The treatment of saline wastewater in presence of organic content represents a challenge for many industrial sectors. Saline wastewater is extremely difficult and expensive to treat, and its discharge represents a major threat to the environment, due to the presence of organic content suspended solids, nutrients (mainly nitrogen and phosphorus) and salt (concentration up to 15%). SaltGae project has received funding from the European Union’s Horizon 2020 research and innovation programme. The aim of the project is to implement and demonstrate at large scale the long-term technological and economic feasibility of an innovative, sustainable and efficient solution for the treatment of high salinity wastewater with the use of algae/bacteria. This kind of solution stands out for its high added value: not only will it provide an effective and ecological solution for wastewater treatment, but also it will represent an innovative way of producing algal biomass, that will subsequently be valorised into different by-products, reducing the economic and environmental impact of the treatment. The aim of this thesis work was to study and characterize microalgae in order to understand if is feasible the use of algae as organic filler for ceramic or alkali-activated geopolymer, which in recent years has become one of the major alternatives to Portland cement. Spirulina Platensis and Tetraselmis Seucica have been take into consideration for the characterization and chemical analysis. Thermogravimetric analysis was used to estimate the water content of the lyophilized microalgae and their heat resistance. Infra-red spectroscopy has been also performed in order to study the chemical composition and the main chemical bonds of the microalgae and geopolymer structure. Rheology study has been conducted in order to understand the influence of the microalgae on the geopolymer paste. Also, a properly modified 3D printer was used in order to carry out several printability tests. In this way samples for the dynamic mechanical analysis and compression tests have been printed. These tests have been done in +Lab, the 3D Printing Lab of Politecnico di Milano.
Il trattamento delle acque reflue industriali con alta concentrazione di sali in presenza di contenuto organico rappresenta una sfida per molti settori. Le acque reflue salate sono estremamente difficili e costose da trattare e, se riversate, rappresentano una grave minaccia per l'ambiente a causa della presenza di sostanze solide in sospensione, sostanze nutritive (principalmente azoto e fosforo) e sale (concentrazione fino al 15%). Il progetto SaltGae ha ricevuto finanziamenti dal programma di ricerca e innovazione dell'Unione Europea Horizon 2020. Lo scopo del progetto è di attuare e dimostrare su grande scala la fattibilità tecnologica ed economica a lungo termine di una soluzione innovativa, sostenibile ed efficiente per il trattamento di acque reflue ad elevata salinità con l'utilizzo di alghe/batteri. Questo tipo di soluzione si distingue per il suo elevato valore aggiunto: non solo fornirà una soluzione efficace ed ecologica per il trattamento delle acque reflue, ma rappresenterà anche un modo innovativo per produrre la biomassa algale, che sarà successivamente valorizzata in diversi sottoprodotti, riducendo l'impatto economico ed ambientale del trattamento. Lo scopo di questo lavoro di tesi è stato quello di studiare e caratterizzare alcune specie di microalghe per capire se fosse possibile utilizzarle come filler organico per ceramica o geopolimero, che negli ultimi anni è diventato una delle principali alternative al cemento di Portland. Spirulina Platensis e Tetraselmis Seucica sono state le due spiecie di alghe prese in considerazione per la caratterizzazione e l'analisi chimica. L'analisi termogravimetrica è stata utilizzata per stimare il contenuto d'acqua della microalga liofilizzata e la loro resistenza al calore. La spettroscopia infrarossa è stata invece eseguita per studiare la composizione e i legami chimici principali nella struttura microalge-geopolimero. Uno studio reologico è stato inoltre condotto per comprendere l'influenza delle microalghe su un impasto fresco di geopolimero e quale effetto avessero sulla viscosità dell’impasto. Inoltre, è stata utilizzata una stampante 3D correttamente modificata per eseguire diversi test di stampabilità. In questo modo sono stati anche stampati in 3D i campioni utilizzati per diverse analisi meccaniche dinamiche e prove a compressione.
Preliminary study on gree-blue microalgae as organic filler in alkali-activated geopolymer binder
CANNAVACCIUOLO, ANTONIO
2016/2017
Abstract
The treatment of saline wastewater in presence of organic content represents a challenge for many industrial sectors. Saline wastewater is extremely difficult and expensive to treat, and its discharge represents a major threat to the environment, due to the presence of organic content suspended solids, nutrients (mainly nitrogen and phosphorus) and salt (concentration up to 15%). SaltGae project has received funding from the European Union’s Horizon 2020 research and innovation programme. The aim of the project is to implement and demonstrate at large scale the long-term technological and economic feasibility of an innovative, sustainable and efficient solution for the treatment of high salinity wastewater with the use of algae/bacteria. This kind of solution stands out for its high added value: not only will it provide an effective and ecological solution for wastewater treatment, but also it will represent an innovative way of producing algal biomass, that will subsequently be valorised into different by-products, reducing the economic and environmental impact of the treatment. The aim of this thesis work was to study and characterize microalgae in order to understand if is feasible the use of algae as organic filler for ceramic or alkali-activated geopolymer, which in recent years has become one of the major alternatives to Portland cement. Spirulina Platensis and Tetraselmis Seucica have been take into consideration for the characterization and chemical analysis. Thermogravimetric analysis was used to estimate the water content of the lyophilized microalgae and their heat resistance. Infra-red spectroscopy has been also performed in order to study the chemical composition and the main chemical bonds of the microalgae and geopolymer structure. Rheology study has been conducted in order to understand the influence of the microalgae on the geopolymer paste. Also, a properly modified 3D printer was used in order to carry out several printability tests. In this way samples for the dynamic mechanical analysis and compression tests have been printed. These tests have been done in +Lab, the 3D Printing Lab of Politecnico di Milano.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/135019