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ZnO thin film were deposited by Spray and Spray Pyrolysis methods on glass substrates at 370 °C. The structural characterization by XRD, Raman spectroscopy, FTIR, EDS, TEM, SEM, RPE and XPS revealed the purity of ZnO Wurtzite variety in both samples. The use of a new loop reactor configuration for the photocatalytic activity was evaluated against/with respect to the degradation of two textile dyes as well as their binary mixture. The ZnO thin film prepared by Spray Pyrolysis kept its photocatalytic properties even after 20 reuse cycles (148 h). The treated solution showed better biodegradability and the absence of phytotoxicity.

Excessive consumption of natural resources to meet the growing demands of building and infrastructure projects has put enormous stress on these resources. On the other hand, a significant quantity of soil is excavated for development activities across the globe and is usually treated as waste material. This study explores the potential of excavated soils in the Brittany region of France for its reuse as earthen construction materials. Characterization of soil recovered from building sites was carried out to classify the soils and observe their suitability for earthen construction materials. These characteristics include mainly Atterberg limits, granulometry, organic matter and optimum moisture content. Soil samples were separated into fine and coarse particles through wet sieving. The percentage of fines (particles smaller than 0.063 mm) in studied soil samples range from 28% to 65%. The methylene blue value (MBV) for Lorient, Bruz and Polama soils is 1, 1.2 and 1.2 g/100 g, and French classification (Guide de terrassements des remblais et des couches de forme; GTR) of soil samples is A1, B5 and A1, respectively. The washing of soils with lower fine content helps to recover excellent-quality sand and gravel, which are a useful and precious resource. However, residual fine particles are a waste material. In this study, three soil formulations were used for manufacturing earth blocks. These formulations include raw soil, fines and restructured soil. In restructured soil, a fine fraction of soil smaller than 0.063 mm was mixed with 15% recycled sand. Restructuring of soil fine particles helps to improve soil matrix composition and suitability for earth bricks. Compressed-earth blocks of 4 × 4 × 16 cm were manufactured at a laboratory scale for flexural strength testing by using optimum molding moisture content and compaction through Proctor normal energy. Compressive strength tests were performed on cubic blocks of size 4 × 4 × 4 cm. Mechanical testing of bricks showed that bricks with raw soil had higher resistance with a maximum of 3.4 MPa for Lorient soil. Removal of coarse particles from soil decreased the strength of bricks considerably. Restructuring of fines with recycled sand improves their granular skeleton and increases the compressive strength and durability of bricks. [ABSTRACT FROM AUTHOR]

Labour productivity growth in the construction sector has been very weak in recent decades in most OECD countries. This paper addresses this issue based on a panel of 23 countries over the period 1995–2015. First, we use the Ackerberg, Caves, and Frazer (2015) method to propose a multifactor explanation for this lack of productivity growth: (i) average TFP growth is close to zero and even negative for most countries; (ii) average contributions to growth of capital and intermediate inputs are positive but weak, respectively of 0.05% and 0.90% per year, and much smaller than in the manufacturing sector over the same period (respectively of 0.40% and 3.10% per year). Then, we investigate whether reforms of regulations specific to the construction sector might boost productivity there. Using regulation indicators from the 'Doing Business Report', we find a negative impact of these regulations on TFP, but not on the intensities of capital and intermediate inputs. Our results suggest that reducing the construction sector regulations might bolster productivity: a switch to the lightest regulations would lead to a long-term TFP increase of 6% on average. [ABSTRACT FROM AUTHOR]

In this study, TiO2 nanospheres (TiO2-NS) were synthesized by the solvothermal method. Firstly, the synthesized nanomaterial was characterized by X-ray diffraction (XRD), Fourier Transformed Infrared (FTIR), scanning electron microscopy (SEM) and UV-Vis Diffuse Reflectance Spectroscopy (DRS). To study the photocatalytic degradation of Tartrazine (TTZ) and Naphthol Blue Black (NBB) in a binary mixture, the influence of some key parameters such as pH, pollutant concentration and catalyst dose was taken into account under visible and UV light. The results show a 100% degradation efficiency for TTZ after 150 min of UV irradiation and 57% under visible irradiation at 180 min. The kinetic study showed a good pseudo-first-order fit to the Langmuir–Hinshelwood model. Furthermore, in order to get closer to the real conditions of textile wastewater, the influence of the presence of salt on TiO2-NS's photocatalytic performance was explored by employing NaCl as an inorganic ion. The optimum conditions provided by the Response Surface Methodology (RSM) were low concentrations of TTZ (2 ppm) and NBB (2.33 ppm) and negligible salt (NaCl) interference. The percentage of photodegradation was high at low pollutant and NaCl concentrations. However, this yield became very low as NaCl concentrations increased. The photocatalytic treatment leads to 31% and 53% of mineralization yield after 1 and 3 h of visible light irradiation. The synthesis of TiO2-NS provides new insights that will help to develop an efficient photocatalysts for the remediation of contaminated water. [ABSTRACT FROM AUTHOR]

In this wok, a new CuO-TiO2-clay composite was synthesized by the sol–gel method and explored as a photocatalyst for wastewater remediation. The synthesized material was characterized by X-ray diffraction (XRD), Raman spectroscopy (RS), diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), X-ray fluorescence (XRF), and Fourier Transformer InfraRed (FTIR). The photocatalytic activity of the composite was tested on tartrazine dye (TARTZ) removal. Particular emphasis was focused on the effect of the key operating parameters such as photocatalyst dose, pH, light intensity, and initial concentration of dye. The optimization of three simultaneous parameters, namely methylene blue concentration (MB; pollutant in competition with TARTZ), NaCl concentration, and irradiation time, was examined via the response surface methodology (RSM). The CuO-TiO2-clay composite showed the best photocatalytic performance with 62.50% of photodegradation yield of TARTZ in visible light irradiation compared to 19.38% and 43.78% for pure TiO2 and TiO2-clay, respectively. This performance reached to 100% in sunlight source during the same time. The optimal conditions provided by the response surface methodology (RSM) were 180 min for irradiation time and 3.6 mg/L for MB concentration. After 120 min, 11.35% of TARTZ mineralization was obtained. The scavenger study revealed the involvement of OH· and h+ species, but especially O 2 -. as the main responsible for the photodegradation of the TARTZ. The current study highlights the potential of CuO-TiO2-clay composite as efficient photocatalytic systems for degrading hazardous organic pollutants in water. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (g-C3N4) based photocatalyst was synthesized and the photocatalytic performance was investigated for the removal of Eriochrome Black T (EBT) and Bromophenol Blue (BPB) under UV irradiation. The prepared materials were characterized by SEM-EDX, XRD, Raman, FTIR and DRS. Higher degradation efficiency for the same initial concentrations of EBT and BPB in presence of TiO2/g-C3N4 have been achieved within 160 min of irradiation. The kinetic study showed that the photodegradation of BPB by TiO2/g-C3N4 follows pseudo-first-order kinetics with an R2 value of 0.98. The addition of persulfate (PS) in BPB solution improved the degradation yield from 8.81% to 80.14% within 20 min of UV light irradiation. A Box-Behnken model was developed from three factors and Response surface methodology (RSM) was employed to identify the optimum conditions for the treatment of BPB solution by TiO2/g-C3N4. The experimental values of degradation of BPB agreed with predicted values obtained from central composite design (CCD) analysis with an R2 value of 0.9999. The scavenger study revealed that superoxide radical anion (O2•−) plays a key role (68.89% of contribution) followed by OH• and h+ with 22.40% and 15.55% of contribution, respectively. This study has obviously exhibited the potential of TiO2/g-C3N4 composite as a promising catalyst for photocatalytic purposes. [ABSTRACT FROM AUTHOR]