Document type
Academic documents
Document subtype
Master's dissertation
Title
Eficiência do Uso de Biotite na Remoção de As em Águas
Participants in the publication
Martins, Lucas Luscher (Author)
Silva, Maria Catarina Rosalino da (Supervisor)
Dep. Geologia
Dep. Geologia
IDL
Africano, Fátima Alexandra Remiz Pereira (Co-Supervisor)
Summary
Arsenic (As) is a carcinogenic and toxic metalloid which may come from natural or anthropogenic sources. As is considered the most dangerous chemical element by Priority List of Hazardous Substances of 2013 in Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), published and established by Agency for Toxic Substances & Disease Registry (ATSDR). As is responsible for several massive intoxications around the world. Due to its harmful consequences, As exposure mainly by intake of inorganic As from water, rises as a major public health issue. Biotite is a mineral that belongs to silicates class, phyllosilicates sub-class and micas group. The utilization of biotite in the heavy metals removal process from water has been studied in the last years due to its high capacity of cationic exchange caused by the isomorphic substitutions between the octahedral and tetrahedral layers, besides the fact that they present peculiar physical properties as plasticity, sorption, hydration and ionic exchange, characteristics that place biotite as an important natural absorbent. Results show an increasing in pH values of acid solutions along with pH values decrease in alkaline solutions, after 24 hours of reaction with biotite solution. Solutions with pH < 3, > 10 and 7 did not show significant variation between corresponding initial and final pH values. Every single solution showed great efficiency in As removal after 24 hours of reaction with biotite. Acid solutions exhibited more efficiency than near neutral or alkaline solutions. The least efficiency in arsenic removal was 32,88% in the solutions group with ≈ 100 mg.L-1 initial concentration (initial pH 6,56) and the maximum efficiency (82,77%) in As removal was achieved in São Domingos, Mértola (initial concentration 0,89 mg.L-1 and initial pH 2,83) natural water samples. We compared solution agitation through air bomb versus orbital plate method. We observed greater agitation through air bomb proceeding. Solutions agitated through air bomb proceeding had an 5,76% increase in arsenic removal compared with solutions agitated in orbital plates. Solutions made of natural waters gathered at Corta (São Domingo, Mértola) and in an aquifer present at an old industrial facility in Barreiro county, showed >70% efficiency in arsenic removal in almost every solution (initial concentration 0,89 and 0,051 mg.L-1 - initial pH 2,83 and 3,98 respectively).
Date of Submisson/Request
2015
Date of Publication
2015
Institution
FACULDADE DE CIÊNCIAS DA UNIVERSIDADE DE LISBOA
Publication Identifiers
Document Identifiers
Keywords
Adsorção Remoção Arsênio Biotite Remediação de Água Teses de mestrado - 2015