Light-driven generation of H2O2 only from water and molecular oxygen could be an ideal pathway for clean production of solar fuels. In this work, a mixed metal oxide/graphitic-C3N4 (MMO@C3N4) composite was synthesized as a dual-functional photocatalyst for both water oxidation and oxygen reduction to generate H2O2. The MMO was derived from a NiFe-layered double hydroxide (LDH) precursor for obtaining a high dispersion of metal oxides on the surface of the C3N4 matrix. The C3N4 is in the graphitic phase and the main crystalline phase in MMO is cubic NiO. The XPS analyses revealed the doping of Fe3+ in the dominant NiO phase and the existence of surface defects in the C3N4 matrix. The formation and decomposition kinetics of H2O2 on the MMO@C3N4 and the control samples, including bare MMO, C3N4 matrix, Ni- or Fe-loaded C3N4 and a simple mixture of MMO and C3N4, were investigated. The MMO@C3N4 composite produced 63 μmol L−1 of H2O2 in 90 min in acidic solution (pH 3) and exhibited a significantly higher rate of production for H2O2 relative to the control samples. The positive shift of the valence band in the composite and the enhanced water oxidation catalysis by incorporating the MMO improved the light-induced hole collection relative to the bare C3N4 and resulted in the enhanced H2O2 formation. The positively shifted conduction band in the composite also improved the selectivity of the two-electron reduction of molecular oxygen to H2O2.
Glyphosate and AMPA in drinking water
Carcinogenic or not? The broad-spectrum herbicide glyphosate is used all over the world in agriculture. Alongside farming, the chemical is also used for weed-killing in domestic gardens and in public and private spaces kept free from «vegetal invasion», such as railway tracks. Glyphosate has been used since the 1970s in pesticides and was hitherto thought to be harmless at typical levels of exposure. However, since the International Agency for Research on Cancer (IARC) – the specialized cancer-re...
Application of Fenton oxidation to reduce the toxicity of mixed parabens
The aims of the present work were to assess the application of a chemical process to degrade a mixture of parabens and determine the influence of a natural river water matrix on toxicity. Model effluents containing either a single compound, namely methylparaben, ethylparaben, propylparaben, butylparaben, benzylparaben or p-hydroxybenzoic acid, or to mimic realistic conditions a mixture of the six compounds was used. Fenton process was applied to reduce the organic charge and toxic properties of the model effluents....
Hand-Mix Case Study: SMR Soil Stabiliser Experience in Devon
Success in the Use of Recycled Aggregate Despite being the Highway Authority with the largest U.K. network, (some 12900 km) and having reputedly one of the strictest Street Works regimes in England; Devon County Council have been very receptive to the correct use ofSMR Soil Stabiliserby Utility Companies since its introduction in late 1999. Initial trials were carried out by John Kennedy (Civil Eng) Ltd, (now Balfour Beatty Utility Solutions Ltd) on behalf of South West Water and under strict monitoring by...
Binary vs. Quaternary Pumps: High Pressure Mixing vs. Low Pressure Mixing
Welcome to the next installment in my series on binary vs. quaternary pumps for liquid chromatography! In myprevious post, I discussed how gradients are created as well as the importance of having accuracy and precision in your gradient. Today I am going to talk about what happens after all that — specifically, mixing. After chromatographic instrument’s pump or the proportioning valve delivers a gradient, the system then needs to mix the solvents to ensure that a homogenous solution gets delivered...
Mixing at double-Tee junctions with unequal pipe sizes in water distribution systems
Pipe flow mixing with various solute concentrations and flow rates at pipe junctions is investigated. The degree of mixing affects contaminant spread in a water distribution system, and many studies have focused on mixing at the cross junctions; however, only a few have focused on double-Tee junctions of unequal pipe diameters. To investigate the solute mixing at such junctions, a series of experiments was conducted in a turbulent regime (Re = 12,500–50,000) with different Reynolds number ratios and connecting...