The elution of lead from vermiculite was investigated by using a novel biodegradable chelating reagent, L asparagic N,N diacetic acid (ASDA) and water soluble depolymerized pectic acid and comparing with a conventiona...The elution of lead from vermiculite was investigated by using a novel biodegradable chelating reagent, L asparagic N,N diacetic acid (ASDA) and water soluble depolymerized pectic acid and comparing with a conventional chelating reagent, EDTA, as well as acetic acid. The influences of the reagent concentration, equilibrium pH and the suspension contact time on Pb extraction were examined. It is concluded that the acetic acid is not effective for Pb removal in any case due to its weak complexing ability with Pb. Although Pb is easier to be released by EDTA with stoichiometric amount, it is by no means the preferable alternative for the purpose because of its low biodegradability. On the other hand, ASDA and depolymerized pectic acid have the potential application because they are not only effective for Pb elution but also environmentally friendly.展开更多
文摘The elution of lead from vermiculite was investigated by using a novel biodegradable chelating reagent, L asparagic N,N diacetic acid (ASDA) and water soluble depolymerized pectic acid and comparing with a conventional chelating reagent, EDTA, as well as acetic acid. The influences of the reagent concentration, equilibrium pH and the suspension contact time on Pb extraction were examined. It is concluded that the acetic acid is not effective for Pb removal in any case due to its weak complexing ability with Pb. Although Pb is easier to be released by EDTA with stoichiometric amount, it is by no means the preferable alternative for the purpose because of its low biodegradability. On the other hand, ASDA and depolymerized pectic acid have the potential application because they are not only effective for Pb elution but also environmentally friendly.