abstract
Serious environmental and health problems arise from the everyday release of industrial wastewater effluents. A wide range of pollutants, such as volatile organic compounds, heavy metals or textile dyes, may be efficiently removed by silica materials advanced solutions such as aerogels. This option is related to their exceptional characteristics that favors the adsorption of different contaminants. The aerogels performance can be selectively tuned by an appropriate chemical or physical modification of the aerogel's surface. Therefore, the introduction of amine groups enhances the affinity between different organic and inorganic contaminants and the silica aerogels. In this work, different case studies are reported to investigate and better understand the role of these functional groups in the adsorption process, since the properties of the synthesized aerogels were significantly affected, regarding their microstructure and surface area. In general, an improvement of the removal efficiency after functionalization of aerogels with amine groups was found, with removal efficiencies higher than 90% for lead and Rubi Levafix CA. To explain the adsorption mechanism, both Langmuir and Freundlich models were applied; chemisorption is most likely the sorption type taking place in the studied cases.
keywords
TOXIC ORGANIC-COMPOUNDS; HEAVY-METALS; WASTE-WATER; AQUEOUS-SOLUTION; GRAPHENE AEROGELS; SURFACE-CHEMISTRY; BETA-CYCLODEXTRIN; METHYLENE-BLUE; REACTIVE DYES; ADSORPTION
subject category
Biochemistry & Molecular Biology; Chemistry
authors
Lamy-Mendes, Y; Torres, RB; Vareda, JP; Lopes, D; Ferreira, M; Valente, V; Girao, AV; Valente, AJM; Duraes, L
our authors
Alyne Cristina Lamy Mendes
PhD Student
Ana Violeta Girão
Junior Researcheracknowledgements
A.L.-M. acknowledges National Council for Scientific and Technological Development (CNPq-Brazil) for the funding of the PhD fellowship project 234184/2014-0/GDE, under the program Ciencia sem Fronteiras. R.B.T. acknowledges the grant under the project AerogelDustFree-Aerogel for Space applications ISO8 without dust release (Contract No 17815), developed by the consortium Active Aerogels/University of Coimbra, funded by the European Regional Development Fund (ERDF) through the Operational Program for Competitiveness and Internationalization and the Regional Operational Program of the Center of Portugal (Centro2020) of PT2020. J.P.V. is grateful to the Fundacao para a Ciencia e a Tecnologia (FCT), the Portuguese Agency for Scientific Research, for the doctoral fellowship SFRH/BD/131280/2017. A.V.G. is thankful for funding by national funds (OE), through FCT, Portugal, in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. This work was developed within the scope of the following research units and projects, co-funded by national funds, through the FCT (Portugal), and by ERDF (EU) under the PT2020 Partnership Agreement: CIEPQPF -Chemical Process Engineering and Forest Products Research Centre (POCI-01-0145-FEDER-006910 and UID/EQU/00102/2019); CICECO-Aveiro Institute of Materials (POCI-01-0145-FEDER-007679 & UID/CTM/50011/2019) and CQC -Coimbra Chemistry Centre (UID/QUI/00313/2019).