The durapatite as a metals absorver

A concentra????o de metais poluentes, como o chumbo (Pb), tem aumentado em ??reas populosas e desenvolvidas devido a polui????o atmosf??rica e outras atividades humanas. Conseq??entemente, o potencial para este elemento alcan??ar a cadeia alimentar aumentou. O chumbo ?? muito t??xico para o ser humano, especialmente para crian??as, e a exposi????o ao chumbo pode causar efeitos adversos ?? sa??de humana. A hidroxiapatita (Hap), um composto de fosfato de c??lcio, ?? o principal constituinte inorg??nico dos ossos e dentes. Pesquisas concluiram que a hidroxiapatita sint??tica tem uma alta capacidade para remover metais pesados divalentes da ??gua em condi????es ambientais. Existem v??rias tecnologias empregadas para tratamento de ??gua e solos contaminados. Estes tratamentos al??m de serem caros, muitas vezes s??o destrutivos. Torna-se ent??o necess??rio, desenvolver novos m??todos para remover ??ons t??xicos de solos e esgotos pela redu????o da solubilidade do Pb e conseq??entemente sua bio-disponibilidade. Visto ser a hidroxiapatita um regulador da concentra????o de c??lcio, f??sforo e chumbo no meio ambiente, este material poderia ser usado com baixos custos, na remo????o de chumbo em solos e ??guas contaminadas. O objetivo ?? elucidar os mecanismos envolvidos na remo????o de chumbo de solu????es aquosas, investigando-se a transforma????o do Pb para uma forma mais est??vel: a piromorfita.The concentration of pollutant metals such as lead (Pb), has increased in populated and developed areas due to atmospheric pollution and other human activities. Consequently, the potential for these elements to enter the human food chain has increased. Lead is very toxic to humans especially to young children and the contamination by lead can cause adverse effects on human health. Hydroxyapatite (Hap), a calcium phosphate compound is the principal inorganic constituent of human bones and teeth. It has been found that synthetic hydroxyapatite has a high capacity for removing divalent heavy metals ions from water under ambient conditions. There are many technologies employed to clean up contaminated water and soils. These treatments are often costly and destructive. Thus, it is important to develop new methods to remove toxic ions from soils and wastewater by reducing Pb solubility and bioavailability. If hydroxyapatite can regulate the concentration of calcium, phosphate and lead in environments this material may provide a cost-effective technology for remediating lead contaminated soils and water. The aim of this work is to elucidate the mechanism involved in the removal of lead from aqueous solution through investigations of Pb and incorporation into a new stable phase: pyromorphite