Mattia Pierpaoli

Influence of Binders and Lightweight Aggregates on the Properties of Cementitious Mortars: From Traditional Requirements to Indoor Air Quality Improvement

Innovative and multifunctional mortars for renders and panels were manufactured using white photocatalytic and non-photocatalytic cement as binder. Unconventional aggregates, based on lightweight materials with high specific surface and adsorbent properties, were adopted in order to investigate the possible ability to passively improve indoor air quality. The reference mortar was manufactured with traditional calcareous sand. Results show that even if the mechanical properties of mortars with unconventional aggregates generally decrease, they remain acceptable for application as render. The innovative mortars were able to passively improve indoor air quality in terms of transpirability (70% higher), moisture buffering ability (65% higher) and depolluting capacity (up to 75% higher) compared to traditional ones under the current test conditions.

Appraisal of a hybrid air cleaning process

Nowadays, there is an amplified interest in maintaining suitable indoor air quality (IAQ). Besides a wide range of available interventions, air cleaners are considered a valuable tool, since based on inexpensive and easily implementing technologies to improve IAQ. The purpose of this work is to combine the TiO2-photocatalysis with the electrostatic and adsorption processes, in order to improve efficiency and reliability. A TiO2-photocatalytic oxidation combined with an electrostatic filter has been studied. Nitrogen oxides reduction and degradation of many VOC over different catalyst support were monitored jointly with CO and CO2 production. The coupling of photocatalysis with an external electric field enhances efficiency of the process. The choice of materials with diversified adsorptive characteristics plays an important role in the durability of the process over time.

Fate and significance of phthalates and bisphenol A in liquid by-products generated during municipal solid waste mechanical-biological pre-treatment and disposal

Samples of liquid by-products generated by municipal solid waste plants (MSWPs) were tested for the presence of phthalates (PAEs) and bisphenol A (BPA). The results indicated that the wastewater generated during mechanical (sorting unit - SU) and biological (composting unit - CU) pre-treatment (MBT) of residual (mixed) solid waste is a significant source of these compounds. The concentrations of PAEs (up to 32222μg/L) and BPA (up to 1795μg/L) in the SU and CU wastewaters were generally higher than those in landfill leachates tested in this and other studies. To date, MBT wastewaters have been poorly studied and are usually overlooked. However, in this study, despite their relatively small quantities, they constituted an important load of ammonia (up to 1610mg/L) and organic matter (COD up to 52980mg/L). Thus, to apply an effective treatment, it is critical to monitor the current quality and quantity of all liquid by-products generated at MSWPs and to prioritize the (micro)pollutants of concern.

A Novel Method for the Combined Photocatalytic Activity Determination and Bandgap Estimation

The ability of a photocatalyst to degrade a target pollutant is a commonly used method to assess its effectiveness for environmental applications, while ultraviolet-visible (UV-vis) spectroscopy and spectroscopic ellipsometry are conventional techniques for the estimation of a semiconductor band gap. In this work, an array of six light-emitting diodes (LEDs), characterized by different emission peaks between 470–370 nm and absorbed power of 3 W, was implemented into an existing standard testing apparatus for the testing of nitrogen oxides degradation in air. The abatement indexes, obtained under different LEDs irradiation, were firstly compared to the ones determined according the standard and, secondly, correlated with the measured LED emission spectrum, in order to estimate the photocatalyst band gap. Results suggest that this expeditious technique can be easily implemented into existing testing apparatus for the estimation of the band gap and for the appraisal of photocatalytic materials under realistic conditions.

Non-Destructive Testing for the In Situ Assessment of the Ionic Flux in Cementitious Materials

The study deals with the design, calibration and testing of a diffusive sampling probe for in situ assessment of ion mobility in binder-based matrix. In parallel, leaching texts were conducted to compare the ions release obtained under equilibrium condition with the dynamic flux induced by the diffusive sampling probe. The probe contains an ionic exchange resin that acts as sink, causing a re-supply of ions from the solid to the solution phase, and inducing diffusion fluxes from the mortar through a thin diffusion chamber. The flux depends on the quantity of mobile ions in the solid phase and on the exchanging rate from solid phase to solution. By means of the in situ sampling with this diffusive probe, information about the interaction of materials with the environment can be obtained. This information is very useful for the environmental impact assessment of the material and its durability.