The photocatalytic treatment of shower water in a pilot scale reactor: Experimentation and modelling

This research looks at the feasibility of photocatalytic treatment of real shower water in a pilot scale reactor (31 litres, 1 lamp). Experiments showed that 57% of total organic carbon (TOC) elimination was obtained after 6 hours treatment at optimised conditions. Further experiments were performed to determine the optical properties of the catalyst used (Aeroxide® P25 TiO2), which were then used to model the kinetics of TOC degradation in the case of single and multiple-lamps

Photocatalytic treatment of shower water using a pilot scale reactor

Treatment of shower water deserves special consideration for reuse not only because of its low pollutant loading but also because it is produced in large quantities. In this study, a pilot scale study of photocatalytic degradation of impurities in real shower water was performed in a 31 L volume reactor using titanium dioxide as the photocatalyst. The reactor was operated in a continuous slurry recirculation mode. Several operational parameters were studied including the slurry initial pH, catalyst concentration, air flow rate, and slurry recirculation rate. Up to 57 of total organic carbon (TOC) elimination was obtained after 6 hours of treatment (for 3.0 slurry initial pH, 0.07 gL -1 catalyst concentration, 1.8 Lmin -1 air flow rate, and 4.4 Lmin -1 slurry recirculation rate). This study showed that photocatalysis could be successfully transposed from bench scale to pilot scale. Furthermore, the ease of operation and the potential to use solar energy make photocatalysis an attractive prospect with respect to treatment of grey water. © 2012 Yash Boyjoo et al

Urban surface water pollution problems arising from misconnections

The impacts of misconnections on the organic and nutrient loadings to surface waters are assessed using specific household appliance data for two urban sub-catchments located in the London metropolitan region and the city of Swansea. Potential loadings of biochemical oxygen demand (BOD), soluble reactive phosphorus (PO4-P) and ammoniacal nitrogen (NH4-N) due to misconnections are calculated for three different scenarios based on the measured daily flows from specific appliances and either measured daily pollutant concentrations or average pollutant concentrations for relevant greywater and black water sources obtained from an extensive review of the literature. Downstream receiving water concentrations, together with the associated uncertainties, are predicted from derived misconnection discharge concentrations and compared to existing freshwater standards for comparable river types. Consideration of dilution ratios indicates that these would need to be of the order of 50–100:1 to maintain high water quality with respect to BOD and NH4-N following typical misconnection discharges but only poor quality for PO4-P is likely to be achievable. The main pollutant loading contributions to misconnections arise from toilets (NH4-N and BOD), kitchen sinks (BOD and PO4-P) washing machines (PO4-P and BOD) and, to a lesser extent, dishwashers (PO4-P). By completely eliminating toilet misconnections and ensuring misconnections from all other appliances do not exceed 2%, the potential pollution problems due to BOD and NH4-N discharges would be alleviated but this would not be the case for PO4-P. In the event of a treatment option being preferred to solve the misconnection problem, it is shown that for an area the size of metropolitan Greater London, a sewage treatment plant with a Population Equivalent value approaching 900,000would be required to efficiently remove BOD and NH4-N to safely dischargeable levels but such a plant is unlikely to have the capacity to deal satisfactorily with incoming PO4-P loads from misconnections

Gas storage

International audienceThe continuous increase of energy demands based on fossil fuels in the last years have lead to an increase of greenhouse gases (GHG) emission which strongly contribute to global warming. The main strategies to limit this phenomenon are related to the efficient capture of these gases and to the development of renewable energies sources with limited environmental impact. Particularly, carbon dioxide (CO2) and methane (CH4) are the main constituents of greenhouse gases while hydrogen (H2) is considered an alternative clean energy source to fossil fuels. Therefore, tremendous research to store these gases has been reported by several approaches and among them the physisorption on activated carbons (AC) have received significant attention. Their abundance, low cost and tunable porous structure and chemical functionalities with an existing wide range of precursors that includes bio-wastes make them ideal candidates for gas applications. This chapter presents the recent developments on CH4, CO2 and H2 storage by activated carbons with focus on biomass as precursor materials. An analysis of the main carbon properties affecting the AC's adsorption capacity (i.e. specific surface area, pore size and surface chemistry) is discussed in detail herein

Alginic acid-derived mesoporous carbon (Starbon®) as template and reducing agent for the hydrothermal synthesis of mesoporous LiMn2O4 grafted by carbonaceous species

An alginic acid-derived mesoporous carbonaceous material (Starbon® A300) was used as a sacrificial porous template providing both a reducing environment and anchoring sites for LMO precursors, KMnO4 and LiOH. After hydrothermal treatment at 180 °C for 24 h, the resulting nanocrystalline LMO particles (≈40 nm) spontaneously aggregated, generating a mesoporous structure with a relatively high mesopore volume (≈0.33 cm3 g-1) and large pore size (≈30 nm). Moreover, a small amount (≈0.6 wt%) of residual carbon was present in this mesoporous LMO. This carbon, which arises from carbonaceous species grafted at the surface of the LMO nanoparticles, was found to significantly enhance the rate capability of LMO by reducing the internal electronic resistance. Finally, a "green" LMO electrode formulated using this Starbon-derived LMO as an active material, Starbon® A800 as a conductive additive and sodium alginate as a binder was tested, showing promising electrochemical performance

Synthesis and applications of porous non-silica metal oxide submicrospheres

© 2016 Royal Society of Chemistry. Nowadays the development of submicroscale products of specific size and morphology that feature a high surface area to volume ratio, well-developed and accessible porosity for adsorbates and reactants, and are non-toxic, biocompatible, thermally stable and suitable as synergetic supports for precious metal catalysts is of great importance for many advanced applications. Complex porous non-silica metal oxide submicrospheres constitute an important class of materials that fulfill all these qualities and in addition, they are relatively easy to synthesize. This review presents a comprehensive appraisal of the methods used for the synthesis of a wide range of porous non-silica metal oxide particles of spherical morphology such as porous solid spheres, core-shell and yolk-shell particles as well as single-shell and multi-shell particles. In particular, hydrothermal and low temperature solution precipitation methods, which both include various structure developing strategies such as hard templating, soft templating, hydrolysis, or those taking advantage of Ostwald ripening and the Kirkendall effect, are reviewed. In addition, a critical assessment of the effects of different experimental parameters such as reaction time, reaction temperature, calcination, pH and the type of reactants and solvents on the structure of the final products is presented. Finally, the practical usefulness of complex porous non-silica metal oxide submicrospheres in sensing, catalysis, biomedical, environmental and energy-related applications is presented

Recent advances in hydrothermal carbonisation:from tailored carbon materials and biochemicals to applications and bioenergy

Introduced in the literature in 1913 by Bergius, who at the time was studying biomass coalification, hydrothermal carbonisation, as many other technologies based on renewables, was forgotten during the "industrial revolution". It was rediscovered back in 2005, on the one hand, to follow the trend set by Bergius of biomass to coal conversion for decentralised energy generation, and on the other hand as a novel green method to prepare advanced carbon materials and chemicals from biomass in water, at mild temperature, for energy storage and conversion and environmental protection. In this review, we will present an overview on the latest trends in hydrothermal carbonisation including biomass to bioenergy conversion, upgrading of hydrothermal carbons to fuels over heterogeneous catalysts, advanced carbon materials and their applications in batteries, electrocatalysis and heterogeneous catalysis and finally an analysis of the chemicals in the liquid phase as well as a new family of fluorescent nanomaterials formed at the interface between the liquid and solid phases, known as hydrothermal carbon nanodots

Synthesis of Micro and Nano-Sized Calcium Carbonate Particles and Their Applications

Calcium carbonate nano and micro-particles have a large number of industrial applications due to their beneficial properties such as high porosity, high surface area to volume ratio, non-toxicity and biocompatibility towards bodily fluids. Consequently, there has been significant research to deliver easy ways of synthesising nano and micro-sized calcium carbonate particles at specific sizes, polymorphs and morphologies. A majority of their synthesis approaches are based on either the biomimetic or the CO2 bubbling methods. This review paper describes these methods, and the effects of experimental parameters such as additive types and concentration, pH, temperature, [Ca2+] : [CO32] ratio, solvent ratio, mixing mode and agitation time on the properties of the particles produced. The current and potential uses of calcium carbonate particles in areas such as material filling, biomedical, environmental and the food industry have also been discussed