Photocatalytic processes are being studied extensively as potential advanced wastewater treatments for the removal of pharmaceuticals, pesticides and other recalcitrant micropollutants from the effluents of conventional wastewater treatment plants (WWTPs). Oxytetracycline (OTC) is a widespread antibiotic which is frequently detected in surface water bodies as a recalcitrant and persistent micropollutant. This review provides an update on advances in heterogeneous photocatalysis for the degradation of OTC in water under UV light, sunlight and visible-light irradiation. Photocatalysts based on pure semiconducting oxides are rarely used, due to the problem of rapid recombination of electron–hole pairs. To overcome this issue, a good strategy could be the coupling of two different semiconducting compounds with different conduction and valence bands. Several methods are described to enhance the performances of catalysts, such as doping of the oxide with metal and/or non-metal elements, surface functionalization, composites and nano-heterojunction. Furthermore, a discussion on non-oxidic photocatalysts is briefly provided, focusing on the application of graphene-based nanocomposites for the effective treatment of OTC.

Cement based materials have a very special presence amongst building and construction materials, and therefore their recycling is of capital importance. In this research, concrete wastes were used as replacement of natural aggregates in cement and cement-lime mortars. The mortars were cured for 28-days with an increasing substitution of fine natural aggregates with recycled aggregates and have been prepared as well as characterized. The results show that, as expected, cement mortars always have better mechanical properties than the corresponding cement-lime mortars. A worsening of mechanical properties is observed upon increasing the amount of recycled aggregates in the cement mortars; on the contrary, cement-lime mortars show an improvement in mechanical properties of up to 60% when increasing the amount of recycled aggregates. The experimental results suggest that this improvement could arise from a synergic effect of lime hydraulicity and the filler effect due to the fine fraction of recycled aggregates within the mix, that lead to better densification of the lime mortars by blocking the capillary pores