João Carvalheiras

João Carvalheiras
University of Aveiro | UA · Division of Materials Engineering

Master in Materials Engineering

About

25
Publications
3,317
Reads
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411
Citations
Education
September 2014 - December 2016
University of Aveiro
Field of study
  • Materials Engineering

Publications

Publications (25)
Article
Full-text available
In this work, alkali-activated fly ash-derived foams were produced at room temperature by direct foaming using aluminum powder. The 1 cm3 foams (cubes) were then evaluated as adsorbents to extract heavy metals from aqueous solutions. The foams’ selectivity towards lead, cadmium, zinc, and copper ions was evaluated in single, binary, and multicompon...
Article
Full-text available
The immobilization of hazardous wastes in ordinary Portland cement (OPC)-based materials has been widely studied and implemented. OPC-based materials have a high carbon footprint associated with their production and geopolymer materials are a sustainable and eco-friendly alternative. Therefore, this work aimed to immobilize two hazardous industrial...
Article
Energy demand in the construction sector has continued to grow over the past years, despite the European commitment to promote energy efficiency. The development of multifunctional materials to tackle the energy consumption and improve the thermal performance of buildings is in huge demand. Herein, we report for the first time the synthesis of a bi...
Article
Full-text available
In anaerobic digestion processes, pH has a vital role due to the direct impacts on the microbial community. An eco-friendly approach has been applied to control pH in anaerobic bioreactors, using waste-containing fly ash geopolymer spheres (GS) instead of powdered chemical compounds, to promote continuous alkalis leaching. The influence of GS poros...
Article
Future generation building materials produced using sustainable precursors and exhibiting multifunctional properties are in huge demand, as they might be a key tool to tackle the carbon dioxide emissions from the building sector. This study provides new insights regarding the impact of the cork particle size on the hardened-state properties of inor...
Article
Red mud-based inorganic polymer spheres were used as alternative pH regulators and process enhancers in sequencing batch anaerobic reactors treating cheese whey. This byproduct tends to quickly acidify under anaerobic conditions, and the common route to control pH and ensure suitable conditions for methane production involves the use of commercial...
Article
This work reports a simple and safe, but powerful, route to depollute lead-containing aqueous solutions. Inorganic polymer foams (cm-size) were used as bulk-type adsorbents. The influence of the specimens’ porosity and activator molarity on the foams’ physical properties and on their lead extraction ability was studied. Then, the best performing sa...
Article
Calcareous sludge is an alkaline waste produced by the paper pulp industry that is commonly disposed of in land-fill. However, recent studies and the European regulations discourage such practice. This work investigates an alternative and innovative way to recycle and reuse this waste, as filler, in the production of green geopolymeric mortars inte...
Article
Full-text available
Reduction of the energy consumption and CO2 emissions by the building sector might be a huge driver to mitigate climate change. One promising approach to mitigate energy consumption is the use of lightweight and low thermal-conductivity materials that could reduce the energy losses inside buildings and at the same time the use of heating and coolin...
Article
DOWNLOAD FREE FOR 50 DAYS AT https://authors.elsevier.com/c/1aWWQ~2-EzKM- . Hexagonal ferrites can be employed in a multitude of applications, the most common hexaferrites are the M ferrites such as BaFe12O19 (barium hexaferrite, BaM). It is known that if Fe3+ is substituted with a combination of Ti4+/Co2+ the coercivity of BaM can be reduced to pr...
Article
In this study, the possibility of using glass fibre wastes as reinforcement agent of waste-based and low thermal conductivity geopolymer mortars was evaluated to expand on previous work performed on dense geopolymers. The individual and combined influence of the glass fibre and the blowing agent amount on the fresh- and hardened-state properties of...
Article
This work evaluates, for the first time, the possibility of producing multifunctional alkali-activated composites combining ultra-low density, low thermal conductivity, high acoustic absorption, and good moisture buffering capacity. The composites were prepared using cork as a lightweight aggregate. This novel material might promote energy savings...
Conference Paper
Alkali-activated materials, also known as geopolymers, are a class of binders that have emerged as an excellent alternative to the use of Portland cement. However, the geopolymers full potential has yet to be fully exploited. A key driver to foster the use of geopolymers is by extending their application range beyond those where Portland cement can...
Article
In this study, and for the first time, the possibility of using bulk type waste-based granulated alkali-activated materials (AAM) for inducing heavy metals extraction by precipitation and adsorption was evaluated. Waste metakaolin and aluminium scrap recycling waste proved to be suitable precursors to create AAM. Results indicate that both methods...
Article
FREE DOWNLOAD FOR 50 DAYS at: https://authors.elsevier.com/c/1Ydn43QCo9UqBU Green liquor dregs are the most challenging waste stream coming from the pulp and paper industry. Despite tremendous efforts, there are not currently any viable recycling alternatives for this massively produced waste (2 Mt/year), which inevitably ends up in landfills. Urge...
Cover Page
Full-text available
Cover of Materials Today 23, March 2019, showing an SEM image of our geopolymer spheres ( a few mm in diameter) made from valorised / recylced industrial wastes.
Article
FREE DOWNLOAD FOR 50 DAYS at https://authors.elsevier.com/a/1YKca3Q2WYbH-2 In this investigation cork was used as a low density aggregate in the production of ultra-lightweight and low thermal conductivity inorganic polymer (geopolymer) composites. This novel and highly sustainable material, synthesised at room temperature (23 ºC), may decrease t...
Preprint
In this study, lightweight waste-based geopolymeric mortars were evaluated for the first time regarding their potential to passively adjust indoor relative humidity (RH) levels. Geopolymer mortars were prepared using a mixture of fly ash (FA) and metakaolin (MK) as a binder, in a proportion of 75:25 wt% (FA:MK), construction and demolition waste as...
Article
In this work, and for the first time, fly ash (FA)-based geopolymer (d = 2.6 mm) spheres were used to extract methylene blue from synthetic wastewaters. The influence of sorption time, dye initial concentration and adsorbent amount on the dye removal efficiency and uptake by the porous spheres was evaluated. The adsorbents’ recyclability and their...
Article
In this investigation, an innovative and sustainable solution for glass fibre off-cuts is proposed. For the first time, glass fibre fabrics (non-woven mat) produced during wind turbine blade manufacture were used to produce reinforced inorganic polymer composites. The influence of fabric amount on the composites’ microstructure, water absorption, s...
Article
Green liquor dregs wastes coming from pulp and paper production are currently disposed in landfills at a huge cost for industry and the environment. In this work, a novel and more sustainable waste manage�ment strategy is proposed. Dregs were used for the first time as fine filler in the production of biomass fly ash-based geopolymeric mortars. The...
Article
In this study, and for the first time, red mud (RM)-based geopolymer spheres were synthesised, with varying porosity and RM content, and then their use as pH regulators was evaluated. The aluminosilicate sources of these inorganic polymers were 100 % waste-based, consisting of a mixture of RM and fly ash wastes. Geopolymer spheres containing up to...
Article
Anaerobic digestion (AD) is a well-known technology for organic waste treatment with recognised environmental benefits including the generation of renewable energy (methane) and other added-value products. However, when applied to very easily biodegradable substrates, there is a need to mitigate the sudden pH drop, in order to improve the stability...
Article
Glass fibre waste (GFW) coming from wind turbine blade production was used for the first time as a reinforcement agent in inorganic polymer (geopolymer) production. The influence of glass fibre content and length on the inorganic polymer microstructure, apparent density, and compressive and tensile strength was evaluated. Results demonstrate that t...

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Projects

Projects (2)
Project
Waste valorisation
Project
Synthesis of waste-based inorganic polymers for environmental remediation applications