of Sudan IV was found in the material prepared by successive treatments of the parent commercial activated carbon Norit ROX 0.8 with nitric acid and urea, followed by thermal treatment at 800 °C under continuous flow of nitrogen. Kinetic and isotherm adsorption models can be employed to simulate the process, since the effect of the presence of water in the adsorption of Sudan IV from the cyclohexane phase was found to be negligible, owing to the high lipophilic character of both adsorbent and adsorbate. All kinetic and isotherm coefficients, coupling with statistical parameters (r², adjusted r² and sum of squared errors), are determined by non-linear regression fitting and compared to literature data. The model of Avrami is found to be the most appropriate model to represent the adsorption of the pollutant in any of the six modified carbons tested, the highest value of the kinetic constant being 0.055 min^-1. The isotherm adsorption is well-modelled by using the general isotherm equation of Tóth and the multilayer Jovanović expression for the adsorption of Sudan-IV on that material, resulting in a high monolayer uptake capacity (q_m = 193.6 mg g^-1).

Integration of nanosized ZIF-8 particles onto mesoporous TiO2 nanobeads for enhanced photocatalytic activity

Hybrid TiO₂/ZIF-8 nanobeads have been prepared by decorating the surface of mesoporous TiO₂ spheres with ZIF-8 nanoparticles and enhanced photocatalytic activity of Cr(vi) reduction than pristine TiO₂ beads due to their hybrid nanostructures.