Rui M. Novais

Rui M. Novais
University of Aveiro | UA · Department of Materials and Ceramics Engineering

Ph.D.

About

91
Publications
16,271
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
2,217
Citations
Introduction
Rui Novais is an Assistant Professor at the Department of Materials and Ceramic Engineering and CICECO-Aveiro Institute of Materials at University of Aveiro (UA). He has expertise in chemistry, physics, polymer and materials science, on the development and characterisation of low thermal conductivity materials (traditional ceramics and geopolymer-foams); on PCM-containing building materials for improving buildings thermal performance; wastes valorisation, synthesis of ecoceramics for energy pro
Additional affiliations
January 2019 - March 2022
University of Aveiro
Position
  • Research Associate
October 2012 - present
University of Aveiro
Position
  • PostDoc Position

Publications

Publications (91)
Article
Full-text available
Alkali-activated materials are generally considered a more sustainable alternative to Portland cement binders. This derives not only from the use of solid wastes as precursors, but also from the low temperatures required for their synthesis. However, to increase the environmental advantages of these materials, alternative activators should be explo...
Article
Full-text available
Environmentally conscious biomorphic ceramics (Ecoceramics) are a new class of material manufactured from renewable resources and wastes. Sustainable cork wastes were pyrolysed, and this activated carbon template infiltrated with a sol-gel precursor (from aqueous green-chemistry) to form TiO2 on heating in air, with the honeycomb microstructure of...
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...
Chapter
Alkali-activated materials (AAMs) are an emerging alternative to the use of common adsorbents in wastewater treatment applications for both environmental and technical reasons. Herein, the most relevant and recent research focusing the use of AAMs as adsorbents to depollute aqueous solutions is summarized and critically discussed. This chapter will...
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
The extraction of raw materials in many productive sectors has become problematic for the environment because of the negative impacts of the process and the inappropriate destination of the generated waste. Stone waste (SW) from the dimension stone industry has physical and chemical characteristics with great potential for use as an alternative raw...
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
Full-text available
Ordinary Portland Cement is the most widely used binder in the construction sector; however, a very high carbon footprint is associated with its production process. Consequently, more sustainable alternative construction materials are being investigated, namely, one-part alkali activated materials (AAMs). In this work, waste-based one-part AAMs bin...
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
In this research, compositional and processing parameters were varied to obtain different typologies of zeolitic crystals in geopolymers produced using mainly biomass fly ash wastes. The hydrothermal cure at 50ºC was suitable to allow the formation of faujasite zeolites with compressive strength of ~ 8 MPa at 7 days of cure. In addition to cure tem...
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
Solar thermochemical conversion of H2O and captured CO2 is considered for the production of high-value solar fuels and CO2 valorization, using non-stoichiometric oxygen-exchange redox materials. This work aims to compare the thermochemical cycle performance of different ceria structures, including biomimetic cork-templated ceria (CTCe), ceria foam...
Article
The use of calcium-rich materials in geopolymerization has been reported in the literature and generally induces an increase in mechanical properties. In this work, stone cutting waste (SW) was used in new geopolymers formulations and the interaction of the components was evaluated. In addition to the filler effect, SW affected the compositional sy...
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
Water splitting by solar energy-driven two-step thermochemical cycles is a promising approach for large-scale production of renewable fuels (e.g. hydrogen). The key challenge is developing materials capable of withstanding the harsh environmental conditions and to ensure high reliability in use, particularly in terms of redox kinetics and better ac...
Article
DOWNLOAD FREE FOR 1 MONTH AT: https://authors.elsevier.com/c/1aRxwI6yu4ckf Geopolymer foams (highly porous materials) have emerged as one of the most exciting materials over the past few years due to their remarkable properties, low cost and green synthesis protocol, enabling their use in various high added-value applications. Review papers on poro...
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
FREE TO DOWNLOAD FOR 50 DAYS AT: https://authors.elsevier.com/c/1ZkEC3O1E1GMLC In this investigation, and for the first time, pyrolysed sustainable cork was used to produce waste-based geopolymer-cork composites with enhanced electromagnetic interference (EMI) shielding properties. The influence of the pyrolysed cork amount and the geopolymer poro...
Article
Full-text available
This review explores the advances in the synthesis of ceria materials with specific morphologies or porous macro- and microstructures for the solar-driven production of carbon monoxide (CO) from carbon dioxide (CO2). As the demand for renewable energy and fuels continues to grow, there is a great deal of interest in solar thermochemical fuel produc...
Article
This study seeks the valorization of industrial residues (fly ash and construction and demolition waste (CDW)) through the production of geopolymer mortars. The effect of the sand substitution by CDW and the influence of the particle size range of CDW fine aggregates on the fresh and hardened properties of the mortars were evaluated. Geopolymer mor...
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...
Article
FREE DOWNLOAD FOR 50 DAYS AT: https://authors.elsevier.com/c/1YZ-u7tGO~9vto For the first time, highly porous ZnO-based biomorphic materials were synthesised using cork as a natural sustainable template. In the first step, waste cork powder was pyrolysed and converted into inorganic carbon. This template was then infiltrated using a novel approach...
Article
Porous inorganic polymer (IP) monoliths were synthesised using a modified bauxite residue (BR) as the reactive fraction with the objective of using them as adsorbents for methylene blue (MB) from synthetic wastewater. First, unreactive, as-produced BR was transformed into a suitable glassy precursor material for IPs by blending BR with minor quanti...
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/c/1YRYU3PCJl7rDJ Cork templates were used to produce lightweight bulk biomimetic ecoceramic (environmentally conscious ceramic) monoliths. Bulk/monolithic ceramics are vital for many applications, i.e. energy materials and fuel cells. Using simple and flexible, aqueous green-chemistry proce...
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...
Article
Microstructure tailoring of metallurgical slags allows the production of alternative construction binders with customized properties. In this study, the variations of rheology and strength of alkali-activated basic-oxygen-furnace (BOF) slags are quantified. Two modifications of BOF slag were created adding amounts of alumina and silica at high temp...
Article
This study aims to evaluate the in-situ synthesis of zeolites through geopolymerization of biomass fly ash wastes at low temperature in a hermetic container. The raw materials were activated using a mixture of sodium silicate and sodium hydroxide, and then the specimens cured at 60 �C to obtain zeolitecontaining geopolymers. Hydrogen peroxide (H2O2...
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
The perception of industrial waste has changed, in the last decades, from an economic and environmental problem to a potential raw material. In this work, the synthesis of a stable pigment was prepared by combining two hazardous and unexplored wastes: red mud (RM, rich in Fe) and electroplating sludge (ES, rich in Ni/Cr). The wastes were mixed in d...
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
This work investigates the production a green geopolymer-based concrete for a sustainable construction material using biomass wastes from a kraft pulp industry: fly ash (as main alumina-silicate source) and grits (as aggregate). Moreover, a simple, reproducible, ambient temperature, and low-cost manufacture is followed. Mix design aims to maximize...
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...
Poster
Synthetic dyes, essentially due to their toxic nature, are considered one of the most serious wastewater pollutants and, once deposited in the water lines, become a problem to be removed. 1,2 Adsorption is considered the most effective and simple method for water decontamination. Activated carbons present singular properties, such as their high spe...
Article
This work addresses the solar-driven thermochemical production of CO and O2 from two-step CO2-splitting cycles, using both ceria granules prepared from cork templates (CG) and ceria foams from polyurethane templates (CF). These materials were cycled in a high-temperature indirectly-irradiated solar tubular reactor using a temperature-swing process....
Article
For the first time the feasibility of using an alkaline wastewater coming from the pulp and paper industry as an activator, partially (50 vol.%) replacing commercial sodium hydroxide, in the production of cork-based activated carbons was evaluated. The activated carbons showed the highest value of specific surface area ever reported for cork-based...
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...
Conference Paper
Full-text available
The application of phase change materials (PCM) in building materials is an emerging field, aiming to improve the energy efficiency of buildings. This article presents part of the work of developing methods for the incorporation of PCMs in ceramic materials for application in the construction. The tests performed show the variability in the incorpo...
Article
The production of low thermal conductivity geopolymers has attracted increasing attention over the past years due to their low cost and green processing technology. In this work, light and porous geopolymers were produced by the proper association of aluminium content and solid-to-liquid ratio. This allowed the production of very low thermal conduc...
Article
Red mud (RM), a highly alkaline iron oxide rich sludge obtained during the production of alumina, was treated to work as a coloring agent for ceramic glazes. The approach aims the valorization of this residue, adding environmental and economic value. RM was sintered at different temperatures (1100 °C, 1150 °C, 1200 °C, 1250 °C, 1300 °C and 1350 °C)...
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
Full-text available
Sustainability in construction is a major concern worldwide, due to the huge volume of materials and energy consumed by this sector. Associated supplementing industries (e.g. Portland cement production) constitute a significant source of CO2 emissions and global warming. Valorisation and reuse of industrial wastes and by-products make geopolymers a...
Article
For the first time biomass fly ash geopolymer monoliths were used as adsorbents for the removal of methylene blue from synthetic wastewaters. Highly porous and lightweight fly ash-based geopolymers were produced and then evaluated as methylene blue adsorbents. The geopolymers’ porosity strongly affects the dye extraction, a threefold increase (from...
Poster
Full-text available
The industrial wastes, FA and c-CDW, show suitable properties for the development of geopolymeric mortars; c-CDW containing mortars show lower spread on table values than the ones prepared with sand, since clay particles are finer in size and tend to adsorb water. Thickening affects are then observed; On the hardened condition, mortars prepared wit...
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...
Conference Paper
The production of lightweight geopolymer concrete has become a hot topic in recent years, due to the increasing awareness regarding the unsustainability of Portland cement1. The geopolymers potential for structural applications has long been recognised, yet they present other interesting properties (e.g. high temperature stability, heavy metal adso...
Data
Winner of the Materials Today cover competition 2016 for his image of cork-derived ecoceramics: http://www.materialstoday.com/materials-today-cover-competition-2016/
Conference Paper
Full-text available
Cork is a highly porous, natural and sustainable material, consisting of polygonal 20-40 µm cells arranged in a honeycomb–type structure [1]. Recently a biomimetic " ecoceramic " (Z-type hexaferrite) was produced using cork as template [2]. The ceramic preserved the cellular structure of the cork, suggesting that this method can be used for the fab...
Article
Environmentally conscious ceramics (ecoceramics) are a new class of biomimetic/biomorphic material that can be manufactured from renewable resources, such as wood from sustainable sources or wood wastes. The idea is to manufacture ceramics with the microstructure of wood. The wood is pyrolysed to convert it into carbon, which is nanoporous, but mai...
Article
In this study novel porous biomass fly ash-containing geopolymer monoliths were produced using a simple and flexible procedure. Geopolymers exhibiting distinct total porosities (ranging from 41.0 to 78.4%) and low apparent density (between 1.21 and 0.44 g/cm3) were fabricated. Afterwards, the possibility of using these innovative materials as lead...
Article
RESUMO Os materiais de isolamento térmico convencionais, tais como a lã de vidro e o poliestireno extrudado, possu-em importantes limitações técnicas. Os geopolímeros emergem como uma alternativa devido às suas excelen-tes propriedades. Neste trabalho, teve-se por objetivo descrever o desenvolvimento de geopolímeros de baixa condutividade térmica....
Article
Barium M-type hexagonal ferrite (BaM, BaFe12O19) is an immensely important magnetic material, which we have successfully made from the simple valorisation of Fe-rich industrial waste from steel wire drawing, with addition of BaCO3 and heating in air to 1000 ºC. The optimum ratio of Fe.Ba (producing 86 wt% BaM) was found to be 11:1 (non-stoichiometr...