New Holistic Conceptual Framework for the Assessment of the Performance of Photocatalytic Pavement.

Despite serious health and environmental burdens associated with air pollution by NO, the emission ceilings have been systematically exceeded in big European cities for several years. Photocatalytic technology can be an efficient solution for the removal of chemical air pollutants. Because diesel engine exhaust is the main source of NO emissions, the application of a photocatalyst onto road pavement appears to be an effective NO abatement method due to the large surface area, proximity to the emission source, and relatively good solar irradiance.

A full-scale experimental study of sub-slab pressure fields induced by underground perforated pipes as a soil depressurisation technique in radon mitigation.

Sub-slab depressurisation systems have proven to effectively mitigate radon entry. A poor understanding of the fluid physics underlying the technique has been shown to lower the success rate substantially. This article describes a study of pressure fields in a sub-slab gravel bed induced by a soil depressurisation system consisting of perforated pipes run under the slab at a depth of 75 cm.

Photocatalytic Activity of Zn Mn O Oxides and ZnO Prepared From Spent Alkaline Batteries.

Oxides with Zn MnO stoichiometries and ZnO were synthesized from the "black mass" material recovered from spent alkaline batteries. The oxides were characterized by XRF, XRD with Rietveld refinement, SEM, and TEM methods. Optical characterization included diffuse reflectance (DRS) and photoluminescence (PL) measurements.

Assessment of urban air pollution related to potential nanoparticle emission from photocatalytic pavements.

The main objective was to evaluate whether wearing and weathering of nanofunctionalized photocatalytic pavement in real urban environment can lead to undesirable emission of potentially toxic nanoparticle aerosols in urban air. The photocatalytic material was thoroughly tested before its application for conformity criteria in terms of photocatalytic effectiveness, intrinsic performance and undesired secondary effects, and then applied on a pilot scale in downtown Madrid. The aerosol monitoring on the pilot street before the coating applications as well as on the neighbouring streets during 10 months was used as a benchmark for evaluation of spatial and temporal variations.

Environmental impact of nano-functionalized construction materials: leaching of titanium and nitrates from photocatalytic pavements under outdoor conditions.

There is a growing use of nano-functionalized construction materials, which contain nanoparticles embedded in their bulk or deposited on their surfaces. In the case of photocatalytic materials, nano-TiO is usually added to provide it's functionality. One concern about these materials, in addition to release of nanoparticles as airborne, is that they can be leached into the aquatic environment.

Characteristic limits of Th in alpha spectrometry with Th as tracer, calculated by simulating interfering tails and overlapping peaks.

This study explores the effect of Th tracer tail interference on the determination of the sensitivity of Th alpha spectrometry of samples with environmental levels of radioactivity. Tracer peak tail interference was calculated with Suma-Alpha, whilst Visual Basic for Applications (VBA in Excel©) software was used to study the variation in sensitivity in terms of the amount of tracer added. Unnecessary increases in the amount of tracer or extended sample measuring times were observed to have adverse effects on method sensitivity (Detection Limit- L).

NO removal efficiency of urban photocatalytic pavements at pilot scale.

Photocatalytic technology implemented in construction materials is a promising solution to contribute to alleviate air quality issues found in big cities. Photocatalysis has been proved able to mineralise most harmful contaminants. However, important problems associated with monitoring the efficiency of these solutions under real conditions still remain, including the lack of affordable analytical tools to measure NO concentrations with enough accuracy.

Self-Compacted Concrete with Self-Protection and Self-Sensing Functionality for Energy Infrastructures.

This paper aims to demonstrate the self-protection and self-sensing functionalities of self-compacted concrete (SCC) containing carbon nanotubes (CNT) and carbon microfibers (CMF) in a hybrid system. The ability for self-sensing at room temperature and that of self-protection after thermal fatigue cycles is evaluated. A binder containing a high volume of supplementary mineral additions (30%BFSand20%FA) and different type of aggregates (basalt, limestone, and clinker) are used.

A Multisensor System for the Characterization of the Field Pressure in Terrain. Accuracy, Response, and Adjustments.

In different disciplines of science, the knowledge of the resulting pressures in the subsoil can help to understand physical phenomena of mass exchange between the atmosphere and the terrain. The measurement of lower differential pressures is complicated given the low range of detected values. In this paper, a multisensor system has been designed and developed to measure differential pressures in radon gas transport studies.

In situ evaluation of the NO removal efficiency of photocatalytic pavements: statistical analysis of the relevance of exposure time and environmental variables.

In the recent past, the NO removal efficiency of photocatalytic materials has been subject of many studies with promising results. However, many of these studies involve laboratory tests carried out under standardized climatic exposure conditions, often not representative of the real-world environment. With the aim to bridge this gap, selected photocatalytic materials have been applied to different substrates in outdoor demonstrator platforms at pilot scale as part of the project LIFE-PHOTOSCALING.

Geolocation of premises subject to radon risk: Methodological proposal and case study in Madrid.

Useful information on the potential radon risk in existing buildings can be obtained by combining data from sources such as potential risk maps, the 'Sistema de Información sobre Ocupación del Suelo de España' (SIOSE) [information system on land occupancy in Spain], cadastral data on built property and population surveys. The present study proposes a method for identifying urban land, premises and individuals potentially subject to radon risk. The procedure draws from geographic information systems (GIS) pooled at the municipal scale and data on buildings possibly affected.

Investigation of gas flow through soils and granular fill materials for the optimisation of radon soil depressurisation systems.

The purpose of this study is to investigate gas flow through different types of granular fill materials and soil by means of a series of experimental laboratory tests, in relation to soil depressurisation systems for radon reduction under buildings and the soil surrounding the foundation. Gas permeability characterisation of materials used as granular fill material beneath the slab in buildings is a key parameter for the optimum performance of soil depressurisation systems to mitigate radon. A test apparatus was developed, adapted from previous studies, to measure the gas permeability of the samples and Finite Element Method numerical simulations were validated to simulate the flow behaviour through them.

Use of Genie 2000 and Excel VBA to correct for γ-ray interference in the determination of NORM building material activity concentrations.

The γ-radiation emitted by building materials is calculated from the activity indices for Th, Ra and K and expressed as the activity concentration index (ACI). Gamma spectroscopy is a non-destructive technique frequently used to simultaneously determine the indices for several radionuclides. Spectral interpretation poses a number of challenges, including identification of γ-lines subject to summing-in effects, interference from other γ-ray emitting radionuclides and the time required to reach secular equilibrium.

A finite element model development for simulation of the impact of slab thickness, joints, and membranes on indoor radon concentration.

The focus of this study is broadly to define the physics involved in radon generation and transport through the soil and other materials using different parameter-estimation tools from the literature. The effect of moisture in the soil and radon transport via water in the pore space was accounted for with the application of a porosity correction coefficient. A 2D finite element model is created, which reproduces the diffusion and advection mechanisms resulting from specified boundary conditions.

Selecting enhancing solutions for electrokinetic remediation of dredged sediments polluted with fuel.

In this paper a procedure for selecting the enhancing solutions in electrokinetic remediation experiments is proposed. For this purpose, dredged marine sediment was contaminated with fuel, and a total of 22 different experimental conditions were tested, analysing the influence of different enhancing solutions by using three commercial non-ionic surfactants, one bio-surfactant, one chelating agent, and one weak acid. Characterisation, microelectrophoretic and electrokinetic remediation trials were carried out.

Turning waste into valuable resource: potential of electric arc furnace dust as photocatalytic material.

This paper explores the potential of a hazardous waste of difficult management, electric arc furnace dust (EAFD), as photocatalytic material. Starting from a real waste coming from a Spanish steel factory, chemical, mineralogical, and optical characterizations have been carried out. Direct trials on EAFD and mortar containing this waste have been performed to evaluate its potential as photocatalyst itself and within a cementitious material.

Influence of the inlet air in efficiency of photocatalytic devices for mineralization of VOCs in air-conditioning installations.

Nowadays, a large proportion of photocatalytic oxidation (PCO) devices are being implemented in heating, ventilation and air-conditioning systems. However, no systematic studies have been carried out regarding the influence of inlet air preconditioning. To analyse the impact of the inlet air-conditions into photocatalytic efficiency, a simulated air-conditioning duct with flowing gas through inside was designed.

New methodology for assessing the environmental burden of cement mortars with partial replacement of coal bottom ash and fly ash.

This paper assess the mechanical an environmental behaviour of cement mortars manufactured with addition of fly ash (FA) and bottom ash (BA), as partial cement replacement (10%, 25% and 35%). The environmental behaviour was studied by leaching tests, which were performed under several temperature (23 °C and 60 °C) and pH (5 and 10) conditions, and ages (1, 2, 4 and 7 days). Then, the accumulated amount of the different constituents leached was analysed.

Controlling the levels of airborne pollen: can heterogeneous photocatalysis help?

Airborne pollen is a worldwide problem because is a very important allergenic agent; it can be altered only by certain microorganisms and by some oxidizers, such as reactive oxygen species (ROS). On the other hand, heterogeneous photocatalysis (HPC) arose as a promising technology for reducing the level of contaminants in the air, based on their degradation by the production of ROS. In this paper, study of the feasibility of HPC to diminish the counts of pollen is undertaken.

Recycling and recovery routes for incinerated sewage sludge ash (ISSA): a review.

The drivers for increasing incineration of sewage sludge and the characteristics of the resulting incinerated sewage sludge ash (ISSA) are reviewed. It is estimated that approximately 1.7 milliontonnes of ISSA are produced annually world-wide and is likely to increase in the future.

Study of the Microstructure Evolution of Low-pH Cements Based on Ordinary Portland Cement (OPC) by Mid- and Near-Infrared Spectroscopy, and Their Influence on Corrosion of Steel Reinforcement.

Low-pH cements are designed to be used in underground repositories for high level waste. When they are based on Ordinary Portland Cements (OPC), high mineral admixture contents must be used which significantly modify their microstructure properties and performance. This paper evaluates the microstructure evolution of low-pH cement pastes based on OPC plus silica fume and/or fly ashes, using Mid-Infrared and Near-Infrared spectroscopy to detect cement pastes mainly composed of high polymerized C-A-S-H gels with low C/S ratios.

An assessment of Mercury immobilisation in alkali activated fly ash (AAFA) cements.

This paper presents total and soluble Mercury contents for three coal fly ashes and alkali-activated fly ash (AAFA) cements consisting of 100% fly ash as starting material. To evaluate the potential of the AAFA cement matrix to immobilise Hg from an external source, another batch of cements, doped with 5000 mg/kg Hg as highly soluble HgCl(2), was prepared. The ashes and control AAFA cements complied with Mercury leaching criteria for non-hazardous wastes according to both TCLP and EN 12457 tests.

Evaluation of a lime-mediated sewage sludge stabilisation process. Product characterisation and technological validation for its use in the cement industry.

This paper describes an industrial process for stabilising sewage sludge (SS) with lime and evaluates the viability of the stabilised product, denominated Neutral, as a raw material for the cement industry. Lime not only stabilised the sludge, raised the temperature of the mix to 80-100°C, furthering water evaporation, portlandite formation and the partial oxidation of the organic matter present in the sludge. Process mass and energy balances were determined.

Experimental study of effectiveness of four radon mitigation solutions, based on underground depressurization, tested in prototype housing built in a high radon area in Spain.

The present paper discusses the results of an empirical study of four approaches to reducing indoor radon concentrations based on depressurization techniques in underground sumps. The experiments were conducted in prototype housing built in an area of Spain where the average radon concentration at a depth of 1 m is 250 kBq m(-3). Sump effectiveness was analysed in two locations: underneath the basement, which involved cutting openings into the foundation, ground storey and roof slabs, and outside the basement walls, which entailed digging a pit alongside the building exterior.

Effect of temperature on the durability of class C fly ash belite cement in simulated radioactive liquid waste: synergy of chloride and sulphate ions.

The durability of class C fly ash belite cement (FABC-2-W) in simulated radioactive liquid waste (SRLW) rich in a mixed sodium chloride and sulphate solution is presented here. The effect of the temperature and potential synergic effect of chloride and sulfate ions are discussed. This study has been carried out according to the Koch-Steinegger test, at the temperature of 20 degrees C and 40 degrees C during a period of 180 days.